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Kennedy/Jenks Consultants

© Kennedy/Jenks Consultants, Inc. SVCW Gravity Pipeline | Page 1

3 April 2017

Planning Level Technical Memorandum No. 4

To: Bruce Burnworth

From: Mark Minkowski, P.E., Kennedy/Jenks Team

Subject: Planning Level Technical Memorandum No. 4 – Shaft Construction

SVCW Gravity Pipeline

K/J Project Number: 1568063.02

Section 1: Introduction For the Introduction and background, refer to Section 1 of Planning Level TM No. 1.

1.1 Objectives The purpose of Planning Level TM No. 4 is to evaluate the shaft support methods for each of the 4

shaft locations, and to make a recommendation on a preferred method for each location. A

secondary objective of Planning Level TM No. 4 is to investigate and establish site conditions at the

staging areas and access requirements. This work includes reviewing the area needed at each

location for construction and for long term maintenance facility needs for accessing each shaft, with

conceptual site layouts showing temporary facilities.

1.2 Gravity Pipeline Description As shown in Figure 1-1, the Proposed Gravity Pipeline, shown in green in the figure, connects to

the recently constructed 48-inch force main project on Inner Bair Island and extends downstream

to connect at the proposed Receiving Lift Station (RLS) at the SVCW wastewater treatment plant

(WWTP). The currently proposed Gravity Pipeline consists of approximately 17,600 feet of 11-foot

diameter wastewater gravity pipeline inside a 13-foot inside diameter tunnel with four shafts. The

tunnel is to be constructed with its invert depth ranging between 35 and 65 feet in primarily firm to

stiff clay soils.

Ideas under consideration by SVCW may change the basic Gravity Pipeline description. SVCW

anticipates additional ideas coming out of the Progressive DB process. The ideas discussed to date

(including concepts suggested by PDBs already in contact with SVCW) include the following.




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Multiple-layers of defense against corrosion, including upstream dosing, enhanced air

circulation, laminar flow, bacteria disruption and high performance precast concrete tunnel

segments with sacrificial thickness. This concept would eliminate the pipe in the tunnel and

the related grout backfill of the annular space.

o Removal of the pipe in the tunnel, would allow SVCW to use the full inside diameter

of the tunnel for equalization of dry and wet weather flows. This approach would

result in deferral of a concrete storage surface structure at the WWTP.

Using Bair Island as the TBM launch location, resulting in elimination of the Airport Access

Shaft. Recent input from contractors interested in proposing in response to SVCW’s

Progressive Design Build planned RFQ/RFP indicates interest in launching the TBM at Bair

Island instead of the Airport Access Shaft. This would involve elimination of the Airport

Access Shaft, partial realignment of the tunnel near the eliminated shaft and a larger

construction footprint on Bair Island. If a selected PDB desires to pursue this alternative,

the alternative would need to be described and reviewed under CEQA and permitted. Both

appear to be challenging given the potential for public impacts and potential impacts on

endangered species.

Reconfiguration of the Receiving Lift Station that would modify the shape, size and

configuration of the shafts at the WWTP.

These ideas are not addressed directly in TM No. 3, but are provided here for reference during the

Progressive DB process.




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Figure 1-1: SVCW Proposed Project (Alternative 4BE)

1.3 Basic Approach The alignment and general shaft locations for the Gravity Pipeline were defined during the

conceptual development phase of design. The alignment and shaft location decisions were made

following a detailed alternatives evaluation process that concluded in July 2015 with a decision by

SVCW to study Proposed Project Alternative 4BE further as part of the CEQA EIR review process.

The alternatives evaluation process included consideration of up to 14 alternative alignments, with

varying trenchless construction methods, shaft options, and horizontal alignments between

upstream and downstream connection locations. Ultimately, the Proposed Gravity Pipeline was

identified for further study based on several success factors, including capital and life cycle cost,

minimal disruption to the public, and lower operations and maintenance impacts.

Section 2 provides a summary of the geologic conditions at each of the shafts. Section 3 discusses

design criteria. Section 4 is the discussion and analysis of alternative shaft construction approaches

for each of the shafts. Finally, Section 5 provides a summary and recommendations for further work

by the PDB.




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Section 2: Geologic Conditions

2.1 Geologic Strata The information about general subsurface conditions along the proposed Gravity Pipeline

alignment is based on the Phase I subsurface exploration program performed by Geotechnical

Consultants Inc. (GTC), and its findings are presented in the "Preliminary Characterization of

Subsurface Conditions" Technical Memorandum dated December 9, 2015. The data from the Phase

II geotechnical investigation program was also utilized to confirm the information used from the

Phase I investigation program. The subsurface conditions consist of four soil layers: Artificial Fill,

Young Bay Mud, Upper Layered Sediments and Old Bay Deposits. Bedrock was not encountered

within the proposed depths of excavation for tunnel or shafts.

Artificial Fill covers the proposed alignment to depths of 2 to 15 feet below the ground surface. The

fill predominantly consists of silt and clay soil materials containing varying amounts of granular

materials (sand and gravel) and poorly graded sand and gravel. Cobbles and varying amounts of

organic materials are contained within the fill layer.

Young Bay Mud underlies the upper fill layer and extends from the bottom of the fill layer to depths

varying between 15 and 50 feet below the ground surface, with a layer thickness varying between 5

and 45 feet. The Young Bay Mud is predominantly light to dark gray, wet, very soft to soft Elastic Silt

or Fat Clay. Locally, the Young Bay Mud contains trace amounts of very fine grained sand in small

pockets, small shells, and organic material, including layers of peat. The organic material has weak

to strong H2S odors and gas (likely methane) is known to occur in Young Bay Mud along the San

Francisco Bay Margin. The layer is generally highly plastic and has a very low shear strength (very

soft to soft), except for the base of the Young Bay Mud directly above the Upper Layered Sediments.

This basal layer measuring up to about 5 feet thick is indistinguishable from the overlying soft

Young Bay Mud except for an increase in density and shear strength (soft to medium stiff).

Pocket penetrometer and torvane field readings indicate an apparent undrained shear strength

ranging from 70 pounds per square foot (psf) near the mudline to 1,050 psf near the bottom of the

thicker deposits. The unit dry density varies from 45 to 60 pounds per cubic foot (pcf) with water

content between 70% and 95%.

Upper Layered Sediments underlie the Young Bay Mud and extend from the bottom of the Young

Bay Mud layer to depths varying between 50 and 95 feet below the ground surface, with a layer

thickness between 25 and 55 feet. The Upper Layered Sediments consist of alternating layers of

silty sands, clayey sands, clean and poorly graded sands, sandy to clayey silts and lean to fat clays.

The thickness, sequencing and consistency of these individual layers are highly variable. The silt

and sand interbeds are generally only about 2 to 5 feet thick. A thick unit of granular materials

comprised primarily of sand and sandy gravel/gravelly sand measures up to about 36 feet thick

near the bottom of the proposed Receiving Lift Station (RLS). The granular materials (sands with




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varying amounts of gravel) are in a dense to very dense state with dry densities varying from 105 to

125 pcf. The fine grained materials (silts and clays) have a stiff to very stiff consistency with dry

densities varying from 80 to 110 pcf and water content varying from 21% to 42%. Laboratory

undrained shear strengths vary from 2,150 to 3,350 psf. Pocket penetrometer and torvane field

readings indicate an apparent undrained shear strength ranging from 1,000 to over 4,500 psf, with

occasional soft to medium stiff layers producing strength readings of 500 to 1,000 psf.

Old Bay Deposits underlie the Upper Layered Sediments and extend to at least the bottom of the

deepest investigations performed, a depth of 150 feet below the ground surface (see CPT C-117).

This layer of marine sediments consists of medium stiff to very stiff fat clay and lean to silty clay

with occasional scattered shell fragments. Pocket penetrometer readings indicate an apparent

undrained shear strength ranging from 1,000 to 4,000 psf. Previous investigations of this layer

indicate a dry density of 80 to 90 pcf, with a water content of varying from 30 to 40%.

Groundwater along the project alignment was encountered generally at depths less than 10 feet

below the ground surface, with the level fluctuating in accordance with tidal stages of the adjacent

water bodies. Below the ground surface at varying depths, water-bearing layers of granular soil

materials were encountered within the generally fine-grained layers of clay and silty clay. In most

of the cases, the static groundwater readings within these granular soil layers indicated that the

readings were consistent with the water level in the surface water bodies, indicative of a hydraulic

connection between the deeper granular layers and the ground surface. In some cases, the water-

bearing layers of granular soil are confined by the relatively impermeable fine-grained soils and

may be under artesian pressure conditions.

Specific subsurface conditions at the individual shaft locations are indicated below in the

appropriate sections.

Section 3: Design Criteria

3.1 Shaft Design Criteria

3.1.1 Initial Support Design Criteria The initial support of each shaft will be designed for lateral soil pressure, hydrostatic pressure and

surcharge loads. The lateral soil pressure will be evaluated for at-rest conditions. The hydrostatic

pressure will be determined based on the 100-year flood data. Surcharge loads can be attributed to

construction equipment and storage, traffic loads and adjacent buildings and structures. For

construction and traffic surcharge loads, the most unfavorable configuration will be considered in

design. The surcharge due to existing buildings and structures will be applied according to the

actual location.




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3.1.2 Seismic Design Criteria The project is located between two of the most active major faults in the San Francisco Bay area,

namely the San Andreas Fault to the west and the Hayward Fault to the east. The closest distance

from the alignment to the San Andreas Fault is 4.2 miles and to the Hayward Fault is 19.6 miles.

Both faults are defined as a type "A" by the California Geological Survey (CGS) with a 30-year

probability of an earthquake equal to or greater than magnitude 6.7. A summary of type "A" and

type "B" faults located near the project alignment are presented in the Geotechnical Data Report

prepared by GTC. Based on the United States Geological Survey (USGS) maps, in addition to the

above listed faults, there are other - inferred faults located between San Andreas and Hayward

faults. Based on the United States Geological Survey (USGS) maps, in addition to the above listed

faults, there are other inferred faults located between San Andreas and Hayward faults. There is no

visual evidence or surface features that indicate such faults actually exist; these faults are inferred

to possibly exist based on indirect geologic data such as differences in groundwater elevations.

The seismic analysis of the shafts initial support should be performed using analytical and

numerical approaches. Considering design ground motions, earthquake actions should be

determined from the free-field displacement. These actions should be evaluated numerically using

a one-dimensional free-field site response software (e.g., SHAKE 2000). A two dimensional (2D)

finite element continuum model should also be developed using PLAXIS, FLAC or other applicable

software to assess the longitudinal bending in the shaft lining.

For shaft/tunnel intersection, a simplified 2D analysis should be used. In addition, a three

dimensional (3D) finite element structural model where the ground support would be represented

by dynamic springs should be developed, if necessary (e.g.,using SAP 2000.)

Section 4: Shaft Construction

Different shaft construction methods have been utilized by contractors throughout the country on

similar projects. The most common shaft construction methods include:

Soldier piles and wood lagging (or steel plates)

Liner plates

Precast concrete segments

Conventional shaft sinking with lattice girders and shotcrete

Steel sheet piles

Secant piles

Drilled shafts

Cutter soil mixing (CSM)

Slurry walls

Ground freezing

Caissons




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Selection Criteria

Some of these methods are only suitable for stiff soils, some only suitable for above groundwater

conditions, and some have depth limitations. Initial screening has been performed to eliminate

unsuitable methods and identify a feasible and best suited method for the Gravity Pipeline for

further evaluation.

The initial selection of shaft construction methods for each shaft was mainly based on the following

criteria:

shaft use,

shaft size/shape/depth

soil conditions

groundwater levels

Additional criteria were considered in evaluation of the selected methods and final

recommendations. These criteria include:

shaft structural behavior under assumed loads

shaft construction cost and schedule (SVCW CIP Program criteria)

site restrictions such as:

o the site size

o presence of existing utilities

o airspace protection height limits.

The criteria noted above were used in lieu of the overall SVCW CIP Program criteria, including

maintenance and operations, due to the inapplicability of these criteria for shaft construction

method evaluations. SVCW CIP Program criteria that have been considered include cost, schedule,

and safety. Safety is inherently considered for all shaft construction methods.

The shafts for the SVCW Gravity Pipeline will be constructed in soft ground with a high

groundwater table. Therefore, it has been determined that only relatively impermeable shaft

support systems will be evaluated. As stated in GTC's "Preliminary Characterization of Subsurface

Conditions" Technical Memorandum, groundwater is affected by tidal influence; therefore, no

dewatering will be permitted. Impermeable shaft construction includes gasketed liner plates, sheet

piles, cutter soil mixing, secant piles, slurry walls, ground freezing and caissons. The groundwater

control at the bottom of the shaft is also considered and described in the following sections

individually for each shaft.

The relatively impermeable shaft support system will be a system that minimizes water leakage

into the shaft and prevents lowering of the ground water level outside of the excavation. Maximum

leakage criteria will be established for each shaft during the design stage of the project.




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Gasketed liner plates are applicable in stiff clays or in dense granular soils above the groundwater

level. On the SVCW Gravity Pipeline, water-bearing granular deposits were encountered in Upper

Layered Sediments stratum, in most cases hydraulically connected to adjacent water bodies. In

addition, all shafts will be constructed in Young Bay Mud, which is a very weak layer and needs to

be supported prior to excavation; liner plates do not offer that support. Therefore, liner plates are

not considered a viable option.

Ground freezing is accepted in the industry as the most expensive excavation support method

available. Ground freezing is utilized in extremely difficult conditions where no other excavation

support is feasible, and where cost is generally not a factor. Drilling cost, time for freezing, power to

keep the freeze and refrigeration equipment, all have led to determining ground freezing is an

unnecessary, uneconomical excavation support system based on our experience.

The impermeable options that remain are: steel sheet piles, CSM, secant piles, slurry walls and

caissons. The requirements for the shafts and the soil conditions at each shaft have been considered

and the suitable and cost-effective shaft construction methods selected for evaluation are presented

in Table 4-1.

Table 4-1: Shaft Construction Methods Matrix

Structure

Slurry

Walls

Secant

Piles CSM Sheet Piles Caisson

RLS/Flow

Splitter Shaft

Airport Access

Shaft

San Carlos Drop

Shaft

Bair Island Inlet

Structure

The following section presents general description of the selected shaft construction methods. The

specific evaluations of construction methods for each shaft are covered in subsequent subsections

of Section 4 for the individual shafts.

Slurry walls

Slurry walls consist of rectangular "primary" and "secondary" panels (refer to Figure 4-1) to form

the circular shape of the shaft. The panels extend below the bottom of the shaft and are excavated

with a specially designed clamshell bucket and/or hydromill. Primary panels are typically

subdivided into three segments; the left and the right segments are excavated first and the middle

segment is excavated last. This process requires utilizing bentonite slurry to support the soils as the




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panel excavation progresses. Once the bottom of the panel is reached, the reinforcement cage is

lowered into position inside the panel. Concrete is pumped into the bottom of the excavation

through vertical pipes called tremies thus replacing the slurry with concrete. Slurry is circulated at

regular intervals throughout the construction period through a slurry plant where the slurry is

cleaned and de-sanded. The secondary panels are constructed between primary wall panels with

milling joints in previous constructed primary panels. After all slurry walls are completed and the

concrete allowed to cure, excavation begins to remove the soil from the interior of the shaft.

Figure 4-1: Slurry Wall Circular Shaft

Secant piles

Secant pile walls are formed by constructing a series of overlapping “primary” and “secondary”

concrete-filled drilled holes to form a circular shape of the shaft (refer to Figure 4-2). The primary

piles are constructed first, followed by secondary piles, which are cut into the previously placed

primary pile concrete. The amount of overlap required between the adjacent piles is a function of

the structural design requirements and the achievable installation tolerance.

There are two (2) methods typically used to install secant piles: the dry hole and the wet hole

methods. The dry hole technique includes using a temporary heavy wall drill casing, advanced

concurrently with the drill tool. Once the bottom of the pile is reached, concrete is pumped and as

the concrete level rises, the casing is removed. The wet hole technique, similarly to the slurry walls

excavation method, utilizes slurry to ensure the stability of the drilled hole before the concrete is

pumped through vertical tremie pipes.




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The concrete chosen for primary piles will often have lower strength with a slower rate of setting in

order to ease the cutting of secondary piles into primary piles. The concrete of the secondary piles

will have higher design strength and may be reinforced with reinforcing cages or steel beams.

Figure 4-2: Secant Pile Circular Shaft


This method involves mixing cement with the existing soil around the perimeter of the shaft to form

a continuous wall conforming to the configuration of the shaft. The CSM extends below the bottom

of the shaft. The CSM wall produces a relatively impermeable wall and permits only minor water

leakage.

The strength of the soil mix wall depends heavily on the existing soils being mixed and the cement

replacement ratio. The cement replacement ratio refers to the percentage of the soil being replaced

with cement. Higher replacement ratios typically result in greater strengths of the soil mass.

However, the achievable strengths of the cutter soil mix are considerably lower than in slurry or

secant pile walls. Consequently, the CSM wall support system for deeper shafts very often requires

additional structural support elements such as a layer of reinforced shotcrete placed against the

interior of the excavated wall in circular shafts, or steel shapes embedded in the walls with shaft

internal bracing in rectangular shafts (refer to Figure 4-3). This cement-soil mixture provides a

stabilized wall (around the perimeter of the shaft) of sufficient strength to allow the interior of the

shaft to be excavated in phases. A structural support system is constructed as excavation

progresses.




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Figure 4-3: CSM Circular Shaft

Sheet Piles

This method utilizes steel structural sections with a vertical interlocking system that can be used to

create shaft walls; the interlocking system ensures the steel sections remain connected. Steel

sheeting is effective in minimizing or nearly eliminating water from entering the shaft. The sheet

piles are typically driven, vibrated in place, or pressed in, depending on the type of soil and noise or

vibration restrictions in the construction area. Once the sheet piles are in place, excavation of the

soil from the inside the shaft can commence. As excavation proceeds utilizing standard soil

excavation techniques, additional structural members may be installed as required. In circular

shafts, steel or concrete ring beams may be installed to provide additional internal support. For

rectangular excavations, a system of steel wales and struts provide the required support for the

walls (refer to Figure 4-4).




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Figure 4-4: Sheet Piling Circular Shaft

Caisson

This method utilizes reinforced concrete sections for the construction of the shaft. The sections are

constructed at the surface to conform to the specified shaft configuration and lowered in place

using self-weight or hydraulic jacks (as required) that control the rate of movement. Typically, the

sections are lowered by slightly overcutting the soils below the cutting edge located at the bottom

of the first segment or by jacks pushing the sections into the ground by adding a vertical force to the

self-weight of the concrete. In very soft soils such as the layer of the Young Bay Muds, the jacks

would suspend the segments and lower them into the ground. Caissons are either installed in-the-

wet or in-the-dry. Shafts that are constructed in-the-wet are filled with water on the inside.

The construction of the caisson shaft commences with the excavation of the shaft area for a depth of

a few feet and the construction of the concrete collar. Concrete collars are constructed to guide the

placement of the concrete sections, to keep the sections vertical and to resist the forces from the

hydraulic jacks. The collars may require pile or other supports, depending on the soils at the shaft

location.

There are three (3) types of concrete sections: precast, segmental precast and cast-in-place

concrete. In each method, the first section is equipped with a steel cutting edge at its bottom to aid

the caisson sinking. The sections are lowered into the ground and the soil is removed from within

the caisson as the construction progresses.




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Precast concrete sections are cast monolithically to the shape of the shaft and have only horizontal

joints between each unit. They are constructed at a precasting plant or onsite in a casting facility

and transported to the shaft location. Typically, precast caissons are suitable for smaller diameter

shafts due to the limitation of the lifting weight and difficulty in transporting larger diameter

sections.

Segmental precast sections have horizontal joints between each section of the shaft lining as well as

vertical joints along the circumference of the shaft. They can be constructed in a precast facility on

or off site. Each full circumferential element is assembled at the shaft location, connected with bolts

at the vertical joints and with tie rods at the horizontal joints. When each section is completed, the

entire shaft is lowered in place and the next section is assembled on top of the previous section.

This process continues until the design depth of shaft is achieved.

The cast-in-place sections have only horizontal construction joints between vertical sections (refer

to Figure 4-5). They are reinforced and formed at the perimeter of the shaft configuration. The

cast-in-place sections are cast one section on top of the other around the perimeter of the shaft to

the shape specified. The first section of the cast-in-place caisson is set on top of the cutting edge and

then lowered in place after it achieves the prescribed strength. Subsequent sections are reinforced,

formed and lowered into the ground until the shaft is complete.

If a high groundwater table is present, gaskets for precast caisson sections or water stops for cast-

in-place caisson sections can be used to provide watertight joints between concrete segments. For

the SVCW Gravity Pipeline, due to the artesian water conditions, it is anticipated that gaskets will be

required.




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Figure 4-5: Construction of Cast-In-Place Caisson Shaft

4.1 Receiving Lift Station

4.1.1 Site Geology The information about general subsurface conditions at the Receiving Lift Station (RLS) is based on

the Phase I subsurface exploration program performed by Geotechnical Consultants Inc., and its

findings are presented in the "Preliminary Characterization of Subsurface Conditions" Technical

Memorandum dated December 9, 2015.

The existing subsurface conditions at the RLS were developed from four borings taken at the

proposed shaft location (B-101, B-109P, B-113P and B-114P), in addition to field and laboratory

test results performed on selected soil samples. The maximum boring depth obtained was 121.5

feet below the ground surface, approximately 55.5 feet below the bottom of the RLS. Piezometers

were installed at boring locations B-109P, B-113P and B-114P with screens located within the

Upper Layered Sediments.

The results from the boring program indicate that Artificial Fill covers the site to a depth of 3 to 6

feet below the ground surface and varies from clay to silt with varying amounts of sand/gravel.

Varying quantities of organic materials, cobbles and debris may be encountered within the fill.

Young Bay Mud underlies the fill with a layer thickness between 45 and 50 feet. The Young Bay

Mud consists of very soft to soft, highly compressible and plastic, near normally consolidated fat

clay. Zones of trace to abundant shell fragments, organic materials and occasional thin layers of

peat (less than a few feet in thickness) are contained within this layer. Standard Penetration Test

(SPT) results generally were "weight of rods" (WOR). Pocket penetrometer field readings indicate

an apparent undrained unconfined compressive strength ranging from 140 to 1,200 pounds per

square foot (psf). Laboratory shear test results varied from 181 to 390 psf. The unit dry densities

were in the 47 to 56 pcf range, with water content between 73% and 94%. The liquid limits and




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plastic limits laboratory test results for the clay varied from 65% to 90% and 28% to 36%,

respectively. Consolidation tests were performed on selected samples of Young Bay Mud.

Below the Young Bay Mud are the Upper Layered Sediments. These sediments contained a layer

thickness varying between 40 and 48 feet. The soil deposits consists of a complex alternating layers

of silty sands, clayey sands, clean and poorly graded sands, sandy to clayey silts and lean to fat

clays. The thickness, sequencing and consistency of these individual layers are highly variable. SPT

results ranged from 16 to 50 blows/foot. The granular materials (sands with varying amounts of

gravel) are in a dense to very dense state. The fine grained materials (silts and clays) have a stiff to

very stiff consistency. A liquid limit of 30% and plastic limit of 19% were obtained on one clay

sample tested in the laboratory. Pocket penetrometer field readings indicate an apparent undrained

unconfined compressive strength ranging from 2,000 to over 5,400 psf.


deepest boring performed at this shaft site, a depth of 121.5 feet below the ground surface. This

layer of marine sediments consists of medium stiff to very stiff fat clay and lean to silty clay with

occasional scattered shell fragments. SPT results ranged from 26 to 33 blows/foot. Pocket

penetrometer readings indicate an apparent undrained compressive strength ranging from 1,000 to

4,000 psf.

Groundwater was encountered within the first few feet below the ground surface at Boring B-101

and was observed to be influenced by tidal fluctuations. Static water levels within the installed

piezometers were at elevation 104.5 which correspond to 1.5 feet above the ground surface

reflecting artesian pressure conditions within this confined aquifer (deep granular layer within

Upper Layered Sediments).

4.1.2 Shaft Excavation 4.1.2.1 Excavation Size and Configuration The final interior of the Receiving Lift Station (RLS) will be comprised of three sections: inlet

channels consisting of two gates and two channels, an ogee ramp and a wet well. Two distinct shafts

are envisioned for the installation of the final shaft interior, including the Flow Splitter and the RLS.

The Flow Splitter Shaft, as a final structure, would serve to receive flows and house gate controls

prior to flows entering the RLS Shaft. The shaft would be also used for the retrieval of the Tunnel

Boring Machine (TBM) and would require a minimum 25-foot internal diameter to accommodate

the retrieval. The RLS Shaft would serve as the lift station where the wastewater from the tunnel

would be pumped up to the plant level for treatment. Both shafts would be constructed by the PDB,

but finished and equipped by others. The two distinct shafts will allow two separate PDBs (Gravity

Pipeline and the Front-of-Plant) to work simultaneously in each space for the duration of the TBM

removal (estimated to be about 6 weeks).

The size of the RLS has not been determined yet and will mainly depend on the final size of the shaft

interior and the selected shaft configuration. It is currently anticipated that the Flow Splitter Shaft




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will be approximately 68-feet deep with a diameter between 25 and 32-feet. The RLS Shaft will be

approximately 84-feet deep and its diameter will be between 28.5 and 52-feet.

The following four configurations were evaluated for the RLS:

1. Two separate shafts with a connection made near the bottom to connect the Flow Splitter

Shaft with the RLS Shaft.

2. One large circular shaft with a baffle wall separating the Flow Splitter Shaft and the RLS

Shaft.

3. Two shafts adjacent to each other forming a figure “8” with a baffle wall in-between.

4. Oval shaft with the baffle wall separating the Flow Splitter Shaft and the RLS Shaft.

One circular shaft configuration was eliminated from further consideration due to larger footprint

and anticipated higher cost as compared to the other options. The remaining configurations: two

separate shafts with a connection made near the bottom, figure "8"and oval shapes are represented

in Figure 4-6 to Figure 4-9, respectively.

Figure 4-7 below displays the first figure "8" configuration based on which a conceptual structural

evaluation was performed. The following Figure 4-8 represents the most recent figure "8"

configuration considered and revised based on the latest dimensions of the RLS Shaft interior.

However, the final size of the shaft interior has not been determined yet and the shaft configuration

depicted in the Figure 4-8 is presented for reference only and could be subject to further changes.




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Figure 4-6: Two Separate Shafts with Connection Tunnel Configuration

Figure 4-7: Figure Eight Shaft Configuration (As Evaluated In This Memorandum)




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Figure 4-8: Figure Eight Shaft Configuration (As Recently Considered)

Figure 4-9: Oval Shaft Configuration

4.1.2.2 Excavation Methods Conventional soil excavation techniques such as a crane and a clamshell bucket or an excavator can

be utilized to excavate the materials within the shafts. The shaft may be excavated in wet or dry

conditions. This will depend on the type of impervious system selected, as described in the

following sections. Under wet conditions, the shaft would be flooded and the excavation would be

performed underwater with a crane using clamshell bucket. Under dry conditions, it is envisioned

that an excavator and buckets hoisted to the surface by a crane would be used.

4.1.3 Initial Support 4.1.3.1 Support Methods and Evaluation Three configurations are envisioned to be suitable for the construction of the RLS: figure "8", oval

and two separate shafts with a connection tunnel in-between. A conceptual structural design was

performed for the RLS in the configuration of the figure "8" and oval to assess the structural

behavior of the shaft under assumed loads and approximate the required sizes of the structural

elements for the initial support. The two separate shafts with a connection tunnel in-between

configuration was added for the detailed evaluation at a late stage in development of this

memorandum. Therefore, no conceptual design was performed for this configuration at this time

and all information presented in this memorandum is based on engineering experience and




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judgment. Further evaluation of the two separate shafts configuration is recommended during the

preliminary design stage.

Due to soil conditions as defined by GTC in the "Preliminary Characterization of Subsurface

Conditions" Technical Memorandum, high groundwater levels and the shaft configuration, only

three initial support methods have been considered for the RLS construction, namely: slurry walls,

secant piles and caisson. The CSM was excluded because of its relatively low strength as opposed to

concrete for applications of this depth and size. The CSM wall is constructed by mixing cement with

the natural soil. The soil conditions at the RLS consisting of a thick layer of clay would produce a

wall with relatively low strength typically ranging from 400-900 pounds per square inch (psi).

Therefore, utilizing the CSM initial support method would require installation of additional

structural supporting elements, such as a reinforced concrete lining or internal bracing with steel

shapes embedded in the wall making this option more costly and difficult. The sheet piling option

was also found to be not suitable, because the shaft depth and the extremely heavy size of internal

bracing.

The following assumptions have been made in the conceptual design: 5 feet of the shaft would be

constructed in very soft Artificial Fill, 45 feet in very soft Young Bay Mud and 16 feet in dense to

very dense Upper Layered Sediments. The Upper Layered Sediments consist of varying quantities of

sands, gravels and clays, and the RLS shafts will terminate in a water-bearing sand layer. The shafts

would be subjected to 68 feet of hydrostatic head measured from 1.5 feet above the surface

elevation to the bottom of the shaft. The interior dividing wall in the final structure, in addition to

axial loads, will be capable of resisting bending moments from the potential difference in water

level in the Flow Splitting and RLS Shafts. These assumptions were based on the initial RLS

information available, and will be reviewed to reflect the most recent dimensions during the

preliminary design stage.

The results of the conceptual design indicate that the oval shaft configuration is not suitable for the

RLS. A bending moment would develop in the shaft lining along the longer sides of the shaft, which

would require continuous structural reinforcement in the horizontal direction. Continuous

reinforcement can only be provided in the cast-in-place caisson option since secant piles can only

be reinforced in the vertical direction and slurry walls and caisson precast concrete elements have

reinforcement discontinuity at vertical joints between panels. Consequently, construction of the

shaft utilizing slurry walls, secant piles or caisson precast concrete elements may not be feasible for

this Gravity Pipeline without internal bracing such as wales and struts. This would be costly and

would require a longer schedule. As for the cast-in-place caisson walls, they would have to be

heavily reinforced to resist the anticipated bending moments. Moreover, using the oval shape

would provide an additional cross sectional area inside of the shaft, which is not needed for the

final structure and would only increase the cost of the shaft excavation and backfilling for the

construction of channels.




Shaft Construction

Therefore, for the RLS structure, the two separate shafts with a connection tunnel at the bottom and

figure "8" configuration are recommended and considered in further evaluation of the initial

support system. The following are summaries of the applicability of each of the remaining

excavation support systems for the RLS.

Slurry walls

Based on the conceptual design of the RLS in the figure "8" configuration, it is anticipated that, as a

minimum, 3-foot thick reinforced concrete slurry walls would be required for both the 32 foot

diameter Flow Splitter Shaft and 52-foot diameter for the RLS Shaft (refer to Figure 4-10). The

structure will consist of a baffle wall in-between the two RLS Shafts. Two methods are envisioned

for the baffle wall construction; slurry walls or cast-in-place. Selection will mainly depend on the

magnitude of the differential pressures in the two shafts. The wall could simply be constructed

from slurry wall panels before the excavation begins. This option would be desirable if no

differential pressures in the two shafts are anticipated. Otherwise, a supplementary wall will need

to be constructed to provide continuous horizontal reinforcement or another wall construction

methods utilized. The other method would include the installation of a cast-in-place wall. The shaft

could be excavated with or without the cast-in place wall. In the latter option, temporary struts at

the wall location would be required for stability during excavation before the wall is casted.

Alternatively, the wall can be constructed as cast-in-place reinforced concrete in vertical segments

as the excavation progresses. However, this method would reduce the progress of the shaft

excavation since the concrete in the baffle wall will have to achieve the required compression

strength before excavation resumes.

It is anticipated that, for the two separate shafts configuration, minimum of 2 feet 6 inches thick

reinforced concrete slurry walls will be required. A connection structure would be constructed in-

between the two RLS shafts (refer to Figure 4-11). Methods of construction of the connection

structure were not evaluated at this time. For the cost estimating purposes, a hand mined tunnel

with jet grouting soil improvement at the tunnel level was assumed. The hand tunneling is typically

performed by tunnel miners using compact equipment or hand tools to excavate the soils. The

improvement of the soils would enhance the soil stand up time providing stable working conditions

and minimizing water inflow during excavation. A more detailed evaluation of the construction

methods of the connection structure will be performed by the PDB.

For both configurations, an additional, cast-in-place reinforced concrete wall may be required at the

tunnel breakout to prevent infiltration and resist the anticipated breakout forces. The breakout wall

may be demolished after the tunnel is completed as required for the final shaft interior. Since the

TBM has to penetrate the slurry walls, fiberglass reinforcement will be used at the tunnel eye in lieu

of steel bars. A mud slab would be poured at the Flow Splitter Shaft invert to provide smooth and

firm working surface for the activities taking place in the shaft.

