More on Things that Go Bump in the Pipe: Implementing ... · the Pipe: Implementing municipal storm sewer pipe condition rating ... approach such as NASSCO PACP / MACP ... Sewerage

8/8/2014

1

More on Things that Go Bump in the Pipe: Implementing municipal storm sewer pipe condition rating

systems

Denise Nelson, PE, LEED AP, ENV SP

August 17, 2014

R C P C M P

• NASSCO PACP Pipe Defect Codes

• Why Change NASSCO PACP Pipe Defect Codes?

• NASSCO "QuickScore" application

• Sampling of other agencies

• Lessons Learned

• City of Chesapeake Pipe Condition Assessment Program

What Have We Learned?

Introduction

2

• Learning Objectives

• Implementation Challenges

• What We Are Finding

• Introduction to Pipe System Basics

Terminology and failure modes

• The WRc/NASSCO story

• Storm and Sanitary Differences

Pipe Material

Structural and O&M Differences

• Launch a standardized asset condition rating protocol for storm sewer maintenance and management

• Advocate for asset prioritization especially when scalable program elements (based on asset condition data) need to match fluctuating funding levels.

• Encourage asset condition ratings, and see the benefits from conducting routine storm sewer pipe condition assessments

Learning Objectives

3

8/8/2014

2

System Issues

4

Storm Pipe Issues

5 5

Voids* Missing Pipe*

Exposed

Rebar Spalling &

Chips

Utility Intrusion Unauthorized

Tap-ins Separated Joints

Misalignment

Dropped

Section Broken Pipe*

Fractured

Pipe*

Surface Damage

ASCE 2013 Infrastructure Report Card

6

8/8/2014

3

7

We don’t like to find this……

We want to avoid this…….

8

9

And this…….

8/8/2014

4

….and this…….

10

Talk about having a bad day…….

11

Implementation

Challenges

8/8/2014

5

Transform from “reactive” to “proactive” mode

Maintain current inventory while inheriting additional facilities (School districts; Home owner

associations; State DOT, Parks Dept., conveyance system give-backs)

Confirming boundaries and pipe/structure ownership where others connect to system

Funding capital and O & M when funding levels fluctuate

Adequate MS4 program management resources (internal and external)

MS4 permit language may require development of an asset management plan

Storm Pipe Condition Rating Implementation Challenges

13 13

• Technically based, defensible approaches to expedite processing of inspection backlog

• Educate/require inspection contractors: – Software function, reliability, consistency and compatibility

– Agency acceptance of installations

– QA / QC procedures for renewal installations (independent testing laboratory)

• Different procurement for sanitary /storm systems – Trenchless technology using felt CIPPL

• Styrene controls – environmental discharge

– Sanitary rehabilitation contract pricing

• Geared toward laterals

• Some trenchless may not be suited to larger sized pipe

• Some agencies pre-determine CIPP liner thicknesses

Implementation Challenges (Cont’d)

14

• Most storm sewer system management programs operate in “reactive” mode

• Agencies have expressed desire to shift from “reactive” to “proactive” mode

• Threat of more MS4 permit requirements is driving physical condition assessments (PCAs) – "open" system –curb and yard inlets, storm drainage and infiltration

ditches and swales, detention and retention ponds

– “closed” system – pipes, manholes, junction boxes/chambers, storm outfalls, endwalls, headwalls

• Agencies recognize the importance of PCAs • PCA results provide infrastructure re-investment decision support

What we are finding…

15

8/8/2014

6

• Maintenance agreements between local municipality and state DOT attempt to address inter-connections and shared resource responsibilities

• Few agencies utilizing a structured pipe condition rating approach such as NASSCO PACP / MACP

• Pipe condition data management is overwhelming public agencies

• Subtle yet important differences between storm and sanitary piped conveyance

• Wide range of agency staff skill sets


16

• Agency staff lack training, awareness and understanding of significance of pipe condition defects – Severity

– Extent

• Agency practices and procedures related to acceptance of new or rehabilitated storm sewer systems need to be enforced

– Development projects released from bond

– Internal inspection requirements

• DOTs concerned with use of laser scanning technology, post-construction inspections, and reporting of findings

