TASK 2.2B DEVELOP WEIR ALTERNATIVES PARSONS SLOUGH … · TASK 2.2B DEVELOP WEIR ALTERNATIVES PARSONS SLOUGH SILL PROJECT Prepared for Elkhorn Slough Foundation P.O. Box 267 Moss

F I N A L T E C H N I C A L M E M O R A N D U M

TASK 2.2B DEVELOP WEIR ALTERNATIVES PARSONS SLOUGH SILL PROJECT

Prepared for

Elkhorn Slough Foundation P.O. Box 267 Moss Landing, CA 95039

November 25, 2009

Ducks Unlimited, Inc. 3074 Gold Canal Drive Rancho Cordova, CA 95670

US-CA-485-1

Dixon Marine Services, Inc

TABLE OF CONTENTSTABLE OF CONTENTSTABLE OF CONTENTSTABLE OF CONTENTS

i

Dixon Marine Services

1. Introduction..................................................................................................................... 1-1

1.1 Background .............................................................................................. 1-1 1.2 Purpose and Scope ................................................................................... 1-1 1.3 Organization of Technical Memorandum................................................ 1-1

2. Site Constraints .............................................................................................................. 2-1

2.1 General ..................................................................................................... 2-1 2.2 Summary of Base Alternatives ................................................................ 2-1

3. Description of Alternatives ............................................................................................ 3-2

3.1 Alternative 1 (Flashboards / Needle Dam) .............................................. 3-2 3.1.1 Description................................................................................... 3-2 3.1.2 Construction................................................................................. 3-3 3.1.3 Construction Cost......................................................................... 3-3 3.1.4 Operation and Maintenance ......................................................... 3-4

3.2 Alternative 2 (Vertical Tide Gate) ........................................................... 3-4 3.2.1 Description................................................................................... 3-4 3.2.2 Construction................................................................................. 3-5 3.2.3 Construction Cost......................................................................... 3-5 3.2.4 Operation and Maintenance ......................................................... 3-5

3.3 Alternative 3 (Weir Gate) ........................................................................ 3-5 3.3.1 Description................................................................................... 3-5 3.3.2 Construction................................................................................. 3-6 3.3.3 Construction Cost......................................................................... 3-6 3.3.4 Operation and Maintenance ......................................................... 3-6

4. Comparison of Alternatives........................................................................................... 4-1

5. Limitations ...................................................................................................................... 5-1

6. References ...................................................................................................................... 6-1

List of Tables, Figures and Appendices

ii


Tables

Table 4-1 Comparison of Adjustable Weir Alternatives

Figures

Figure 1-1 Project Location

Figure 2-1 Existing Conditions

Figure 3-1A Adjustable Weir - Alternative 1A (Flashboards)

Figure 3-1B Adjustable Weir - Alternative 1B (Needle Dam)

Figure 3-2 Adjustable Weir - Alternative 2 (Vertical Tide Gate)

Figure 3-3 Adjustable Weir - Alternative 3 (Weir Gate)

Appendices

Appendix A Conceptual Construction Cost Estimates for Adjustable Weir Alternatives

SECTIONSECTIONSECTIONSECTIONONE Introduction

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1. Section 1 ONE Introduction

1.1 BACKGROUND

Elkhorn Slough Foundation (ESF) has been awarded a grant from the National Oceanic and Atmospheric Administration (NOAA) through the American Reinvestment and Recovery Act (ARRA) for design, permitting and construction of a sill and adjustable weir at the mouth of Parsons Slough in Monterey County, California (see Figure 1-1). The proposed location of the sill and adjustable weir is just downstream of UPPR Bridge Milepost (MP) 103.27 Coast Subdivision. Increased tidal energy in Parsons Slough resulting from historical development and subsequent restoration are resulting in accelerated tidal marsh loss and habitat degradation. The purpose of the sill and adjustable weir is to allow for the adaptive reduction of erosive energy into Parsons Slough due to tidal exchange while allowing for sufficient flushing to maintain water quality.