Also, for both configurations, due to the presence of water-bearing granular layers at the tunnel

level, soil improvement will be implemented for ground treatment at the tunnel breakout. This will




Shaft Construction

minimize water infiltration into the Flow Splitter Shaft during TBM breaking in for retrieval. As an

additional protection measure, a seal around the tunnel breakout inside of the shaft will be installed

to aid in minimizing or eliminating groundwater inflow into the shaft.

The slurry wall would provide a relatively impermeable shaft lining and could serve as a permanent

lining for the RLS shafts capable of withstanding the long-term permanent loads. The installation of

a corrosion protection layer will be determined by others.




Shaft Construction

Figure 4-10: Slurry Wall Alternative – Figure "8"Configuration

Figure 4-11: Slurry Wall Alternative – Two Separate Shafts Configuration

Secant piles

It has been determined that, for the RLS in figure "8" configuration, approximately 4 foot diameter

unreinforced concrete piles would be required to resist the circumferential compression generated

around the shaft and to accommodate any vertical pile deviations (refer to Figure 4-12). Similarly

to the slurry wall option, the baffle wall could be constructed utilizing secant piles at the same time

as the shaft walls or cast in place either after or simultaneously with the shaft excavation. The

selection of the construction method for the baffle wall will depend mainly on the magnitude of the

differential pressures. Some of the piles, especially those in the vicinity of the baffle wall connection

between the circular shafts, would have to be reinforced to resist the forces at the intersection and

facilitate the wall construction if the cast-in-place option is selected.

It is anticipated that for the two separate shaft configuration, a minimum of 3.5 foot diameter

unreinforced concrete piles would be required to resist the circumferential compression generated

within the initial support and accommodate any vertical pile deviations (refer to Figure 4-13).

Similarly, to the slurry wall option this shaft configuration will require the construction of a

connection structure.

For both configurations, the secant pile wall may require an additional cast-in-place reinforced

concrete wall to resist forces at the tunnel breakout. The piles adjacent to the tunnel will be




Shaft Construction

reinforced to aid in resisting the forces on the side of tunnel breakout. At the breakout location,

where the TBM will penetrate the secant piles, fiberglass reinforcement will be used at the tunnel

eye in lieu of steel bars. The breakout portion of the wall inside the shaft may be demolished after

the tunnel is completed as required for the final shaft interior.

A mud slab would be poured in the Flow Splitter Shaft (the TBM retrieval location) invert to

provide smooth and firm working surface for the activities taking place in the shaft. Similarly to the

slurry wall option, soil improvement and a seal at the tunnel breakout will be used to prevent

groundwater ingress into the shaft during breaking for the TBM retrieval.

The secant pile shaft support could be designed to serve as a permanent structure for the RLS and

the Flow Splitter Shafts since the secant piles are capable of withstanding the long-term permanent

loads the structure will be subject to. However, the large number of joints in the secant pile wall

would make the system more susceptible to water infiltration. A layer of fiber reinforced shotcrete

would enhance the impermeability of the system. The installation of a corrosion protection layer

will be determined by the PDB in collaboration with SVCW.




Shaft Construction

Figure 4-12: Secant Piles Alternative – Figure "8" Configuration

Figure 4-13: Secant Piles Alternative – Two Separate Shafts Configuration

Caisson

For the Caisson option, it is envisioned that approximately 3-foot thick concrete walls would be

required (refer to Figure 4-14) for the RLS in figure "8" configuration and approximately 2-foot

thick walls for the two separate shafts configuration (refer to Figure 4-15). The shaft lining would

be constructed at the surface, in vertical sections, and then lowered into the ground while

excavation progresses.

For the figure "8" configuration, the caisson would be constructed from cast-in-place concrete. It is

anticipated that the precast type of caisson will not be applicable to the RLS in figure "8"

configuration due to the large size of the shaft and its shape. Therefore, this option was not

investigated further. However, for the two separate shafts configuration, both options are viable.

This caisson construction would start with an excavation and installation of a cast-in-place concrete

collar which would provide support for the surcharge loads at the surface, resist the forces from

hydraulic jacks, and act as a guide for shaft sinking. Due to soil conditions at the RLS, it is

envisioned the collar would have to be supported by series of vertical piles or other supports

extending down to the Upper Layered Sediments or even deeper to the Old Bay Deposits stratum.




Shaft Construction

Hydraulic jacks (strand jacks with cables) would suspend each section of the structure in the Young

Bay Mud and lower it into the ground as excavation progresses. Once the Upper Layered Sediments

are reached, the caisson self-weight and overcutting of the soil slightly below the cutting edge is

anticipated to be utilized in order to sink the shaft. The usage of jacks for pushing of the caisson

segment is not envisioned. However, the final procedure will depend on the PDB's selected means

and methods of shaft construction.

The precast concrete segments, if utilized for the two shaft configuration, would be cast on or off

site and transported to the shaft location. There, they will be assembled around the circumference

of the shaft to form a complete circle. Each vertical joint would be connected with bolts. Tie rods

will be used to connect segments in horizontal joints. After the completion of a full section, it would

be lowered in place by the use of hydraulic jacks. The area within the caisson would be excavated

and the next caisson section would be assembled. This process would continue until the shaft is

completed.

The cast-in-place concrete sections would be constructed at the shaft final location. They would be

reinforced, formed and cast to follow the configuration of the shaft. The shaft would be constructed

in vertical lifts with water stops at each construction joint. The joints would be doweled to provide

continuous reinforcement in the lining of the shaft. Similarly to the precast segments, the cast-in-

place sections would be lowered evenly into the ground aided by hydraulic strand jacks, the area

within the circumference would be excavated as the shaft is lowered into the ground and the cycle

repeated.

It is anticipated that the dividing wall in figure "8" configuration will be constructed simultaneously

with the shaft walls. The construction type of the baffle wall would follow the construction type of

the main outside walls; cast-in-place.

Similarly, to the other options, soil improvement and a seal at the tunnel breakout will be used to

prevent groundwater ingress into the shaft during breaking for the retrieval of the TBM. For both

shaft configurations, an additional, cast-in-place reinforced concrete wall may be required at the

tunnel breakout to resist the anticipated breakout forces. The breakout wall may be demolished

after the tunnel is completed as required for the final shaft interior. At the breakout location, where

the TBM will penetrate the caisson wall, fiberglass reinforcement will be used at the tunnel eye in

lieu of steel bars. A mud slab would be poured at the Flow Splitter Shaft invert to provide smooth

and firm working surface for the activities taking place in the shaft.

The caisson would provide relatively impermeable walls, which could serve as a permanent lining

for the RLS Shafts capable of withstanding long-term permanent loads. The installation of a

corrosion protection layer will be determined by the PDB in collaboration with SVCW.




Shaft Construction




Shaft Construction

Figure 4-14: Caisson Alternative – Figure "8" Configuration

Figure 4-15: Caisson Alternative – Two Separate Shafts Configuration

Groundwater control at RLS

Only an impermeable shaft support system will be utilized for the RLS construction. Since the shafts

will be terminated in water-bearing granular soils with artesian conditions, the construction of a

sealing element at the shaft invert would be required to minimize water inflow into the excavation

and facilitate construction. The sealing element at the shaft invert in conjunction with the

impermeable excavation support would provide a relatively impervious system minimizing the

groundwater inflow into the structure. The following six (6) options of impervious systems have

been investigated:

Option 1 - Extended initial support

This system would include the extension of the excavation support into the impermeable layer

(refer to Figure 4-16). The linings of the Flow Splitter and RLS Shafts would be extended

approximately 34 feet and 18 feet respectively down through the permeable layers of the Upper

Layered Sediments into the lower relatively impermeable clays of the Old Bay Deposits to provide a

water cut-off barrier.

This option would minimize the water inflow into the excavation during the construction of the RLS

structure and provide a short term relatively impermeable barrier, adequate during construction.

However, with time, the hydrostatic pressure would build up at the invert of the RLS structure and

the installation of permanent groundwater control system would be required. Two (2) options are




Shaft Construction

envisioned for the permanent groundwater control at the RLS invert: a structural slab designed to

resist the hydrostatic pressure or drainage holes penetrating the final invert interior to relieve the

pressure.

Figure 4-16: Extended Excavation Support

The advantages and disadvantages of this system are listed in Table 4-2.

Table 4-2: Advantages and Disadvantages – Option 1

Advantages Disadvantages

Fast installation since only the support

will be extended

Permanent groundwater control system at

invert of RLS would be required

Reliable system Not suitable with caisson excavation

support method

Relatively low cost since equipment

will be onsite

Not recommended for secant pile method

as the system would reach its practical

depth

Allows for relatively dry excavation




Shaft Construction

Option 2 - Excavation support and permeation grouting curtain

In lieu of extending the excavation support into the impermeable layer, a water cut-off barrier could

be constructed utilizing permeation grouting (refer to Figure 4-17). The permeation grouting

would be accomplished from the surface before the excavation of the shafts begins. Two grout

placement methods could be used. A series of grout holes could be drilled along the shaft perimeter

through grout pipes embedded in the excavation support. A low viscosity grout would be injected

into in-situ soil at relatively low pressures allowing the grout to permeate into the soils. The

permeation grouting was selected for this option as it suits the ground conditions well at the

bottom of the RLS (consisting of sands and gravels) and it is the simplest and least expensive

grouting method. Another type of soil improvement could be utilized in lieu of permeation grouting,

such as jet grouting or soil freezing. However, it is anticipated that the cost of these systems would

be much higher than permeation grouting or extended excavation support (Option1). Therefore,

they are not recommended at this time. The additional soil improvement methods (jet grouting and

soil freezing) may be revisited during preliminary design if determined that they are best suited for

the construction of the shaft.

The excavation support and permeation grouting curtain option would minimize the water inflow

into the shafts during construction; however, it would require substantially more labor and cost for

verification (testing) than Option 1. Similarly, this option would require the installation of a

permanent groundwater control system in the invert of the RLS. Therefore, the excavation support

and permeation grouting curtain option is not recommended and excluded from further

investigation.




Shaft Construction

Figure 4-17: Permeation Grouting Curtain

The advantages and disadvantages of the system are listed in Table 4-3.



Suitable with all three excavation

support methods

Permanent groundwater control system at invert

of RLS would be required

Good shaft foundation

Substantially more labor and verification

(testing) necessary to ensure system constructed

as designed

Mobilization of grouting equipment at the surface

is required




Shaft Construction

Option 3 - Excavation support with gravity concrete plug

This system would include the installation of an impermeable excavation support and a sealing

element consisting of a concrete gravity plug (refer to Figure 4-18). It is estimated that a 48 and

60-foot thick gravity concrete plugs are required to resist the hydrostatic pressure at the invert of

the Flow Splitter and RLS Shafts respectively. Since the impermeable layer is only 28 and 12 feet

below the shaft inverts, the additional 20 and 48-feet of concrete plug will not be required through

this layer to achieve a relatively impermeable system for the construction of the RLS Shafts. The

system will require the initial support to extend below the bottom of the plug to ensure stability of

the excavation before pouring in the concrete plug. It would also require excavation of the soils

inside of the shaft for the plugs construction. The plugs would work as a groundwater cut–off

barrier and a final slab for the RLS.

The extension of the shaft initial support system and the excavation to accommodate the concrete

plug construction would make this option costly. Therefore, the impermeable excavation support

with gravity concrete plug option is not recommended and is excluded from further investigation.

Figure 4-18: Concrete Plug





Shaft Construction




support methods

Extension of the initial support system

required

Permanent groundwater control

system at RLS invert not required

Excavation of the inside of the shaft for

the plug construction required

Expensive option overall

Longer shaft construction duration

Option 4 - Excavation support with jet grouting gravity plug

This system would consist of the installation of an impermeable excavation support system and a

sealing element consisting of a jet grouting gravity plug (refer to Figure 4-19). The jet grouting will

be performed from the surface before the excavation of the shafts begins. The jet grouting

technique injects grout at a high pressure and velocity destroying the soil structure and mixes grout

and soil to form a homogeneous impervious mass.

The 28 and 12-feet thick jet grout plugs in conjunction with the impermeable excavation support

will function as a sufficient impervious system during construction of the RLS Shafts. As for the final

structure, the installation of permanent groundwater control system to accommodate potential

hydrostatic pressure that could develop in the future behind the invert of the structure might be

required. In lieu of the permanent groundwater control system, additional grouting of the plug

could be performed to make the jet grouting plug completely watertight and suitable for an

impermeable final invert. The plug would also provide an excellent foundation for the structure.




Shaft Construction

Figure 4-19: Jet Grouting Plug




Suitable with all three excavation support

methods


system at structure invert might

be required

Provides excellent foundation for the RLS walls Expensive option overall

Could serve as a permanent groundwater

control system if additional grouting of the

plug is performed to make the jet grouted plug

completely watertight




Shaft Construction

Option 5 - Excavation support with structural concrete invert slab

This system would include the installation of an impermeable excavation support system and a

sealing element consisting of a structural concrete invert slab (refer to Figure 4-20). The dividing

wall and the impermeable excavation support system would need to be installed simultaneously, so

there would be an adequate amount of weight to resist buoyancy after installation of the invert slab.

The structural concrete invert slab would be a minimum of 8-foot thick with steel reinforcement

and would be designed for artesian hydrostatic uplift pressures.

The installation process requires flooding of the shaft to counterbalance the hydrostatic uplift

pressures. The excavation to the bottom of the impermeable excavation support system would be

performed underwater. Once excavated, the invert slab reinforcement and connections to the

impermeable excavation support system would be installed by underwater divers. The concrete

would then be installed using the tremie concrete placement method. This impervious system

would be considered as part of the final structure and would not require installation of

supplementary groundwater control system.




Shaft Construction

Figure 4-20: Structural Concrete Slab


Table 4-6: Advantage and Disadvantage – Option 5



system at structure bottom not

required

Installation of middle wall and approximately 8

feet thick slab required to resist buoyancy

Not recommended with secant pile wall system,

as it would be difficult to key the structural slab

into the secant piles, which makes the option

more costly

Option 6 – Caisson with jet grouting water cutoff curtain

In this option, a water cut-off curtain constructed utilizing jet grouting (refer to Figure 4-21) would

be extended through the permeable layers of Upper Layered Sediments into the lower relatively

impermeable clays of the Old Bay Deposits.

The jet grouting will be performed from the surface around the perimeter of the RLS structure prior

to the excavation. The jet grouting technique injects grout at a high pressure and velocity breaking

down the soil structure and mixes grout with the soil to form a homogeneous impervious mass. The

jet grouting curtain will provide water cut-off barrier and act as a support for the concrete collar

required for the caisson installation.

As for the final structure, the installation of permanent groundwater control system to

accommodate potential hydrostatic pressure that could develop in the future behind the shaft final

interior would be required.




Shaft Construction

Figure 4-21: Caisson with Jet Grouting Water Cutoff Curtain

The advantages and disadvantages of this system are listed in Table 4-7.



Allows for relatively dry excavation Permanent groundwater control system at

invert would be required

Provide excellent support for the

concrete collar around the shaft.

Impermeable systems comparison cost

Relative comparison costs for the RLS impermeable system options are shown in Table 4-8 and 4-

9. The costs were developed in 2015 prices. Mark-up of 25 percent for indirect cost and 15 percent

for overhead and profit are included in the costs. The costs do not include contingency and

escalation. Refer to Appendix A.




Shaft Construction

Table 4-8: RLS Impermeable System Cost Comparison - Figure "8" Configuration

Initial

Support

Method

Option 1:

Initial Support +

Extended Initial

Support Cost

(Millions)

Option 4:

Initial Support +

Jet Grouting Plug

Cost

(Millions)

Option 5:

Initial Support +

Structural

Concrete Slab

Cost

(Millions)

Option 6:

Caisson with Jet

Grouting Curtain

Cost

(Millions)

Slurry walls $5.5 $6.5 $5.9 N/A

Secant piles $5.0 $5.8 $5.7 N/A

Caisson N/A $7.0 $6.4 $8.2

Table 4-9: RLS Impermeable System Cost Comparison - Two Separate Shafts Configuration

Initial

Support

Method

Option 1:

Initial Support +

Extended Initial

Support Cost

(Millions)

Option 4:

Initial Support +

Jet Grouting Plug

Cost

(Millions)

Option 5:

Initial Support +

Structural Concrete

Slab Cost

(Millions)

Option 6:

Caisson with Jet

Grouting Curtain

Cost

(Millions)

Slurry walls $5.8 $5.8 $5.5 N/A

Secant piles $5.3 $5.2 $5.3 N/A

Caisson N/A $6.8 $6.4 $7.8

4.1.4 Site Conditions The RLS Shaft and Flow Splitter Shaft site would be located east of the Redwood Shores Parkway

and Radio Way intersection, in Redwood City. The shaft site would be located on SVCW property,

adjacent to the existing WWTP. This site will serve as the location for the Receiving Lift Station

(RLS) Shaft and Flow Splitter Shaft. The Flow Splitter Shaft will ultimately be used for channelizing

flow upstream of the RLS which will be constructed within the RLS Shaft.

Areas adjacent to the site will be used for construction of various SVCW Conveyance System

Program Front of Plant (FOP) wastewater facilities including headworks, flow diversion structure,

and odor control facilities. FOP facilities including the RLS inside the RLS Shaft are being designed




Shaft Construction

by others. Due to the various facilities to be designed and constructed by multiple entities, close

coordination of site staging for different phases of construction at this location is required.

4.1.4.1 Site Ingress/Egress Access to the site would be from Radio Road via Redwood Shores Parkway. The site location and

access to/from the site from Highway 101 and surrounding areas is shown in Figure 4-22.

Figure 4-22: RLS and Flow Splitter Shaft Site Ingress and Egress

Specific ingress/egress gate location and access requirements within the site for construction

vehicles is considered in the site staging requirements for the site and is discussed in further detail

in Section 4.1.4.3.

4.1.4.2 Existing Site Conditions The RLS and Flow Splitter Shafts site would be installed in an area that has historically been used for

an ornamental pond within the SVCW WWTP property. As a result of the historical use of the

property, there are currently no known surface utilities or other existing features within the shaft

site area. There is an elevated corridor adjacent to the site, along the northern site boundary, that

contains various subsurface utilities. Existing recycled water facilities are located within this

corridor. Other utilities including electrical, sewer, gas, communication and storm drain facilities

are located adjacent to the site along Radio Road.

Shaft Construction Site




Shaft Construction

4.1.4.3 Staging Area Requirements The site area will need to be drained of water prior to construction and cleared of vegetation. As a

result of the historical use of the site and soft bay mud soil conditions, the site will require

stabilization consisting of lime treatment in some areas (permanent paving for FOP facilities) and

reinforcing fabric for subgrade stabilization in other areas (temporary construction staging areas).

The site elevation will be graded and will receive a layer of base rock to provide an all-weather

surface for construction.

There will be two phases of construction activities related to tunneling and shaft construction at

this location. The first phase will be construction of the shafts and the second phase will be

retrieval of the TBM at this location. The required staging area for each phase is as follows:

Flow Splitter Shaft and RLS Shaft Construction: Approximately 2.5 Acres (including

common access entrance area, fenced in site area approximately 2.3 Acres)

TBM Retrieval: Approximately 0.4 Acres

The following have been considered in developing the Flow Splitter Shaft and RLS Shaft

construction staging area requirements:

Shaft Location relative to overall staging area

Shaft excavation size, configuration and potential excavation method

Site access from public right-of way

Design Vehicle Type: WB-50 (semi-trailer combination)

Shaft Excavation Rate: Approximately 4 vertical linear feet (VLF) per day

Excavated Material Storage: 3-day (7,200 sf)

The staging plan for the Flow Splitter Shaft and RLS Shaft construction is shown in Figure 4-23.

RLS/FLOW SPLITTER SHAFT CONSTRUCTION STAGING AREA - PLAN

Slurry Wall Construction

Approx. 2.5 ac (including entrance area)

LEGEND

Slurry Separation Plant Generator

Compressor

Cage Fabrication/Storage

Area

Storage Boxes

Excavated Material Storage (3 Days)

Entry/Exit gate

Crane

Stabilized Construction Entrance

Vehicle Type: WB-50

Optional excavated material storage area for re-use

Front of Plant Stabilization and Staging Areas During

Shaft Construction (By Others)

Constructed in Parallel with RLS Shaft (By Others)

Temporary Construction Wall (By Others)

Radio R

d

Radio Rd

C PROPOSED 15' OD

DIA. TUNNEL

L

Trailer City

Area for

SITE

CIVIL

32' INSIDE DIA.

FLOW SPLITTER

SHAFT

52' INSIDE DIA.

RLS SHAFT


SILICON VALLEY CLEAN WATER

TUNNEL PROJECT - TM No. 4

RLS/FLOW SPLITTER SHAFT

CONSTRUCTION - SITE STAGING PLAN

Radio

Road

2

1

3

4

5

6

7

8

10

9

11

12

13

14

12

11

13

9

7

10

6

5

4

1

8

23

STAGING AREA

LIMITS

14

1"=100'

0 100 200

K/J 1568063.02

JUNE 2016 FIGURE 4-23




Shaft Construction

This plan reflects slurry wall construction and a Figure “8” configuration. As noted previously, two

construction methods (slurry wall and caisson) and two configurations (Figure “8” and two

separate shafts) are recommended for further evaluation during preliminary design. It is

anticipated that the overall staging area shown in Figure 4-23 can accommodate both methods and

configurations. Major construction equipment and laydown areas are identified in the staging plan

including: a designated area for slurry separation plant, generator, compressor, and cage

fabrication/storage area. As shown in Figure 4-23, all vehicles can access the site from Radio Road

at the stabilized construction entrance and gate on the north side of the site. Adequate space would

be available for larger vehicles to make U-turns in the middle of the site and exit through the same

gate.

The main considerations for establishing the requirements for the TBM removal staging area from

the Flow Splitter Shaft include: FOP construction which will be occurring adjacent to the site and in

parallel with the TBM removal, sufficient working area for the crane retrieving the TBM

andsufficient area for loading the TBM pieces onto the transport vehicle. The staging plan during

TBM Retrieval from the Flow Splitter Shaft is shown in Figure 4-23A.




Radio R

d

Radio Rd

LEGEND

1 ENTRY/EXIT GATE

2 COMPRESSOR

3 GENERATOR

4 EXIT FROM THE SITE THROUGH FRONT OF PLANT

PAVED ACCESS ROAD

5 TEMPORARY CONSTRUCTION WALL (BY OTHERS)

6 VEHICLE TYPE: WB-50

6

AREA FOR

SHAFT

CONSTRUCTION

STAGING

AREA FOR

RLS

CONSTRUCTION

STAGING

Work

Area

FLOW SPLITTER SHAFT (TBM RETRIEVAL) STAGING AREA - PLAN

Approx. 0.4 ac

L PROPOSED

15' DIA. OD TUNNEL

C

1

AREA FOR

HEADWORKS

CONSTRUCTION

STAGING

32' INSIDE DIA.

FLOW SPLITTER

SHAFT

5

2

3

RADIO ROAD

K/J 1568063.02 JUNE 2016

FIGURE 4-23A

1

4

STAGING AREA

1"=100'

0 100 200

FLOW SPLITTER SHAFT (TBM RETRIEVAL) SITE STAGING PLAN




Shaft Construction

The WB-50 design vehicle type selected for both site layouts at this location has similar wheel base

and overall dimensions to a standard lowboy tractor trailer combination vehicle anticipated for in

use in delivery of construction material and equipment to the site during shaft construction. It is

anticipated a standard lowboy tractor trailer combination transport vehicle would also be used for

transporting the TBM from the site.

4.1.4.4 Utility Requirements Utility requirements for this site will include temporary power during shaft construction and TBM

removal. Further coordination with SVCW is required to determine if the shaft construction power

will be supplied as part of the overall FOP improvements. Anticipated electrical requirements for

shaft construction and TBM removal include 480V, 3 phase, 4-wire electrical line power with

generator facilities for back-up power.

Additional utility requirements include potable water and sewer service facilities for the onsite

construction trailer facilities (likely constructed by others). Existing potable water and sewer

facilities are located along Radio Road adjacent to the project site. It is anticipated that service

connections into these facilities will be utilized for construction facilities associated with shaft

construction as well as FOP improvements. Site drainage facilities will also be provided as part of

FOP improvements.

4.1.4.5 Long Term Operations and Maintenance Facility Requirements Long term operation and maintenance (O&M) requirements of the flow diversion facilities which

would be installed in the Flow Splitter Shaft and the RLS Shafts are anticipated to be developed by

others.

4.1.5 Construction Considerations

4.1.5.1 Mobilization Two separate mobilization periods are anticipated to occur at this site. An initial mobilization

period would occur for shaft construction and a subsequent mobilization period would occur for

TBM removal from the Flow Splitter Shaft. Initial mobilization for shaft construction would occur

after the site is stabilized and construction screening wall is constructed (by others). Initial

mobilization at this location would include transportation of contractor's personnel, equipment,

and operating supplies to the site required for shaft construction. Mobilization for shaft

construction would also include installation of contractor’s field offices, site fencing, gates, utilities

and other necessary general facilities for the contractor's operations at the site. The initial

mobilization period will also consist of the contractor obtaining all the required insurance, bonds

and permits specific to working at this location such as addressing dirt hauling concerns working

with Redwood City. Mobilization for TBM removal from the Flow Splitter shaft would include

transportation of equipment and materials required to remove the TMB from the shaft. For more

details of the staging area, refer to the "Staging Area Requirements" section above.




Shaft Construction

4.1.5.2 Excavated Material Handling Soil from shaft excavation would either be temporarily stock-piled onsite for off-site hauling and

disposal at a suitable disposal site in accordance with applicable federal, state and local regulations,

or dried and treated (if necessary) for use as fill for other FOP construction. An area for temporary

stockpiling of shaft excavation material to be re-used, adjacent to and outside of the RLS/Flow

Splitter Shaft staging area, has been identified in the FOP preliminary staging layouts. This area is

shown on Figure 4-23. The potential for re-use and associated re-use quantities will be

determined during design and coordinated with FOP activities.

For the purpose of this TM and for the purpose of establishing areas for temporary soil stockpiling

onsite, it has been assumed all of the excavated soil would be temporarily stockpiled onsite and

hauled away for offsite disposal. Excavated material that cannot be hauled away during the hauling

hours each day would be stored onsite for hauling on the following work day. Approximately three

(3) days of excavated material can be accommodated onsite based on the preliminary site staging

layout, utilizing a shaft excavation rate of 4 vertical linear foot per day (VLF/day) and average 5-

foot high stockpiles.

The excavated material would need to be sampled and analyzed to characterize the soil and

determine if there is any soil contamination. Soil characterization is necessary to confirm the

disposal classification for off haul, prior to offsite disposal or re-use. Acceptance of the soil at a

landfill will depend upon overall disposal quantity and soil characterization and or contamination.

Non-contaminated and contaminated material would be subjected to the profiling requirements of

the disposal facility. Ox Mountain Sanitary Landfill, located in Half Moon Bay, is the closest landfill

that accepts this type of construction excavated material. Habitat restoration fill is another off-site

disposal option. Ultimately, the Contractor will identify the excavated material disposal location(s)

unless SVCW either uses the material on-site or makes arrangements for use in habitat restoration.

Hauling of excavated material from this site will require dirt hauling on the City of Redwood City

streets. Hauling within Redwood City is generally not allowed on weekends or holidays. Hauling is

also generally not allowed before 7:30 am or after 4:00 pm. SVCW has intergovernmental

immunity for local agency permits, however SVCW cooperates with local agencies to minimize

impacts on residents. Due to the close proximity of location to residential areas along Redwood

Shores Parkway and Sand Piper Elementary, additional hauling hour restrictions maybe

appropriate. Hauling could potentially be limited to the hours of 8 am and 1 pm from this site due

to elementary location along the haul route and elementary school hours of 8 am to 2 pm.

A preliminary analysis of the anticipated excavated material handling for this site and anticipated

excavated material quantities for this site is provided below.

Excavated Soil: Approximately 11,120 cubic yard (CY)

Hauling Trucks: 3 average commercial 12.5 loose cubic yard (LCY) dump trucks

Hauling Duration: 27 weeks




Shaft Construction

Potential ultimate disposal site: Ox Mountain Sanitary Landfill or wetland restoration area

Average round-trip haul distance: 28 miles

4.1.5.3 Water Handling, Treatment and Disposal Although an impervious system for the RLS/Flow Splitter Shaft construction will be utilized to

minimize water inflow into the excavation due to the artesian conditions at this site, it is anticipated

some level of water handling and disposal will be required. The anticipated water handling

quantities for this location during shaft construction will be established based on the selected

impervious system and groundwater information which will be included in geotechnical baseline

report for this Gravity Pipeline and utilized for sizing the water handling facilities.

Construction related water, including contaminated groundwater, would be collected and

temporarily stored in baker tank(s) and pumped to the WWTP Plant Storm Water System which is

diverted to the WWTP for treatment, as required by Regional Water Quality Control Board

(RWQCB) regulations. Since this shaft location falls within the boundaries of the drainage footprint

of the WWTP, storm water (which would be diverted away from the shaft excavation) would also

be collected from the shaft staging site during shaft construction and ultimately routed to the

WWTP Plant Storm Water System for treatment.

Water handling facilities at this site are anticipated to include sump pump(s) during shaft

excavation for pumping groundwater inflow from the excavation to the surface, baker tank(s) for

collection of contaminated groundwater and additional pumping equipment to pump/divert water

to the Plant Storm Water System. The Contractor will be responsible for meeting the requirements

of the “REGULATIONS of Silicon Valley Clean Water” (Amended 2005), specifically ARTICLE II,

PROHIBITIONS, in its entirety (Refer to Appendix B) and SVCW Standard Specification Section

01060. Both of the above referenced requirements summarize the specific wastes and discharges

prohibited from entering the sewerage facilities.

Further coordination with SVCW is required during preliminary design to establish potential

allowable discharge flow rates into the WWTP to avoid overloading of the sewerage facilities.

4.1.5.4 Shaft Site Restoration and Permanent Facilities The RLS/Flow Splitter Shaft finish-out including flow channelizing facilities which will be located

within the shaft utilized for TBM removal, lift station facilities and site restoration will be designed

by others as part of the FOP improvements. Preliminary layouts prepared by others indicated the

site restoration will include raising the site elevation and site grading, a permanent frontage wall,

landscaping and trees along the western perimeter of the site, along Radio Road. Other site civil

improvements include, but are not limited to, storm drainage improvements to prevent flooding,

driveway and roadway improvements to create a safe vehicle routing and asphalt concrete (AC)

pavement to provide a drivable, weather proof surface to access and serve the new facilities. The

area around the permanent RLS facilities will receive AC pavement.




Shaft Construction

4.1.5.5 Geotechnical Instrumentation and Monitoring During the shaft excavation operation, it is essential to maintain soil materials and groundwater

conditions outside of the excavation as close to pre-excavation conditions as reasonably possible.

Changes (disturbances) to the in situ conditions surrounding the excavation (soil loss,

lateral/vertical soil movement, drop of groundwater, etc.) could result in detrimental settlement of

structures or utilities supported by the "disturbed" soils. As a result, the initial support system used

during shaft excavation are designed to maintain the in situ pre-excavation conditions by

supporting the soil and keeping the groundwater table at a normal level as possible.

Existing structures, pavements and underground utilities within the influence zone of the shaft

excavation would be monitored during the shaft excavation work. Typically, 150 to 200 feet radius

from the center of the shaft is considered for the influence zone. Further evaluation of the influence

zone will be performed taking into consideration the selected initial support method. In a manner

similar to monitoring performed during tunnel operations, the shaft monitoring will provide timely

warning before excavation related settlement can affect adjacent structures, pavements and

underground utilities. If the recorded movements reach action levels, the Contractor will stop his

operations and modify his shaft excavation methods and procedures to eliminate the unacceptable

ground movements.

Regular periodic recording of instrument readings and data review/evaluation will be specified to

assess ground behavior near shaft excavation.

The proposed location of the RLS Shaft will be in an open field adjacent to Radio Road; this areawill

be paved as part of the completion of construction in the Front-of-Plant area. There are existing

underground utilities, including an 18-inch force main in vicinity of the shaft. There are no existing

structures within the influence zone. Therefore, the monitoring program proposed for the RLS Shaft

excavation would include instruments to measure vertical and lateral ground movements,

settlement of utilities and pavement, and groundwater fluctuations outside of the shaft excavation.

Specifically, the type of instruments required for the Gravity Pipeline will include:

Settlement Indicator Points to measure pavement and utility settlements.

Subsurface Shallow Settlement Indicators to measure settlement of ground near surface.

Inclinometers installed adjacent to the initial shaft supports to measure lateral earth

movements as the shaft excavation progresses.

Control groundwater observation wells installed adjacent to the shaft excavation to

measure groundwater levels.

Prior to commencement of work, a pre-construction survey will be implemented to document the

existing conditions of all pavement structures located entirely or partially within the shaft

excavation influence zone. The pre-construction survey will document condition of pavement

structure to provide baseline data for evaluating construction claims.