– Plastic pipe materials subject to stretching, deformation, rebound

– Issue of ovality and deformation


17

Intro to Pipe System

Basics

8/8/2014

7

Pipe Installation

Trench Width

Emb

edm

ent

zon

e -

bac

kfill

19

Emb

edm

ent

zon

e -

bac

kfill

19

Pipe Installation

20 20

Pipe Installation

Source: American Concrete Pipe Association - ACPA 21 21

8/8/2014

8

• Loss of soil surrounding pipe

• Groundwater fluctuations

• Hydraulic regime

• Physical loads on sewer pipe (live and “dead” loads)

• Methods and materials of construction

• 3rd party damage/intrusion

• Roots, grease, debris causing increased water depths and possibly blockages (may require more frequent maintenance and service calls)

22

Summary of Major Conveyance System Deterioration Factors

Source: Water Research Centre

Sewerage Rehabilitation Manual

Sewer Subsidence

23

STAGE 2: Infiltration of groundwater or infiltration/exfiltration caused by

surcharging of the sewer washes in soil particles. Loss of soil support around the sewer allows pipe to move, opening

joints and increasing the in wash of soil.

Visible defects: Open and displaced joints, loss of line and level.

Infiltration. History of surcharge. NOTE: Care must be exercised

when viewing video tape recordings as displaced or slightly displaced joints can be overcompensated by the camera’s lighting

system.

STAGE 3: Uneven loading of pipes due to joint displacement causes cracking of

pipes. Process then accelerates and cracked pipes may also deform. Visible Defects: Open and displaced joints, cracked and fractured

pipes, loss of line and level. NOTE: The camera may be submerged

due to loss of gradient.

Development of Zones of

Loose ground or voids caused by loss of

soil into sewer

STAGE 1: Gap in sewer at joint or a poor lateral connection.

Visible defects: Offset joint, badly made connection. Infiltration, lack of long lived joint sealing method.



24

Loss of Pipe Support



STAGE 1 Initial defect, still intact, sewer/pipe is cracked but remains supported and held in position by the surrounding soil.

STAGE 2

Development of zones of loose ground or voids

caused by loss of ground; soil particles washed

away due to infiltration/exfiltration. Side support

is lost and allows deformation.

STAGE 3

Continued loss of support allows crown to drop.

This deformation leads to pipe collapse,

blockage and failure.

8/8/2014

9

Structural Related

Deterioration Mechanisms

Maintenance Related

Construction/Design Related

25

Structural Influences

• Cracks become fractures which become broken which could lead to collapse

• Open/offset joints allow root intrusion and/or soil wash-away which reduce support of pipe

• Surface damage can have exposed metal reinforcing which corrodes and reduces ability to support soil

• Improper repairs allow for root intrusion and soil subsidence

26 26

Infrastructure Needs-Structural

Pipe appears to be

deformed (out of round) 27 27

8/8/2014

10

Maintenance Influences

• Cleaning pipe can result in damage if improper tools are used

• Obstacles and debris – May cause flooding

– Erode inside wall of pipe

• Roots (typically chemical treatment in storm sewers not

allowed) and leaks can threaten surrounding soil support; if left unchecked could force joints apart

28 28

Infrastructure Needs – O&M

29 29

Construction & Design Influences

• Joint failures or gasket material failure can contribute to subsidence of soil

• Unauthorized lateral connections to pipe (hard-tap break-ins) jeopardize structural integrity

• Reverse and flat grades don’t allow system to clean itself (low scouring velocity)

30 30

8/8/2014

11

Infrastructure Needs – Construction Impacts

31 31

The WRc/NASSCO

Story

NASSCO Website

33 33

Primary purpose was to develop a

uniform approach based on

standard inspection observation

codes and ratings

8/8/2014

12

34

• Grade 5 – Collapsed or collapse imminent

• Grade 4 – Collapse likely in foreseeable future

• Grade 3 – Collapse un-likely in near future

• Grade 2– Minimal collapse risk

• Grade 1 - Acceptable structural condition

General Assignment of NASSCO Pipe Condition Grades

Based on internal inspection without consideration to external

consequence of failure, soil conditions, O&M impacts,

distribution of defects and maintenance history

35

General Pipe Condition Grades

• Infrastructure in failure; high consequence of failure

5 – Urgent Attention

• Severe defects that will become Grade 5 defects in near future; critical assets