1.2 PURPOSE AND SCOPE

The ESF has retained Ducks Unlimited teamed with URS Corporation and Dixon Marine Services to provide professional engineering services for the 30 percent design of the Parson Slough Sill Project. As part of the 30 percent design, our scope of services, dated October 15, 2009, includes development of alternatives for the adjustable weir at a concept level. Twelve options were identified in Technical Memorandum 2.2a. This technical memorandum presents the three alternatives that were selected to move forward for evaluation in Task 2.3.

1.3 ORGANIZATION OF TECHNICAL MEMORANDUM

After this introductory section, this technical memorandum is organized into the following sections:

• Section 2 describes the site constraints.

• Section 3 discusses the adjustable weir alternatives.

• Section 4 discusses the comparison of alternatives.

• Section 5 describes the limitations of this technical memorandum.

• Section 6 lists pertinent references related to this report.

The appendices for this report are as follows:

• Appendix A is the conceptual construction cost estimates for the adjustable weir alternatives.

SECTIONSECTIONSECTIONSECTIONTWO Site Constraints

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2. Section 2 TWO Site Constraint s

2.1 GENERAL

The proposed location for the sill and adjustable weir is just downstream of UPPR Bridge MP 103.27 Coast Subdivision, which was replaced in 2003. The bridge is a 165-foot-long concrete slab girder bridge with new concrete abutments that were set just inboard of the previous abutments, which are still present, so as to not widen the existing channel. Sheetpiles were driven between the old and new abutments. The bridge is supported on ten bents each having three 24-inch-diameter concrete filled pipe piles that extend down approximately 100 feet below the rail line (Moffat and Nichol, 2008a). The bents are spaced at distances of 9 to 14 feet apart. The rail line embankment has a crest elevation of about 8 feet1 in the vicinity of the bridge based on LIDAR data. A fiber optic cable line is buried along the east side of the rail line within the UPRR rail corridor right of way (Moffat and Nichol, 2008a).

The existing topographic and bathymetric conditions are shown on Figure 2-1. As shown on Figure 2-1, the channel invert ranges between elevation -10 to -14 feet in the area downstream of the bridge. Rip-rap has been placed below the UPRR bridge for scour protection, however, the extent of the rip-rap is unknown (Kleinfelder, 2002). Based on Kleinfelder (2002), the rip-rap was had a maximum size of 3 feet in diameter and was delivered in forty 50-cubic yard capacity rail cars.

2.2 SUMMARY OF BASE ALTERNATIVES

Technical Memorandum 2.1 identified three alternatives for the base structure that will support the adjustable weir structure. The alternatives are Rockfill, Sheetpile and Pile/Sheetpile. The rockfill base structure would settle significantly over time and would require a longer construction period, however this alternative would provide the most substantial base structure. Sheetpiles would experience some settlement, but less than the rockfill alternative, and with lower cost, shorter construction period and less fill in waters of the U.S. Sheetpiles supported on end bearing piles would experience negligible settlement and would be the most stable base structure. The cost, construction time and environmental impacts of the Pile/Sheetpile alternative are comparable to the Sheetpile alternative.

1 The elevation datum used in this technical memorandum is NAVD 88.

SECTIONSECTIONSECTIONSECTIONTHREE Description of Alternatives

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3. Section 3 THREE Description of Alternatives

All three of the base structure alternatives would be constructed with the same basic geometry. The central 25 feet of the base structure sill has a top elevation of -5 feet. This central 25 feet (central bay) will be the location of the permanently open portion of the adjustable weir structure being evaluated in a separate technical memorandum. On either side of the central bay, the top elevation of the sill structure rises to -2 feet for 37.5 feet. These areas will serve as the base for the adjustable portion of the weir structure being evaluated in this technical memorandum. Outside of this area, the structure top elevation will be at 8 feet until it transitions to an earthen connection embankment (also at a top elevation of 8 feet) to the UPRR railroad embankment.