Shaft Construction

4.1.6 Recommendations The following criteria were considered in the evaluation of the RLS structure construction methods:

shaft use

size/shape/depth

constructability

soil condition

groundwater levels

shaft construction cost

schedule

A comparison table of the three (3) evaluated initial support methods is presented below.

Table 4-10: RLS Initial Support Methods Comparison

Slurry Wall Secant Piles Caisson

Method well known and utilized in the United States. Competitive bidding expected.

Method well known and utilized in the United States. Competitive bidding expected.

Not common method in the majority of the United States. Further evaluation is recommended.

Median shaft construction duration.

Shortest shaft construction duration. However, additional layer of shotcrete may be necessary to provide required smoothness of the shaft surface for corrosion protection installation, which would affect the duration.

Longest shaft construction duration.

Slurry Wall Secant Piles Caisson

The cost of these methods will depend on the water-sealing element at the shaft bottom. For the comparison cost of the initial support systems refer to Tables 4-8 and 4-9.

Reinforcement can be provided to carry unbalanced lateral pressures.

Sensitive to unbalanced lateral pressures. Additional layer of structural lining may be required.

Reinforcement can be provided to carry unbalanced lateral pressures. Reinforcement can be continuous in both directions.

Relatively smooth walls achievable.

Irregular surface. Provides uniform interior surface of structure.




Shaft Construction

From all three (3) initial support methods evaluated, the slurry walls and caisson are the

recommended options for further evaluation. The secant piles are not recommended since the

system would be reaching its practical limits of installation and would produce the most amount of

infiltration from the three systems evaluated. During the preliminary design, an actual initial

support system will be recommended once the structure configuration is selected.

Two configurations for the RLS Shaft construction are envisioned at this time: figure "8" and two

separate shafts with a connection tunnel near the bottom. These two configurations will be further

evaluated by the PDB.

4.2 Airport Access Shaft

4.2.1 Site Geology The information about general subsurface conditions at the Airport Access Shaft is based on the

Phase I subsurface exploration program performed by Geotechnical Consultants Inc., and its



The existing subsurface conditions at the Airport Access Shaft were developed from two borings at

the proposed shaft location (B-106 and B-110) in addition to in situ field test results performed on

selected soil samples. The maximum boring depth obtained was 84.5 feet below the ground surface.

Following the corrosion protection layer installation, all three initial support methods will offer the same shaft finish.

Some leakage may occur through joints. Grouting of leaks may be required prior placing of the corrosion protection layer.

The most amount of leakage is anticipated due to large number of joints. Additional layer of shotcrete is recommended to enhance the long term impermeability of the system. Grouting of leaks may be also required prior to placing of the corrosion protection layer.

The least amount of leakage is anticipated due to the presence of gaskets or water stops at the joints. Grouting of leaks may be required prior placing of the corrosion protection layer.

Achievable depth of slurry wall can be up to 200 ft. RLS walls are well within the practical range of the system.

Achievable depth of secant piles is approximately 80 ft. Not recommended for extending the system to the Old Bay Deposits for water cut-off as the system would reach approximately 100 feet.

No depth limits.

This method is recommended for further evaluation.

This method is not recommended for further evaluation since the system would be reaching its practical limits of installation and would produce the most amount of infiltration.

This method is recommended for further evaluation.




Shaft Construction

No piezometers were installed at these boring locations and no laboratory tests were performed on

soil samples obtained at this shaft location.

Artificial Fill covers the site to a depth of 5 to 8 feet below the ground surface and consists of clay

and silt with varying amounts of sand/gravel. Varying quantities of organic materials, cobbles and

debris were encountered within the fill. Young Bay Mud underlies the fill with a layer thickness

between 10 and 12 feet. The Young Bay Mud consists of very soft to soft, highly compressible and

plastic, near normally consolidated fat clay. Zones of trace to abundant shell fragments, organic

materials and occasional thin layers of peat (less than a few feet in thickness) are contained within

this layer. Standard Penetration Test (SPT) results ranged from WOR to 4 blows/foot. Pocket

penetrometer field readings indicate an apparent undrained compressive strength of 1,200 psf.

Below the Young Bay Mud, Upper Layered Sediments are encountered with a layer thickness

between 39 and 40 feet. These soil deposits consist of complex alternating layers of lean clay, silty

clay and sandy clay. The thickness, sequencing and consistency of these individual layers are highly

variable. SPT results ranged from 4 to 36 blows/foot. The fine grained materials (silts and clays)

have a generally stiff to very stiff consistency. Pocket penetrometer field readings indicate an

apparent undrained compressive strength ranging from 1,000 to over 5,200 psf.


deepest boring performed at this shaft site, a depth of 84.5 feet below the ground surface. This layer

of marine sediments consists of stiff to hard fat clay and lean to sandy clay with occasional

scattered shell fragments. SPT results ranged from 12 to 50 blows/foot. Pocket penetrometer

readings indicate an apparent undrained compressive strength ranging from 2,000 to 8,000 psf.

Groundwater was not encountered in either of the two borings since the materials penetrated

consist predominantly of fine grained soil materials (silts and clays).

4.2.2 Shaft Excavation 4.2.2.1 Excavation Size and Configuration The Airport Access Shaft would serve as a temporary structure intended to provide enough work

area for the proposed Gravity Pipeline construction. It will serve as the launch location for the TBM.

Selecting the necessary size of this shaft is directly related to the tunnel size, construction activities

within the shaft and the Gravity Pipeline schedule. Based on the latter criteria, it has been

determined that the Airport Access Shaft would be circular, approximately 52 feet deep and 35 feet

in diameter. The criteria for the shaft size selection are as follows:

The maximum excavated tunnel diameter is 15 feet.

Construction activities related to the excavation of the two proposed tunnels (one to WWTP

and another to Inner Bair Island) will be conducted in sequence.

The pipe installation will follow the tunnel completion.




Shaft Construction

A circular shape was selected since it is the most efficient shape for shaft construction. Under

lateral pressures, the predominant force that develops is compression, well resisted by concrete.

Typically, circular shafts provide a stiff continuous support that does not require internal bracing or

toe embedment for shaft wall stability.

It is anticipated that after completion of the gravity sewer, an access structure to the sewer system

will be installed at the shaft location. The details of the structure are covered in Technical

Memorandum No. 5 (TM 5).


be utilized to excavate the materials within the shafts. The excavated muck would be hoisted to the

surface by a crane directly in the clamshell or lifting buckets.

4.2.3 Initial Support 4.2.3.1 Support Methods and Evaluation From five shaft initial support methods selected for the Gravity Pipeline in Section 4 of this

memorandum, four are considered for the Airport Access Shaft construction, namely: slurry walls,

secant piles, CSM and sheet piling. The caisson method was excluded as it is more suitable for

permanent type structures.

A conceptual design was performed for each of the selected support systems to determine the

structural behavior of the systems under estimated loads. The following geological conditions have

been considered in the evaluation of support of shaft excavation: the first 8 feet of the shaft would

be constructed in very soft Artificial Fill, followed by 12 feet of very soft to soft Young Bay Mud,

then 32 feet of stiff to very stiff Upper Layered Sediments.

Slurry walls

Based on the conceptual design, it is anticipated that a minimum 2.5 feet thick reinforced slurry

wall would be required for the Airport Access Shaft (refer to Figure 4-24). A circular shaft

constructed from reinforced concrete slurry wall panels would provide a very rigid initial support,

which would minimize soil movement and settlements during shaft excavation.

The slurry wall would extend to a level of few feet below the invert. The excavation could then

proceed down to the required target depth. A mud slab would be installed at the shaft invert to

provide smooth and firm working surface for tunneling activities taking place in the shaft. In lieu of

steel reinforcement, fiberglass bars will be used at the eye of the tunnel in the slurry wall panels to

allow for TBM penetration. An additional cast in place reinforced concrete wall may be required at

the tunnel eye to resist the breakout forces.

The excavation for the slurry walls can be performed with equipment requiring low overhead

constraint of 21 feet and less; however, the height of the reinforcing cages in one unit (where the




Shaft Construction

reinforcing cages would be preassembled and dropped into the wall in one piece) would be about

55 feet and thus require equipment with an overhead clearance of approximately 80 feet. For the

low overhead clearance requirement, the reinforcing cages can be spliced and installed in several

lifts. This method would increase the cost and duration of installation of the slurry walls. The cost of

the slurry wall system is the most expensive compared to other systems.

Figure 4-24: Slurry Wall Alternative

Secant piles

It has been determined that approximately 3.5 feet diameter unreinforced piles would be required

for the Airport Access Shaft to efficiently resist the circumferential compression in concrete and

accommodate the vertical pile construction deviations (refer to Figure 4-25). The piles would be

unreinforced except for the piles at breakouts, which would have steel shapes or a reinforcing cage

within them. The reinforcing within the pile would not extend for the whole depth of the shaft, but

be localized around the breakout opening. Similarly, to slurry walls, the secant pile wall would

provide very rigid initial support minimizing soil movements and settlements during shaft

excavation.

A mud slab would be installed at the shaft invert to provide smooth and firm working surface for

the tunneling activities taking place in the shaft. Two cast-in-place reinforced concrete breakout

walls would be constructed and connected to the secant pile wall to resist the TBM breakout forces.




Shaft Construction

The secant pile system is commonly used and can be installed with low overhead clearance

requirements of 21 feet and less. It is a relatively low cost option for the construction of the Airport

Access Shaft.

Figure 4-25: Secant Pile Alternative


Two options are envisioned for the CSM system. The first would comprise of a thick wall of CSM

layer with no additional internal support within the wall. The second option would be a

combination of CSM and a layer of shotcrete reinforced with welded wire fabric. For both systems,

the CSM wall would be installed down a few feet below the tunnel invert to anchor the wall and

prevent invert instability.

For the CSM wall alone (Option 1), it is anticipated that a 5-foot thick unreinforced CSM wall would

be required for the Airport Access Shaft to efficiently resist the circumferential compression. The

construction would entail two rings with a combined total thickness of 5 feet (refer to Figure 4-

26).

The second system (Option 2) can be achieved by constructing a double wall system. First, an

approximately 3 foot thick CSM wall ring would be installed followed by an inner layer of reinforced

shotcrete sprayed on the wall of the shaft as the excavation progresses. The overall system results

in a thinner wall (refer to Figure 4-27).




Shaft Construction

The CSM wall would provide a rigid initial support limiting soil movements and settlements. A mud

slab would be installed at the shaft invert to provide smooth and firm working surface for the

tunneling activities taking place in the shaft. Two cast-in-place reinforced concrete breakout walls

would be constructed to resist TBM breakout forces.

The CSM is a commonly used construction method and can be installed with low headroom

requirements of 21 feet and less. However, the equipment available and commonly used in the

United States is approximately 60 foot in height and above. The CSM low overhead equipment had

been used on several overseas projects. Procuring this equipment for this Gravity Pipeline is

optional, however, it could have a negative effect on the shaft construction schedule and cost. In

addition, the CSM shaft construction method it is best suited for granular soils where adequate

strength of the final system is achievable. In the case of the tAirport Access Shaft, where the soils

are mainly clays, the strength of the CSM is less predictable and reliable.

Figure 4-26: Double CSM Ring Alternative – Option 1




Shaft Construction

Figure 4-27: CSM Ring with Reinforced Shotcrete Alternative – Option 2

Sheet piles

It is anticipated that a sheet pile wall with circular rings consisting of wide flange shape ribs or

reinforced concrete beams would be required for the Airport Access Shaft to efficiently resist the

anticipated loads at the shaft site (refer to Figure 4-28). This method of initial support would

require driving steel sheet piles approximately 12 to 15 feet below the shaft invert to provide

sufficient embedment for the system stability. The bracing of the sheet piles would be installed as

the excavation progresses. The sheet piles would be the most flexible shaft initial support method

from all proposed for the Airport Access Shaft construction and would have the larger shaft

excavation influence zone where monitoring would be required.

At the two breakout locations, steel reinforcing members would be installed around the opening to

allow for the sheet piling to be cut or pulled up. To provide stability at the launch eye when the

sheet piling is cut, jet grouting would need to be performed to create a stable soil mass in front of

each TBM breakout location. Two cast-in-place reinforced concrete breakout walls would be

constructed to install a breakout seal.

Over 60 feet of headroom would be required at the Airport Access Shaft to install the sheet piling in

one piece. For low headroom requirements, sheet piles can be spliced and installed in sections. This

would increase the cost and the duration of construction. Sheet pile driving produces a higher level

of noise and vibrations than the other options presented in this memorandum.




Shaft Construction

Figure 4-28: Sheet Piling Alternative

Groundwater Control at Airport Access Shaft

Based on the results of the geotechnical sampling program, no special groundwater control

mitigation at the bottom of the shaft is anticipated at the Airport Access Shaft. The shaft would be

constructed entirely in fine-grained silts and clays generally characterized by low permeability.

However, an impermeable excavation support is recommended since the shaft would be located in

the vicinity of a nearby open water channel (Phelps Slough) and Steinberger Slough. Even with an

impermeable support system, a small amount of water can be expected at the bottom of the shaft

due to infiltration; the water would be pumped out as it accumulates.


Relative comparison costs for the Airport Access Shaft impermeable system options are shown in

Table 4-11. The costs were developed in 2015 prices. Mark-ups of 25 percent for indirect costs and

15 percent for overhead and profit are included in the costs. The costs do not include contingency

and escalation. Refer to Appendix A.




Shaft Construction

Table 4-11: Airport Access Shaft Initial Support Cost Comparison

Initial Support Method Initial Support Cost (Millions)

Slurry Walls $2.9

Secant Piles $2.6

CSM $2.7

Sheet Piling $2.4

4.2.4 Site Conditions The Airport Access Shaft site is located north of the Shoreway Road and Redwood Shores Parkway

(Holly Street) intersection, in Redwood City. This site will serve as the TBM launching location and

primary staging area for tunnel construction as well as staging area for the San Carlos Drop Shaft,

which has limited construction area.

4.2.4.1 Site Ingress and Egress Access to the Airport Access Shaft site would be provided from Shoreway Road. The site location

and ingress and egress to/from the site from Highway 101 and surrounding areas is shown in

Figure 4-29, below.




Shaft Construction

Figure 4-29: Airport Access Shaft Site Ingress and Egress



in Section 4.2.4.3.

4.2.4.2 Existing Site Conditions The existing ground surface at the Airport Access Shaft staging area is mostly undeveloped dirt with

dense tree and bush coverage along the property boundary, particularly on the eastern side of the

site. There is a swale (approximately 1-2 ft deep) parallel to Shoreway Road near the eastern edge

of the site. There is a 14-inch drainage culvert across the proposed site entrance. The site is gently

undulating with a ridge along the site from north to south and generally slopes east and west from

the ridge along the Airport Access Shaft of the site. An open drainage channel borders the western

edge of the site.

WRA Environmental Consultants recently performed jurisdictional wetland delineation of the

proposed shaft site area and the northern, western and eastern areas surrounding the site. The

purpose of the delineation was to determine the presence and extent of wetlands and waters

potentially subject to jurisdiction by the U.S Army Corps of Engineers (ACE), Regional Water Quality





Shaft Construction

Control Board (RWQCB) or California Department of Fish and Wildlife (CDFW). The study area

encompassed approximately 18.96 acres. The draft delineation map of the area (provided in

Appendix C) identifies wetland areas on the northern, western and eastern boundaries of the

proposed staging area. In addition, a small area (approximately 0.06 acres) of jurisdictional waters

was identified within the drainage easement bordering the northeast site boundary.

There are existing overhead power lines and power poles located across the extents of the site from

northwest to southeast. Based upon communication with Beecher Engineering staff (working on

PG&E permit for this location), the overhead power wires include primary conductors with nominal

voltage up to 12 kilovolts (kV).

A 66-inch reinforced concrete pipe (RCP) storm drain is located beyond the southeast side of the

site draining to a natural drainage channel along the east side. This storm drain is connected to a

culvert with a headwall located at the edge of the sidewalk. This culvert drains water collected from

the Phelps Slough located on the east side of Redwood Shores Parkway. Another 66-inch RCP

storm drain is located near the northern border of the site. This storm drain collects water from

the open drainage channel and storm drain facilities along Twin Dolphin Road. In addition to

power and drainage facilities, various communication facilities exists outside of the staging limits in

the sidewalk within public right-of way along Redwood Shores Parkway.

4.2.4.3 Staging Area Requirements The Airport Access Shaft site staging area is planned to accommodate staging for construction

activities associated with the 42-foot OD (35-foot ID) TBM Airport Access Shaft launch shaft, 15-

foot OD tunnel and carrier pipe and the 15 to 20-foot outside diameter shaft at San Carlos. The

TBM launch shaft will be constructed first, prior to tunnel construction. The San Carlos Drop Shaft

will is expected to be constructed concurrently with the tunnel. It is conservative to plan the

staging area assuming the Gravity Pipeline and the San Carlos Drop Shaft will be constructed at the

same time.

Prior to construction, the staging area would be cleared of trees, vegetation, and groundcover. The

staging area perimeter would be fenced with a 6-foot high security fence to prevent unauthorized

access and enhance the safety of the public. A surface layer of base rock or gravel would be installed

to provide a working surface for construction activities and a stabilized construction entrance

would be installed at the site entrance/exit to reduce the tracking of construction mud and dirt

onto public roads by construction vehicles.

The staging area would accommodate construction trailers, locker room(s), 2-week muck storage,

2-week ring segment/pipe storage, storage box, fuel storage area, grout material storage area,

topman house (tunnel staff enclosure/shelter), electric substation, air supplies, warehouse, first aid

station, polymer storage area for grout additives used in stabilizing soil ahead of tunnel excavation,

and parking area in front of the trailers. The required area for excavated material storage is

discussed in Section 4.2.5.2. The site staging area plan is shown in Figure 4-30.

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K/J 1568063.02

February 2017

OPEN CHANNEL EASEMENT

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DIA. TUNNEL

STAGING AREA

LEGEND

OWNER/CM TRAILER

CONTRACTOR TRAILERS

LOCKER ROOM

JOB PARKING

MIDDLE OUT/SAN CARLOS SHAFT -

2 WEEKS MUCK STORAGE (486'X112.5')

2 WEEKS SEGMENT/PIPE STORAGE (487'X69')

ENTRY/EXIT GATE

STORAGE BOXES

FUEL STORAGE

GROUT MATERIAL STORAGE

TOP MAN HOUSE

SAN CARLOS

STAGING AREA

AIRPORT ACCESS SHAFT STAGING AREA - PLAN

Approx. 6.3 ac

ANTICIPATED CRANE

LOCATION ZONE

AIRPORT ACCESS SHAFT - SITE STAGING PLAN

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1"=100'

0 100 200

FIGURE 4-30

POWER POLE SAFETY

BUFFER (TYP)

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FAA AIRSPACE PROTECTION

SURFACES (SEE NOTES)

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FAA AIRSPACE PROTECTION NOTES:

1. AIRSPACE PROTECTION SURFACE ELEVATIONS ON THIS EXHIBIT ARE EXPRESSED IN FEET

ABOVE MEAN SEA LEVEL (MSL). THE ELEVATION OF SAN CARLOS AIRPORT IS 5 FEET MSL.

2. LOCATIONS WHERE THE GROUND/TERRAIN PENETRATES THE FAR PART 77 AIRSPACE

SURFACES ARE APPROXIMATE AND WERE DEVELOPED USING ALUCP EXHIBIT 4-4 WHICH

UTILIZED GROUND ELEVATION CONTOURS PROVIDED BY THE SAN MATEO COUNTY

PLANNING AND BUILDING DEPARTMENT 2014.

3. SOURCE: SAN CARLOS AIRPORT ALUCP, EXHIBIT 4-4 (ESRI, 2014; SAN MATEO COUNTY

PLANNING AND BUILDING DEPARTMENT, 2014; ESA AIRPORTS, 2014).

35' INSIDE DIA. AIRPORT

ACCESS SHAFT

L

FAA AIRSPACE PROTECTION

SURFACES (SEE NOTES)

ELECTRIC SUBSTATION

AIR SUPPLIES/COMPRESSOR

WAREHOUSE

FIRST AID

SECURITY SHACK

POLYMERS STORAGE

WATER TREATMENT FACILITIES

RESTROOM FACILITIES

INGRESS/EGRESS ROUTE TO HWY 101

STABILIZED CONSTRUCTION ENTRANCE

VEHICLE TYPE: WB-50

12

13

15

16

14

19

18

20

22

21

17

WETLANDS

WETLANDS

WETLANDS

SURVEYED PERMIT

AGREEMENT

BOUNDARY

TEMPORARY

POWER DROP

AND METER




Shaft Construction

Approximately 6.4 acres of staging area within airport property (airport permitted area) is planned

for the Airport Access Shaft site location. An additional area of approximately 0.1 acres of

construction area is anticipated within public right-of-way due to the proximity of the Airport

Access Shaft to the adjacent right-of-way. Pedestrian protection along the sidewalk on Redwood

Shores Parkway, near the shaft, may be required.

The following have been considered in developing the staging area requirements:

Tunnel Excavation Rate: Approximately 100 feet per day

Design Vehicle Type: WB-50 (semi- trailer combination)


Location of adjacent wetland boundaries

Additional storage area for San Carlos Drop Shaft construction

Site access from public right-of-way

The WB-50 design vehicle type selected for this site has similar wheel base dimensions to standard

lowboy tractor trailer combinations anticipated for in use in delivery pipe and other construction

material and equipment to the site.

It should be noted that additional survey and staging area refinement will be needed during design

to confirm that the area permitted by the San Carlos Airport will not include any wetland, drainage

easement or street right of way areas.

4.2.4.4 San Carlos Airport and Federal Aviation Administration Considerations The Airport Access Shaft staging area is located within the San Carlos Airport (SCA) Inner

Approach/Departure Zone. In addition, the staging area for this site also encroaches into the

Runway Protection Zone. Refer to TM No. 1, Appendix A (Exhibit 4-3) for SCA safety zones.

Airspace protection surfaces are imaginary surfaces in the airspace surrounding airports defined in

accordance with criteria set forth in 14 Code of Federal Regulations, Part 77, Subpart C. Except as

noted below in items 1-3, no structure or object, including a temporary object such as a

construction crane, shall have a height that would result in penetration of any of the airspace

protection surfaces. Any object that penetrates one of these surfaces is, by Federal Aviation

Administration (FAA) definition, an obstruction. A proposed structure or object having a height

that exceeds the airspace protection surfaces for San Carlos Airport is compatible with the airspace

protection goals if all of the following apply:

1. As the result of an aeronautical study, the FAA determines the object would not be a hazard

to air navigation; and

2. FAA or the airport operator concludes that, despite being an airspace obstruction (not

necessarily a hazard), the object would not cause any of the following:

An increase in the ceiling or visibility minimums at San Carlos Airport for an existing or

planned instrument procedure;




Shaft Construction

A diminution of the established operational efficiency of the airport, such as by causing

the usable length of the runway to be reduced;

Conflict with the visual flight rules (VFR) airspace used for the airport traffic pattern or

en route navigation to and from San Carlos Airport.

3. Marking or lighting of the structure/object is installed as directed by the FAA aeronautical

study or the Division of Aeronautics and in a manner consistent with FAA standards in

effect at the time the construction is proposed.

FAA Airspace protection surfaces across the site staging area are shown Figure 4-30. The staging

area is primarily located within 55-foot to 105-foot airspace protection elevation contours. It

should be noted these contour elevations represent an elevation in feet above mean sea level.

Based upon the location of these contours across the staging area, the estimated protection surface

elevation above the existing site grade elevation near the shaft construction area is estimated to be

62–81 feet above grade. Refer to Table 4-12 for additional information. The crane used for

construction of the shaft and lowering the TBM into the shaft is anticipated to be up to

approximately 80 feet in height, encroaching in the protection surface elevation. However, a

smaller crane could be used for lowering the TBM if it is lowered into the shaft in smaller segments.

The lifting system such as a smaller crane or electric gantry over the shaft for use during tunneling

activities and pipe installation at this location is anticipated to be approximately 50-feet in height.

Table 4-12: Airport Access Shaft Site Airspace Protection Height Restrictions

Notes:

(a) Heights are based upon SCA Part 77 Airspace Protection Surfaces, SCA 2015 ALUCP Exhibit 4-4. Height represents

lowest height within the preliminary anticipated crane working zone.

(b) Based upon preliminary site elevations using Gravity Pipeline vertical datum of NGVD 29 + 100 feet. Grade elevation

relative to MSL was determined by subtracting 100 feet from the preliminary site elevations.

Proposed construction at this location is subject to review and approval by the Federal Aviation

Administration (FAA) (as administered by the SCA) and requires a Federal Aviation Administration

Form 7460-1 be submitted. Specific FAA requirements and conditions associated with the

proposed construction and anticipated crane height encroachment into the in the FAA jurisdictional

areas for the site would be included in the Notice of Determination by the FAA.

4.2.4.5 Utility Requirements The Contractor would be required to provide temporary facilities, including but not limited to,

power, lighting, water, sanitation services, heating and ventilation, communication facilities and

other utilities needed for the construction and the Contractor’s construction trailer at the site. The

nearest fire hydrants to the Airport Access Shaft site are located approximately 400 to 700 feet

Site Height Restriction

(Feet Above MSL)(a)

Grade Elevation (relative to

MSL)(b)

Estimated Height Limit Above Existing Grade

Elevation

Airport Access Shaft 66 – 85 4 62 -81




Shaft Construction

north and northeast of the site along Twin Dolphin Drive. There is a waterline located along

Redwood Shores Parkway. Use of this waterline for temporary potable water service during

construction would require tapping into the waterline and constructing temporary facilities across

Redwood Shores Parkway. The nearest sanitary sewer is also located along Twin Dolphin Drive.

The electrical line power requirement for this site is expected to be 4160V electrical line power.

The estimated electrical line power requirement is based on the estimated electrical power

requirements during tunneling of approximately 3,000 kilowatts and ancillary power requirements

for water handling, construction trailers, site lighting. Based upon previous team discussions

regarding temporary power at the Airport Access Shaft location, PG&E has confirmed the required

temporary power for tunnel boring machine (TBM) operations can be provided at this location

from the existing power lines that cross the site.

The existing overhead power lines across the site have been confirmed to be 12kV. The California

Division of Occupational Safety and Health (Cal/OSHA) regulations require minimum safe working

and traveling distances be maintained from cranes to overhead electric lines which are often more

stringent than PG&E clearance requirements.

Tables 1-2 and 1-3 included in PG&E’s Green Book note the minimum Cal/OSHA safe working

distances from 0.6 kV to 50 kV nominal voltage conductors are as follows:

Boom-type lifting or hoisting equipment: 10 feet

Scaffolds, equipment, tools, structures, and people: 6 feet

Based upon review of Cal/OSHA clearance requirements for nominal voltage conductors less than

50kV, anticipated crane operating area, anticipated crane height, and surveyed location of the

onsite power poles and overhead power lines, relocation of the power poles and overhead power

lines is not required to meet clearance requirements.

Relocation of power poles and associated overhead power lines is not anticipated at this site. The

staging area provides sufficient area for the Contractor to work around. Should the Contractor

choose to relocate existing power poles and associated power lines, he/she will be required

responsible for relocation. A temporary service drop and meter would be provided near the

southwest corner of the site, adjacent to the existing power pole. Refer to Figure 4-30.

4.2.4.6 Long Term Operation and Maintenance Requirements The anticipated long-term operation and maintenance requirements at the Airport Access Shaft

location may include infrequent manhole inspections. Should inspection of the tunnel using

advanced technologies (such as sonar) be required after the gravity line is in service, the Airport

Access Shaft site would likely be used for access and inspection due to its central location along the

alignment. Both a bolted on lower flanged cover close to the tunnel and an upper cover at the

surface are recommended to avoid sewer gasses collecting in the access shaft. At a minimum, a




Shaft Construction

large corrosion resistance double door hatch (Bilco type) or 48-inch manhole frame and cover

access for lowering equipment and people access are recommended for this shaft site.


4.2.5.1 Mobilization Mobilization will include all activities for transportation of contractor's personnel, equipment, and

operating supplies to the Airport Access Shaft staging site necessary for shaft construction. It will

also comprise of the installation of field offices, laboratories, fencing, gates, utilities and other

necessary general facilities for the contractor's operations at the site. For more details on the

Airport Access Shaft staging area, refer to the "Staging Area Requirements" section above. The

mobilization will also consist of obtaining by the contractor all required insurance, bonds and

permits.

4.2.5.2 Excavated Material Handling All excavated material (muck) from Airport Access Shaft construction and overall tunneling

activities for the Gravity Pipeline (approximately 17,600 lineal feet of 15’ OD diameter tunnel)

would be handled at the Airport Access Shaft site location. Excavation of the tunnel includes

removal of the excavated material from the tunnel by use of a conveyor system or muck cars pulled

by a locomotive on rails installed as the tunnel advances. Once the excavated material is brought to

the surface at the Airport Access Shaft location, it would be temporarily stockpiled onsite for

loading and off-site hauling and disposal at a suitable disposal site in accordance with applicable

federal, state and local regulations. In addition, excavated material from the San Carlos Drop Shaft

excavation may be hauled to this location for ultimate off-site hauling and disposal.

Excavated material that cannot be hauled away during the permitted hauling hours each day would

be stored onsite for hauling on the following work day. A staging area for onsite storage of

approximately two (2) weeks of excavated material associated with tunnel production at an

excavation rate of 100 LF is planned for this site based on the preliminary site staging layout and

average 5-foot high stockpiles. Onsite storage for excavated materials stockpiling at this location

would encompass an area of approximately 1.3 acres.

Similar to all excavated material for the Gravity Pipeline, the material would need to be sampled

and analyzed to characterize the soil and determine if there is any soil contamination. Soil

characterization is necessary to confirm the disposal classification for off haul, prior to offsite

disposal or re-use. Acceptance of the soil at a landfill will depend upon overall disposal quantity

and soil characterization and or contamination. Non-contaminated and contaminated material

would be subjected to the profiling requirements of the disposal facility. Ox Mountain Sanitary

Landfill, located in Half Moon Bay, is the closest landfill that accepts this type of construction

excavated material. Ultimately, the Contractor will identify the excavated material disposal

location(s) and/or potential areas for re-use (such as wetland restoration projects).




Shaft Construction

Similar to the excavated material from the RLS/Flow Splitter Shaft site, excavated material from

this site will require dirt hauling on the City of Redwood City streets. Based upon the general

Redwood City hauling permit application, hauling within Redwood City is not allowed on weekends

or holidays and hauling is also not allowed before 7:30 am or after 4:00 pm. While SVCW has

intergovernmental immunity and is not required to obtain a permit for dirt hauling, SVCW will

review dirt hauling activities with Redwood City and include appropriate requirements for the

contractor to minimize impacts on the public.


excavated material quantities to be handled at this site is provided in Table 4-13 below.

Table 4-13: Summary of Airport Access Shaft Site Excavated Material Handling

4.2.5.3 Water Handling, Treatment and Disposal

Based on the Phase I subsurface exploration program performed by Geotechnical Consultants Inc.,

and its findings presented in the "Preliminary Characterization of Subsurface Conditions" Technical

Memorandum dated December 9, 2015, large quantities of inflow into the shaft excavation during

shaft construction are not anticipated due to the site geology. However, it is anticipated that water

handling and disposal will be required at this site during construction. Additional groundwater

monitoring information for the Gravity Pipeline will continue to be collected as part of the

geotechnical efforts and will be included in geotechnical baseline report for this Gravity Pipeline.

The information will be considered in sizing the water handling facilities during preliminary and

final design.

Groundwater encountered during the construction of the Airport Access Shaft would be pumped

from the excavation to the surface utilizing sump pumps for treatment. Groundwater encountered

during tunneling would also be collected at the Airport Access Shaft location. The vertical tunnel

alignment from the Bair Island Inlet Structure Shaft location to the Airport Access Shaft location

slopes toward the Airport Access Shaft location. It is anticipated that water from within the tunnel

Component Airport Access

Shaft Construction

Tunneling Component

San Carlos Drop Shaft Construction

Estimated Excavated Material Quantity (LCY)

3,000 149,690 720

Hauling Trucks 3 8 1

Hauling Duration (weeks) 4 75 3

Average Round-Trip Haul Distance (miles)

24 24 24

Potential Disposal Site Ox Mountain Sanitary Landfill / Wetland Restoration Project Areas




Shaft Construction

would flow at the tunnel invert to a sump location at the Airport Access Shaft and would be pumped

to the surface for temporary containment, treatment and disposal. The vertical alignment from the

Airport Access Shaft site to Flow Splitter Shaft slopes away from the Airport Access Shaft location to

the Flow Splitter Shaft. Water from the tunnel along this tunnel alignment would be captured

within the tunnel and pumped to the Airport Access Shaft location for temporary containment,

treatment and disposal.

Preliminary water infiltration estimates based on three (3) times the typical allowable leakage

criteria for final tunnel and shaft lining are provided below. This information will be refined by the

PDB.

Tunnel: 1.5-2 gallons per minute per 1,000 linear feet of tunnel (1.5-2 gpm/1,000 LF)

Shafts: 3 gpm

The groundwater infiltration from the tunnel and shafts would be cumulative over the length of the

tunnel. Based upon the preliminary estimates noted above, water flow to the Airport Access Shaft

would be approximately 40 gallons per minute (gpm) or approximately 55,000 gallons per day

(GPD).