4 – Poor

• Moderate defects that will continue to deteriorate; moderate criticality

3 – Fair

• Infrastructure defects that have not begun to deteriorate; low criticality

2 – Good

• Minor defects with little consequence of failure

1 – Acceptable

5.1 – Immediate Action

• Portions have failed and will continue to fail if left un-corrected

Use the

rating system to prioritize

maintenance and capital

projects

Pipe Defect Coding & Rating Process

Collect/Record Internal Pipe Defects

Evaluate Internal Pipe Defects; Assign Modified PACP Defect Codes

Apply PACP “QuickScore” to Defect Code Results

Structural O & M

Prioritize and Program for CIP

and O&MReview “QuickScore” Pipe Rating Results

36

8/8/2014

13

• As defined by NASSCO, on a per defect basis:

– Grade 5 – Pipe has failed or will likely fail within 5 years

– Grade 4 - Pipe will probably fail in 5 - 10 years

– Grade 3 – Pipe may fail in 10 – 20 years

– Grade 2 - Pipe unlikely to fail for at least 20 years

– Grade 1 – Failure unlikely in foreseeable future

Likelihood of Failure

37

Storm and Sanitary

System Differences

Pipe Material

39

8/8/2014

14

Pipe Material

40

H D P E

Structural Differences Between Storm and Sanitary Pipe Systems

41

Feature Wastewater Collection System Stormwater Conveyance System

Construction Quality High Stretched inspection forces, reliance on

contractor

Pipe section lengths Longer (10', 12', 20') pipe sections have fewer

joints Shorter (4', 6' & 8') pipe sections have many

joints

Lateral connections Essential Not permitted, treated as unauthorized

connection

Lift holes None, use slings or pipe hooks 18" dia. and above may have them; if not properly sealed, may leak or allow root

intrusion. May lead to pipe crack/fracture.

System depth Deeper, below storm, force main may be

shallower than gravity lines Shallower, above sanitary, exposed to vehicular

loads

Acceptance Tests Mandatory to protect health, welfare and

water quality, leaks not tolerated Not required, might have visual inspection

Chemical breakdown Constant flows (diurnal) with chemicals and

gaseous exposure and possible corrosive attack on pipe walls

Episodic flows with storm events. Water usually free of contaminants and not contributing to

deterioration.

Structural Differences Between Storm and Sanitary Pipe Systems (Cont’d)

42


Other utility intrusions

Susceptible. Not included under programs to locate underground utilities prior to

digging.

Susceptible, higher occurrence due to shallower nature. Not included under programs to locate

underground utilities prior to digging.

Infiltration type

Groundwater infiltration is more likely as system is deeper in the ground;

Stormwater from defects or deterioration in system

Shallower pipe is subjected to saturating water infiltration, less soil overburden so voids surface

quicker and easier

Infiltration leaks Impacts capacity and increases treatment

costs

Carries soil from pipe envelope, creating or causing voids, sink holes and safety concerns to citizens.

Increased standards for mastic, gaskets, etc.

Abrasive flow

Turbulence associated with pumping and elevation and directional changes

Debris in flow may scour pipe walls; debris particles are generally larger, more dense

Pressure flow

Yes Not usually; prevalent more in coastal areas

Gravity flow

Yes Yes

Destination Treatment plant Stream (Waters of the U.S.)

8/8/2014

15

O & M Differences Between Storm and Sanitary Pipe Systems

43


Capacity Critical; overflows are regulatory violations Overland relief can be incorporated into design

Joints Watertight, minimizes root intrusion, joints

are subject to acceptance tests Lack of joint seals may result in root intrusion,

especially in shallow installations

Line Maintenance and Monitoring

Fat, oil and grease accumulation requires frequent cleaning. Cleaning can damage pipe

walls.

Heavy debris and deposition can clog system resulting in flooding. Debris is generally larger

which can clog pipes easier.

Surface Impacts Force mains typically shallower than gravity

sewers

Shallower pipe systems are susceptible to damage from vehicular loads and other utility

intrusions

Flow pattern Stable with diurnal swings Episodic. Supplemented with overland relief.

Usually free of contaminants. Usually does not contribute to pipe deterioration.

Vermin Roaches, spiders, snakes Nocturnal mammals, crickets, frogs, critters ….