Flow through 100 feet of the structure would be controlled using adjustable weirs and the central bay. The adjustable weirs would be constructed to allow full, unrestricted flow through the 100-foot span, or to reduce flow up to the 25-foot central bay.

This section describes the adjustable weir alternatives that will be selected to move forward for further evaluation in Task 2.3, Evaluate Alternatives. Of the twelve alternatives listed in Technical Memorandum 2.2a, eight alternatives were not selected during an initial screening. The eight alternatives not selected and the reasons for not selecting them are as follows:

• Vertical Sluice Gate because it would require a 20 foot tall structure to remove the gate from the water.

• Self Regulating Tide Gate would not be practicable due to the large number of gates that would be required to cover the 75 foot span and for the high cost of the gates.

• Radial Gate, Mitre Gate, Wicket Gate, Tilting Gate, Inflatable Dam and Pneumatic Gate were considered to be not practicable because they all require a substantial base structure for support and are not designed for bi-directional flow.

The three alternatives that were selected are: Flashboards/Needle Dam, Vertical Tide Gate and Weir Gate. The selected alternatives are described below:

3.1 ALTERNATIVE 1 (FLASHBOARDS / NEEDLE DAM)

3.1.1 Description

Flashboards

Alternative 1A consists of a series of flashboards and associated frame structure as shown in Figure 3-1A. The structure would consist of approximately eight 10-foot by 10-foot bays, comprised of a steel frame structure into which boards could be stacked at various heights to control flow through each bay. Flashboards would allow flexibility with the weir invert elevation to accommodate changes in operation or future settlement or sea level rise. Flashboards control flow by raising or lowering the height of the weir.

Needle Dam

Alternative 1B is similar to 1A except that the boards would be stacked vertically in the steel frame, as shown in Figure 3-1B. This alternative would also consist of eight 10-foot by 10-foot bays. The needle dam allows flexibility in flow control by adjusting the width of the weir


3-3


available to flow for the entire water column. Water passes through the weir opening as apposed to over the boards, as in the flashboard structure. Adding and removing needles adjusts the width available to flow. The weir invert elevation is not adjustable.

Dual Configuration

Alternative 1C is a combination of the flashboards and needle dam, and would have the same bay geometry. This alternative would consist of a steel frame structure that would allow boards to be placed horizontally or vertically. This alternative would offer the most flexibility in flow control. It is possible to create orifices at the base of the weir by using spacers with the horizontal flashboards. Another adaptive capability would be to furnish flap gates mounted to a panel 10’ wide and of a desired height (i.e. 4’ tall x 10’ wide or 10’ tall x 10’ wide.) These could be lifted or lowered into a partially full bay or an entire bay.

3.1.2 Construction

The boards and steel frame for Alternatives 1A, 1B and 1C would consist of similar geometry and materials. The boards could be manufactured from various materials, including wood, fiberglass, reinforced HDPE or other synthetic that will provide a relatively light weight, stiff board. The approximate dimensions of the boards would be 10 feet long by 2 feet high by 4.5 inches thick. The boards would abut one another and would include a hook or a hole for placement or removal.

The frame structure could be constructed with H beams, supported by the base structure and bracing/connections.

Access for construction of the adjustable weir would be from the water and possibly the base structure. Construction would most likely be performed using the same barge and crane equipment described in Technical Memorandum 2.1, Base Structure Alternatives.

3.1.3 Construction Cost

The construction cost estimate is a Class 4 estimate as described by the Association for the Advancement of Cost Engineering (AACE, 2005) as follows:

“Class 4 estimates are generally prepared based on limited information and

subsequently have fairly wide accuracy ranges. They are typically used for project

screening, determination of feasibility, concept evaluation, and preliminary budget

approval. Typical engineering is from 1% to 15% complete. The expected range of

accuracy for this class estimate is –15% to –30% on the low side and +20% to +50% on

the high side.”