Construction activities involving water management are regulated under the National Pollutant

Discharge Elimination System (NPDES) General Permit for Storm Water Discharges Associated with

Construction and Land Disturbances Activities (State Water Resources Control Board [SWRCB]

Order No. 2009-0009-DWQ, NPDES Permit No. CAS000002, and subsequent amendments generally

referred to as the General Permit [GP]). For this Project, the San Francisco RWQCB enforces the

General Permit. Coverage under a General Permit requires the submission to the SWRCB of the

Permit Registration Documents (PRDs) and receipt from the SWRCB of a Waste Discharge

Identification Number (WDID) for the Project.

Options for disposal of construction water include discharge to the storm drain, Redwood City’s

sanitary system or hauling offsite for deposal at a permitted facility. If construction water meets

the RWQCB water quality standards including effluent limitations and monitoring requirements it

may be discharged into the storm drain as allowed by the General Permit. Otherwise, the water

would be treated to concentration levels acceptable for discharge to the sanitary sewer. Non-

contaminated water that does not exceed the criteria set forth by Redwood City could potentially be

discharged into the sanitary sewer system. Prior to discharging into Redwood City’s sanitary sewer

collection system, the Contractor would be required to acquire a sewer discharge permit from

Redwood City. Coordination with Redwood City is required to determine the specific wastes and

discharges prohibited from entering the sewerage facilities.

Water handling facilities at this site are anticipated to include sump pump(s) for pumping

groundwater inflow from the Airport Access Shaft excavation to the surface, temporary

containment facilities and control measures such as sediment traps, sediment basin or Baker tank

to remove settleable solids prior to discharge to the storm drain system and/or sewer facility, and




Shaft Construction

additional pumping equipment as necessary to pump/divert water adjacent storm drain system or

sewer facility. The need for additional treatment of the water prior to discharge would depend

upon water quality limitations at the proposed discharge location.

Contaminated water that cannot be treated onsite would require offsite transportation and offsite

disposal at a properly permitted treatment facility.

Requirements for discharge to the adjacent storm drain facilities at the Airport Access Shaft

location as well as Redwood City sanitary sewer facilities will be investigated further as the design

progresses.

4.2.5.4 Shaft Site Restoration and Permanent Facilities The shaft site construction staging area restoration would include site clean-up and re-grading of

the site to restore site slopes and drainage patterns and re-vegetation to grades near the original

grade unless otherwise approved by the landowner. Drainage would be restored towards the open

drainage facility located to the west and the wetlands located to the north and west of the site. The

constructions staging be would be re-vegetated or left as base as determined by the landowner.

Permanent facilities would include surface expression of the finished shaft manhole access

openings, including H-20 traffic rated access hatches or similar large equipment access opening and

H-20 traffic rated manhole frame and covers. These surface openings would be 3-6 inches above the

finished grade, and the area surrounding the manhole would be graded away from the openings.

The elevation will need to be confirmed with the landowner by SVCW.

4.2.5.5 Geotechnical Instrumentation and Monitoring The proposed location of the Airport Access Shaft will be in an open field adjacent to Holly Street

and Shoreway Road, which are both paved. It is expected that Holly Street may contain subsurface

utilities. There are also existing utility poles within the influence zone of the shaft. Considering the

fact, that there are no buildings in the close proximity of the shaft, the influence zone would extend

about 150 feet in order to monitor two roadways, Redwood Shores Parkway and the Airport Way

and their intersection. Further evaluation of the influence zone will be performed, taking into

consideration the selected initial support method.

The monitoring program proposed for the Airport Access Shaft excavation would include

instruments to measure vertical and lateral ground movements, settlement of utilities and tilting of

utility poles. Specifically, the type of instruments required for the project will include:


Subsurface Shallow Settlement Indicators to measure settlement of ground near surface.

Tiltmeters to measure rotational movement of utility poles.


movements as the shaft excavation progress.




Shaft Construction


existing conditions of all pavement structures and utility poles located entirely or partially within

the shaft excavation influence zone. The pre-construction survey will document condition of

pavement structures to provide a baseline data for evaluating construction claims.

4.2.6 Recommendations The following criteria were considered in evaluation of the Airport Access Shaft construction

methods:

shaft use

soil condition

groundwater levels

shaft construction cost

schedule

site restrictions such as airspace protection height limits

A comparison table of the four (4) initial support methods evaluated is presented below.

Table 4-14: Airport Access Shaft Initial Support Methods Comparison

Slurry Wall Secant Piles CSM Sheet Piling

Can be installed with

equipment meeting the FAA

height restriction of 62 feet.

However, the installation of

reinforcing cages in one unit

would require an

approximately 80-foot high

crane. The reinforcing cages

can be spliced vertically as

they are installed, but that

would be time consuming and

more costly.

Can be installed

with equipment

meeting the FAA

height restriction

of 62 feet.

Can be installed with

equipment meeting the

FAA height restriction of

62 feet. However, the

equipment has not been

used in United States yet

and procuring it may

impact the schedule and

cost of the shaft

construction.

Over 60 feet of

headroom would be

required to drive the

sheet piling in one

piece. The sheet

piling could be

installed in sections;

however, that would

increase the cost

and construction

duration.

Longest construction duration. Median

construction

duration.

Construction duration similar

to slurry walls.

Shortest construction

duration.




Shaft Construction

For the Airport Access Shaft, it is recommended to use secant piles as the best suited construction

method. It will provide a relatively rigid support which will limit soil movements and settlements.

Although, the Airport Access Shaft is a temporary structure, the initial support method needs to be

sufficiently durable for the time span of construction. The shaft will be the center of all tunneling

activities. The utilization of secant piles fulfills this requirement. Upon completion, the shaft would

be backfilled, therefore, the most robust structure is not warranted. In addition, the shaft can be

constructed utilizing equipment not encroaching the FAA height restrictions, and not producing

significant construction noise and vibration.

$3.3 million construction

cost.

$3.0 million

construction cost.

$3.1 million construction

cost.

$2.8 million

construction cost.

Slurry Wall Secant Piles CSM Sheet Piling

Low construction site noise

and vibration level.

Low

construction site

noise and

vibration level.

Low construction site noise

and vibration level.

Significantly higher

level of noise and

vibrations than the

other options.

Robust initial support. Rigid structure. The soils at the Airport

Access Shaft are mainly

clay. Mixing clay with

cement will produce walls

with significantly lower

strength than slurry wall or

secant piles. Also, the

strength of the CSM is less

predictable and reliable.

Very thick walls (min. 5

feet) or additional

shotcrete layer would be

required.

Most flexible initial

support from all

proposed. This is

the only option

which would

require installation

of internal bracing.




Shaft Construction

4.3 San Carlos Drop Shaft

4.3.1 Site Geology The information about general subsurface conditions at the San Carlos Drop Shaft is based on the

Phase I subsurface exploration program performed by Geotechnical Consultants Inc., and its



The existing subsurface conditions at the San Carlos Drop Shaft were developed from three borings

made at the proposed shaft location (B-107, B-111Pd and B-111Ps) in addition to in situ field and

laboratory test results performed on selected soil samples. The maximum boring depth obtained

was 71.5 feet below the ground surface. Piezometers were installed at boring locations B-111Pd

and B-111Ps.

Artificial Fill covers the site to a depth of 5 feet below the ground surface and consists of clay and

silt with varying amounts of sand/gravel. Varying quantities of organic materials, cobbles and

debris may be encountered within the fill. Young Bay Mud underlies the fill with a layer thickness of

12 to 18 feet. The Young Bay Mud consists of very soft to soft, highly compressible and plastic, near

normally consolidated fat clay. Zones of trace to abundant shell fragments, organic materials and

occasional thin layers of peat (less than a few feet in thickness) are contained within this layer.

Standard Penetration Test (SPT) results ranged from WOR to 10 blows/foot. Pocket penetrometer

field readings indicate an apparent undrained compressive strength of 900 to 2,100 psf.

Below the Young Bay Mud, Upper Layered Sediments are encountered with a layer thickness

between 48 and 51 feet. These soil deposits consist of complex alternating layers of lean clay, fat

clay, silty clay and silty sand, and sandy silt. The thickness, sequencing and consistency of these

individual layers are highly variable. SPT results ranged from 8 to 49 blows/foot. The fine grained

materials (silts and clays) have a generally stiff to hard consistency. Pocket penetrometer field

readings indicate an apparent undrained compressive strength ranging from 2,000 to over 9,400

psf.


deepest boring performed at this shaft site, a depth of 71.5 feet below the ground surface. This layer

of marine sediments consists of stiff to very stiff fat clay and lean clay with occasional scattered

shell fragments. SPT results ranged from 3 to 21 blows/foot. Pocket penetrometer readings indicate

an apparent undrained compressive strength of 2,800 psf.

Groundwater was encountered in boring B-111Ps at a depth of 13 feet below the ground surface

during boring operations. In addition, two water-bearing layers were encountered at depths of 16

feet and at 64 to 68 feet below the ground surface. Groundwater level readings in the installed

piezometers indicated that both of these layers have low permeability and are of limited extent.

Also, the water level readings (6.6 feet below ground surface) indicate that the upper layer may be




Shaft Construction

unconfined and hydraulically connected to the Young Bay Mud deposit. The lower layer readings

(5.2 feet below ground surface) appear to be confined by the overlying thick layer of clay deposits.

4.3.2 Shaft Excavation

4.3.2.1 Excavation Size and Configuration The San Carlos Drop Shaft would be approximately 52-feet deep and 15 to 20-feet in diameter. The

centerline of the shaft will be offset approximately 20-feet from the centerline of the tunnel. A short

tunnel called an “adit” will be constructed to provide a connection between the shaft and the main

tunnel. The shaft will serve as a work area for the adit construction and provide sufficient space to

install a drop structure within the shaft. The size of the shaft will be selected based on the required

size of the drop structure and construction activities related to the adit construction. Details of the

drop structure are covered in TM No. 5 – Shaft Connections.

The optimal configuration for the San Carlos Drop Shaft would be circular in shape as it is the most

efficient in resisting the anticipated lateral loads. Circular shafts provide a rigid continuous support

and do not require internal bracing or toe embedment for stability. The adit could be constructed at

60 to 90 degrees angle to facilitate flow into the tunnel. The recommended angle is discussed in TM

No. 5.




4.3.3 Initial Support

4.3.3.1 Support Methods and Evaluation Based on the soil conditions, site restrictions such as the FAA height limitation of 21 feet, the close

proximity of the existing 48-inch diameter force main and very limited staging area, only two initial

support methods were considered for the construction of the San Carlos Drop Shaft; the CSM and

caisson. Slurry walls, secant piles and sheet piling were excluded from the evaluation due to several

reasons. The slurry wall would require a utilization of a slurry separation plant and the compact

size of the site would not provide sufficient room for the plant. In addition, slurry walls would

require the installation of reinforcing cages which would require approximately 80 feet of

headroom clearance. Even though splicing of the reinforcement could be utilized, it would be

unpractical, costly and time consuming. The secant piles option would require slurry separation

plant on the site, similarly to the slurry walls or the placement of a temporary casing in the pile hole

to ensure the stability of the drilled hole before the tremie concrete is placed. The height limitation

and available space restriction make the slurry walls and secant piles options unfavorable and not

suitable for the San Carlos Drop Shaft construction. As for the sheet piling, driving of piles in close

proximity to existing utilities and buildings would be prohibited due to noise and vibrations

produced during installation.




Shaft Construction

In the area where the adit will be constructed and connected to the tunnel, a soil improvement zone

would be required to stabilize the ground and allow for the adit excavation (refer to Figure 4-31

and 4-32). Two options are considered for the ground improvement: the CSM and jet grouting. The

ground improvement using either method would minimize water inflow during excavation and

enhance the stand-up time providing stable working conditions during adit excavation.

Hand tunneling will be utilized for the construction of the adit and its connection to the tunnel. This

method is typically performed by tunnel miners using compact equipment or hand tools to excavate

the soils. It is envisioned that the adit would be a modified horseshoe shape. A sequential

excavation method could be utilized for the construction of the adit and the adit to tunnel

connection. This approach would involve dividing the adit cross section into two areas: heading and

bench. The heading would be excavated first. Reinforced shotcrete would then be installed to

provide excavation support. After the heading is completed, the bench would be constructed. This

method would minimize the stresses in the ground around the opening. The need for implementing

this method will depend on the size of the adit and will be evaluated further during the design stage

of the project.

A mud slab will be installed at the shaft invert to provide a smooth and firm working surface for

adit construction activities taking place in the shaft. A breakout for the adit in the shaft wall will be

designed and the walls will be strengthened with additional reinforcement to efficiently resist the

breakout forces developed in the shaft.

CSM

The CSM method would consist of mixing cement with native soil to create a relatively impermeable

and stable zone as shown in Figure 4-31. A layer of reinforced shotcrete, approximately 9 to 12

inches thick, will be installed as the shaft excavation progresses to provide structural stability of the

system.

The CSM could be also used for the ground improvement around the adit and adit to tunnel

connection. The soil improvement would be constructed prior to excavation of the tunnel and shaft.

The strength of the zone would be designed to allow for the soft ground TBM to mine through this

zone and allow for the construction of the adit and adit to tunnel connection.

The CSM method is the more suitable and cost efficient initial support system for the San Carlos

Drop Shaft. The same equipment could be utilized to construct both the shaft and the soil

improvement, saving cost and time on mobilization of a new system. However, the equipment

available and commonly used in the United States for CSM wall at the depth of this shaft is

approximately 70 feet high. This exceeds the FAA height restriction of 21 feet (refer to section

4.3.5.4 for the FAA height restrictions). Low overhead CSM equipment had been used on several

overseas project. Procuring this equipment for this project is possible, however it could have a

negative impact on the shaft construction schedule and cost.




Shaft Construction

Figure 4-31: CSM Alternative

Caisson

It is envisioned that approximately 1'-6" reinforced concrete wall would be required to effectively

resist the forces on the caisson shaft. The shaft lining could be precast or cast in place, constructed

at the surface at the location of the proposed shaft wall, in vertical sections, and then lowered into

the ground as excavation progresses. The caisson can be installed using a gantry or small crane,

both with low height under 21 feet. The caisson construction would start with an excavation of the

shaft area to a depth of few feet and the installation of a cast-in-place concrete collar. The collar

would provide support for the surcharge load at the surface, resist the forces from hydraulic jacks,

and act as a guide for shaft sinking.

In the area where the adit will be constructed to connect the shaft and the tunnel, a soil

improvement zone is required to stabilize the ground and to allow for the construction of the adit

(Refer to Figure 4-32). It is anticipated that with the Caisson shaft construction method, jet

grouting soil improvement would be utilized. Jet grouting can be performed from the surface or

from the shaft after the shaft is constructed. If performed from the surface, the equipment for jet

grouting is available in heights within the 21-foot restriction, but adding stems (splicing the

sections) would be required. For jet grouting from the shaft, the equipment can be placed within

the excavation, therefore not encroaching on the height mandated by the FAA.




Shaft Construction

Figure 4-32: Caisson Alternative

Comparison Cost

Relative comparison costs for the San Carlos Drop Shaft impermeable system options are shown in

Table 4-15. The costs were developed in 2015 prices. Mark-ups of 25 percent for indirect costs and

15 percent for overhead and profit are included in the costs. The costs do not include contingency

and escalation. Refer to Appendix A.

Table 4-15: San Carlos Drop Shaft Initial Support Cost Comparison

Initial Support Method

Initial Support Cost + Soil

Improvement

(Millions)

CSM $2.2

Caisson $2.6

4.3.4 Groundwater Control at San Carlos Drop Shaft No special groundwater mitigation at the bottom of the shaft is expected at the San Carlos Drop

Shaft location. The CSM soil improvement implemented at the shaft site would allow for relatively

dry excavation.




Shaft Construction

4.3.5 Site Conditions The San Carlos Drop Shaft site is located at the northwest end of Monte Vista Drive adjacent to the

San Carlos Airport in the City of San Carlos on the San Carlos Pump Station (SCPS) property, owned

by the City of San Carlos. This site will serve as the construction area for the San Carlos Drop Shaft.

This shaft will be used to construct an adit to the tunnel and ultimately to connect and divert

Belmont and San Carlos wastewater flow to the proposed gravity pipeline which will be installed

within the tunnel.

4.3.5.1 Site Ingress/Egress Access to the San Carlos Drop Shaft site would be provided from Skyway Road and Monte Vista

Drive. The site location and ingress and egress to/from the site from Highway 101 and surrounding

areas is shown in Figure 4-33.

Figure 4-33: San Carlos Drop Shaft Site Ingress and Egress



in Section 4.3.5.3.





Shaft Construction

4.3.5.2 Existing Site Conditions The SCPS located at this site is active and currently pumps wastewater from the City of San Carlos

and unincorporated areas of San Mateo County into the SVCW force main system. The pump station

building is located to the west to the staging area and is enclosed with chain link fence. There are

two access gates to the pump stations one located at the northeast end of the site and another

located at the southwest end of the site. At the southeast side of the building, there is structure

with above grade access to a valve vault. This valve vault contains diversion gates utilized to route

flow from the existing 48-inch force main which is located directly under the vault into the San

Carlos PS during wet weather flows. The exiting 48-inch force main is aligned along the north east

boundary of the site and will be crossed by the Gravity Pipeline alignment (below) at the valve vault

location. Overhead power lines are located on the east side of the site, over the southern access

driveway to the SCPS. Based upon work on the 48-inch Force Main Reliability Improvement Project

Unit 3 along Monte Vista Drive (not constructed), the overhead power wires most likely include

primary conductors with nominal voltage of 12 kV.

There is a transformer and electrical facilities located near the middle of the site in front of the

pumps station in a landscaped area. The power pole adjacent to the transformer has a guy wire and

below-grade anchorage for the guy wire. The site is mainly paved with a small landscaped area

with irrigation facilitates located on the east side, adjacent to Monte Vista Drive. The site slopes

approximately 5-7 percent from west to east towards a paved access road, which has catch basins

on either side. There is an existing SCA access gate (Gate W-1) and automatic gate keypad and

associated conducted located at the end of Monte Vista Drive. Various underground utilities are

located at the site including potential high voltage electrical facilities (to be confirmed), 36-inch

gravity sewer, 48-inch sanitary sewer force main, valve vault structure, 12-inch RCP storm drain,

12-inch potable water main and associated lateral, communication and gas utilities.

Electrical facilities and unknown metal reading utility markings have been identified at the

proposed shaft location and will require further investigation to address potential conflicts with

these utilities as the design progresses.

4.3.5.3 Staging Area Requirements Due to the existing paved condition of the site, clearing and grubbing of this site prior to staging

would not be required. The space available for staging and construction of the San Carlos Drop

Shaft at this location is limited. The following site constraints have been considered in developing

shaft staging area requirements:

Continued access to the existing SCPS during shaft construction.

Location of existing above grade facilities including overhead electrical wires and

other facilities which require protection during construction including the pump

station building, existing power poles, transformer and above grade piping located

adjacent to pump station building.

Continued access to SCA access gate (Gate W-1) during construction.




Shaft Construction

Access to the existing Hiller Aviation waste bin structure located at the end on Monte

Vista Drive.

The following additional items have been considered in developing the construction staging area

requirements:


Shaft excavation size, configuration and equipment required for the recommended

caisson shaft construction method

Site access to the SCPS from public right-of way

Design Vehicle Type: WB-40 (semi-trailer with 40-foot wheel base)


Due to the limited space available, the shaft excavation materials will not be stored onsite prior to

hauling to the ultimate disposal location. Excavated material from shaft from this site will be stored

at the Airport Access Shaft site, approximately 1 mile away from the San Carlos Drop Shaft site.

Although the overall SCPS site is approximately 0.6 acres, the majority of the staging area will be

located in front of the pump station in an area encompassing approximately 0.2 acres if storage is

necessary. The staging plan for the San Carlos Drop Shaft site is shown in Figure 4-34.

SAN CARLOS AIRPORT

M

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IZZY'S STEAKS & CHOPS

F

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STAGING AREA

1

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P

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1

SAN CARLOS DROP SHAFT STAGING AREA - PLAN

APPROX 0.6 AC

3

4

3

5

SEE NOTE 1 & 2

(E) PARKING

(E) WASTE BIN STRUCTURE

LEGEND

1. ENTRY/EXIT GATE

2. GENERATOR

3. STORAGE BOXES

4. COMPRESSOR

5. EMERGENCY GATE

6. K-RAIL

7. EXCAVATED MATERIAL LOADING AREA

8. VEHICLE: WB-40

9. WATER TREATMENT FACILITIES

T

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IC

H

A

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L K

IN

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S

M

IT

H

R

E

S

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NOTES:

1. FOR ADDITIONAL STAGING AREA REFER TO AIRPORT ACCESS SHAFT STAGING AREA FIGURE 4-30.

2. PUMP STATION ACCESS MAINTAINED

THROUGHOUT CONSTRUCTION.

B

U

R

G

E

R

K

I

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G

7




SAN CARLOS DROP SHAFT

SITE STAGING PLAN

0

1"=60'

60 10030

(E) POWER POLE

(E) GUY WIRE

CAISSON INSTALLATION

EQUIPMENT / CRANE WORKING ZONE

(E) AIRPORT ACCESS GATE

W-1 MAINTAIN ACCESS

20' OUTSIDE DIA.


6

FAA AIRSPACE PROTECTION SURFACES (SEE NOTES)

9

K/J 1568063.02 JUNE 2016

FIGURE 4-34


1. AIRSPACE PROTECTION SURFACE ELEVATIONS ON THIS EXHIBIT ARE EXPRESSED IN FEET

ABOVE MEAN SEA LEVEL (MSL). THE ELEVATION OF SAN CARLOS AIRPORT IS 5 FEET MSL.

2. LOCATIONS WHERE THE GROUND/TERRAIN PENETRATES THE FAR PART 77 AIRSPACE

SURFACES ARE APPROXIMATE AND WERE DEVELOPED USING ALUCP EXHIBIT 4-4 WHICH

UTILIZED GROUND ELEVATION CONTOURS PROVIDED BY THE SAN MATEO COUNTY

PLANNING AND BUILDING DEPARTMENT 2014.

3. SOURCE: SAN CARLOS AIRPORT ALUCP, EXHIBIT 4-4 (ESRI, 2014; SAN MATEO COUNTY

PLANNING AND BUILDING DEPARTMENT, 2014; ESA AIRPORTS, 2014).




Shaft Construction

The staging area will include limited space for caisson construction equipment a generator, two

storage boxes and compressor. An area for excavated material loading is designated on the plan. It

is anticipated a 40 cubic yards container would temporarily hold the excavated material during the

day’s excavation activities and would be hauled off to the Airport Access Shaft site 1 to 2 times a day

during shaft excavation.

Based upon the proposed layout, vehicles exiting the SCA Gate W-1 would access Monte Vista Drive

through the adjacent parking area. Similarly, access to and from the existing waste bin structure

would be through the existing adjacent parking lot. Coordination with Michael King Smith Research

Library and Hiller Aviation Museum will be required.

Sufficient space is not available for construction vehicles to make a U-turn at the site; however

construction vehicles can access the site and back into the gate, as shown on Figure 4-34, for turn

around. The largest vehicle that can be accommodated at this site is a WB-40 vehicle. Additional

staging for construction crew parking, lockers and material storage needed for shaft constriction

will be provided at the Airport Access Shaft site.

4.3.5.4 San Carlos Airport and Federal Aviation Administration Considerations The San Carlos Drop Shaft staging area is located within the San Carlos Airport (SCA) Inner

Approach/Departure Zone. In addition, the staging area for this site also encroaches into the

Runway Protection Zone. Refer to TM No. 1, Appendix A (Exhibit 4-3) for SCA safety zones.

FAA Airspace protection surfaces across the San Carlos site staging area are shown Figure 4-34.

The staging area is primarily located within 25-foot to 47-foot airspace protection elevation

contours. It should be noted these contour elevations represent an elevation in feet above mean

sea level. Based upon the location of these contours across the staging area, the estimated

protection surface elevation above the existing site grade elevation is estimated to be 21-33 feet

above grade near the equipment/crane working area. Refer to Table 4-16 for additional

information. Caisson installation equipment can be procured with an overall height below the FAA

height restrictions for this location, avoiding encroachment in the protection surface elevation. The

overall height of a conventional crane and equipment for installation of the drop structure and shaft

finish-out is anticipated to be approximately 40-feet in height. Potential encroachment into FAA

airspace during shaft finish-out work would require night work and would be limited to 2-3 non-

consecutive days.




Shaft Construction

Table 4-16: San Carlos Drop Shaft Airspace Protection Height Restrictions

Notes:


lowest height within the preliminary anticipated equipment/ crane working zone.

(b) Based upon preliminary site elevations using project vertical datum of NGVD 29 + 100 feet. Grade elevation relative

to MSL was determined by subtracting 100 feet from the preliminary site elevations.

Proposed construction at this location is subject to review and approval by the Federal Aviation

Administration (FAA) (as administered by the SCA) and requires an FAA Form 7460-1 be

submitted. Specific FAA requirements and conditions associated with the proposed construction

and anticipated crane height encroachment into the in the FAA jurisdictional areas for the site

would be included in the Notice of Determination by the FAA.

4.3.5.5 Utility Requirements Utility requirements during construction include protection of existing facilities identified in

Section 4.3.5.2. Temporary k-rail would be installed around the existing transformer, power pole

and associated guy wire to protect these utilities in-place during construction. Potholing of existing

electrical conduit(s) and unknown utility located in the proposed shaft location is recommended to

confirm locations and establish a relocation plan for the utilities prior to shaft construction.

Additional investigation and coordination with PG&E is required to determine the specific

requirements for temporary power during construction, confirm nominal voltage of existing power

lines, and confirm required clearances from the existing facilities. Although the overhead power

lines do not cross over the proposed shaft excavation area, the overhead power wires likely include

primary conductors with nominal voltage of 12kV. The California Division of Occupational Safety

and Health (Cal/OSHA) regulations require minimum safe working and traveling distances be

maintained from cranes to overhead electric lines which are often more stringent than PG&E

clearance requirements.

Tables 1-2 and 1-3 included in PG&E’s Green Book note the minimum Cal/OSHA safe working distances from 0.6 to 50 kV nominal voltage conductors are as follows:

Boom-type lifting or hoisting equipment: 10 feet

Scaffolds, equipment, tools, structures, and people: 6 feet

Although the space at this location is limited, it is not likely that the operation of the crane and

caisson construction equipment will encroach within the 10-foot clearance requirement for crane

type equipment. A 10-foot horizontal buffer from the existing conductor would be located outside

Site Height Restriction

(Feet Above MSL)(a)

Grade Elevation (relative to MSL)(b)

Estimated Height Limit Above Existing

Grade Elevation

San Carlos Drop Shaft 25 - 37 4 21 - 33




Shaft Construction

of the caisson construction equipment and crane operation area. It is understood OSHA’s clearance

requirement is from the primary conductor and not necessarily on the horizontal plane. The

horizontal buffer provides a reference point considering the height of the primary conductors

relative to the crane is unknown at this time. Confirmation of the nominal voltage of existing

overhead power lines and coordination with PG&E is required to confirm these clearance

requirements and confirm temporary relocation during construction is not required.

Additional utility requirements and considerations for this site are provided below:

Temporary power requirements: 480V, 3 phase, 4-wire Potable water: Access to potable water is available onsite. The Contactor would be

responsible for installing backflow prevention and metering devices. Temporary portable restroom(s) would be provided during construction. Protection of existing 48-inch sanitary sewer force main.

4.3.5.6 Long Term Operation and Maintenance Facility Requirements Infrequent operation and maintenance (O&M) activities are anticipated for the San Carlos Drop

Shaft. A vortex drop structure will be installed within the San Carlos Drop Shaft. Although vortex

structures are typically designed to convey wastewater flow at self-cleaning velocities,

accumulation of debris and material over time should be anticipated due to the spiral configuration

of vortex units and debris that is often carried in raw wastewater. However, wastewater from

Belmont Pump Station will pass through a coarse bar screen and demuter and San Carlos flow will

pass through coarse bar screens upstream of the drop structure which will help to minimize the

accumulation of debris. The frequency for cleaning of the vortex structure will depend upon actual

flow conditions and wastewater characteristics. Based upon on the reported required frequency of

cleaning for utilities with installed vortex structures, cleaning of the vortex structure can be

anticipated to occur once every 5 to 10 years. Cleaning is usually performed by a third-party

contractor. Cleaning crews typically utilize a tripod with a safety harness to lower maintenance

staff off a winch into the manhole.

The following features are recommended for optimum cleaning:

Access for an 8-wheel, dual axle vacuum truck approximately 42 feet long with a 30-foot wheel base.

All weather access approach capable of handling the load of a vacuum truck filled with 3,000 to 4,000 gallons of water.

Open vortex top to allow for removal of debris accumulation at the top of the vortex structure.

Access opening over the top of the vortex structure. Maintenance platform/bench above the flow. Minimum of two large manhole ring and cover openings, one over the vortex structure and

another over the work bench or a corrosion resistant double-door hatch (Bilco type hatch, 6’ x 6’ or 4’ x 8’) over the platform and vortex structure.

Multiple openings (one over the vortex structure) can eliminate confined space entry. Harness Tie-offs (anchor bolts of 316SS).




Shaft Construction


4.3.6.1 Mobilization Mobilization will include all activities for transportation of contractor's personnel, equipment, and

operating supplies to the San Carlos Drop Shaft staging site necessary for shaft construction. Due to

the limited space available at the San Carlos Drop Shaft staging area, the Airport Access Shaft site

will also be used by the San Carlos Drop Shaft Contractor, as an additional staging area for field

office and any necessary general facilities. The mobilization of the San Carlos Drop Shaft site will

include installation of temporary equipment, fencing, gates and utilities necessary for the

Contractor's operations at the site. For more details on the SCPS shaft staging area, refer to the

"Staging Area Requirements" section above. Mobilization will also consist of the Contractor

obtaining all required insurance, bonds and permits.

4.3.6.2 Excavated Material Handling The SCPS site has limited space for construction activities. For this reason, excavated material

produced from the shaft excavation activities will likely be hauled to the Airport Access Shaft site

for characterization and hauling and disposal. The total estimated quantities for excavated material

from the San Carlos Drop Shaft site are included in Table 4-13. It is anticipated the excavated

material would be temporarily placed in on onsite 40-yard dumpster or placed directly onto a

dump truck for daily hauling to the Airport Access Shaft site. Based on the anticipated shaft

excavation rates it is anticipated the dumpster would be retrieved and emptied at the Airport

Access Shaft site twice, daily during shaft excavation.

4.3.6.3 Water Treatment and Disposal Groundwater was encountered during geotechnical investigations at the SCPS site. Geotechnical

investigations indicate the water bearing layers have low permeability. The soil improvement

implemented at the shaft site described herein would allow for relatively dry excavation. Should

water handling facilities be needed at this site they would include sump pump(s) for pumping

incidental groundwater inflow from the shaft excavation to the surface, and temporary containment

facilities to remove settleable solids prior to discharge. The options for discharge of groundwater

are similar to those discussed for the Airport Access Shaft site. However, in this case the storm

drain and sanitary sewer facilities are owned by the City of San Carlos. Sanitary sewer facilities and

storm drain facilities are both located adjacent to the shaft site.

Further coordination is required during predesign to establish potential allowable discharge flow

rates into the SCPS wetwell to avoid potentially overloading of the sewerage facilities, although

large quantities of water are not anticipated at this site.

4.3.6.4 Shaft Site Restoration and Permanent Facilities After the new gravity sewer conveyance system is in service, the existing San Carlos Pump Station

(SCPS) would no longer be required. The SCPS would be decommissioned and repurposed by

others. Final site restoration is anticipated to be performed by others following the repurposing of

the SCPS. The repurposing of the SCPS would include construction of improvements required to




Shaft Construction

connect the flow from the Cities of San Carlos and Belmont to the new gravity pipeline are

complete.

Permanent facilities at the shaft would include the drop structure within the shaft, and access

openings discussed in section 4.3.5.6. An air handling pipe is anticipated to be constructed from

within the drop shaft to air handling facilities anticipated to be constructed (by Others) at the

existing San Carlos Pump Station location. Permanent access approach to the shaft would be asphalt

concrete paved. In the interim, it is anticipated temporary hot mix asphalt would be placed in the

area surround the permanent shaft facilities.

4.3.6.5 Geotechnical Instrumentation and Monitoring The proposed location of the San Carlos Drop Shaft will be in a paved area adjacent to the SCPS, the

San Carlos Airport taxiway, the Monte Vista Drive and the existing 48" force main. The area

contains various subsurface utilities. There are also existing building structures in vicinity of the

shaft. Therefore, the monitoring program proposed for the SCPS Shaft excavations would include

instruments to measure vertical and lateral ground movements, vertical and lateral structure

movements, settlement of utilities, and groundwater fluctuations outside of the shaft excavation.