Alligators are not unheard of.

Closed and Open Characteristics

Closed system, may have lift stations Open and transitional system, open channels to

pipe then to open channel. Some submerged outlets to impoundments

Security Intrusion alarms typically installed on critical

assets; SCADA, telemetry Difficult to keep secure and free of vandalism,

critters and person entries

Trenchless Differences Between Storm and Sanitary Pipe Systems

44


Lateral connections Many None to few

Bypass flows

Requires on-site pump operations during installation; may need a pipe de-

commissioning and sanitizing step prior to dis-assembly

Rehab installation can be scheduled during 'dry' days, eliminating need for pump and bypass

Styrene Curing and contaminated flows are treated

at POTW

Not permitted in discharge to stream; requires new liner to be flushed and contact flows are pumped

into sanitary sewer, treated at POTW

Spatial Distribution of Priority Pipes

45

NASSCO PACP Defect Code Results

Priority One - Urgent corrective

measures required.

Priority Two - Near term corrective

measures required 2 – 3 years

Priority Three - Rehab/Repair

recommended, asset failure possible

in within 5 years

“Maintenance“ - No structural

defects or maintenance issues; re-

inspect asset approximately every 20

years

8/8/2014

16

NASSCO PACP Pipe

Defect Codes

Why Inspect Storm Pipe?

• Be responsive to citizen complaints and service calls

• MS4 annual and other agency reporting

• Accurately record and archive descriptive data

• Develop and maintain pipe condition rating for each pipe segment

• Provide results in format for use by field staff and independent contractors (Hard copy and electronic)

• Establish condition benchmark to compare with future pipe segment inspections

• Estimate probability of failure & remaining service life

• Acceptance of new construction 47 47

NASSCO PACP Coding (Version 6.0.2)

48

8/8/2014

17

Sample Index of Defect Codes

49

PACP Pipe Defect - Example

50

Structural Deformed (D) (Pipe) D < 10% = 4

D > 10% = 5

R C P

Why Change

NASSCO PACP Pipe Defect Codes?

8/8/2014

18

Structural

– Installation defects (Improper handling and storing; joint damage; lack of gaskets-joint material)

– Greater potential for shallower system with severe defects (lift holes, cracks, fractures, and corrosion of metal pipes)

– “Reinforcement visible” is downgraded because the corrosivity potential isn’t as great and the flow episodic

– Infiltration/exfiltration more likely with storm – may be cause for defect scoring change, soil erosion causes or leads to more severe defects

– Presence of roots – shallow storm depth more susceptible to root intrusion; pipe joints not airtight like sanitary

Why Change PACP Scoring

52

O&M

– Roots and leaks must be accompanied with the defect coding through which the intrusion (pipe barrel vs. joint) is occurring

– Defect severity ratings were increased on some roots (barrel) and leaks to reflect seriousness affecting shallower piping

52

NASSCO “Scoring” – Sampling of Modified PACP Structural Defect Codes

53

Family Group Descriptor Modifier Code Structural Grade

Structural Crack (C) Circumferential ( C) CC 1

Longitudinal (L) CL 2 (3)

Multiple (M) CM 3 (4)

Hinge (CH2) CH2 4

Hinge (CH3) CH3 5

Hinge (CH4) CH4 5

Spiral (S) CS 2 (3)

Structural Fracture (F) Circumferential ( C) FC 2

Longitudinal (L) FL 3 (4)

Multiple (M) FM 4

Hinge (H2) FH2 4

Hinge (H3) FH3 5

Hinge (H4) FH4 5

Spiral (S) FS 3

Structural Joint (J) Offset (displaced) (O) Med (M) JOM 1

Large (L) JOL 3 (4)

Separated (open) (S) Med (M) JSM 1

Large (L) JSL 3 (4)

Angular (A) Med (M) JAM 1

Large (L) JAL 2 (3)

Structural Joint (J) Offset (displaced) (O) Med (M) JOM 1

Large (L) JOL 3 (4)

Separated (open) (S) Med (M) JSM 1

Large (L) JSL 3 (4)

Angular (A) Med (M) JAM 1

Large (L) JAL 2 (3) 53

Rating Parameter Modified PACP Rating Justification

Cracks (CL CM, CS) Increase rating value by 1 Shallower, concrete pipe more susceptible to influences that could potentially cause further damage.