The construction cost estimate prepared for Alternatives 1A, 1B and 1C is based on the conceptual plans presented in Figures 3-1A and 3-1B. Quantities were measured manually from the drawings. Unit cost ranges were developed based on a combination of previous, similar project experience and vendor quotes. The conceptual construction cost estimates are included in this technical memorandum as Appendix A. The costs for Alternatives 1A, 1B and 1C are assumed to be the same and are estimated to be $363,000 to $705,000. This estimate includes material and labor.


3-4


3.1.4 Operation and Maintenance

Adjusting the weirs for the flashboards, needle dam and dual configuration alternatives is accomplished by the removal and placement of boards. Needles or flashboards could be installed or removed using a small winch and A-frame mounted to a work boat, with the use of an overhead structure consisting of a rail and rolling winch system, or portable davits that can be temporarily mounted on top of the bays. For all options swift currents could hinder or prevent management of boards. Flashboards would be lowered horizontally down rails along the sides of the bays. These would keep the boards captive and aid in installation. The rails could cause submerged boards to bind upon removal however. The needles are installed vertically and could be swept offline by current. This could be alleviated somewhat by constructing needles with notches on their abutting faces that could function as guides. Needles are not anticipated to bind since they would be removed vertically from the structure. The boards could weigh up to 450 pounds and additional friction due to currents and/or binding could be fairly substantial. All mechanical mechanisms would need to be sized appropriately. If hand operated systems are used the reduction gearing could result in substantial installation time. For the boat water access option, boards would be managed with an overhead winch mounted to a boat. This would be purchased as part of the project or could be rented from a contractor when necessary for adjustments. Boat access may require timing maintenance activities to correspond with certain tides for safety concerns and ease of operation. Depending on tide conditions and board configurations, currents could prevent access to the structure. .

Biofouling could make the removal and placement of boards difficult, if they are moved infrequently. Buildup could be cleared from the boards in some cases, but when this is not possible, it may be necessary to destroy boards for removal. Needle dam boards may be less susceptible to jamming due to the vertical installation. Differential settlement in the base structure could change the geometry of the steel frame and make removal and placement of the boards difficult.

3.2 ALTERNATIVE 2 (VERTICAL TIDE GATE)

3.2.1 Description

Alternative 2 is a vertical tide gate, as shown in Figure 3-2. Six to eight 10-foot by 10-foot gates would be mounted on a steel frame and open with the flood tide. These gates hinge along their vertical edge and are mounted to operate with minimal headloss with flooding flow to allow full capacity inflow. Ebb tides push the gates closed, or to a point limited by an adjustable catch, restricting flow. A variation to an adjustable catch is an adjustable orifice in the gate face.


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3.2.2 Construction

The vertical tide gates would be approximately 10 feet by 10 feet and could be manufactured from various materials, including steel, aluminum and some plastics. The gates would be mounted on a steel frame structure supported by the base structure. The steel frame structure could be constructed with hollow rectangular steel sections.

Mounting the gates along the designed alignment is crucial to correct operation with the tides. For this reason, care must be taken in mounting the gates. Furthermore, differential settlement in the base structure could cause poor performance by changing the orientation of the gates and steel frame.

Like Alternative 1, access for construction of the adjustable weir would be from the water and possibly the base structure. Construction would most likely be from the same type of barge and use the same potential staging areas described for the previous alternatives.


The construction cost estimate for Alternative 2 was prepared as described for Alternative 1, based on Figure 3-2. The costs for Alternative 2 are estimated to be $1,300,000 to $1,850,000. This estimate includes material and labor.


Vertical tide gates are designed to operate with the tides, however they can be bolted shut. Adjustment or changes to the catch can limit full closure of the gates when unbolted, thus allowing some water to discharge during an ebb tide. Depending on the setting, debris can inhibit gate operation and create obstructions. Moving parts on the gates can be subject to corrosion and failure, as has been experienced with similar applications in North Marsh.