Specifically, the type of instruments required for the project will include:

Surface Settlement Markers installed on building walls and foundations to measure vertical

displacement.

Tiltmeters to measure rotational movement of utility poles.

Crackmeters to determine if existing cracks in structures are progressively widening.


Subsurface Shallow Settlement Indicators installed adjacent to foundations to measure

settlement.


movements as the shaft excavation progresses.




existing conditions of all structures and pavement located entirely or partially within the shaft

excavation influence zone. The zone of influence would be determined based on a site specific

evaluation to determine which structures need to be monitored. The instrumentation would be

installed at all structures, roadways and other objects of concern located within approximately 200

feet from the shaft. Further evaluation of the influence zone will be performed, taking into

consideration the selected initial support method. The pre-construction survey will document

interior and exterior condition of all structures and pavements to provide a baseline data for

evaluating construction claims.




Shaft Construction

4.3.7 Recommendations The San Carlos Drop Shaft site is the smallest and most congested shaft location on the project. With

the surface utilities, the existing pump station, and very close proximity of the San Carlos Airport,

the smallest equipment footprint possible is best suited for this site. Two shaft initial support

methods are considered for the San Carlos Drop Shaft: CSM and Caisson. It is envisioned that CSM

could be also utilized for the soil improvement at the adit where CSM shaft construction methods is

used, otherwise jet grouting would be suggested. A comparison table of the two initial support

methods evaluated is presented Table 4-17 below.

Table 4-17: San Carlos Drop Shaft Initial Support Comparison

CSM Caisson with Jet Grouting for Soil Improvement

Can be installed with equipment

meeting the FAA height restriction of

21 feet. However, the equipment has

not been used in United States yet and

procuring it may impact the schedule

and cost of the shaft construction

Can be installed with equipment meeting the FAA


$2.4 million construction cost $0.5 million construction cost.

Shorter construction duration. The

construction time is relatively rapid if

no obstructions are encountered.

Longer construction duration. The construction

time is longer due to the need of collar installation

and jet grouting for ground improvement.

The same equipment would be utilized

to construct the shaft and the soil

improvement saving time on mobilizing

new equipment.

Separate equipment would be used for the soil

improvement and for shaft construction.

Procuring low headroom equipment

could negatively affect the construction

schedule and cost.

Jet grouting can be utilized for ground

improvement, but splicing is required which

increases the cost and time of construction.

Low construction site noise and

vibration level.

Low construction site noise and vibration level.

The final lining would be cast in place

shotcrete which would provide

relatively smooth walls.

The caisson final lining will provide uniform

interior surface.




Shaft Construction

The suggested method of shaft construction is the caisson option. The caisson installation

equipment can be procured with an overall height below the 21 foot limit. All other methods

exceed the FAA height restriction.

For the required ground modification at the adit connection between the shaft and the tunnel, the

use of jet grouting is deemed optimal. The grouting can be performed from the surface or within the

shaft after excavation and the required equipment can be obtained to be below the FAA height

restriction limit. With jet grouting, the difficulties with height of equipment and any potential

interference with the existing 48-inch force main are eliminated.

4.4 Bair Island Inlet Structure Shaft

4.4.1 Site Geology The information about general subsurface conditions at the Bair Island Inlet Structure Shaft is

based on the Phase I subsurface exploration program performed by Geotechnical Consultants Inc.,

and its findings are presented in the "Preliminary Characterization of Subsurface Conditions"

Technical Memorandum dated December 9, 2015. The available data from currently ongoing Phase

II geotechnical investigation program was also utilized to confirm the information used from the

Phase I investigation program.

The existing subsurface conditions at the Bair Island Inlet Structure Shaft were developed from

three borings made at the proposed shaft location (B-108, B-112Pd and B-112Ps) in addition to in

situ field test results performed on selected soil samples. The maximum boring depth obtained was

74.5 feet below the ground surface. Piezometers were installed at boring locations B-112Pd and B-

112Ps. No laboratory tests were performed on soil samples obtained at this shaft location.

Artificial fill covers the site to a depth of 13 to 17 feet below the ground surface and consists of clay

and silt with varying amounts of sand/gravel. Varying quantities of organic materials, cobbles and

debris may be encountered within the fill. Young Bay Mud underlies the fill with a layer thickness of

up to 4 feet. The Young Bay Mud consists of very soft to soft, highly compressible and plastic, near

normally consolidated fat clay. Standard Penetration Test (SPT) results generally varied from

weight of rods (WOR) to 3 blows/foot.

Below the Young Bay Mud, Upper Layered Sediments are encountered with a layer thickness of at

least 46 feet and in some cases extend to at least the bottom of the deepest boring performed at this

shaft site, a depth of 74.5 feet below the ground surface. These soil deposits consist of a complex of

alternating layers of lean clay, silty clay, silty sand, sandy clay, and clayey gravel. The thickness,

sequencing and consistency of these individual layers are highly variable. SPT results ranged from 9

to 34 blows/foot. The fine grained materials (silts and clays) have a generally stiff to hard

consistency and the granular materials (sands and gravels) are in a medium dense to dense state.

Pocket penetrometer field readings indicate an apparent undrained compressive strength ranging

from 3,500 to over 6,500 psf. Old Bay Deposits underlie the Upper Layered Sediments and extend to

at least the bottom of the deepest boring performed at this shaft site, a depth of 74.5 feet below the




Shaft Construction

ground surface. This layer of marine sediments consists of stiff to hard silt with varying amounts of

sand/clay and lean clay with occasional scattered shell fragments. Standard Penetration Test (SPT)

results ranged from 32 to 40 blows/foot. Pocket penetrometer readings indicate an apparent

undrained compressive strength of 7,000 to 7,400 psf.

Groundwater bearing layers were encountered at depths of 22 to 32 feet and 46 to 49 feet below

the ground surface. Piezometers installed at borings B-112Pd and B-112Ps indicated static water

levels at a depth of 7.5 feet below the ground surface at both locations. This level is consistent with

the water level at an adjacent water body and indicates that the water-bearing layers are

hydraulically connected to the surface water bodies.

4.4.2 Shaft Excavation

4.4.2.1 Excavation Size and Configuration At this shaft location, a connection will be constructed between the new gravity sewer to the

recently completed existing high density polyethylene (HDPE) 48-inch force main sewer. The shaft

will serve as a temporary structure required for the construction of the connection and as a

receiving shaft for the TBM. Based on the construction activities and requirements for the

connection to the existing sewer, it was determined that the Bair Island Inlet Structure Shaft will be

a rectangular pit, 25 x 42 feet in plan dimension and approximately 27 feet deep. After retrieving

the TBM and constructing the sewer connection, an access structure and ogee pipe connection to

the existing 48-inch force main will be installed within the shaft. The annular space between the

access structure and the shaft will be backfilled. Details of the sewer connection and the access

structure are rendered in Planning Level TM No. 5.




4.4.3 Initial Support

4.4.3.1 Support Methods and Evaluation From the five initial support methods selected for the project, only three have been considered for

the Bair Island Inlet Structure Shaft construction, namely: secant piles, CSM and sheet piling. The

caisson and slurry wall initial support methods were excluded due to anticipated higher cost and

their complexities of construction comparing to the selected systems. A conceptual design was

performed for each of the remaining systems to estimate its size and applicability for this location

under the anticipated lateral loads.

The following geological conditions have been considered in the design of support of shaft

excavation: the first 13 feet of the shaft would be constructed in very soft Artificial Fill, followed by

up to 4-feet of very soft to soft Young Bay Mud, then 10 feet of loose to very stiff Upper Layered

Sediments.




Shaft Construction

Secant piles

It is anticipated that approximately 2.5 feet diameter reinforced piles would be required to

adequately resist the lateral pressures and accommodate the vertical construction tolerances (refer

to Figure 4-35). Every second pile would be reinforced with a wide flange steel shape or steel

reinforcement cages. An installation of internal bracing consisting of wales and struts would be

required. The bracing will be placed as the excavation progresses. A mud slab would be poured at

the shaft invert to provide smooth and firm working surface for the activities taking place in the

shaft. The secant piles would provide a relatively rigid initial support limiting soil movements and

settlements. The secant pile system is commonly used and can be installed with low overhead

clearance requirements of 21 feet and less.

Due to the presence of water bearing granular layers at the tunnel level, soil improvement would be

implemented for ground at the tunnel breakout to prevent water ingress into the shaft during

breaking in for the TBM retrieval. In addition, a seal around the tunnel breakout inside of the shaft

would be installed to aid in minimizing the groundwater inflow into the shaft.

Figure 4-35: Secant Pile Alternative

Cutter Soil Mixing (CSM)

It is anticipated that approximately 2-foot thick CSM walls would be required for shaft construction

(refer to Figure 4-36). The walls would need to be reinforced with steel wide flange shapes

embedded in the walls and supported with shaft internal bracing. Typically, wales and struts are




Shaft Construction

used for wall bracing. The bracing would be installed as the excavation progresses. A mud slab

would be poured at the shaft invert to provide a smooth and firm working surface for the activities

taking place in the shaft. The CSM would provide a relatively rigid initial support, limiting soil

movements and settlements. The CSM system can be installed with a low overhead clearance

requirement of 21 feet and less. However, the equipment available and commonly used in the

United States is approximately 60 feet in height and above. This exceeds the FAA restriction of 49

feet (refer to section 4.4.4.4 for FAA height restrictions). The CSM low overhead equipment has

been used on several overseas projects. However, it is not readily available in the United States.

However, it is not readily available in the United States. Procuring this equipment for this project

may have a negative effect on the shaft construction schedule and cost.

Similarly to the secant pile option, soil improvement and a seal at the tunnel breakout would be

used to prevent groundwater ingress into the shaft during breakout for TBM retrieval.

Figure 4-36: Cutter Soil Mixing Alternative

Sheet Piles

To support the excavation, steel sheet piling would be driven to follow the rectangular

configuration of the shaft (refer to Figure 4-37). The sheet pile wall would be constructed in

conjunction with the shaft's internal bracing consisting of wales and struts. The bracing would be

installed as the excavation progresses. A mud slab would be poured at the shaft invert to provide a

smooth and firm working surface for the activities taking place in the shaft. The sheet piles would




Shaft Construction

be the most flexible shaft initial support method from all proposed for the SVCW project. Similarly

to the other options, soil improvement and a seal at the tunnel breakout would be used to prevent

groundwater ingress into the shaft during breakout for TBM retrieval.

In addition, approximately 40 to 60 feet of headroom would be required to install sheet piling at the

Bair Island Inlet Structure. The exact height clearance required will depend on the depth of the

sheet piling to be driven. Splicing and welding of sheet piling could be utilized to adhere to the FAA

height limit of 49 feet (refer to section 4.4.4.4 for FAA height restrictions). However, this would

increase the cost and duration of the shaft construction.

Figure 4-37: Sheet Piling Alternative

Groundwater Control at Bair Island Inlet Structure Shaft

Only an impermeable shaft support system will be utilized for the Bair Island Inlet Structure Shaft

construction. Since the shaft would be terminated in or near the water-bearing granular soil layer,

the construction of a sealing element at the shaft invert will be required to minimize water inflow

into the excavation and to facilitate construction. The sealing element at the shaft invert, in

conjunction with the impermeable excavation support, would provide a relatively impervious

system minimizing the groundwater inflow into the shaft. The following five options of impervious

systems have been investigated:




Shaft Construction

Option 1 - Extended initial support

This system would include the extension of the excavation support system into the impermeable

layer (refer to Figure 4-38). The shaft lining would be extended approximately 25-feet down

through the permeable layers of Upper Layered Sediments into the lower relatively impermeable

silts and clays of the Old Bay Deposits to provide a groundwater cut-off barrier. This option would

minimize the water inflow into the excavation during the construction of the shaft and the sewer

connection.

Figure 4-38: Extended Excavation Support

The advantages and disadvantages of this system are listed in Table 4-18 below.



Fast installation since only the

support will be extended

The height of the CSM and sheet piling

equipment required for the installation of the

extended support may encroach on the FAA


Relatively low cost since

equipment will be onsite




Shaft Construction

Option 2 - Excavation support and permeation grouting curtain

In lieu of extending the excavation support into the impermeable layer, a water cut-off barrier could

be constructed. The barrier would be formed by utilizing permeation grouting (refer to Figure 4-

39). Another type of soil improvement could be used in lieu of permeation grouting, such as jet

grouting or soil freezing. However, it is anticipated that the cost of these systems would be much

higher than permeation grouting or extended excavation support (Option1). Therefore, they are not

recommended at this time. The additional soil improvement methods (jet grouting and soil

freezing) may be revisited during preliminary design if determined that they are best suited for the

construction of the shaft.

The permeation grouting would be accomplished from the surface before the shaft excavation

begins. Two grout placement methods could be used. A series of holes could be drilled along the

shaft perimeter or through grout pipes embedded in the excavation support. A low viscosity grout

would be injected into in-situ soil at relatively low pressures allowing the grout to permeate into

the soils. The installation of a grouting curtain would minimize the water inflow into the shaft

during construction; however, it would require substantially more labor and cost for verification

(testing) than Option 1. Therefore, the impermeable excavation support and permeation grouting

option is not recommended and excluded from further investigation.

Figure 4-39: Permeation Grouting Curtain

The advantages and disadvantages of this system are listed in Table 4-19 below:




Shaft Construction




support methods.

Mobilization of grouting equipment at the surface is

required.

Good shaft foundation. Requires verification testing which increases cost and time

of construction.

All three initial support methods

could be installed with

equipment height below the FAA


Commonly used United States CSM equipment for a 34 foot

deep excavation would be approximately 60 feet high.

Procuring low headroom equipment from overseas may be

required.

Option 3 - Excavation support with gravity concrete plug

This system would include the installation of an impermeable excavation support and a sealing

element consisting of concrete gravity plug (refer to Figure 4-40). It is estimated that a 15-foot

thick concrete plug would be required to resist the hydrostatic pressure at the shaft invert. The

system would also require the initial support to extend below the bottom of the plug to ensure the

stability of the excavation before pouring in the concrete plug. It would also require excavation of

the inside of the shaft for the plug installation, which would make this option costly. Therefore, the

impermeable excavation support with gravity concrete plug option is not recommended and is

excluded from further investigation.

Figure 4-40: Gravity Concrete Plug




Shaft Construction

The advantages and disadvantages of this system are listed in Table 4-20 below:




support methods.

Extension of the excavation support system

required.

Excavation of the inside of the shaft for the

plug construction required.

Expensive option overall.

Longer shaft construction duration.

The height of the CSM and sheet piling

equipment required for the installation of

the extended support may encroach on the

FAA height restriction of 49 feet.

Option 4 - Excavation support with jet grouting gravity plug

This system would consist of the installation of an impermeable excavation support system and a

sealing element consisting of a jet grout gravity plug (refer to Figure 4-41). The jet grouting would

be performed from the surface before the shaft excavation begins. The jet grouting technique

injects grout at a high pressure and velocity destroying the soil structure and mixes grout and soil

to form a homogeneous impervious mass.




Shaft Construction

Figure 4-41: Gravity Jet Grouting Plug





support methods.

Mobilization of grouting equipment

at the surface is required.

Provides excellent foundation for

the shaft walls.

Expensive option overall.


could be installed with

equipment height below the FAA


Commonly used CSM equipment in

the United States for a 34 foot deep

excavation would be approximately

60 feet high. Procuring low

headroom equipment from overseas

may be required.




Shaft Construction

Option 5 - Excavation support with structural concrete invert slab

This system would include the installation of an impermeable excavation support system and a

sealing element consisting of a structural concrete invert slab (refer to Figure 4-42). The structural

concrete invert slab would be reinforced concrete with a minimum thickness of 3 feet.

The installation process requires flooding of the shaft to counterbalance the hydrostatic uplift

pressures. The excavation to the bottom of the impermeable excavation support system would be

performed underwater. Once excavated, the invert slab reinforcement and connections to the

excavation support system would be installed by underwater divers. The concrete would then be

installed using the tremie concrete placement method.

This system is not suitable in combination with sheet piling. The shaft walls would not weigh

enough to counterbalance the uplift forces transferred trough the structural slab.

Figure 4-42: Structural Concrete Slab





Shaft Construction



Will serve as a mud slab for

construction activities

The system with sheet piling initial support method

would not be sufficient to resist buoyancy.


could be installed with equipment

height below the FAA height

restriction of 49 feet.

Difficult to install with all three support methods.

Commonly used CSM equipment in the United States

for a 34 foot deep excavation would be approximately

60 feet high. Procuring low headroom equipment from

overseas may be required.


Relative comparison costs for the Bair Island Inlet Structure Shaft impermeable system options are

shown in Table 4-23. The costs were developed in 2015 prices. Mark-ups of 25 percent for indirect

costs and 15 percent for overhead and profit are included in the costs. The costs do not include

contingency and escalation. Refer to Appendix A.

Table 4-23: Bair Island Inlet Structure Shaft Initial Support Cost Comparison

Initial Support

Method

Initial Support +

Extended Initial

Support Cost

(Millions)

Initial Support +

Jet Grouting

Plug Cost

(Millions)

Initial Support +

Structural Concrete

Slab Cost

(Millions)

Secant piles $2.8 $2.9 $2.9

CSM $2.5 $2.8 $2.8

Sheet Piling $2.1 $2.3 N/A

4.4.4 Site Conditions The Bair Island Inlet Structure Shaft staging area would be located along the levee road of Inner

Bair Island, north of Whipple Avenue in the City of Redwood City. This site would serve as the

location for TBM retrieval following tunneling from Airport Access Shaft to Bair Island Inlet

Structure Shaft and as the staging area for Bair Island Inlet Structure Shaft construction.




Shaft Construction

4.4.4.1 Site Ingress/Egress Access to Inner Bair Island for Bair Island Inlet Structure Shaft construction and TBM retrieval will

be provided from the east end of Whipple Avenue, across Inner Bair Island via an existing unpaved

access road located along the perimeter of Inner Bair Island. The site location and ingress and

egress to/from the site from Highway 101 and surrounding areas are shown in Figure 4-43, below.

Figure 4-43: Bair Island Inlet Structure Shaft Site Ingress and Egress



below.

4.4.4.2 Existing Site Conditions Inner Bair Island is part of the USFWS Don Edwards San Francisco Bay National Wildlife Refuge

(NWR). The project site is located on San Carlos Airport property and subject to airspace

limitations. The staging area at the Inner Bair Island site is located on a relatively flat peninsula

produced from manmade fill. A levee was recently constructed by the USFWS as part of the Bair

Island Restoration Project (BIRP). This staging area is covered with grass and shrub. The levee is

considered upland habitat. Existing utilities onsite include a 48-inch sanitary sewer force main

(SSFM) located along the western island boundary, within a portion of the BIRP levee. Fiber optic

conduit is located parallel to the existing 48-inch SSFM.





Shaft Construction

4.4.4.3 Staging Area Requirements Due to the flat, gently sloping, and clear topography of the site major, clearing and grading of the

site would not be required prior to construction. The construction area would be stabilized with

filter fabric and a layer of gravel or base rock to provide an all-weather surface for construction.

The staging area perimeter would be fenced with a 6 to 8-foot high security fence to prevent

unauthorized access. A stabilized construction entrance from the public right-of way would be

constructed at the east Whipple Avenue entrance to the unpaved road which provides access to the

northern portion of Inner Bair Island where the construction site would be located. It is anticipated

that biological protection fencing would be required for salt marsh harvest mouse habitat

protection. The onsite mitigation measures required for environmental protection are anticipated

to be included in the CEQA documents for this project and incorporated into the design.

The following items have been considered in developing the construction staging area

requirements for this site:


Location of the existing 48-inch SSFM

Shaft excavation size, configuration and equipment required for the recommended

excavation method


Excavated Material Storage: 3 Days

Design Vehicle Type: WB-50 (intermediate semi-trailer with 62-foot wheel base)

The staging area can accommodate turnaround of a WH-50 design vehicle. This design vehicle has

similar wheel base and overall dimensions to a standard lowboy tractor trailer combination vehicle

anticipated for in use in delivery of construction material and equipment to the site during shaft

construction. It is anticipated a standard lowboy tractor trailer combination transport vehicle

would also be used for transporting the TBM from the site.

The staging area for this site is shown in Figure 4-44 Approximately 1.5 acres is needed for this

staging area.

4.4.4.4 San Carlos Airport and Federal Aviation Administration Considerations The Inner Bair Island area is located within the San Carlos Airport (SCA) Inner Approach/

Departure Zone. In addition, the staging area for this site also encroaches into the Runway

Protection Zone. Refer to TM No. 1, Appendix A (Exhibit 4-3) for SCA safety zones.

FAA Airspace protection surfaces across the Bair Island Inlet Structure Shaft site staging area are

shown in Figure 4-44.

183+

00

184+

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185+

91

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PULGAS CREEK

C PROPOSED 15'Ø

OD TUNNEL

25' X 42' BAIR ISLAND RECEIVING PIT (CLEAR)

STAGING AREA

L

APPROXIMATE EXTENSION OF FAA PRIMARY SURFACE LINE

E

X

IS

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IN

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EQUIPMENT/CRANE

WORKING ZONE

NEW 48" DIA

FORCE MAIN

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BAIR ISLAND INLET STRUCTURE SHAFT STAGING AREA - PLAN

APPROX. 1.5 AC

SOIL TREATMENT AREA

EXISTING 48" DIA

FORCE MAIN




BAIR ISLAND INLET STRUCTURE SHAFT SITE STAGING PLAN

11

1

2

5

6

3

4

8

10

9

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13

12

SITE INGRESS/EGRESS SEE FIGURE 4-43 FOR SITE ACCESS FROM HWY 101

14

FAA AIRSPACE PROTECTION SURFACES (SEE NOTES)

K/J 1568063.02 JUNE 2016 FIGURE 4-44


1. AIRSPACE PROTECTION SURFACE ELEVATIONS ON THIS EXHIBIT ARE EXPRESSED IN

FEET ABOVE MEAN SEA LEVEL (MSL). THE ELEVATION OF SAN CARLOS AIRPORT IS 5

FEET MSL.

2. LOCATIONS WHERE THE GROUND/TERRAIN PENETRATES THE FAR PART 77

AIRSPACE SURFACES ARE APPROXIMATE AND WERE DEVELOPED USING ALUCP

EXHIBIT 4-4 WHICH UTILIZED GROUND ELEVATION CONTOURS PROVIDED BY THE

SAN MATEO COUNTY PLANNING AND BUILDING DEPARTMENT 2014.

3. SOURCE: SAN CARLOS AIRPORT ALUCP, EXHIBIT 4-4 (ESRI, 2014; SAN MATEO

COUNTY PLANNING AND BUILDING DEPARTMENT, 2014; ESA AIRPORTS, 2014).

0

1"=60'

60 10030

20' WIDE SANITARY

SEWER EASEMENT

6557 OR. 480

NOTES:

1. EXISTING 48" FORCEMAIN TO BE ABANDONED AFTER NEW 48" FM IS INSTALLED.

2. EXISTING 48" FORCEMAIN TO REMAIN IN SERVICE AFTER NEW 48" FM IS INSTALLED

AND PROTECTED IN PLACE.

LEGEND

2

1

3

4

5

6

7

8

10

9

11

12

13

14

CONTRACTOR TRAILER

JOB PARKING

CM TRAILER

ENTRY/EXIT GATE

COMPRESSOR

GENERATORS: DUTY AND STANDBY LOCKER ROOM

MATERIAL STORAGE

STORAGE BOXES

EXCAVATED STORAGE (3 DAYS) 40'X125'

WATER TREATMENT FACILITIES

RESTROOM FACILITIES

SHAFT CONSTRUCTION SITE INGRESS/EGRESS. SEE

FIGURE 4-37 FOR SITE INGRESS/EGRESS FROM HWY 101

VEHICLE PATH: WB-50

SEE

NOTE 1

SEE

NOTE 2




Shaft Construction

The staging area, including soil stabilization area, is primarily located within 54-foot to 88-foot

airspace protection elevation contours. It should be noted these contour elevations represent an

elevation in feet above mean sea level. Based upon the location of these contours across the staging

area, the estimated protection surface elevation above the existing site grade elevation is estimated

to be 49-64 feet above grade near the equipment/crane working area. Refer to Table 4-24 for

additional information. As noted in Section 4.4.3.1, both secant pile and sheet pile shaft

construction methods can meet the FAA height limitations with equipment available in the United

States. Should the sheet pile method be selected, the overall height of the pile driving equipment

would depend upon the overall length of spliced sections (5 feet plus the height of the spliced

sheet). The spliced sheet piling alternative would allow for construction utilizing the sheet piling

method, without encroaching in the protection surface elevation. The longest vertical sheet pile

section which could be accommodated without encroaching in the protection surface elevation

would be approximately 42 feet. The typical equipment utilized for the secant pile method would

be well within the height restrictions for this site.

Table 4-24: Bair Island Inlet Structure Shaft Airspace Protection Height Restrictions

Notes:


lowest height within the preliminary anticipated crane working zone.

(b) Based upon preliminary site elevations using project vertical datum of NGVD 29 + 100 feet. Grade elevation relative

to MSL was determined by subtracting 100 feet from the preliminary site elevations.

Proposed construction at this location subject to review and approval by the FAA (as administered

by the SCA) and requires an FAA Form 7460-1 be submitted. Specific FAA requirements and

conditions associated with the proposed construction and anticipated crane height encroachment

into the in the FAA jurisdictional areas for the site would be included in the Notice of Determination

by the FAA.

4.4.4.5 Utility Requirements Stabilization and protection of the existing 48-inch sewer force main utilizing surface injection soil

stabilization techniques or another stabilization method, prior to shaft construction and tunneling

approaching the facility at Inner Bair Island will be required. The method for utility stabilization

will be investigated further as the design progresses. Approximate limits for soil stabilization for

protection of the 48-inch force main are shown on Figure 4-44.

The contractor would be required to provide the temporary facilities necessary to provide lighting,

power, water, sanitation services, heating and ventilation need for construction and the

Site

Height Restriction

(Feet Above MSL)(a)

Grade Elevation (Relative to

MSL)(b)

Estimated Height Limit Above Existing Grade

Elevation

Bair Island Inlet Structure Shaft

55 – 72 8 47 - 64




Shaft Construction

Contractor’s construction trailer at the site. Due to the remote location of the shaft site and

inaccessibility to existing utilities it is anticipated generators would be used for power and portable

sanitation facilities would be utilized.

4.4.4.6 Long Term Operation and Maintenance Requirements Long-term O&M activities are not anticipated to occur at a frequent interval at this location.

Manhole access for infrequent inspection activities would be provided via a 32 to 48-inch manhole

frame and cover and/ or double leaf hatch. Provisions for grit removal/cleanout and air handling

devices such as air limiting device/air valve within a vault are anticipated at this location.

Ultimately, O&M activities and access requirements to final structure(s) will depend upon the

selected connection method.

4.4.5 Construction Considerations 4.4.5.1 Mobilization Mobilization will include all activities for transportation of contractor's personnel, equipment, and

operating supplies to the Bair Island Inlet Structure Shaft staging site necessary for shaft

construction. It will also comprise of installation of field offices, laboratories, fencing, gates, utilities

and other necessary general facilities for the contractor's operations at the site. For more details on

the Bair Island Inlet Structure Shaft staging area, refer to the "Staging Area Requirements" section

above. Mobilization activities will also consist of the contractor obtaining all required insurance,

bonds and permits.

4.4.5.2 Excavated Material Handling Operations All excavated material from the 25-ft x 42-ft Bair Island Inlet Structure Shaft would be handled at

the location. Excavated material that cannot be hauled away during the permitted hauling hours

each day would be stored onsite for hauling on the following work day. A staging area for onsite

storage of approximately three (3) days of excavated material based a shaft excavation rate of 4

VLF/day and average 5-foot high stockpiles would be provided. Onsite storage for excavated

materials stockpiling at this location would encompass an area of approximately 5,000 sf (refer to

Figure 4-44).

Similar to all excavated material for the project, the material would need to be sampled and

analyzed to characterize the soil and determine if there is any soil contamination. Soil

characterization is necessary to confirm the disposal classification for off haul, prior to offsite

disposal or re-use. Acceptance of the soil at a landfill will depend upon overall disposal quantity

and soil characterization and or contamination. Non-contaminated and contaminated material

would be subjected to the profiling requirements of the disposal facility. Ox Mountain Sanitary

Landfill, located in Half Moon Bay, is the closest landfill that accepts this type of construction

excavated material. Ultimately, the Contractor will identify the excavated material disposal

location(s) and/or potential areas for re-use. The hauling requirements noted above for dirt hauling

in the City of Redwood City would apply to this location as well.




Shaft Construction


excavated material quantities for this site is provided below.

Excavated Soil: Approximately 1,470 LCY

Hauling Trucks: 2 average commercial 12.5 loose cubic yard (LCY) dump trucks

Hauling Duration: 3 weeks

Potential ultimate disposal site: Ox Mountain Sanitary Landfill

Average round-trip haul distance: 34 miles

4.4.5.3 Water Treatment and Disposal Although the proposed sealing element at the shaft invert, in conjunction with the impermeable

excavation support, would provide an impervious system to limit the groundwater inflow into the

shaft, it is anticipated that some level of water handling and disposal will be required. The

anticipated water handling quantities for this location during shaft construction will be established

based on the selected impervious system and groundwater information, which will be included in

geotechnical baseline report to be prepared by the PDB.

Similar to the other shaft sites, water handling facilities at this site are anticipated to include sump

pump(s) for pumping groundwater inflow from the shaft excavation to the surface, temporary

containment facilities and control measures such as sediment traps, sediment basin or Baker tank

to remove settleable solids prior to discharge. The need for additional treatment of the water prior

to discharge would depend upon water quality limitations for at the proposed discharge location.

Water could potentially be discharged to one or more of the existing water channels on Inner Bair

Island, similar to the approach utilized during construction of the 48-inch FM receiving shaft

construction on Inner Bair Island. This option will be investigated further by the PDB.

Contaminated water that cannot be treated onsite would require offsite transportation and offsite

disposal of at a properly permitted treatment facility.

4.4.5.4 Shaft Site Restoration and Permanent Facilities The shaft site construction staging area restoration would include site clean-up and re-grading of

the site to restore the original site slopes and drainage patterns. The constructions staging area

would be re-vegetated. An access way would be installed upon completion of this shaft for

entrance into the shaft in the event access would be needed in the future for manhole inspection

and/or access to the tunnel. The access opening would likely include an H-20 traffic rated,

watertight manhole frame and cover and/or double leaf hatch. In addition, provisions for grit

removal (cleanout with surface expression) and air handling provisions (air valve vault with

potential air limiting devise) are anticipated at this location.

This site is located within Federal Emergency Management Agency (FEMA) Flood Zone AE.

According to FEMA definitions, designation as Zone AE indicates the area is subject to inundation

by the 1-percent-annual-chance flood event (100-year floodplain) to an elevation of 10 (NAVD 88)




Shaft Construction

based on Flood Insurance Rate Map (FIRM) 06081C0188E. FIRM map elevation will need to be

converted to the project datum (NAVD+100) during preliminary design. The manhole opening for

this site would be located 6-12 inches above the flood plain elevation at this location and be

watertight to prevent inflow in the gravity sewer in the event of flooding.

4.4.5.5 Geotechnical Instrumentation and Monitoring The proposed location of the Bair Island Inlet Structure Shaft will be in an open area adjacent to an

unpaved road. There are no structures or pavements within the influence zone around the

perimeter of the shaft. There are underground utilities, including a 48-inch force main in the

vicinity of the shaft excavation. Therefore, the monitoring program proposed for the Bair Island

Inlet Structure Shaft excavation would include instruments to measure lateral ground movements,

settlement of utilities and groundwater fluctuations outside of the shaft excavation. Specifically, the

type of instruments required for the project will include:

Settlement Indicator Points to measure utility settlements.

Subsurface Shallow Settlement Indicators installed adjacent to underground utilities to

measure settlement.


movements as the shaft is excavated.




existing conditions of all underground utilities located entirely or partially within the shaft

excavation influence zone. A 100 to 150-foot limit outside of the shaft perimeter may be considered

as the influence zone. Further evaluation of the influence zone will be performed during design,

taking into consideration the selected initial support method. The pre-construction survey will

document condition of existing utilities to provide a baseline data for evaluating construction

claims.

4.4.6 Recommendations The following criteria were considered in evaluation of the Bair Island Inlet Structure Shaft:

shaft use soil conditions ground water levels shaft construction cost schedule site restrictions such as airspace protection height limits

A comparison table of the three (3) initial support methods evaluated is presented in Table 4-25

below.




Shaft Construction

Table 4-25: Bair Island Inlet Structure Shaft Initial Support Methods Comparison

From the three initial construction methods evaluated, the secant piles and sheet piling are

considered to be best suited for the Bair Island Inlet Structure Shaft construction. Both methods can

be constructed with equipment below FAA height restrictions. Even though, the secant pile method

is the most expensive option, it could be easily extended below the Upper Layered Sediments to

provide a cut-off for water-bearing sands encountered in this layer. It would allow the construction

the shaft with low construction vibrations considering the fact of close proximity of the shaft to the

existing utilities. It would also permit to construct the shaft with relatively low noise and avoid any

potential problem with noise effecting people across the Pulgas Creek.