Fractures (FL) Increase rating value by 1 Shallower concrete piping more susceptible

Broken pipe (B) No change from default value

1 clock pos – 3; 2 clock pos – 4;

> 3 clock pos - 5

Representative rating accounting for shallower concrete piping

Deformed pipe (D) No change from default value

< 10% = 4; > 10% = 5 Lift holes may exhibit additional stress and be coded separately

Collapsed pipe (X) No change from default value Score

of “5”

High score representative of severity

Holes (H) No change from default value

1 clock pos – 3; 2 clock pos – 4;

> 3 clock pos - 5

High score representative of severity

Joint Offset (JOL) Increase rating value by 1 Large offset by definition is 1.5 times the pipe wall thickness and warrants the increase

Damaged or defective joint gasket material

No change from default value

Change from Construction Defects to Structural

Defective point repairs No change from default value Scores are representative of severity

Potential Pipe Defect Coding

Adjustments – Structural

54 54

8/8/2014

19

Potential Pipe Defect Coding Adjustments – Structural


Joint Angular Large

(JAL)

Increase rating value by 1 By definition, a JAL is greater than 1.5 times the

pipe wall thickness

Surface Reinforcement

Chemically Affected

Retain or Reduce from 5 to 4

(concrete pipes)

Chemical attack in storm pipe would be an

extenuating circumstance.


Mechanically Affected

Retain or Reduce from 5 to 4

(concrete pipes)

Mechanically damaged reinforcement in storm pipe

would be an extenuating circumstance.


Affected, Not Evident

No change from default value Cause of defect is unknown

Evidence of infiltration

Increase value of weeper from 2 to 3 and add rating of 1 for evidence of staining

Relates to eroding bedding and fill materials around pipe resulting in settlement and collapse

Evidence of exfiltration

New field – addition as “5”

Relates to eroding bedding and fill materials around pipe resulting in settlement and collapse

Unauthorized connections

New field – addition as “5”

By definition they may be unauthorized. If defective include related defect code as well.

55 55

Potential Pipe Defect Coding Adjustments – O&M


Deposits No change from default values

Considers reduced cross sectional area of piping; may be due to pipe sagging

Debris / Obstruction No change from default values

Considers reduced cross sectional area of piping; may be due to pipe sagging

Encrustation No change from default values Considers reduced cross sectional area of piping

Roots – Heavy (Ball) @ Joint

Increase from 4 to 5

Increased Root Ball at Joint value to reflect same score as Root Ball at Barrel; should also be accompanied by score associated with whatever structural defect is allowing root penetration

Roots – Medium @ Joint

Increase from 3 to 4

Increased Root Medium at Joint value to reflect same score as Root Medium at Barrel; should also be accompanied by score for whatever defect is allowing root penetration

Roots – Light (Fine) on pipe barrel

Increase from 2 to 3 Increased value by one due to represent severity of root intrusion in shallow pipe.

Roots – Light (Fine) on pipe barrel

Increase from 2 to 3 Increased value by one due to represent severity of root intrusion in shallow pipe.

56 56

Example Modified PACP Pipe Defect

57

Structural Joint (J) : Offset (displaced) (O) Large (L) JOL (3) – now “4”

Separated (open) (S) Large (L) JSL (3) – now “4”

Angular (A) Large (L) JAL (2) – now “3”

RCP

8/8/2014

20

NASSCO PACP Coding

58

HOLE – is it a lift hole? Utility intrusion?

(Commonly found with concrete pipe)

If Lift Hole, are there associated defects

(cracks, fractures, staining)

Insert related pipe

defect here

Insert related pipe

defect here

Insert related pipe

defect here

R C P

NASSCO PACP Pipe

“QuickScore”

60

Pipe Defect Inspection Data

8/8/2014

21

NASSCO PACP Quick Score Example

61

A four digit result representing:

Digit 1 – Greatest defect score found in that pipe = 5 (on a 1-5 scale)

Digit 2 – The frequency of the greatest defect score = 2

Digit 3 – The second greatest score found in that pipe = 2 (on a 1-5 scale)

Digit 4 – The frequency of the second greatest score = 6

Example, for structural assessment, a segment with 2 grade 5’s, 0 grade 4’s, 0 grade 3’s and 6 grade 2’s, result would be:

PACP Quick Score Example

62

Inspection Number

Inspected Length

(ft)

Material Listed in Video

Diameter (inches) Listed

in Video

Structural Quick Score

O & M Quick Score

5 151 CMP 48 5E00 0000

8 109 RCP 15 5436 4122

7 143 RCP 15 5144 2100

29 226 RCP 15 5111 2300

99 195 RCP 4E3G 0000

66 167 RCP 33 4D32 0000

37 233 RCP 30 4A3Y 0000

110 70 RCP 24 4A00 0000

34 102 RCP 24 4936 0000

94 242 RCP 21 3H21 0000

54 135 RCP 21 3211 1200

83 93 RCP 48 3200 1A00

4 147 CP 15 1100 312C

63

PACP Quick Score Defect Count and Corresponding Characters

Defect Count Corresponding

Character

1 1

2 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

10 - 14 A

15 - 19 B

20 - 24 C

25 – 29 D

30 – 34 E

35 – 39 F

40 – 44 G

45 – 49 H

50 – 54 I

Defect Count Corresponding

Character

55 – 59 J 60 – 64 K

65 – 69 L

70 – 74 M

75 – 79 N

80 – 84 O

85 - 89 P

90 - 94 Q

95 - 99 R

100 - 104 S

105 - 109 T

110 - 114 U

115 - 119 V

120 - 124 W

125 - 129 X

130 - 134 Y

>= 135 Z

8/8/2014

22

Typical Structural Score Priorities

Modified NASSCO PACP Defect Code Results

Greatest Structural Score – “5” - Urgent corrective measures required.

Structural Score – “4” - Near term

corrective measures required within 2 - 5

years

Structural Score – “3” - Rehab/Repair

recommended, asset failure possible in

within 5 - 10 years 64

64

Typical O&M Score Priorities

Modified NASSCO PACP Defect Code Results

Greatest O&M Score – “5” - Urgent

corrective measures required.

O&M Score – “4” - Near term corrective

measures required within 2 years

O&M Score – “3” - Rehab/Repair

recommended, asset failure possible in

within 5 years

65

Other Programs

8/8/2014

23

67

Summary of Other Agency Practices

NASSCO PACP Default Method Modified PACP Other

City of Chesapeake, VA Fairfax County Stormwater

Cobb County, GA ; Grand Rapids, MI– Business Risk Exposure, similar to PACP

City of Virginia Beach, VA Fairfax County Wastewater Collection Division

Aurora Water, Colorado – Project specific based on RedZone Robotics condition rating - similar to PACP

City of Newport News, VA City of St. Albert, Alberta, Canada

Australia - Auburn, Mitchell Shire Council, Wagga Wagga – each similar to PACP

Hampton Roads Sanitation District and other Public Wastewater Agencies (Norfolk, Chesapeake, Portsmouth)

DC Water Houston, TX – CIP Process Manual for Infrastructure Plans

Olympia, WA - relies on pipe material and age to prioritize storm system assets Cities of Gary, IN and

Fort Wayne, IN

Cincinnati, OH

Sacramento County, CA

Municipality of Anchorage, AK

Seattle, WA (Combined Sewers)

67

Lessons Learned – Shifting to an Effective Condition Assessment Program

68

FROM: Reactive mode and “fix worst first” Culture of individual specific project needs Cost administration based on historical needs and trends Capital planning strictly as en engineering function O&M staff disconnected from asset decisions Technology as barrier

TO: Proactive mode and continuous and improved service delivery Customer service driven practices and asset life cycle valuation Financial management based on structured condition approach Capital planning as a collaborative opportunity; recognize O&M elements and needs O&M staff are indispensable asset experts Technology as enabling

• Iterative pipe defect coding process, for storm systems, still evolving from NASSCO aspect

• Pipe inspection database management crucial - avoid data “sitting on shelf” with no review and related action

• Many differences between types of pipe systems

• Need to establish cultural change incorporating system condition assessment practices and infrastructure re-investment justification

Lessons Learned

69

8/8/2014

24

• Be flexible, responsive and adaptive – Changed direction (accommodate citizen expectations)

– Fluctuating and scalable funding/budgets

– Don’t be afraid to customize defect codes for your system

• Simple, defensible and ease of implementation (pipe defect coding method)

• On-going need to invest in staff training and technology

• Pipe installation, inspection and acceptance method is critical

• System interconnections with other agencies and private systems

Lessons Learned – 2

70

City of Chesapeake,

VA Storm Condition

Assessments

• 351 sq. miles • 228,500 million population

• Phase I MS4

• TMDLs

Chesapeake, VA

72

8/8/2014

25

Public drainage system

1,200 miles of gravity storm pipe Ranges 12” to 66” dia.