Tide gates adjustments would be relatively simple in concept but potentially difficult in practice. The structure would be accessed by boat. A boat operator would need to maintain the boat in position while one to two people adjusted the gate. This would be accomplished using a wrench or socket to adjust the stop arm and cam to change the amount the gate is left open on the ebb tide. Bolting the gate shut would be accomplished in a similar fashion. Work would most likely need to be timed around tides, with a flood tide used to adjust the cam and an ebb tide to bolt the gate shut.

3.3 ALTERNATIVE 3 (WEIR GATE)

3.3.1 Description

Alternative 3 is a weir gate, as shown in Figure 3-3. Six to eight 10-foot by 10-foot gates would be mounted on a steel frame, similar to the frame for Alternative 2. The weir gates slide down on vertical tracks or channels, to allow water to pass over the gate. The gates are lifted or lowered by overhead motors or manual wheels, which are connected to one or more stems. These gates allow flexibility with the bottom height, since they are lowered to the open position. The gates


3-6


could be dual panel to minimize the area below the base sill required to store the lowered gates. Weir gates control flow by raising or lowering the height of the weir.

3.3.2 Construction

The weir gates would be metal and approximately 10 feet by 10 feet. The gates would be mounted on a steel frame structure supported by the base structure and similar to the structure described for Alternative 2. The steel frame could be constructed with hollow rectangular steel

sections, and would support the tracks or channels for raising and lowering the gates.

Like Alternatives 1, and 2, access for construction of the adjustable weir would be from the water and possibly the base structure. Construction would most likely be from the same type of barge and use the same potential staging areas described for the previous alternatives.


The construction cost estimate for Alternative 3 was prepared as described for Alternative 1, based on Figure 3-3. The costs for Alternative 3 are estimated to be $1,290,000 to $1,706,000. This estimate included material and labor.


Weir gate adjustments would require overhead access for personnel. The lifting mechanism has several options. The most expensive options would be to have individual motors for each gate that are diesel, gas or electrically powered. Electrically powered motors would require that electrical service be brought to the site. A less expensive option would be to have a portable diesel or gas motor to lift and lower one gate at a time. This would be more time consuming than individual motors and impossible to automate. It is not feasible to lift and lower the weir gates with a hand wheel due to the time it would take to adjust it. For example, a hand wheel or crank from a gate of comparable size would take 2,880 to 5,760 rotations to completely raise or lower the gate.

The stem, or stems, necessary to operate the gates can collect debris, obstructing the opening. Biofouling of the mechanical components and submerged portions of the gate can also hinder operation. Motors and threaded stems may require periodic replacement or repair. As with the tide gates, the increased amount of moving parts has the potential to increase repairs and maintenance.

SECTIONSECTIONSECTIONSECTIONFOUR Comparison of Alternatives

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4. Section 4 FOUR Comparison of Alt ernatives

The three adjustable weir alternatives were compared for the following criteria:

• performance;

• operation and maintenance;

• environmental impact; and

• construction schedule and costs.

The comparison of the adjustable weir alternatives is summarized in Table 4-1. As shown in Table 4-1, Alternatives 1A, 1B and 1C offer the lowest cost, least maintenance and most robust system. While 1A offers base height flexibility, 1B offers superior fish passage (due to maintaining low weir invert and limiting the potential for significant flow drops). Alternative 1B could be vulnerable to flow obstruction if bays were operated partially open. Alternative 1C offers the flexibility to operate the weirs in both configurations, which allows the weirs to meet changing priorities, such as sea level rise and fish passage. Alternative 2 offers the most flow control because the ebb tide and flood tide restrictions can be set separately. This alternative offers low impact to fish passage; however it has the highest cost and is sensitive to differential settlement, biofouling, corrosion and flow obstructions. Alternative 3 offers base height flexibility, but is costly and sensitive to the same items as Alternative 2, with inferior fish passage while gates are partially open.

It is noted that there will be a permanent 25 foot wide opening in the center of the weir with an invert of -5 ft that will allow fish passage at most tides. The fish passage described above refers to fish passage through the adjustable weir structures.

There are several combinations possible between the three alternatives. One combination would be to use a tide gate in combination with stop logs to add management flexibility.