The sheet piling would be the least expensive option. It would require installation of jet grouting

plug at the shaft bottom to provide groundwater cut-off. However, this option could pose a noise

problem for the buildings across the Pulgas Creek and the vibrations may have negative effect on

the existing utilities. Noise attenuation measures may have to be employed. One option would be to

install fencing with noise absorbing blankets. These two support methods will be further evaluated

in preliminary design phase of the project.

Secant Piles CSM Sheet Piling

Requires excavation of secant piles, concrete placement, installation of vertical beams and internal bracing. Longest duration.

Requires mixing of soil with cement, installation of vertical beams and internal bracing. Duration relatively similar to secant piles.

Requires only installation of sheet piling and internal bracing. Shortest duration.

Relatively impermeable system.

Relatively impermeable system.

The steel sheet piling will permit minor flows into the shaft. Flows are anticipated to be handled with pumping within the shaft.

Most expensive option. Relatively similar cost to the secant pile option.

Least expensive option.

Can be installed with equipment meeting the FAA height restriction of 49 feet.

Can be installed with equipment meeting the FAA height restriction of 49 feet. However, the equipment has not been used in the United States yet and procuring it may impact the cost and schedule of the shaft construction.

Can be installed with equipment meeting the FAA height restriction of 49 feet except for Option 1 (extended excavation support). Approximately 60 feet of headroom is required to drive the sheet piling in one piece. The sheet piling could be installed in sections; however, that would increase the cost and construction duration.



Significantly higher level of noise and vibrations than the other options. Noise during installation may pose a problem for the buildings across Pulgas Creek. Vibrations may negatively affect the existing force main.




Shaft Construction

4.5 Construction Schedule The SVCW Conveyance System Planning Group is maintaining an overall schedule (Version 12 at

the time of preparation of this TM) for design and construction of the conveyance system

improvements. Anticipated dates for construction are not included herein as these dates are subject

to significant change as the project develops and policy decisions are made that affect the schedule.

Within the overall schedule, the Airport Access Shaft and RLS/Flow Splitter Shafts are anticipated

to be constructed concurrently so that the Flow Splitter Shaft will be available for TBM retrieval

once the tunneling activity from Airport Access Shaft to the RLS/Flow Splitter Shaft is completed.

The construction sequencing of the Bair Island Inlet Structure Shaft will be such that it is complete

and available for TBM retrieval in advance of the tunneling activity from the Airport Access Shaft

reaching Inner Bair Island. The San Carlos Drop Shaft is offset from the tunnel, such that an adit

connection to the tunnel is required. Soil stabilization will be necessary at the San Carlos Drop

Shaft location and must be completed prior to tunnel activity reaching this site.

Anticipated shaft construction durations, as shown in the Program Schedule (Version 12) are

summarized in Table 4-26, below.

Table 4-26: Shaft Construction Durations

Shaft Construction Duration (Working Days)

RLS /Flow Splitter 140

Airport Access 207

San Carlos Drop 250

Bair Island Inlet Structure 107

The PDB will produce and maintain the overall schedule for the Gravity Pipeline, recording

refinements to the durations and sequence of activities as more details are developed.

Section 5: Summary and Recommendations

This section summarizes the findings and recommendations of TM No. 4. Further details can be

found in the respective sections of the TM. Table 5-1 presents the recommended shaft

configuration and dimensions. Based on a review of the geology at the shaft sites, conventional soil

excavation techniques such as a crane and a clamshell bucket or an excavator can be utilized to

excavate the materials within the shafts.

Table 5-1: Shaft Structure Configuration and Dimensions

Shaft Structure Configuration Dimensions

RLS Shaft(a) Figure “8” (combined with Flow 28.5 to 52 feet in diameter x 84-ft




Shaft Construction

Splitter Shaft) or separate shaft deep

Flow Splitter

Shaft(a)

Figure “8” (combined with RLS

Shaft) or separate shaft

25 to 32 feet in diameter x 68-ft

deep

Airport Access

Shaft Circular 35-ft in diameter x 52-ft deep

San Carlos Drop

Shaft Circular

15 to 20 feet in diameter x 52-feet

deep

Bair Island Inlet

Structure Shaft Rectangular

25-ft x 42-ft plan dimension x 27-

feet deep

Notes:

(a) Final configuration for RLS and Flow Splitter Shafts will be determined by the PDB.

Table 5-2 summarizes the recommended shaft support method for each of the four (4) sites and

the primary benefits of the recommended method(s).




Shaft Construction

Table 5-2: Shaft Support Method Recommendations

Shaft Recommended Method Comments

RLS Slurry Walls or Caisson(a)

Greater achievable construction depths as

compared to secant piles which would be

reaching the practical limit of installation at the

proposed shaft depths.

Less infiltration anticipated with the

recommended methods as compared to secant

piles.

Provide more robust support system for the

Receiving Lift Station structure than secant piles.

Refer to Tables 4-8, 4-9 and 4-10 for cost and

methods comparison.

Airport

Access Shaft Secant Piles

Can be constructed with low headroom

restrictions.

Commonly used system.

Low vibration and noise during installation.

Rigid system as compared to sheet piling

Economical.

San Carlos

Drop Shaft Caisson


restrictions of 21 feet.

Low noise and vibrations during installation.

Best suits the site constraints.

Bair Island

Inlet

Structure

Shaft

Secant Piles or Sheet

Piling(b)


restrictions of 49 feet with equipment available

in the United States.

Refer to Tables 4-23 and Table 4-25 for cost

and methods comparison.

Notes:

(a) Recommendation for initial support system will be made by the PDB once the structure configuration for RLS and

Flow Splitter Shafts is selected and further evaluation is performed.

(b) Recommendation for the initial support system will be made by the PDB following further evaluation of the two

options.




Shaft Construction

Additional evaluation of secant piles and sheet piling shaft support methods for the Bair Island Inlet

Structure Shaft is recommended during primary design. In addition, further evaluation of the

following two shaft configurations and initial support methods for the RLS and Flow Splitter Shaft

during preliminary design is also recommended. Final selection of the initial support system for RLS

is dependent upon on the final shaft configuration and type of corrosion protection layer selected.

Figure “8” configuration or two shaft configuration

Slurry Walls or Caisson

Table 5-3 summarizes the recommended staging area sizes at each shaft site.

Table 5-3: Shaft Staging Area Sizes

Shaft Site Proposed Area

(Acres)

RLS

RLS and Flow Splitter Shafts 2.5

Flow Splitter Shaft (for TBM

retrieval purposes) 0.4

Airport Access 6.5

San Carlos Drop 0.6

Bair Island Inlet Structure 1.5

THIS PAGE INTENTIONALLY BLANK

AppendixA

General Info:

Option 1 Option 4 Option 5

Shaft diameter - ID FT 32.0 - 52.0 32.0 - 52.0 32.0 - 52.0

Shaft depth FT 67.5 - 83.5 67.5 - 83.5 67.5 - 83.5

Wall embedment FT 33.5 - 17.5 5.0 5.0

Depth of panels FT 101.0 72.5 - 88.5 80.5 - 96.5

Wall thickness FT 3.0 3.0 3.0

Thickness of bottom slab FT 1.0(1) 1.0(1) 8.0(2)

Shaft penetration by tunnels Ea 1 1 1

Option 1: Extended Initial Support

Option 4: Jet Grouting Plug

Option 5: 8'-0" Structural Concrete Slab


0. Jet Grouting Plug - 32'-6" Thick (Flow Splitter Shaft), 16'-6" Thick (RLS Shaft) -$ 950,000$ -$

1. Set Guides 350,000$ 350,000$ 350,000$

2. Excavate Panels 870,000$ 710,000$ 780,000$

3. Slurry Cleaning and Desanding 150,000$ 120,000$ 140,000$

4. Set up and Install Rebar Cages 880,000$ 880,000$ 970,000$

5. Slurry Walls - Place Tremie Concrete 710,000$ 620,000$ 660,000$

6. Excavate Inside Shaft 570,000$ 570,000$ 600,000$

7. Bottom Slab 80,000$ 80,000$ 380,000$

8. Tunnel Breakout 250,000$ 250,000$ 250,000$

TOTAL DIRECT COST 3,860,000$ 4,530,000$ 4,130,000$

Indirect Cost 25% 965,000$ 1,132,500$ 1,032,500$

4,825,000$ 5,662,500$ 5,162,500$

Overhead and Profit 15% 723,750$ 849,375$ 774,375$

5,548,750$ 6,511,875$ 5,936,875$

TOTAL BID PRICE 5,548,750$ 6,511,875$ 5,936,875$

TOTAL COST 5,500,000$ 6,500,000$ 5,900,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 8'-0" thick Structural Concrete Slab.(3) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(4) Sales tax of 9% is applied to the cost of materials in the estimate.

(5) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that this isnot a final estimate.

RLS - Figure "8" Configuration

Slurry Walls

Shaft Initial Support Cost Summary

RLS COST - Figure Eight Configuration(3)

(Flow Splitter Shaft - RLS Shaft)

June 9th, 2016

General Info:



Shaft depth FT 67.5 - 83.5 67.5 - 83.5 67.5 - 83.5


Pile depth FT 101.0 72.5 - 88.5 80.5 - 96.5

Pile diameter FT 4.0 4.0 4.0








1. Set Guides 310,000$ 310,000$ 310,000$

2. Excavate and Install Secant Piles 2,280,000$ 1,870,000$ 2,070,000$


4. Bottom Slab 80,000$ 80,000$ 730,000$

5. Tunnel Breakout 250,000$ 250,000$ 250,000$


Indirect Cost 25% 872,500$ 1,007,500$ 990,000$

4,362,500$ 5,037,500$ 4,950,000$


5,016,875$ 5,793,125$ 5,692,500$

TOTAL BID PRICE 5,016,875$ 5,793,125$ 5,692,500$

TOTAL COST 5,000,000$ 5,800,000$ 5,700,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 8'-0" thick Structural Concrete Slab.(3) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(4) Sales tax of 9% is applied to the cost of materials in the estimate. (5) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that this isnot a final estimate.


Secant Piles




June 9th, 2016

General Info:



Shaft depth FT 67.5 - 83.5 67.5 - 83.5 67.5 - 83.5

Wall embedment FT 5.0 5.0 5.0

Wall depth FT 73.5 - 89.5 80.5 - 96.5 77.0 - 93.0






Option 6: Jet Grouting Water Cut-off Curtain


0. Jet Grouting Plug - 32'-6" Thick (Flow Splitter Shaft), 16'-6" Thick (RLS Shaft) 950,000$ -$ -$

1. Concrete Collar 200,000$ 200,000$ 370,000$

2. Excavate Piles 190,000$ 190,000$ 210,000$

3. Install Piles - Place Tremie Concrete 170,000$ 170,000$ 170,000$


5. Bottom Slab 140,000$ 380,000$ 260,000$

6. Tunnel Breakout 250,000$ 250,000$ 250,000$

7. Caisson Walls 2,420,000$ 2,640,000$ 2,540,000$

8. Jet Grouting Water Cut-off Curtain -$ -$ 1,290,000$


Indirect Cost 25% 1,222,500$ 1,107,500$ 1,417,500$

6,112,500$ 5,537,500$ 7,087,500$

Overhead and Profit 15% 916,875$ 830,625$ 1,063,125$

7,029,375$ 6,368,125$ 8,150,625$

TOTAL BID PRICE 7,029,375$ 6,368,125$ 8,150,625$

TOTAL COST 7,000,000$ 6,400,000$ 8,200,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 8'-0" thick Structural Slab.(3) 4'-6" thick Structural Slab.(4) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(5) Sales tax of 9% is applied to the cost of materials in the estimate. (6) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that thisis not a final estimate.


Caisson




June 9th, 2016

General Info:



Shaft depth FT 67.5 - 83.5 67.5 - 83.5 67.5 - 83.5


Depth of panels FT 101.0 72.5 - 88.5 77.0 - 93.0





Option 5: 4'-6" Structural Slab



1. Set Guides 290,000$ 290,000$ 290,000$

2. Excavate Panels 610,000$ 510,000$ 540,000$

3. Slurry Cleaning and Desanding 110,000$ 80,000$ 100,000$

4. Set up and Install Rebar Cages 580,000$ 580,000$ 610,000$

5. Slurry Walls - Place Tremie Concrete 470,000$ 400,000$ 410,000$


7. Bottom Slab 70,000$ 70,000$ 160,000$

8. Tunnel Breakout 250,000$ 250,000$ 250,000$

9. Soil Improvement: Jet Grouting at Connection Tunnel 800,000$ 590,000$ 640,000$

10. Connection Tunnel 620,000$ 620,000$ 620,000$


Indirect Cost 25% 1,005,000$ 1,007,500$ 962,500$

5,025,000$ 5,037,500$ 4,812,500$


5,778,750$ 5,793,125$ 5,534,375$

TOTAL BID PRICE 5,778,750$ 5,793,125$ 5,534,375$

TOTAL COST 5,800,000$ 5,800,000$ 5,500,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 4'-6" thick Structural Slab.(3) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(4) Sales tax of 9% is applied to the cost of materials in the estimate.


RLS - Two Separate Shaft with Connection Tunnel

Slurry Walls


RLS COST - Two Separate Shaft with Connection Tunnel(3)


June 9th, 2016

General Info:



Shaft depth FT 67.5 - 83.5 67.5 - 83.5 67.5 - 83.5


Pile depth FT 101.0 72.5 - 88.5 77.0 - 93.0





Option 5: 4'-6" Structural Slab



1. Set Guides 250,000$ 250,000$ 250,000$

2. Excavate and Install Secant Piles 1,470,000$ 1,210,000$ 1,220,000$


4. Bottom Slab 70,000$ 70,000$ 510,000$

5. Tunnel Breakout 250,000$ 250,000$ 250,000$




Indirect Cost 25% 920,000$ 907,500$ 930,000$

4,600,000$ 4,537,500$ 4,650,000$


5,290,000$ 5,218,125$ 5,347,500$

TOTAL BID PRICE 5,290,000$ 5,218,125$ 5,347,500$

TOTAL COST 5,300,000$ 5,200,000$ 5,300,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 4'-6" thick Structural Slab.(3) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(4) Sales tax of 9% is applied to the cost of materials in the estimate. (5) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that this isnot a final estimate.


Secant Piles




June 9th, 2016

General Info:



Shaft depth FT 67.5 - 83.5 67.5 - 83.5 67.5 - 83.5

Wall embedment FT 5.0 5.0 5.0

Wall depth FT 72.5 - 88.5 77.0 - 93.0 77.0 - 93.0





Option 6: Jet Grouting Water Cut-off Curtain


0. Jet Grouting Plug - 32'-6" Thick (Flow Splitter Shaft), 16'-6" Thick (RLS Shaft) 420,000$ -$ -$

1. Concrete Collar 310,000$ 310,000$ 490,000$

2. Excavate Piles 240,000$ 240,000$ 260,000$

3. Install Piles - Place Tremie Concrete 200,000$ 200,000$ 200,000$


5. Bottom Slab 130,000$ 160,000$ 160,000$

6. Caisson Wall 1,760,000$ 1,830,000$ 1,830,000$

7. Tunnel Breakout 250,000$ 250,000$ 250,000$



10. Jet Grouting Water Cut-off Curtain -$ -$ 740,000$


Indirect Cost 25% 1,185,000$ 1,120,000$ 1,355,000$

5,925,000$ 5,600,000$ 6,775,000$

Overhead and Profit 15% 888,750$ 840,000$ 1,016,250$

6,813,750$ 6,440,000$ 7,791,250$

TOTAL BID PRICE 6,813,750$ 6,440,000$ 7,791,250$

TOTAL COST 6,800,000$ 6,400,000$ 7,800,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 4'-6" thick Structural Slab.(3) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(4) Sales tax of 9% is applied to the cost of materials in the estimate. (5) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that thisis not a final estimate.


Caisson




June 9th, 2016

General Info:

Slurry Walls Secant Piles CSM(1) Sheet Piles

Shaft diameter - ID FT 35 35 35 35

Shaft depth FT 52 52 52 52

Wall embedment FT 5 5 5 5

Depth of panels/piles FT 57 57 57 57

Wall thickness FT 2.50 3.75 5.00 0.031

Thickness of bottom slab FT 1.0 1.0 1.0 1.0

Slurry Walls Secant Piles CSM Sheet Piles

1. Set Guide Wall 140,000$ 140,000$ 100,000$ -$

2. Excavate and Install Temporary Support 740,000$ 560,000$ 630,000$ 550,000$

3. Excavate Inside Shaft 130,000$ 130,000$ 130,000$ 130,000$

4. Bottom Slab - 1'-0" Thick Mud Slab 60,000$ 60,000$ 60,000$ 60,000$

5. Tunnel Breakout (2) 200,000$ 200,000$ 200,000$ 200,000$

6. Shaft Interior 730,000$ 730,000$ 730,000$ 730,000$

TOTAL DIRECT COST 2,000,000$ 1,820,000$ 1,850,000$ 1,670,000$

Indirect Cost 25% 500,000$ 455,000$ 462,500$ 417,500$

2,500,000$ 2,275,000$ 2,312,500$ 2,087,500$

Overhead and Profit 15% 375,000$ 341,250$ 346,875$ 313,125$

2,875,000$ 2,616,250$ 2,659,375$ 2,400,625$

TOTAL BID PRICE 2,875,000$ 2,616,250$ 2,659,375$ 2,400,625$

TOTAL COST 2,900,000$ 2,600,000$ 2,700,000$ 2,400,000$

Notes

(3) Sales tax of 9% is applied to the cost of materials in the estimate. (4) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that this isnot a final estimate.

AIRPORT ACCESS SHAFT

Slurry Walls - Secant Piles - Cutter Soil Mixing (CSM) - Sheet Piles


AIRPORT ACCESS SHAFT COST(2)

(2) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.

(1) Double CSM Ring Configuration.

June 9th, 2016

General Info:

CSM Caisson

Shaft diameter - ID FT 20 20

Shaft depth FT 52 52

Wall embedment FT 2 2

Wall depth FT 54 54

Wall thickness FT 1.0(1) 1.5(2)

Thickness of bottom slab FT 1.0 1.0

CSM Caisson

1. Concrete Collar -$ 160,000$

2. Soil Improvement: Cutter Soil Mixing (CSM) - Jet Grouting (Caisson) - 35'-0" Thick 550,000$ 310,000$

3. Excavate Inside Shaft 60,000$ 60,000$

4. Bottom Slab - 1'-0" Thick Mud Slab 20,000$ 20,000$

5. Tunnel Breakout 250,000$ 250,000$

6. Shotcrete Lining 160,000$ -$

7. Caisson Walls -$ 480,000$

8. Shaft Interior 220,000$ 220,000$

9. Adit 290,000$ 290,000$

TOTAL DIRECT COST 1,550,000$ 1,790,000$

Indirect Cost 25% 387,500$ 447,500$

1,937,500$ 2,237,500$

Overhead and Profit 15% 290,625$ 335,625$

2,228,125$ 2,573,125$

TOTAL BID PRICE 2,228,125$ 2,573,125$

TOTAL COST 2,200,000$ 2,600,000$

Notes

(4) Sales tax of 9% is applied to the cost of materials in the estimate. (5) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that thisis not a final estimate.

(1) 1'-0" thick Shotcrete Lining.(2) 1'-6" thick Caisson Wall.


Cutter Soil Mixing (CSM) - Caisson


SAN CARLOS DROP SHAFT COST(5)


June 9th, 2016

General Info:


Inside shaft length FT 42 42 42

Inside shaft width FT 25 25 25

Shaft depth FT 27 27 27

Wall embedment FT 25 7 7

Depth of piles FT 52 34 37








0. Jet Grouting Plug - 15'-0" Thick -$ 240,000$ -$

1. Set Guide Wall 170,000$ 170,000$ 170,000$

2. Excavate and Install Secant Piles 750,000$ 600,000$ 610,000$

3. Install Bracing System 150,000$ 150,000$ 150,000$


5. Bottom Slab 40,000$ 40,000$ 240,000$

6. Tunnel Breakout 250,000$ 250,000$ 250,000$

7. Shaft Interior 500,000$ 500,000$ 500,000$


Indirect Cost 25% 485,000$ 507,500$ 502,500$

2,425,000$ 2,537,500$ 2,512,500$


2,788,750$ 2,918,125$ 2,889,375$

TOTAL BID PRICE 2,788,750$ 2,918,125$ 2,889,375$

TOTAL COST 2,800,000$ 2,900,000$ 2,900,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 3'-0" thick Structural Concrete Slab.

(4) Sales tax of 9% is applied to the cost of materials in the estimate. (5) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that this isnot a final estimate.

BAIR ISLAND INLET STRUCTURE SHAFT

Secant Piles


BAIR ISLAND INLET STRUCTURE SHAFT COST(3)


June 9th, 2016

General Info:


Inside shaft length FT 42 42 42

Inside shaft width FT 25 25 25

Shaft depth FT 27 27 27

Wall embedment FT 25 7 7

Depth of panels FT 52 34 37








0. Jet Grouting Plug - 15'-0" Thick -$ 240,000$ -$

1. Guide Trench 150,000$ 150,000$ 150,000$

2. CSM Wall Panels: Cutting and Mixing 600,000$ 570,000$ 570,000$

3. Install Bracing System 150,000$ 150,000$ 150,000$


5. Bottom Slab 40,000$ 40,000$ 240,000$

6. Tunnel Breakout 250,000$ 250,000$ 250,000$

7. Shaft Interior 500,000$ 500,000$ 500,000$


Indirect Cost 25% 442,500$ 495,000$ 487,500$

2,212,500$ 2,475,000$ 2,437,500$


2,544,375$ 2,846,250$ 2,803,125$

TOTAL BID PRICE 2,544,375$ 2,846,250$ 2,803,125$

TOTAL COST 2,500,000$ 2,800,000$ 2,800,000$

Notes

(1) 1'-0" thick Mud Slab.(2) 3'-0" thick Structural Concrete Slab.

(4) Sales tax of 9% is applied to the cost of materials in the estimate.



Cutter Soil Mixing




June 9th, 2016

General Info:

Option 1 Option 2

Inside shaft length FT 42 42

Inside shaft width FT 25 25

Shaft depth FT 27 27

Wall embedment FT 25 7

Depth of piles FT 52 34

Thickness of bottom slab FT 1.0 1.0

Shaft penetration by tunnels Ea 1 1



Option 1 Option 2

0. Jet Grouting Plug - 15'-0" Thick -$ 240,000$

1. Steel Sheet Piles Installation 410,000$ 300,000$

2. Install Bracing System 150,000$ 150,000$

3. Excavate Inside Shaft 80,000$ 80,000$

4. Bottom Slab - 1'-0" Thick Mud Slab 40,000$ 40,000$

5. Tunnel Breakout 250,000$ 250,000$

6. Shaft Interior 500,000$ 500,000$

TOTAL DIRECT COST 1,430,000$ 1,560,000$

Indirect Cost 25% 357,500$ 390,000$

1,787,500$ 1,950,000$

Overhead and Profit 15% 268,125$ 292,500$

2,055,625$ 2,242,500$

TOTAL BID PRICE 2,055,625$ 2,242,500$

TOTAL COST 2,100,000$ 2,300,000$

Notes(1) The estimate DOES NOT INCLUDE bond and insurance, builders risk insurance, comprehensive general liability insurance, contingency and soft costs.(2) Sales tax of 9% is applied to the cost of materials in the estimate. (3) We have utilized our tunneling experience, local labor rates and benefits and current prices for each listed items. No design has been conducted at this point. Therefore, it should be noted that this isnot a final estimate.


Sheet Piles



June 9th, 2016

AppendixB

REGULATIONS

of

Silicon Valley Clean Water

1990 Regulations 1991 Amendments 2000 Amendments 2005 Amendments

TABLE OF CONTENTS

ARTICLE I. GENERAL .............................................................................................................................. 1

SPECIFIC DEFINITIONS ........................................................................................................................ 1

ARTICLE II. PROHIBITIONS ................................................................................................................... 8

GENERAL PROHIBITIONS .................................................................................................................... 8

SPECIFIC SOURCES PROHIBITED .................................................................................................... 10

WASTEWATER STRENGTH LIMITATIONS .................................................................................... 10

SPECIFIC WASTES PROHIBITED ...................................................................................................... 11

SPECIFIC USER LIMITATIONS .......................................................................................................... 12

ARTICLE III. WASTEWATER VOLUME DETERMINATION ............................................................ 12

METERING ............................................................................................................................................ 13

EXCEPTIONS - ESTIMATED VOLUME............................................................................................. 13

ARTICLE IV. REPORTS, PERMITS AND ADMINISTRATION .......................................................... 14

REPORTS ............................................................................................................................................... 14

MANDATORY WASTEWATER DISCHARGE PERMITS ................................................................ 16

DISCRETIONARY WASTEWATER DISCHARGE PERMITS .......................................................... 16

APPLICATIONS FOR MANDATORY WASTEWATER DISCHARGE PERMITS .......................... 17

APPLICATIONS FOR DISCRETIONARY WASTEWATER DISCHARGE PERMITS .................... 18

PERMIT CONDITIONS ......................................................................................................................... 19

DURATION OF PERMITS .................................................................................................................... 20

NON-ASSIGNABILITY......................................................................................................................... 21

MONITORING FACILITIES ................................................................................................................. 21

INSPECTION AND SAMPLING ........................................................................................................... 22

PRETREATMENT ................................................................................................................................. 23

ACCIDENTAL DISCHARGES ............................................................................................................. 24

PUBLIC INFORMATION ...................................................................................................................... 25

SPECIAL AGREEMENTS ..................................................................................................................... 25

ARTICLE V. CHARGES AND FEES ...................................................................................................... 25

USER CLASSIFICATIONS, ADMINISTRATION ............................................................................... 25

SPECIFIC CHARGES AND FEES ........................................................................................................ 26

COMBINED FEES AND CHARGES .................................................................................................... 26

ARTICLE VI. ENFORCEMENT .............................................................................................................. 27

RESPONSIBILITY ................................................................................................................................. 27

UNAUTHORIZED DISCHARGES ....................................................................................................... 27

CEASE AND DESIST ORDERS ........................................................................................................... 28

TIME SCHEDULES ............................................................................................................................... 28

EMERGENCY CORRECTIONS ........................................................................................................... 29

DAMAGES TO SEWERAGE FACILITIES .......................................................................................... 29

EMERGENCY TERMINATION OF SERVICE .................................................................................... 29

PERMIT REVOCATION ....................................................................................................................... 30

NOTICE OF VIOLATION ..................................................................................................................... 31

ENFORCEMENT HEARING ................................................................................................................ 31

APPEALS ................................................................................................................................................ 33

PUBLIC NUISANCE.............................................................................................................................. 34

CIVIL ASSESSMENTS.......................................................................................................................... 34

AGENCY'S REGULATIONS ................................................................................................................ 35

AUTHORITY'S DISCRETION .............................................................................................................. 35

S:\Information Management System\Website\New SVCW Site Development\Website i.s\Environmental Services\SVCW Conformed Regulations.doc printed 05/27/15 2:59 PM

page 1

REGULATIONS OF THE SILICON VALLEY CLEAN WATER

ESTABLISHING UNIFORM STANDARDS, CONDITIONS AND

REQUIREMENTS FOR THE USE OF THE SANITARY SEWERAGE

FACILITIES OF SAID AUTHORITY AND ITS MEMBER AGENCIES

ARTICLE I. GENERAL.

SECTION 1.1. The purpose of these regulations is to establish standards, conditions and

requirements relating to the use of the sanitary sewerage facilities of the Silicon Valley Clean Water and

its member agencies. In adopting these regulations the Commission of Silicon Valley Clean Water

intends that, pursuant to the Joint Exercise of Powers Agreement hereinafter defined, the member

agencies of the Authority shall likewise adopt these regulations as uniform wastewater ordinances

enforceable throughout their respective jurisdictions. It is further the purpose of these regulations to

enable this Authority and the member agencies thereof to comply with and meet applicable laws,

regulations, standards and conditions established by federal and state law, or by agencies thereof in the

implementation of such law. The Commission of Silicon Valley Clean Water hereby finds and declares

that the health, safety and welfare of the people within its service area, and within the respective service

areas of the member agencies of this Authority, require the enactment and uniform implementation of

these regulations throughout said service areas. SECTION 1.2. TECHNICAL TERMINOLOGY.

Words, phrases, or terms not specifically defined herein, and having a technical or specialized meaning

shall be defined as set forth in the latest edition of "Standard Methods for the Examination of Water and

Wastewater", published by the American Public Health Association, the American Water Works

Association, and the Water Pollution Control Federation.

Waste constituents and characteristics, and measurements thereof, as used herein shall have the

meanings and descriptions ascribed thereto in the aforesaid publication, or as established by federal or

state regulatory agencies.

SECTION 1.3.0. SPECIFIC DEFINITIONS. The following words or phrases wherever used in

these regulations shall have the meanings respectively ascribed thereto.


page 2

SECTION 1.3.1. ACT or the ACT. The Federal Water Pollution Control Act as amended by the

Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500), and as amended from

time to time thereafter (33 U.S.C. §1251 et seq.), commonly referred to as the Clean Water Act.

SECTION 1.3.2. AGENCY or AGENCIES. The member agencies of the Silicon Valley Clean

Water, to wit: the Cities of Belmont, Redwood City, and San Carlos, municipal corporations of the State

of California, and the West Bay Sanitary District, a political subdivision of the State of California,

together with public agencies which, pursuant to contract with the Authority or its member agencies, use

the sanitary sewerage facilities of said member agencies and the Authority.

SECTION 1.3.3. AGENCY’S DIRECTOR or AGENCIES’ DIRECTORS.

The officer or employee of each Agency vested with the power by said Agency to administer its uniform

wastewater regulations, or his or her designees, including, but not limited to, duly authorized personnel

of Authority. The plural form shall refer to the Directors of all Agencies.

SECTION 1.3.4. AUTHORITY. The Joint Exercise of Powers Authority for the Silicon Valley

Clean Water, a public entity established by agreement between the Cities of San Carlos, Belmont, and

Redwood City, California, and the Menlo Park Sanitary District (now named the West Bay Sanitary

District) dated November 13, 1975, and any successor entity thereto.

SECTION 1.3.5. AUTHORITY’S COMMISSION. The governing body of Authority.

SECTION 1.3.6. AUTHORITY’S MANAGER. The Manager of the Authority, or his or her

designee.

SECTION 1.3.7. BUILDING SEWER. A sewer conveying wastewater from the premises of a

user to the sewerage facilities.

SECTION 1.3.8. BENEFICIAL USES. Uses of the waters of an Agency or the State which

may, or do require protection against quality degradation thereof, including, but not necessarily limited

to, waters used for domestic, municipal, agricultural, industrial, power generation, recreation, aesthetic

enjoyment, or navigation purposes, or for the preservation and enhancement of fish, wildlife or other


page 3

aquatic resources or reserves, and such other uses, both tangible or intangible, as are or may be

specified by federal or state law as beneficial uses.

SECTION 1.3.9. CATEGORICAL STANDARDS. National pretreatment standards

specifying quantities or concentrations of pollutants or pollutant properties which may be discharged

into the sewerage facilities by existing or new industrial users classified in specific industrial

subcategories established as separate regulations under the appropriate subpart of 40 Code of Federal

Regulations, Chapter I, Subchapter N. Unless specifically provided otherwise, said standards shall be

adhered to in addition to the general prohibitions established in Article II of these regulations.

SECTION 1.3.10. CHARGE. A rental or other charge established pursuant to these regulations

or an Agency’s uniform wastewater ordinance for services and facilities furnished by the Authority or an

Agency to any premises in connection with

the operation of the sewerage facilities.

SECTION 1.3.11. COMPATIBLE POLLUTANT. Biochemical oxygen demand, suspended

solids, pH and fecal coliform bacteria, additional pollutants identified in the Authority’s NPDES permit,

and such other pollutants as may be designated by Authority’s Manager upon a finding by him or her

that such pollutants are substantially treated and removed by the sewerage facilities.

SECTION 1.3.12. CONTAMINATION. An impairment of the quality of the waters of an

Agency or the State by waste to a degree which creates a hazard to the public health. Contamination

shall include any equivalent effect resulting from the disposal of wastewater whether or not waters of an

Agency or State are affected thereby.

SECTION 1.3.13. DETRIMENTAL DISCHARGE. A discharge which, alone or in conjunction

with a discharge or discharges from other sources, does, or may, endanger the health, safety or welfare

of persons, or the environment, or threatens to, or reasonably may be deemed to threaten, the operation

of the sewerage facilities, or causes or may reasonably be deemed to cause a violation of the Authority’s


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NPDES permit, or any applicable federal, state, or local regulation relating to the operation of the

sewerage facilities.

SECTION 1.3.14. HAZARDOUS WASTE. Any liquid, semisolid, solid, or gaseous waste which

conforms to the definition of "Hazardous Waste" in Section 25117 of the California Health & Safety

Code, as said section may from time to time be amended, revised or recodified.

SECTION 1.3.15. HOLDING TANK WASTE. Any waste from sewage or waste disposal

holding tanks as, e.g., those which are associated with vessels, chemical toilets, campers, trailers, septic

tanks, and vacuum pump tank trucks.

SECTION 1.3.16. INCOMPATIBLE POLLUTANT. Any pollutant which is not a compatible

pollutant.

SECTION 1.3.17. INTERFERING DISCHARGE. A discharge into the sewerage facilities

which, alone or in conjunction with a discharge or discharges from another source or sources, inhibits or

disrupts the sewerage facilities, the treatment processes or operations thereof, the sludge processes

thereof, or the use or disposal of said sludge, or the disposal of sewage, and which causes or

significantly contributes to either a violation of the Authority’s NPDES permit or to the inability of the

Authority to use or dispose of sewage sludge in compliance with the federal or state regulations or

permits promulgated or issued thereunder.

SECTION 1.3.18. MASS EMISSION RATE. The weight of material discharged into the

sewerage facilities during a specified time interval. Unless otherwise specified, the mass emission rate

shall mean pounds per day of a particular waste constituent or combination of constituents.

SECTION 1.3.19. NEW SOURCE. Any building, structure, facility, or installation from which

there is or may be a discharge of Pollutants, the construction of which commenced after the publication

of proposed Pretreatment Standards under Section 307(c) of the Act which will be applicable to such

source if such Standards are thereafter promulgated in accordance with that section.

SECTION 1.3.20. NPDES PERMIT, OR AUTHORITY’S NPDES PERMIT.


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The National Pollutant Discharge Elimination System Permit issued to Authority pursuant to the

provisions of the Act, as said permit may from time to time be amended, revised or superseded.

SECTION 1.3.21. PASS THROUGH. The discharge of pollutants through the sewerage

facilities into surface waters in quantities or concentrations which cause or significantly contribute to

violation of the Authority’s NPDES permit.

SECTION 1.3.22. PERSON. Any individual, firm, company, partnership, association, private

corporation, public corporation, or governmental entity, authority, or agency, and the officers, agents, or

employees of such organizations.

SECTION 1.3.23. POLLUTANT. The human-made or human-induced waste which alters the

chemical, physical, biological, or radiological integrity of waters of an Agency or of the State

manifesting pollution.

SECTION 1.3.24. POLLUTION. An alteration of the chemical, physical, biological, or

radiological integrity of waters of an Agency or of the State by waste made or induced by humans which

unreasonably affects such waters for any beneficial use or so affects facilities serving such beneficial

use. The term pollution may also include contamination.

SECTION 1.3.25. PREMISES. A parcel of land, or portion thereof, including any

improvements thereon, which is directly or indirectly connected to the sewerage facilities for purposes

of receiving, using, and paying for service, or other purposes relating to the sewerage facilities, by an

individual user. Each dwelling unit of a duplex, apartment, or any other multi-family residence shall be

deemed separate premises. Subject to the foregoing, the Agencies’ Directors shall determine what

constitutes a premises.

SECTION 1.3.26. PRETREATMENT. The reduction of the amount of pollutants, the

elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater to a less

harmful state prior to, or in lieu of, discharging or otherwise introducing such pollutants into the


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sewerage facilities. Such reduction or alteration may be obtained by physical, chemical or biological

processes, or process changes or other means, except as prohibited by requirements of law.

SECTION 1.3.27. RECLAIMED WATER. Water which, as a result of treatment of waste, is

suitable for direct beneficial use, or a restricted beneficial use, which would not otherwise occur but for

such treatment.

SECTION 1.3.28. REQUIREMENT OF LAW or OTHER REQUIREMENTS OF LAW. Any

pertinent provision of the Act, or of any statute, ordinance, rule, regulation, order, or directive

implementative of the Act, or of Authority’s NPDES permit, or of any amendments, revisions, or other

superseding provisions or requirements of the foregoing authorities.

SECTION 1.3.29. SEWERAGE FACILITIES. Any or all devices, facilities, equipment,

improvements or systems owned or used by the Agencies or the Authority in the collection, storage,

treatment, recycling, reclamation, or disposal of wastes or wastewater, including interceptor sewers,

outfall sewers, or lines, sewage collection systems, pumps, power plants, treatment plants, recycling or

reclamation plants, and other equipment and appurtenances thereto; extensions, improvements,

remodeling, modifications, additions or alterations thereof; chemicals, materials, or supplies used in

connection therewith; or any other facilities, including land and improvements thereon, which are an

integral part of the sewage collection, transporting or treatment process of the Agencies or the Authority,

or which are used for ultimate disposal of residues, effluent, or discharges resulting from such treatment,

or any other method or system for preventing, abating, reducing, storing, treating, separating or

disposing of wastes or wastewater, including storm water runoff, industrial wastes, domestic wastes, or

any combination thereof.

SECTION 1.3.30. SIGNIFICANT INDUSTRIAL USER.

(a) Any user within an industry subject to Categorical Pretreatment Standards under 40 CFR

chapter I, subchapter N; or


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(b) Any user that discharges an average of 25,000 gallons per day or more of process wastewater

to the POTW (excluding sanitary, non-contact cooling and boiler blowdown wastewater); or

(c) Any user that contributes a process wastestream which makes up 5 percent or more of the

average dry weather hydraulic or organic capacity of the POTW treatment plant; or

(d) Any user within a user classification listed in Division D (Manufacturing) of the Standard

Industrial Classification Manual, 1972 edition, issued by the Executive Office of the President, Office

of Management and Budget, as said manual may from time to time be amended, revised, or superseded,

who or which discharges 1,000 gallons or more per day of process wastewater into the sewerage

facilities; or

(e) Any user who or which discharges, or causes or permits a discharge of wastewater which

would or does have a reasonable potential for adversely affecting the sewerage facilities or for violating

any pretreatment standard or requirement (as determined by an Agency’s Director or Authority’s

Manager), either individually or in combination with other contributing industries, on the sewerage

facilities, or on the quality, of effluent from the sewerage facilities.

(f) Upon a finding that a user, meeting the criteria above in subsections (b) through (d), has no

reasonable potential for adversely affecting the sewerage facilities or for violating any pretreatment

standard or requirement, the Authority may at any time, on its own initiative or in response to a petition

received from a user or agency, and in accordance with 40 CFR 403.8(f)(6), determine that such user is

not a significant industrial user.

SECTION 1.3.31. UNPOLLUTED WATER. Water to which no constituent has been added,

either intentionally or accidentally, which would render such water unacceptable to an Agency or the

Authority for disposal to storm or natural drainages, or directly to surface waters.

SECTION 1.3.32. USER. Any person who or which discharges, causes or permits the discharge

of wastewater into the sewerage facilities.


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SECTION 1.3.33. USER CLASSIFICATION. A classification of users based upon

classifications set forth in the Standard Industrial Classification Manual, 1972 edition, issued by the

Executive Office of the President, Office of Management and Budget, as said manual may from time to

time be amended, revised, or superseded.

SECTION 1.3.34. WASTE. Sewage and any and all waste substances, whether liquid, solid,

gaseous, or radioactive, associated with human habitation, or of human or animal origin, or from any

producing, manufacturing or processing operation of whatever nature, including such waste placed

within containers of any nature prior to, and for purposes of, disposal.

SECTION 1.3.35. WASTEWATER. Waste and water, whether treated or untreated, discharged

into, or permitted to enter into the sewerage facilities.

SECTION 1.3.36. WASTEWATER CONSTITUENTS AND CHARACTERISTICS.

The individual chemical, physical, bacteriological and radiological parameters, including volume

and flow rate, and such other parameters that serve to define, classify or measure the contents, quality,

quantity, or strength of wastewater.

SECTION 1.3.37. WATERS OF THE AGENCIES OR STATE. Any water, whether surface,

underground, and whether saline or non-saline, within the boundaries of the agencies, or within the

boundaries of an Agency flowing into, touching, or otherwise combined with waters outside the limits of

said Agency but within the boundaries of the State.

ARTICLE II. PROHIBITIONS.

SECTION 2.1 GENERAL PROHIBITIONS.

(a) No person shall discharge waste into the sewerage facilities which cause, threaten to cause, or

are capable of causing, either alone or by interaction with other substances:

(1) A fire or explosion;

(2) Obstruction of flow in, or injury to, the sewerage facilities, or any portion thereof;

(3) Danger to life or safety of persons;


page 9

(4) Conditions inhibiting or preventing the effective maintenance or operation of the

sewerage facilities;

(5) Strong or offensive odors, air pollution, or any noxious, toxic, or malodorous gas or

substance, or gas producing substances;

(6) Interference with the wastewater treatment process, or overloading of the sewerage

facilities, or excessive collection or treatment costs, or use of a disproportionate share of

the capacity of the sewerage facilities;

(7) Interference with any wastewater reclamation process, which does or may operate in

conjunction with the sewerage facilities, or overloading, or a breakdown of such

reclamation process, or excessive reclamation costs, or any product of the treatment

process which renders such reclamation process impracticable or not feasible under

normal operating conditions;

(8) A detrimental environmental impact, or a nuisance wherever located, or a condition

unacceptable to any public agency having regulatory jurisdiction over operation of the


(9) Discoloration, or any other adverse condition in the quality of the effluent from the

sewerage facilities such that receiving water quality requirements established by any

statute, rule, regulation, ordinance, or permit condition cannot be met by an Agency or

the Authority;

(10) Conditions at or near the sewerage facilities, or any portion thereof, which cause, or may

cause, an Agency or Authority to be in violation of the requirements of law.

(11) Pollutants introduced into the sewerage facilities which pass through or interfere with the

operation or performance of the sewerage facilities.

(b) No person shall discharge hazardous waste into the sewerage facilities except pursuant to

a permit issued by Authority’s Manager upon a determination that such hazardous waste will not

constitute or create a detrimental discharge.

(c) Except pursuant to an express applicable Pretreatment Standard, no user shall ever

increase the use of process water or, in any other way, attempt to dilute a discharge of waste or

wastewater as a partial or complete substitute for adequate treatment to achieve compliance with a

Pretreatment Standard. The Authority may impose limitations upon mass emission rates on users which

are using dilution to meet applicable Pretreatment Standards or in other cases where the imposition of

mass limitations is appropriate.


page 10

SECTION 2.2. SPECIFIC SOURCES PROHIBITED. No person shall discharge, cause to be

discharged, or permit to be discharged, either directly or indirectly into the sewerage facilities, waste or

wastewater from any of the following sources unless a permit therefor is issued by an Agencyts Director

subject to the concurrence of Authority’s Manager:

(a) Any stormwater, groundwater, rainwater, street drainage, sub-surface drainage, or yard

drainage;

(b) Any unpolluted water, including, but not limited to, cooling water, process water, or

blow-down water from cooling towers or evaporative coolers;

(c) Waste from garbage grinders, provided, that wastes generated in preparation of food

normally consumed on the premises may be so discharged, provided, further, that such

grinders shall be of such design and capacity to shred waste used therein such that all

waste particles shall be carried freely under normal flow conditions into and through the


(d) Any wastes or wastewater, or any object, material, or other substance directly into a

manhole or other opening into the sewerage facilities other than wastes or wastewater

through an approved building sewer;

(e) Any holding tank waste, provided, that such waste may be placed into facilities designed

to receive such wastes and approved by an Agency’s Director;

(f) Any radioactive waste, provided, that persons authorized to use radioactive materials by

the State Department of Health or other governmental agency with regulatory jurisdiction

over the use of radioactive materials may discharge, cause to be discharged, or permit to

be discharged such wastes, provided that such wastes are discharged in strict

conformance with current California Radiation Control regulations (California Code of

Regs. Title XVII, Ch. 5, Sub.Ch. 4, Group 3, Art. 5), and federal regulations and

recommendations for safe disposal of such wastes, and, provided further, that the person

so acting does so in compliance with all applicable rules and regulations of all other

regulatory agencies having jurisdiction over the matter.

SECTION 2.3. WASTEWATER STRENGTH LIMITATIONS. Except pursuant to a permit

issued under Section 2.5, no Person shall discharge, cause to be discharged, or permit to be discharged

any Wastewater into the Sewerage Facilities containing any of the following Wastewater constituents in

excess of the maximum allowable amounts respectively hereinafter established therefor:


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Amount in Milligrams

Wastewater Constituent per Liter (mg/L) (a) Arsenic 0.1

(b) Cadmium 0.04

(c) Chromium 0.2

(d) Copper 0.2

(e) Lead 0.2

(f) Mercury 0.002

(g) Nickel 0.06

(h) Silver 0.1

(i) Zinc 1.0

(j) Pheno1ic Compounds 2.6

(k) Cyanide 0.06

(1) Polycyclic Aromatic Hydrocarbons 0.2

(m) Methylene Chloride 0.07

(n) Chloroform 0.03

(o) Perchloroethylene 0.03

(p) Benzene 0.002

(q) Carbon Tetrachloride 0.001

(r) Carbon Disulfide 0.008

SECTION 2.4. SPECIFIC WASTES PROHIBITED. No Person shall discharge, cause to be

discharged, or permit to be discharged any Wastewater into the Sewerage Facilities:

(a) The temperature of which is higher that 150° Fahrenheit (65° centigrade); (b) Containing more than 300 mg/l of oil or grease of animal or vegetable origin; (c) Containing more than 100 mg/l of oil or grease of mineral or petroleum origin; (d) Having a pH lower than 6.0 or having a corrosive property capable of causing damage or

hazard to structures or equipment of the Sewerage Facilities, or any portion thereof; (e) Any sand, grit, straw, metal, glass, rags, feathers, paper, tar, plastic, wood, leaves, garden

clippings, manure, dead animals, offal, or any other solid or viscous substance capable of causing obstruction to the flow in the Sewerage Facilities, or which in any way interferes with the proper operation of the Sewerage Facilities;

(f) Any Pollutant not otherwise specifically prohibited in these regulations, in sufficient

quantities to constitute a hazard to humans or animals, or to create a hazard to the Sewerage Facilities, or to injure or interfere with the operation thereof;

(g) Any Waste containing suspended solids not otherwise specifically prohibited under the

provisions of these regulations, the characteristics or quantity of which require or requires unusual attention, treatment, or expense in handling or treating in the Sewerage Facilities, or any portion thereof;

(h) Any Waste streams with a closed cup flashpoint of less than l40 Fahrenheit

(i) Any trucked or hauled Wastes except at points designated by the Authority or Agency.


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SECTION 2.5. SPECIFIC USER LIMITATIONS. Notwithstanding the limitations upon the

characteristics or quantity of Wastewater discharged, caused to be discharged, or permitted to be

discharged into the Sewerage Facilities pursuant to this Article, Authority’s Manager may, in connection

with the issuance of permits pursuant to the provisions of Article IV, establish additional or different

specific limitations on Wastewater strength, or deny an application for any such permit, upon a finding

by him or her that:

(a) The limitations set forth in this Article may not be sufficient to protect the operation of

the Sewerage Facilities, or any portion thereof, or the Waste or Wastewater proposed to

be discharged constitutes a hazard to, or an unreasonable burden upon, such operation, or

otherwise causes or may cause, or significantly contributes, or may contribute, to a

violation of Authority’s NPDES Permit; or

(b) The limitations set forth in Section 2.3 may be unreasonably restrictive when applied to a

specific User or User Category and the proposed discharge, if allowed, when added to the

total amount authorized by existing permits issued pursuant to these regulations will not

cause the amount of any of the following Wastewater constituents to exceed the

aggregate maximum allowable amount respectively hereinafter established therefore:

Aggregate Maximum Permitted Amounts Wastewater Constituent in Pounds per day (lbs/day) (i) Arsenic 11.4 (ii) Cadmium 6.11 (iii) Chromium 31.3 (iv) Copper 19.9 (v) Lead 22.7 (vi) Mercury 0.915 (vii) Nickel 6.82 (viii) Silver 12.5 (ix) Zinc 113.0 (x) Phenolic Compounds 385.0 (xi) Cyanide 5.25 (xii) Polycyclic Aromatic Hydrocarbons 15.2

(c) Notwithstanding the provisions of (a) and (b) above, in no event shall any permit be

issued which allows an Interfering Discharge, or a Pass Through, or allows a violation of

a Categorical Standard.

ARTICLE III. WASTEWATER VOLUME DETERMINATION.

SECTION 3.1. GENERAL. For the purposes of these regulations unless otherwise provided

pursuant to the provisions of this Article, wastewater volumes shall be determined upon the basis of

volumes of freshwater, including all sources of non-wastewater, used by, or furnished to, a user.


page 13

SECTION 3.2. METERING. Upon application of a user, and upon a finding by Authority’s

Manager, subject to the concurrence of the Agency’s Director of the Agency within the boundaries of

which the premises to be served by the sewerage facilities is located, that a significant portion of

freshwater or non-wastewater, received by the user from any metered source does not flow into the

sewerage facilities because of the principal activity of the user, or by reason of removal of wastewater

by other means, Authority’s Manager, with the concurrence of said Agency’s Director, may authorize

determination of the volume of wastewater discharge to be made by an appropriate metering device.

Upon such determination, a metering device, of a type approved by Authority’s Manager, and at a

location approved by Authority’s Manager, shall be installed at the user’s expense. Such metering

device shall measure either the amount of wastewater discharged into the sewerage facilities, or the

amount of freshwater or non-wastewater diverted from the sewerage facilities. Upon installation, such

meters shall be maintained and tested periodically for accuracy in accordance with requirements

established by Authority’s Manager, all of which maintenance and testing shall be at the expense of the

user.

SECTION 3.3. EXCEPTIONS - ESTIMATED VOLUME. In lieu of use of a metering device

as specified in section 3.2, and upon a determination by Authority’s Manager, subject to the concurrence

of the Agency’s Director of the Agency within the boundaries of which the premises to be served by the

sewerage facilities is located, that it would be unnecessary or impracticable to install, maintain, or

operate such metering device, wastewater volume discharged by a user into the sewerage facilities may

be based upon an estimate thereof determined by Authority’s Manager, with the concurrence of said

Agency’s Director. The determination of such estimated wastewater volume shall be based upon such

factors as the number of fixtures through which wastewater flows into the sewerage facilities from the

user’s premises, seating capacity of buildings or improvements upon the premises, the population

equivalent associated with the premises, annual production of goods and services related to the premises,


page 14

or other factors reasonably relating to water use, wastewater volume calculations, and/or diversions of

wastewater flow from the sewerage facilities.

SECTION 3.4. BASIS FOR DETERMINATION, AGENCY’S CONCURRENCE. The

determination by Authority’s Manager to require measurement of wastewater volumes by metering

devices or calculation of estimated flows pursuant to Section 3.2 or 3.3, respectively, shall be based

upon such data, statistics, description of premises to be served by the sewerage facilities and operations

conducted thereon together with corresponding reasons submitted by the user in support of use of such

metering devices or calculations, as the case may be, and such other information deemed necessary or

appropriate by Authority’s Manager to enable him or her to make a reasoned determination.

ARTICLE IV. REPORTS, PERMITS AND ADMINISTRATION.

SECTION 4.1. REPORTS.

SECTION 4.1.1. GENERAL. Reports required to be submitted pursuant to permits issued under

these regulations or otherwise required by the Act, or regulations implementative thereof, including, but

not limited to, compliance schedule progress reports, reports on compliance with categorical deadlines,

periodic compliance reports, notice of changed discharge reports, and reports from noncategorical

industrial users, shall conform to pertinent provisions of such permits, these regulations, or other

requirements of law, and shall be submitted in accordance with applicable filing requirements,

including, but not limited to, deadlines.

SECTION 4.1.2. PERIODIC DISCHARGE REPORTS. In addition to all other reports which

may be required to be submitted by a user, upon a determination by Authority’s Manager, or the

Agency’s Director of the Agency within the boundaries of which the premises to be served by the

sewerage facilities is located, that such information is necessary or appropriate for them reasonably to

carry out their respective duties and to exercise their respective authority under these regulations, each

or either of them may require that any person discharging, causing to be discharged, permitting to be

discharged, or proposing to discharge wastewater into the sewerage facilities shall file a periodic


page 15

discharge report, the cost of which shall be borne by such person. Such report may include, but shall not

necessarily be limited to, information relating to the nature of manufacturing, fabricating, or other

processes, fresh or non-wastewater volumes, wastewater volumes, rates of flow, mass emission rates,

production quantities, hours of operation, number and classification of employees, or other information

relating to the generation of waste, including wastewater constituents and characteristics of the pertinent

wastewater discharge. Authority’s Manager or said Agency’s Director may also require that such reports

include chemical constituents and quantity of liquid or gaseous materials stored on the premises relating

to such discharge, even though such materials are not normally discharged into, or become a part of the

wastewater in, the sewerage facilities.

Such reports shall be in addition to self-monitoring reports, information furnished in connection

with wastewater discharge permits, or other permits authorized under these regulations. The reports

authorized and required under this section shall be filed with Authority’s Manager or said Agency’s

Director periodically and/or at such other times as either of them may reasonably require.

SECTION 4.1.3. SIGNATORY REQUIREMENTS. Baseline and Monitoring Reports, 90 Day

Compliance Reports, and Periodic Reports on Continued Compliance (as said reports are defined and

described in Subdivisions (b), (d) and (e) of Section 403.12 of Title 40, Code of Federal Regulations,

and such other reports as may be specified by Authority’s Manager, shall be signed by an authorized

representative of the industrial user, or other user or other person required to submit such report. An

authorized representative may be:

(1) A principal executive officer of at least the level of vice president, if the industrial user,

other user or other person submitting such report is a corporation;

(2) A general partner or proprietor if the industrial user, other user, or other person

submitting such report is a partnership or sole proprietorship, respectively; or


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(3) A duly authorized representative of the individual designated in (1) or (2) above, if such

representative is responsible for the overall operation of the facility with respect to which such report

pertains.

SECTION 4.1.4. CERTIFICATION. Reports required to be submitted pursuant to permits

issued under these regulations, or otherwise required that by these regulations, by the Act, or by

regulations implementative thereof, shall, unless otherwise specified by Authority’s Manager, include

the following certification of the signatory thereto:

"I certify under penalty of law that this document and all attachments were prepared

under my direction or supervision in accordance with a system designed to assure that qualified

personnel properly gathered and evaluated the information submitted. Based on my inquiry of

the person or persons directly responsible for gathering the information, or the person or persons

who has or have knowledge of the substance of the information, the information submitted is, to

the best of my knowledge and belief, true, accurate and complete. I am aware that there are

significant penalties for submitting false information, including the possibility of a fine and

imprisonment for knowing violations."

SECTION 4.2. MANDATORY WASTEWATER DISCHARGE PERMITS. No significant

industrial user shall connect to, or discharge waste or wastewater into, the sewerage facilities without

first obtaining a wastewater discharge permit therefor. No significant industrial user, or other user

discharging, or proposing to discharge wastewater having characteristics or quantities equivalent to that

of a significant industrial user whose premises are connected to the sewerage facilities upon the effective

date of these regulations shall discharge wastewater into the sewerage facilities on or after 90 days after

such effective date without a wastewater discharge permit therefor.

SECTION 4.3. DISCRETIONARY WASTEWATER DISCHARGE PERMITS. A wastewater

discharge permit may be issued to any user, upon application therefor, who (1) requests that charges and

fees established pursuant to these regulations be based upon an estimated volume of wastewater

discharged, or to be discharged, into the sewerage system, or (2) establishes to the satisfaction of

Authority’s Manager that wastewater proposed to be discharged from such user’s premises into the

sewerage system has, or will have, wastewater strength characteristics less than the normal range for the


page 17

user classification to which such user is assigned, by reason of pretreatment, process changes, or other

factors affecting such wastewater characteristics, or (3) requests or requires a permit pursuant to the

provisions of Sections 2.1(b), 2.2., or 2.5.

SECTION 4.4. WASTEWATER DISCHARGE PERMITS.

SECTION 4.4.1. APPLICATIONS FOR MANDATORY WASTEWATER DISCHARGE

PERMITS. Applications for mandatory permits required under Section 4.2 shall be made to Authority’s

Manager in writing in such form as Authority’s Manager shall require, and shall set forth the following:

(a) The name and address of the applicant/user and the business name or other designation by which the premises or facility located thereon to which the application pertains is known, the address of said premises or facility (if different than the name and address of the applicant), and the name or names of the manager or other person in charge of said facility or premises;

(b) A list of any environmental control permits held by the applicant for the facility or

premises;

(c) A brief description of the nature, average rate of production and standard industrial classification of the operation(s) carried out by the applicant;

(d) Flow measurement showing average daily and maximum daily flow from each process

stream to which the application pertains;

(e) Wastewater constituents and characteristics of the wastewater proposed to be discharged into the sewerage facilities, including, but not limited to, those categories thereof described in Sections 2.2, 2.3, and 2.4, the presence and amount of which shall be determined by a laboratory competent to test and describe such constituents and characteristics, and approved by Authority’s Manager;

(f) The time and duration of the proposed wastewater discharge; (g) The average and thirty minute peak wastewater flow rates proposed to be discharged,

including daily, monthly, and seasonal variations, if any; (h) Site plans, floor plans, mechanical and plumbing plans, in detail necessary or appropriate

to show and to describe all building sewers and appurtenances by size, location and elevation;

(i) A description of the activities, facilities, and plant processes conducted, or proposed to be

conducted on the premises, including, but not necessarily limited to, all materials manufactured, fabricated, or processed, and the types of materials which are or could be discharged into the sewerage facilities;

(j) Identification of pretreatment standards applicable to each process;

(k) A statement, reviewed by an authorized representative of the applicant and certified by a

qualified professional, stating whether categorical standards are being or will be met on a consistent basis and, if not, whether additional operation and maintenance and/or


page 18

additional pretreatment is required for the applicant to meet such standards and requirements;

(1) Requirements, if any, for additional pretreatment and/or operation and maintenance in

order to meet categorical standards and the shortest schedule by which the applicant will provide such additional pretreatment and/or operation and maintenance (the completion date in said schedule shall not be later than the compliance date established for any applicable categorical standard);

(m) Such other information deemed necessary by Authority’s Manager to determine the effect

upon the sewerage facilities of the proposed discharge or activities related thereto, or otherwise reasonably necessary to enable Authority’s Manager or the Agency’s Director of the Agency within the boundaries of which the premises to be served by the sewerage facilities is located, to carry out the provisions of these regulations, or any other requirements of law.

SECTION 4.4.2. APPLICATIONS FOR DISCRETIONARY WASTEWATER DISCHARGE

PERMITS. Applications for wastewater discharge permits which may be issued pursuant to Section

2.1(b), Section 2.2, Section 2.5 and Section 4.3, shall be made to Authority’s Manager in writing in such

form as Authority’s Manager shall require and shall set forth the following:

(a) The name and address of the applicant/user and the business name (if applicable) or other designation by which the premises or facility located thereon to which the application pertains is known, the address of said premises or facility (if different then the name and address of the applicant), and the name or names of the manager or other person in charge of said facility or premises;

(b) The time and duration of the proposed wastewater discharge; (c) A description of the activities, facilities, or other operations pertaining to the proposed

discharge including, but not necessarily limited to, types of materials which are or could be discharged into the sewerage facilities;

(d) Such other information deemed necessary by Authority’s Manager to determine the effect

upon the sewerage facilities of the proposed discharge or activities related thereto, or otherwise reasonably necessary to enable Authority’s Manager or the Agency’s Director of the Agency within the boundaries of which the premises from or with respect to which the proposed discharge is located, to carry out the provisions of these regulations, or any other requirements of law.

SECTION 4.4.3. SIGNATORY REQUIREMENTS. Applications for permits shall be signed by

the persons designated in Section 4.1.3 (pertaining to signatories for certain reports) and shall contain

the certification specified in Section 4.1.4 (pertaining to certification for certain reports).

SECTION 4.4.4. ISSUANCE. Upon evaluation of and approval of all pertinent data and

information, Authority’s Manager shall issue a wastewater discharge permit, subject to the consent of


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the Agency’s Director of the Agency within the boundaries of which the premises to be served by the

sewerage facilities is located, and further subject to terms and conditions required or authorized under

the provisions of these regulations, the said Agency’s regulations pertaining to use of its sewerage

facilities not inconsistent with these regulations, and deemed necessary or appropriate by Authority’s

Manager or said Agency’s Director, as the case may be, to carry out the purposes and intent of these

regulations or said Agency’s regulations.

SECTION 4.5. PERMIT CONDITIONS.

SECTION 4.5.1. GENERAL. Wastewater discharge permits authorized under these regulations

shall be subject to all applicable provisions and requirements of these regulations, the regulations of the

Agency within the boundaries of which the premises to be served by the sewerage facilities is located

and which are implementative hereof and not inconsistent with the provisions of these regulations, and

to all other applicable requirements of law.

SECTION 4.5.2. EXPRESS CONDITIONS. Permits authorized under these regulations may

include any or all of the following:

(a) The unit charge or schedule of charges and fees for the service and use of the sewerage

facilities to be paid by the permittee, and the terms and conditions of such payment;

(b) The allowable average and maximum wastewater constituents and characteristics thereof

permitted to be discharged into the sewerage facilities;

(c) Limitations upon time and rate of wastewater discharge, or requirements for flow

regulations and equalization thereof;

(d) Requirements for the installation of inspection, sampling or testing facilities;

(e) Pretreatment requirements;

(f) Specifications for monitoring programs which may include, but shall not necessarily be

limited to, sampling locations, frequency and method of sampling, number, types and

standards for tests, and reporting schedule;

(g) Requirements for submission of technical reports or wastewater discharge reports;

(h) Requirements for maintaining, for not less than 3 years, plant records relating to the

wastewater discharge as specified by Authority’s Manager and providing for access


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thereto of Authority’s Manager or the Agency’s Director of the Agency within the

boundaries of which the premises to be served by the sewerage facilities is located,

including provisions pursuant to which such records shall be made available for copying

and inspection by Authority’s Manager or said Agency’s Director;

(i) The mean and maximum mass emission rates, or other appropriate limits when

incompatible pollutants are proposed to be discharged into, or are present in, the

permittee’s wastewater discharge;

(j) Requirements for submission, prior to closure or abandonment of the permittee’s

facilities, of a closure plan detailing the means by which the permittee’s sanitary

facilities, including pretreatment facilities, shall be secured upon such closure or

abandonment; and

(k) Such other conditions, requirements, or provisions deemed appropriate by Authority’s

Manager or the aforesaid Agency’s Director to ensure compliance with the provisions of

these regulations, or said Agency’s regulations, or other requirements of law.

SECTION 4.6. DURATION OF PERMITS. Wastewater discharge permits authorized under

these regulations shall be effective for the period described therein, but in any event, for no longer than

five years from the date of issuance. The period specified in a permit may be less than a year, may be

expressed in years, or may specify a date of expiration.

Upon expiration of the express term of wastewater discharge permit, the term thereof shall be

deemed renewed automatically for successive 1-year periods, the first of which shall commence upon

the day next following the last day of the express term; provided, however, that in the event Authority’s

Manager gives written notice to the permittee of the termination or expiration of the permit not less than

30 days prior to the expiration of the express term thereof, or prior to the expiration of any successive 1-

year term thereof, then a new permit shall be required subject to the provisions of these regulations.

Every permit shall be subject to modification, amendment, or other revision during the term

thereof by Authority’s Manager with the concurrence of the Agency’s Director of the Agency within the

boundaries of which the premises to which the permit pertains is located, as determined necessary by

Authority’s Manager and said Agency’s Director in order to obtain compliance by the user with the

requirements of these regulations, or other requirements of law. To the extent practicable, Authority’s

Manager shall give written notice to a permittee of any proposed modification, amendment or revision


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not less than 30 days prior to the effective date of such modification, amendment or revision. To the

extent reasonably necessary or appropriate, Authority’s Manager may specify a reasonable time

schedule for compliance with any new conditions, provisions, or requirements established by

modification, amendment or revision to a permit.

SECTION 4.7. NON-ASSIGNABILITY. Wastewater discharge permits shall be personal to

each permittee, and shall relate only to the use or operation described therein. No person shall assign,

reassign, sell, lease, sublet, or otherwise transfer a wastewater discharge permit, or any interest therein,

to any person other than the permittee, or use, cause to be used, or permit to be used, such permit in

connection with a different premises, or a different operation than that specified in the permit, or with a

new, expanded, or modified operation.

SECTION 4.8. MONITORING FACILITIES. Authority’s Manager may require a user to

construct, operate, and maintain, at the user’s own expense, monitoring, sampling, or metering facilities

or other equipment to allow inspection, sampling, and flow measurement of the user’s building sewer, or

internal drainage systems, or waste or wastewater discharges. Such monitoring, sampling, or metering

facilities or equipment shall be located on the user’s premises; provided, however, that Authority’s

Manager may allow such equipment or facility to be constructed upon public property adjacent to the

user’s premises upon a determination by Authority’s Manager, with the concurrence of the Agency’s

Director of the Agency within the boundaries of which the premises to which the permit pertains is

located, that location of such equipment or facilities upon the user’s premises would be impracticable or

cause unnecessary or undue hardship. In the event that Authority’s Manager makes the foregoing

determination with the concurrence of said Agency’s Director, and the public property upon which such

facilities or equipment are proposed to be constructed or installed is outside said Agency’s boundaries,

the user shall obtain permission for such installation or construction, and for the maintenance and

operation of such facilities or equipment, from the governmental Agency which owns or exercises

managerial control over such property.