Based on input from Elkhorn Slough Foundation and stakeholders, a decision will be made as to which of the alternatives will move forward to the final concept evaluation in Task 2.3.

SECTION

SECTION

SECTION

SECTIONFOUR

Comparison of Alternatives

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Table 4-1 - Comparison of Weir Alternatives

Alternative 1

(Flashboards/Needle Dam)

Alternative 2

(Vertical Tide Gate)

Alternative 3

(Weir Gate)

Performance

Sea Level1

Rise/Settlem

ent

- Alt. 1A is fully flexible

- Alt. 1B is partially flexible

- Alt. 1C depends on configuration

- Partially flexible

- Fully flexible

Tolerance to

Differential Settlem

ent

- Least sensitive to differential

settlement

- Sensitive to differential settlem

ent

- Sensitive to differential settlem

ent

Ability to Restrict Ebb

Flow2

- No additional control over ebb flow

- Flexibility to provide additional

restriction of ebb flow (relative to flood

flow)

- No additional control over ebb flow

Operations and M

aintenance

Adjustment

- Moderately difficult; required lifting

awkward heavy objects

- Required timing with tides and

working off of a boat.

- Adjustment by motor actuator or hand

wheel

Biofouling

- Operation is least sensitive to

biofouling

- Moderately sensitive to biofouling

- May require more frequent removal of

buildup

- Most sensitive to biofouling

- May require more frequent removal of

buildup

Corrosion

- Least vulnerable to corrosion

- Moderately vulnerable to corrosion

- Moderately vulnerable to corrosion

Potential for Flow

Obstruction

- Alt. 1A is least vulnerable to flow

obstruction

- Alt. 1B is moderately vulnerable to

flow obstruction (for partial open)


- Moderately vulnerable to flow

obstruction

- May require more frequent monitoring

for obstruction

- Most vulnerable to flow obstruction

Frequency of

Inspection

- Least frequent inspection

- Moderately frequent inspection

- Moderately frequent inspection

Environmental Impact

Fish Passage3

- Alt. 1A moderate impact to fish

passage

- Alt. 1B least impact to fish passage


- Least impact to fish passage

- Moderate impact to fish passage

Construction Schedule and Cost

Construction Cost 4

$363,000-705,000

$1,300,000-1,852,000

$1,290,000-1,706,000

1 Partially flexible refers to the weir’s ability to have its top height raised, without ability to raise bottom invert elevation. Fully flexible refers to weir’s ability to have both

bottom and top elevations raised.

2 All weir alternatives restrict flows equally for ebb and flood tides. Restricting ebb flow refers to ability to restrict ebb and flood flows to different degrees.

3 When weirs are fully closed or fully open, there is no difference in fish passage. These comparisons are for partially open weirs.

4 Estimated construction costs are 4th quarter 2009 costs.

SECTIONSECTIONSECTIONSECTIONFIVE Limitations

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5. Section 5 F IVE Limit ations

The conceptual design and engineer’s opinion of cost herein were performed for conceptual adjustable weir alternatives for presentation and comparison purposes only. Information presented in this memorandum should not be used for any purpose outside those indicated above. This technical memorandum is for the use and benefit of the Elkhorn Slough Foundation. Use by any other parties is at their own discretion and risk.

The Ducks Unlimited, URS Corporation and Dixon Marine Services team represents that the services were conducted in a manner consistent with the standard of care ordinarily applied as the state of practice in the profession within the limits prescribed by our client. Standard of care is defined as the ordinary diligence exercised by fellow practitioners in this area performing the same services under similar circumstances during the same period. No other warranties, either expressed or implied, are included or intended in this technical memorandum.

SECTIONSECTIONSECTIONSECTIONSIX References

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6. Section 6 SIX References

Association for the Advancement of Cost Engineering International (AACE) (2005). Recommended Practice No. 18R-97, Cost Estimate Classification System, February.

Dixon Marine Services, Inc. and Ducks Unlimited, Inc (2009). Parsons Slough Project, Phase 1: 30% Design Subtask 2.2a: Adjustable Weir Literature Review Memorandum, prepared for the Elkhorn Slough Foundation, November 10.

Moffat and Nichol (2008a). Draft Report of Existing Conditions for the Parsons Slough Complex Wetland Restoration Plan, prepared for the California State Coastal Conservancy and Elkhorn Slough National Estuarine Research Reserve, November 24.

Moffat and Nichol (2008b). Draft Report of Analysis of Restoration Alternatives for the Parsons Complex, prepared for the California State Coastal Conservancy and Elkhorn Slough National Estuarine Research Reserve, November 24.

Ducks Unlimited, Inc. (2009). Draft Technical Memorandum 2.1 Base Structure Alternatives for Parsons Slough Project, prepared for the Elkhorn Slough Foundation, November 13.

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Appendix A

Conceptual Construction Cost Estimates for Adjustable Weir Alternatives

APPENDIX A

CONCEPTUAL CONSTRUCTION COST ESTIMATES FOR ADJUSTABLE WEIR ALTERNATIVES

Project Name: Parsons Slough

Project Number: US-CA-485-1

ALTERNATIVE 1 - FLASHBOARDS/NEEDLE DAM

Line Item

Unit

Quantity

Unit Price

Extended

Unit Price

Extended

1Boards

EA

80

$107

$8,560

$1,800

$144,000

2Construct Support Structure

LB

40,000

$5.00

$200,000

$6.00

$240,000

3Construct Walkway Structure (or Service Boat)

LS

1$15,000

$15,000

$50,000

$50,000

Sub Total

$223,560

$434,000

General Requirements (10%)

$22,356

$43,400

Overhead and Profit (20%)

$44,712

$86,800

Sub Total

$290,628

$564,200

Design Contingency (25%)

$72,657

$141,050

Estimated Total Construction Costs

$363,285

$705,250

LS Lump sum

LF Lineal feet

LB Pounds

CY Cubic Yard

EA Each

LOW END

HIGH END

A-1

APPENDIX A




ALTERNATIVE 2 - TIDE GATES

Line Item

Unit

Quantity

Unit Price

Extended

Unit Price

Extended

1Furnish and Install Gates

LS

1$600,000

$600,000

$900,000

$900,000


LB

40,000

$5.00

$200,000

$6.00

$240,000

Sub Total

$800,000

$1,140,000


$80,000

$114,000


$160,000

$228,000

Sub Total

$1,040,000

$1,482,000

Design Contingency (25%)

$260,000

$370,500

Estimated Total Construction Costs

$1,300,000

$1,852,500

LS Lump sum

LF Lineal feet

LB Pounds

CY Cubic Yard

EA Each

LOW END

HIGH END

A-2

APPENDIX A




ALTERNATIVE 3 - W

EIR GATES

Line Item

Unit

Quantity

Unit Price

Extended

Unit Price

Extended

1Furnish Gates

EA

8$63,000

$504,000

$78,750

$630,000

2Install Gates

EA

8$5,000

$40,000

$7,500

$60,000


LB

40,000

$5.00

$200,000

$6.00

$240,000

4Construct Walkway Structure

LS

1$50,000

$50,000

$120,000

$120,000

Sub Total

$794,000

$1,050,000


$79,400

$105,000


$158,800

$210,000

Sub Total

$1,032,200

$1,365,000

25% Design Contingency

$258,050

$341,250

Estimated Total Construction Cost

$1,290,250

$1,706,250

LF Lump Sum

LF Lineal feet

LB Pounds

CY Cubic Yard

EA Each

LOW END

HIGH END

A-3

Documents

TASK 2.2B DEVELOP WEIR ALTERNATIVES PARSONS SLOUGH … · TASK 2.2B DEVELOP WEIR ALTERNATIVES PARSONS SLOUGH SILL PROJECT Prepared for Elkhorn Slough Foundation P.O. Box 267 Moss