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Monitoring, sampling, or metering facilities or equipment to be provided, installed, maintained

and operated pursuant to the provisions of this section shall be so situated, constructed and installed as to

permit safe and immediate access thereto by Authority’s Manager; provided, however, that Authority’s

Manager may, at the option of the user, secure such equipment or facilities with a lock furnished by

Authority’s Manager, at the expense of the user. The user shall provide sufficient space, as determined

by Authority’s Manager, at or near such equipment or facilities so as to allow ready and accurate

monitoring, sampling, and compositing of samples for analysis. Such equipment and facilities, and the

sampling and measuring equipment to be maintained and operated in connection therewith, shall be so

maintained and operated at all times in a safe and proper condition, by and at the expense of the user.

Monitoring, sampling or metering equipment or facilities to be furnished pursuant to the

provisions of this section shall be provided in accordance with all reasonable requirements of

Authority’s Manager relating thereto, and all applicable construction standards and specifications of the

Agency, or other governmental authority regulating such matters wherein such equipment or facilities

are located. Installation and construction of such facilities or equipment shall be completed within 90

days following written notification requiring such installation or construction from Authority’s

Manager; provided, however, that Authority’s Manager may, at his or her discretion, extend the time of

performance of such installation or construction.

SECTION 4.9. INSPECTION AND SAMPLING. Authority’s Manager is hereby authorized to

inspect the premises, and inspect and copy the records, of any user at all reasonable times to ascertain

whether such user is in compliance with the provisions of these regulations, or the provisions of any

permit issued pursuant to these regulations. Owners or occupants of premises where wastewater is

created, held or discharged shall allow Authority’s Manager ready access at all such reasonable times to

all parts of the premises for the purposes of inspecting the facilities and appurtenances thereon,

inspecting and copying records, sampling, monitoring, or performing any or all of the duties reasonably

necessary or appropriate in carrying out or enforcing the provisions of these regulations, or any permit


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issued pursuant to these regulations. Authority’s Manager shall further have the right to install and use

on the user’s premises such devices as are reasonably necessary or appropriate to conduct sampling,

metering, or monitoring operations or other of the aforesaid duties. In the event a user has established

security measures requiring identification and clearance prior to entry onto such user’s premises, the

user shall furnish and provide such identification or clearance to Authority’s Manager so as to permit

ready access of Authority’s Manager to the premises for the purposes described in this section.

SECTION 4.10. PRETREATMENT. Pretreatment of wastes or wastewater shall be furnished

by every user on the user’s premises when such waste or wastewater, prior to pretreatment, does not

comply with the minimum acceptable requirements and criteria therefor for discharge into the sewerage

facilities as set forth in Article II. Such pretreatment facilities shall be provided and maintained at the

user’s expense, and shall be of sufficient design and capacity to pretreat waste or wastewater discharged

from the premises into the sewerage facilities to a level meeting such minimum requirements, and such

other requirements established by Authority’s Manager reasonably necessary or appropriate for the

sewerage facilities to treat adequately such waste or wastewater under normal operating and treatment

conditions.

Prior to the installation of pretreatment facilities, plans and specifications therefor shall be

submitted to Authority’s Manager, together with such data and descriptive material relating to the waste

or wastewater prior to, and after such proposed pretreatment as Authority’s Manager may require, in

order that Authority’s Manager may ascertain the wastewater constituents and characteristics and

volume of the wastewater discharge after pretreatment. The user shall make such modifications,

amendments or revisions to said plans and specifications as Authority’s Manager may reasonably

require in order that the provisions of these regulations, or any permit issued, or to be issued pursuant to

these regulations, shall be complied with. Upon approval of such plans and specifications by Authority’s

Manager, the user may proceed with the construction of the pretreatment facilities in conformance

therewith; provided, however, that such approval shall not be deemed to waive or modify any other


page 24

requirement of these regulations, or of any permit issued pursuant to these regulations, or of any other

requirements of law.

Approval of plans and specifications of pretreatment facilities pursuant to this section shall not

relieve the user from the responsibility of modifying such pretreatment facilities as necessary to produce

effluent therefrom complying with all pertinent provisions of these regulations, or any permit issued

pursuant to these regulations, or any other requirements of law. Any proposed cessation of use, or

alteration, modification, or other change to approved pretreatment facilities or any portion thereof, or

any change in method of operation thereof, shall be reported to Authority’s Manager prior to

commencement thereof, and shall be subject to the approval of Authority’s Manager. Such approval may

be withheld, granted, or granted subject to such terms, conditions, or requirements as Authority’s

Manager may reasonably require in order to ensure compliance with the provisions of these regulations,

or any permit issued pursuant to the provisions of these regulations.

SECTION 4.11. ACCIDENTAL DISCHARGES. Every user shall provide protective measures

against accidental or unauthorized discharges of prohibited wastes, wastewater constituents or

characteristics, or volumes into the sewerage facilities as set forth in Article II, or as may be otherwise

set forth in any permit issued pursuant to these regulations. Such measures shall consist of operational or

other procedures and/or facilities as determined reasonably necessary or appropriate by Authority’s

Manager. All costs of such measures shall be borne by the user.

Authority’s Manager may specify standard procedures and/or facilities for each classification of

user, and, to the extent so specified, he or she is hereby authorized and directed to require the institution

and use of such procedures, and the installation and construction of such facilities for each such

classification. Alternatively, Authority’s Manager may require any user to propose such procedures

and/or facilities, which proposals shall be submitted to Authority’s Manager for review, with such

supporting plans, specifications, data, explanations, or other matters as may reasonably be required by

Authority’s Manager in order to ascertain the effectiveness of the procedures and/or facilities proposed.


page 25

Authority’s Manager may require such revisions, amendments, modifications, or other changes to such

proposals, or approve, or reject the same, as Authority’s Manager deems reasonably necessary or

appropriate in order that such proposals ensure protection against accidental or unauthorized discharge.

SECTION 4.12. PUBLIC INFORMATION. All information and data furnished by, or

regarding the operations of, a user obtained from reports, questionnaires, permit applications, permits,

monitoring programs, inspections, or from other sources provided or required under the provisions of

these regulations shall be available to the public or other governmental agencies without restriction

unless the user requests in writing that such information be maintained confidential, and establishes to

the satisfaction of Authority’s Manager that the disclosure of the information to other persons would

result in unfair competitive disadvantage to the user; provided, however, that in no event shall

wastewater constituents, characteristics, or volumes be deemed confidential information.

Notwithstanding the foregoing, information approved by Authority’s Manager as confidential shall be

available for use by an Agency, the Authority, the State, the federal government, or any official or

agency of said entities, in connection with enforcement proceedings, or any judicial proceedings to

which the user is a party.

SECTION 4.13. SPECIAL AGREEMENTS. The provisions of these regulations shall not be

deemed a limitation upon the Authority or an Agency to enter into agreements, and to recover costs

relating thereto, with any user relating to treatment, pretreatment, or other matters in furtherance of the

provisions of these regulations and the purposes thereof, and not inconsistent therewith, when unique,

unusual or extraordinary circumstances require such special agreements; provided, however, that no

such agreement shall authorize an extension of the final dates for compliance with required federal

standards nor waive such standards.

ARTICLE V. CHARGES AND FEES.

SECTION 5.1. USER CLASSIFICATIONS, ADMINISTRATION. For the purpose of

imposing the charges and fees in this Article V authorized, Authority’s Commission shall, by resolution,


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establish user classifications based upon standard limitations upon wastewater characteristics,

constituents, and volumes uniformly applicable to users within each such classification, and shall

establish terms and conditions for payment and collection of such charges and fees.

SECTION 5.2. GENERAL. Authority’s Commission shall, by resolution, establish a schedule

of charges and fees to be imposed by Authority and collected from all owners of premises served by the

sewerage facilities, or from users of the sewerage facilities, based upon user classifications, for the use

of the sewerage facilities and services furnished to said premises or users, in such amounts as will

provide for each user to pay his or her proportionate share of the costs of operation and maintenance

(including replacement) of the sewerage facilities; provided, that such charges shall also provide for

payment by industrial users of the sewerage facilities of that portion, if any, of Authority’s treatment

works which is allocable to the treatment of such industrial user’s waste. The schedule of fees and

charges authorized hereunder shall also compensate Authority for services ancillary to the foregoing.

SECTION 5.3. SPECIFIC CHARGES AND FEES. Authority’s Commission may adopt

charges and fees which may include, but shall not necessarily be limited to:

(a) Fees for reimbursement of costs of establishing and operating Authority’s pretreatment program;

(b) Fees for monitoring, inspections and surveillance procedures; (c) Fees for reviewing accidental discharge procedures and construction; (d) Fees for processing permit applications and issuing permits; (e) Fees for processing and hearing appeals; (f) Fees for consistent removal by Authority of pollutants otherwise subject to Authority’s

pretreatment requirements;

(g) Such other fees and charges as Authority may deem necessary or appropriate to carry out the provisions of these regulations or otherwise to reimburse Authority for the transmission, treatment and disposal services provided by Authority.

SECTION 5.4. COMBINED FEES AND CHARGES. To the extent convenient or appropriate,

certain of the fees and charges authorized under this Article V may, with the consent of the governing

bodies of each of the Agencies, be combined with fees and charges imposed and collected by the


page 27

Agencies, respectively. Nothing herein contained shall be deemed a limitation upon the obligation of the

Agencies to impose and collect uniform charges pursuant to the Joint Exercise of Powers Agreement

establishing Authority and described in Section 1.3.4.

SECTION 5.5. AGENCIES’ CHARGES EXCLUDED. Nothing contained in this Article V

shall be deemed a limitation upon each of the Agencies to impose and collect such fees and charges as

they, respectively, may establish with respect to that portion of the sewerage facilities furnished by said

Agencies, or with respect to ancillary services or facilities likewise so furnished.

ARTICLE VI. ENFORCEMENT.

SECTION 6.1. RESPONSIBILITY. The primary responsibility for enforcement of the

provisions of these regulations shall be vested in Authority’s Manager; provided, however, that said

Manager shall be, and he or she hereby is, authorized and empowered to delegate his or her authority

hereunder to such officers, employees or agents of Authority as he or she shall designate; and, provided

further, that field inspectors or other employees of Authority, upon written certification thereof from

Authority’s Manager to the respective Agencies’ Directors, are hereby authorized to act as enforcement

agents of each of their respective agencies with respect to regulations consistent herewith adopted said

by Agencies in accordance with the provisions of Section 6.14 hereinafter.

SECTION 6.2. UNAUTHORIZED DISCHARGES.

SECTION 6.2.1. NOTIFICATION. Every user shall notify Authority’s Manager immediately

upon discharging wastes or wastewater in violation of the provisions of these regulations, or any permit

issued pursuant to these regulations. A user who discharges, causes to be discharged, or permits to be

discharged such wastes or wastewater shall, within 15 days of the occurrence thereof, submit a written

report to Authority’s Manager describing the cause or causes of such unauthorized discharge, and

measures taken, or proposed to be taken, to prevent future similar occurrences. Such report shall not

relieve any user of liability for any expense, loss, or damage suffered or incurred by an Agency or the

Authority, directly or indirectly, by reason of such unauthorized discharge. Such report shall not relieve


page 28

or absolve any person from civil liabilities, or imposition of civil or criminal penalties in any manner

whatsoever.

SECTION 6.2.2. NOTICES TO EMPLOYEES. Every non-domestic user, every user issued a

mandatory wastewater discharge permit pursuant to Section 4.2, and every user issued a discretionary

wastewater discharge permit pursuant to Section 4.3 shall prominently post a notice on the premises to

which the permit pertains advising of the requirement to notify Authority’s Manager of any

unauthorized discharge, including the telephone number of Authority’s Manager to be called in the

event of such discharge. Authority’s Manager may require any user to inform and advise his or her

officers, agents, and employees of any particular provisions of these regulations, any permit issued

pursuant to these regulations, or other requirements of law, or of any other information which may be of

assistance in ensuring compliance with these regulations, such permit, or other requirements of law.

SECTION 6.3. CEASE AND DESIST ORDERS. Upon a determination by Authority’s

Manager that a discharge of waste or wastewater has occurred, or is occurring, or is about to occur in

violation of any provision of these regulations, or of any provision of any permit issued pursuant to these

regulations, Authority’s Manager may issue an order to cease and desist such discharge, or practice, or

operation likely to cause such discharge, and further order such person to:

(a) Comply forthwith with the provisions of these regulations, or the provisions of any

permit issued pursuant to these regulations;

(b) Comply in accordance with a time schedule established by Authority’s Manager; and/or

(c) Take appropriate remedial or preventive action.

SECTION 6.4. TIME SCHEDULES. Upon a determination by Authority’s Manager that a

discharge of waste or wastewater has occurred, or is occurring, or is about to occur in violation of the

provisions of these regulations, or in violation of any provision of a permit issued pursuant to these

regulations, Authority’s Manager may require the person or user having so discharged, or discharging,

or about to discharge, to submit for approval, subject to such modifications, terms and conditions as


page 29

Authority’s Manager reasonably deems necessary or appropriate, a detailed time schedule of specific

actions which the person or user shall take in order to eliminate or prevent such violation or violations.

SECTION 6.5. EMERGENCY CORRECTIONS. In the event repairs, construction, or other

public work is performed on any premises pursuant to any provision of law relating to the emergency

performance of public work and the expenditure of public funds therefor, or pursuant to any other

provision of law authorizing public work on private property in order to correct, eliminate or abate a

condition upon such premises which threatens to cause, causes, or caused damage to the sewerage

facilities or which otherwise threatens to cause, causes, or caused a violation of any provision of these

regulations, or of any permit issued pursuant these regulations, or of any other requirement of law, the

user responsible for the occurrence or condition giving rise to such work, the occupant and the owner of

the premises shall be liable for such public expenditures, jointly and severally to the Authority and any

Agency or Agencies having made such expenditures.

SECTION 6.6. DAMAGES TO SEWERAGE FACILITIES. In the event damages are caused

to the sewerage facilities, or any portion thereof, by reason of a waste or wastewater discharge from any

premises in violation of the provisions of these regulations, or any permit issued pursuant to these

regulations, or of any other requirement of law, the user responsible for the occurrence or condition

giving rise to such damages, the occupant and the owner of the premises shall be liable, for the full

amount thereof, jointly and severally, to the Authority and/or any Agency or Agencies having incurred

such damages.

SECTION 6.7. EMERGENCY TERMINATION OF SERVICE. Authority’s Manager or an

Agency’s Director, as applicable, are hereby authorized and empowered immediately to terminate

sanitary sewerage service to any premises for the purpose of halting or preventing any discharge into the

sewerage facilities which the Manager or Agency’s Director, as applicable, reasonably determines to

constitute a detrimental discharge, or otherwise significantly imperils the public health, safety or

welfare. In such case, the Manager or said Agency’s Director, as applicable, shall make a reasonable


page 30

effort to notify the user and/or the owner of the premises prior to halting or preventing such discharge;

provided, however, that the failure of the user or owner to receive such notice shall not affect any action

taken hereunder, so long as the determination of detrimental discharge or imperilment of the public

health, safety or welfare made by Authority’s Manager or said Agency’s Director, as applicable, was

reasonable and made in good faith.

In the event that the Manager or an Agency’s Director, as the case may be, terminates sanitary

sewerage service to any premises pursuant to the provisions of this section, the Manager or said

Agency’s Director, shall notify the user and the owner and occupant of the premises (if such persons are

not the same as the user) that sanitary sewerage service has been terminated, and shall provide said user,

owner or occupant an opportunity to be heard on the matter of termination not more than ten (10) days

following such termination. Notice of such hearing shall be given in the manner provided for giving

notices of violation pursuant to Section 6.9 and such hearing shall be conducted in the manner provided

for enforcement hearings pursuant to Section 6.10. Appeals from the determination of Authority’s

Manager may be taken in the manner provided for appeals pursuant to Section 6.11.

SECTION 6.8. PERMIT REVOCATION. Authority’s Manager may revoke, after a hearing on

the question of revocation, any permit issued pursuant to the provisions of these regulations upon a

determination by him or her that:

(a) The permittee has failed to report factually the wastewater constituents, characteristics, or volume of the permitted wastewater discharge;

(b) The permittee has failed to report significant or substantial changes in the operations

conducted upon the premises to which the permit pertains, or significant or substantial changes in wastewater constituents, characteristics, or volumes pertaining to said premises;

(c) The permittee has refused, or failed to permit, reasonable access to the premises to which

the permit pertains; or

(d) The permittee has violated, caused to be violated, or permitted to be violated, any term, condition, or provision of the permit.


page 31

In the event that Authority’s Manager preliminarily determines that a permit should be revoked

for any of the foregoing reasons, he or she shall notify the permittee and the owner and occupant of the

premises (if such persons are not the same as the user) to which the permit pertains of a hearing on the

question of revocation. Notice of such hearing shall be given in the manner provided for giving notices

of violation pursuant to Section 6.9 and such hearing shall be conducted in the manner provided for

enforcement hearings pursuant to Section 6.10. Appeals from the determination of Authority’s Manager

may be taken in the manner provided for appeals pursuant to Section 6.11.

SECTION 6.9. NOTICE OF VIOLATION. Whenever Authority’s Manager or an Agency's

Director of the Agency within the boundaries of which a user’s premises is located finds that any such

user has violated or is threatening to violate any provision or requirement of these regulations, or any

provision or requirement of any permit issued pursuant to these regulations, or any prohibition,

limitation, or requirement of law, Authority’s Manager, or said Agency’s Director, as the case may be,

shall serve upon such user written notice stating the nature of the violation, ordering cessation thereof

and directing submittal of a written explanation of the cause of the violation. Service of such notice shall

be made personally or by certified or registered mail (return receipt requested), addressed to the

premises which is the source or location of such violation, the address of the user or permittee

theretofore specified by said user or permittee to Authority’s Manager or said Agency’s Director (if

different than the address of the premises) and also to the owner of said premises as shown on the last

equalized assessment roll prepared by the County Assessor, County of San Mateo. Within 30 days of the

date of said notice, the user, permittee, and/or owner of the premises shall submit to Authority’s

Manager (with a copy to said Agency’s Director) a written explanation of the cause of such violation.

SECTION 6.10 ENFORCEMENT HEARING.

SECTION 6.10.1. HEARING. Authority’s Manager may order any user who causes or allows

an unauthorized discharge to enter the sewerage facilities or who has otherwise violated, or is

threatening to violate, any provision or requirement of these regulations, or any provision or


page 32

requirement of any permit issued pursuant to these regulations, or any prohibition, limitation or

requirement of law, to show cause before him or her why a proposed enforcement action should not be

taken. Notice of a hearing thereon shall be served on the user and/or permittee (if such violation

pertains to a permit issued pursuant to these regulations) specifying the time, place and date of the

hearing, the nature of the violation of these regulations or of any permit issued pursuant to these

regulations or of any other requirement of law giving rise to the enforcement proceedings, a proposed

enforcement action or actions and directing the user to show cause before Authority’s Manager why the

proposed enforcement action should not be taken. Said notice may be combined with a notice of

violation issued pursuant to Section 6.9.

Notice of the hearing shall be served personally or by certified mail (return receipt requested)

addressed, in the case of a user or permittee, to the premises where the alleged violation has taken, or is

taking place, to the address theretofore specified by said user or permittee to Authority’s Manager or

said Agency’s Director (if different than the address of the premises) and also to the owner of said

premises as shown on the last equalized assessment roll prepared by the County Assessor, County of

San Mateo. Said hearing shall be held within 60 days following the date of service of the notice.

SECTION 6.10.2. PROCEDURE. At the hearing the user and/or permittee, the owner of the

premises above—mentioned, and the Agency’s Director of the Agency within the boundaries of which

the premises is located shall be given the opportunity to be heard. Formal rules of evidence shall not be

applicable, provided however, that oral and documentary evidence shall be received by Authority’s

Manager relevant to the issue being heard.

A verbatim transcript of the record need not be prepared; provided, however, that if the user,

permittee, or owner of the premises requests a transcript, the Authority shall cause a transcript to be

prepared; provided, further, that the cost of preparing such transcript shall be borne by the party

requesting it. A request for the preparation of a transcript shall be made not less than five (5) business

days prior to the hearing. The requesting party shall deposit with Authority’s Manager the estimated


page 33

cost of providing a transcript prior to commencement of the hearing. Failure to deposit the estimated

cost shall be deemed a waiver of the request, and in such instance the Authority shall not be required to

provide a transcript. The notice of hearing shall contain notification of the requirements hereof relating

to the preparation of a transcript.

SECTION 6.10.3. DECISION. Upon completion of the hearing, and upon a finding by

Authority’s Manager that a violation of these regulations or of any permit issued pursuant to these

regulations or any other requirement of law has occurred, Authority’s Manager may issue an order to

the user, permittee, or owner of the premises to which the violation pertains, who or which Authority’s

Manager finds responsible for said violation, directing that, following a specified time period, sewerage

service shall be discontinued, and/or the permit with respect to which the violation occurred shall be

revoked unless (i) adequate treatment facilities, devices or other related appurtenances shall have been

installed or used in conjunction with existing treatment facilities, devices or other related

appurtenances, or (ii) existing treatment facilities, devices or related appurtenances are properly

operated, maintained or repaired, or (iii) other appropriate remedial action specified by Authority’s

Manager shall have been taken. Authority’s Manager may issue such other orders and directives as are

necessary or appropriate to obtain compliance with the provisions of these regulations, any permit

issued pursuant to these regulations or any other requirement of law.

SECTION 6.11. APPEALS.

SECTION 6.11.1. RIGHT TO APPEAL. Any user, permittee, applicant, or owner of premises

aggrieved by the determination of Authority’s Manager may appeal such determination to Authority’s

Commission by filing a written notice of appeal with Authority’s Manager within 30 days of the date of

said Manager’s determination. The notice of appeal shall set forth the facts and reasons supporting the

appeal. Hearing on the appeal shall be held by Authority’s Commission within 60 days from the date of

filing the notice of appeal. Notice of the date, time and place of the hearing on the appeal shall be given

in the manner specified for hearings under Section 6.10.1 and shall include notice of the appellant’s


page 34

right to preparation of a transcript of the appeal hearing upon request therefor and depositing the

estimated cost thereof in the manner provided under Section 6.10.2.

SECTION 6.11.2. PROCEDURE. Hearing on the appeal by Authority’s Commission, shall be

conducted in the manner provided for enforcement hearings specified in Section 6.10.2, including,

without limitation, the provisions relating to preparation of a transcript of the hearing.

SECTION 6.11.3. DECISION. Upon conclusion of the hearing, Authority’s Commission may

affirm, reverse or modify the determination of Authority’s Manager as the Commission deems just and

equitable, and in furtherance of the provisions, purposes and intent of these regulations. During the

pendancy of any such appeal, the determination of Authority’s Manager shall remain in full force and

effect. The determination of Authority’s Commission on the appeal shall be final.

SECTION 6.12. PUBLIC NUISANCE. Any discharge, or threatened discharge, or any

condition which is in any manner in violation of the provisions of these regulations, or of any permit, or

any order or directive of Authority’s Manager issued or made pursuant to these regulations, shall be, and

the same is hereby declared to be a public nuisance. Such nuisance may be abated, removed, or

enjoined, and damages assessed therefor, in any manner provided by law.

SECTION 6.13. CIVIL ASSESSMENTS. Any user, permittee, or owner of premises or other

person who or which violates any requirement of these regulations, or of any permit, directive, or order

issued or made pursuant to these regulations requiring pretreatment of any industrial waste which would

otherwise be detrimental to the sewerage facilities or their proper and efficient operation and

maintenance, the health and safety of the employees of the Authority or the environment or which

requires the prevention of the entry of such waste into the sewerage facilities, may be civilly liable

pursuant to the provisions of California Government Code Sections 54740 or 54740.5. The Authority’s

Manager is hereby authorized to issue administrative complaints pursuant to Government Code Section

54740.5. (Amended, Res. SVCW No. 05-39, 06/14/05)


page 35

SECTION 6.14. AGENCY’S REGULATIONS. Pursuant to the provisions of the Joint

Exercise of Powers Agreement referenced in Section 1.3.4, each Agency shall enact an ordinance,

uniform in content with these regulations; provided, however, that in addition to the enforcement

provisions herein contained, each such ordinance shall include provisions to the effect that any person

violating or causing the violation of any provision of such ordinance or of any permit issued pursuant to

these regulations or otherwise issued by Authority’s Manager, shall be guilty of a misdemeanor, and

upon conviction thereof, shall be punishable by a fine of not more than One Thousand Dollars

($1,000.00), or by imprisonment in the County jail for a term not exceeding six months, or by both such

fine and imprisonment, and that every day such violation shall continue shall constitute a separate

offense. Nothing in this section, or these regulations, contained shall be deemed a limitation upon any

Agency to enact regulations pertaining to said Agency’s portion of the sewerage facilities, or otherwise

pertaining to the sewerage facilities, not inconsistent with the provisions of these regulations. Said

Agency regulations shall also vest Authority’s Manager and Authority’s Commission with the powers,

functions and authority granted to them, respectively, pursuant to these regulations.

SECTION 6.15. AUTHORITY’S DISCRETION. Authority, or Authority’s Manager, as the

enforcing agent or officer so designated by each of the Agencies’ regulations adopted pursuant to

Section 6.14 hereof, and as empowered and vested with the authority and functions correspondingly

herein provided, shall have, and are hereby granted, the discretion to proceed with enforcement actions

pursuant to either said Agencies’ regulations or these regulations in any particular instance.

SECTION 6.16. REMEDIES CUMULATIVE. The remedies provided for in these regulations

shall be cumulative and not exclusive, and shall be in addition to any and all other remedies available to

Authority in the exercise of its powers.

SECTION 6.17. SEVERABILITY. If any provision of these regulations or the application

thereof to any person is held invalid, such invalidity shall not affect any other provision or application of


page 36

these regulations which can be given effect without the invalid provision or application, and to this end

the provisions of these regulations are severable.

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IMPORTANT NOTICE TO DISCHARGERS You have contacted Silicon Valley Clean Water (SVCW) regarding the discharge of liquid waste into the sanitary sewers. Be advised that it is illegal to discharge hazardous waste into the sanitary sewers. It is the responsibility of your company to determine whether the liquid waste is classified as a hazardous waste; SVCW does not make this determination. To help with this evaluation you should contact your facility’s Environmental Health and Safety staff, a private consultant, or San Mateo County Environmental Health at (650) 363-4305. Once the waste is determined to be non-hazardous, SVCW will evaluate the waste for acceptance into the sanitary sewers. Complete the attached form and fax to SVCW. The review process typically takes 1-3 days and the results will be returned to you by fax. You should be aware that many non-hazardous wastes may impact the SVCW treatment processes. Our treatment facility was designed to treat a limited range of pollutants found in residential wastewater. We encourage you to pursue any available reuse or recycle options before considering discharge to the sanitary sewers.

SVCW NON-ROUTINE DISCHARGE APPLICATION File # 70-60.01

Person Requesting: Phone No.

Company: Fax No.:

Affected Business: Assessors Parcel No.:

Address: City: Zip:

Waste Description:

Constituents in Wastewater: Concentration: Units:

Volume to Discharge (gal):

Date of Discharge: Preferred Time of Discharge:

Preferred Discharge Method:

Exact location, description and address of sanitary sewer discharge point:

Comments:

Waste Certification: I certify that the information above is true and complete to the best of my knowledge. I certify that the proposed discharge is not a hazardous waste. I understand that it is illegal to discharge hazardous waste to the sanitary sewers. Signed: __________________________ Title: ____________________ Date: __________ Submit Application to: Silicon Valley Clean Water Environmental Services Division Phone: (650) 591-7121 1400 Radio Road E-Mail [email protected] Redwood City, CA 94065

PAGE 1 OF 2 (Page 1 to be completed by Discharger; page 2 to be completed by SVCW)

Received at SVCW: Date: ______________ Time: _____________ By: ________________

SVCW NON-ROUTINE DISCHARGE APPLICATION File # 70-60.01

PAGE 2 OF 2 (Page 2 to be completed by SVCW)

Expected Impact of Discharge:

Collection System:

SVCW Pump Station:

SVCW Plant Processes:

SVCW Effluent Quality:

SVCW Sludge Quality:

Air Quality & Odors:

Work Health & Safety:

Additional Discussion:

SVCW Authorization: Discharge Approved Not Approved

Signature _________________________________ Date: _____________________

Allowable Flow Rate: gallons/day gallons/minute

Total Discharge Allowed: gallons

Time of Discharge: Time/Date Start: Time/Date Stop: ____

Other Conditions:

This authorization applies only to the material described on Page 1. The discharge of hazardous waste is not allowed. The discharge must be in compliance with the SVCW Regulations and any applicable provisions of Federal, State, or local regulations.

Sanitary Sewer District/City Authorization:

Date Application Received: DISTRICT USE:

Local Authorization Required? Yes No PERMIT #:

Discharge Approved: PERMIT FEE: $

Discharge NOT Approved: SAMPLING & MONITORING: $

By: Date: TOTAL FEES: $

Title: INVOICE #:

District/City: DATE FEES PAID: * * * FEES MUST BE PAID PRIOR TO DISCHARGE * * *

Additional Discussion/Conditions:

IMPORTANT NOTICE TO DISCHARGERS

You have contacted Silicon Valley Clean Water (SVCW) regarding the discharge of liquid waste

into the sanitary sewers. Be advised that it is illegal to discharge hazardous waste into the

sanitary sewers. It is the responsibility of your company to determine whether the liquid

waste is classified as a hazardous waste; SVCW does not make this determination. To help

with this evaluation you should contact your facility’s Environmental Health and Safety staff, a

private consultant, or San Mateo County Environmental Health at (650) 363-4305.

Once the waste is determined to be non-hazardous, SVCW will evaluate the waste for acceptance

into the sanitary sewers. Complete the attached form and fax to SVCW. The review process

typically takes 1-3 days and the results will be returned to you by fax.

You should be aware that many non-hazardous wastes may impact the SVCW treatment

processes. Our treatment facility was designed to treat a limited range of pollutants found in

residential wastewater. We encourage you to pursue any available reuse or recycle options

before considering discharge to the sanitary sewers.

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SVCW LOW VOLUME DISCHARGE AUTHORIZATION FORM File # 70-60.02

INFORMATION TO BE COMPLETED BY DISCHARGER

Name of Discharger:

Address of Discharger:

City: Zip:

Person to Contact for More Information:

Phone: Fax:

Description, Source of Wastewater and Pollutants:

Discharge volume expected per day: Maximum _____ gallons; Average _____ gallons

Discharge Frequency/Period: __________

Is this waste a hazardous waste under federal or state law? YES NO

Is the volume of process wastewater from all manufacturing at this site less than 1000 gallons per

day? YES NO

Waste Certification: I certify that the information above is true and complete to the best of my knowledge. I certify that the proposed discharge is not a hazardous waste. I understand that it is illegal to discharge hazardous waste to the sanitary sewers. Signed _________________________Title _________________________ Date ____________

_________________________ (print name if different than person to contact above)

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SVCW LOW VOLUME DISCHARGE AUTHORIZATION FORM File # 70-60.02

REVIEW AND AUTHORIZATION TO BE COMPLETED BY SVCW

Expected Impact of Discharge

Collection System:

Pump Station:

SVCW Plant Processes:

Effluent Quality:

Sludge Quality:

Air Quality / Odors:

Worker Health & Safety:

Additional Discussion:

Discharge Authorization The discharge described above is allowed is not allowed

Maximum allowable flowrate: _____ gallons/day; _____ gallons/minute

Signed _________________________Title _________________________ Date ____________

Other conditions:

This authorization applies only to the discharge described above. This authorization will remain in effect for 5 years; the discharger must reapply in order to renew this authorization. The discharger must contact SVCW if there is an increase in discharge volume or pollutant concentration. The discharge of hazardous waste is not allowed. The discharge must be in compliance with the SVCW Regulations and any applicable provisions of Federal, State or local regulations.

Silicon Valley Clean Water – Environmental Services Division Phone (650) 591-7121 1400 Radio Road E-Mail [email protected] Redwood City, CA 94065 form version 4/26/05

mailto:[email protected]

AppendixC

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Path: L:\Acad 2000 Files\20000\20171-15\GIS\ArcMap\FigX_Delin_20150528.mxd

Study Area - 17.96 acres

Waters - 0.06 acre

Wetland - 3.99 acres

Sample Point

Map Prepared Date: 5/28/2015Map Prepared By: dchanBase Source: ESRI World Imagery (2010)Data Source(s): WRA

Figure X. DRAFT Delineation Map

SVCW Airport Staging AreaSan Mateo County, California

.0 100 20050

Feet