30% of system is tidally influenced

2200 miles Public Storm Drain Ditches

61,613 drainage structures

540 Detention / Retention Basins

Ground elevations range from 1 to 28-feet above sea level

Sampling of Maintenance Responsibilities

73

What is City Responsibility?

• NASSCO PACP “QuickScores” – Issue Work Orders based on urgency

• Residential Areas • Private Drainage • City Roads & Ditches • Driveway Culverts • Integrated Road Drainage System

74

City’s Use of NASSCO PACP

• City plans to inspect 1,200 miles of storm pipe – Inspection frequency: once

every 3-4 years

• First seven months: – CCTV’d 23,000 LF – Peak day 827 LF

• NASSCO PACP “QuickScores” – CCTV inspections completed

in two storm drainage basins – Evaluating other technologies

(under water camera systems)

75

8/8/2014

26

Example of City’s NASSCO PACP Results

76

Address PACP QuickScore

Overall Rating 1335 Lindale Dr 5221

4001 Grant Ct 5121

565 Saddlehorn Dr 4131

1204 Woodstream 4121

3021 Oak Dr 3228

2901 Sir Thomas crossing Sir

Thomas 3111

3241 Bruin Dr 3111

Shadyside @ Wisteria Ct 3111

4224 Foxxglen Run 2400

Grant Ct to 3108 Tyre Neck 231A

Grant Ct 2312

Oak Dr E. 2300

905 Saddleback Trail Ct 2211

Meadowbrook to Pineridge 2211

Wythe Ln 2200

2505 Foreman Lndg 2112

Address PACP QuickScore

Overall Rating 3500 Avondale Ct 2111

3117 Dean 2100

102 American Legion Rd 2100

Mapleton Cres at Shadyside 1500

Foxgrove Ln 1500

Woodcroft Ln 1500

Western Branch Blvd at Dunedin

Dr 1400

2017 Phyllis Dr 1300

3537 Kentucky Trl 1200

Hawksley 1200

Poplar Hill /Kenley Ct 1200

3221 PineridgenDr 1100

713 Sparrow Rd 1100

Helensburgh Dr 1100

853 Woodstream Way 1100

608 Guisborne Ct 0000

816 Dawson Cir 0000

Example City’s NASSCO PACP Inspection Observations

77

So, what did we find?

FROG INSPECTOR WOOD

78

8/8/2014

27

79

So, what did we find? (Cont’d)

So, what did we find? (Cont’d)

80

• City assessing storm pipe inspection results to determine prioritization and resource needs

• Match “renewal” need with available funding

• Coordinate with City’s CIP and implementation schedule

• Address processing of inspection backlog

– Incorporate findings with CIP and maintenance plan

• Learn from other agencies’ related experiences

• Get City DPW staff trained as NASSCO PACP users

NASSCO PACP QuickScore Role

81

8/8/2014

28

• NASSCO PACP storm pipe defect coding and the resulting scores provide a good screening tool

• Follow-on engineering evaluation and judgment is needed to confirm the extent and severity of the inspection condition observations.

• Need to have staff and contractors certified as NASSCO PACP users in order to provide compliant and consistent pipe defect condition observations

So, What Have We Learned?

82

• Produce a program schedule that is realistic, train staff, and deploy inspection equipment capable of doing the work

– 1.5 CCTV trucks cannot reasonably be expected to do what we set out to do even averaging 1,000 LF/day

– With the purchase of 2 fully equipped new CCTV trucks (out of funding cycle), need to decommission the oldest truck

– Rolling stock – Total of 2.5 CCTV trucks

– Need to verify CCTV inspection NASSCO-compliant software produces reliable pipe condition scores

So, What Have We Learned (cont’d)?

83

• Communicate with staff, superiors, Council, and citizens:

– The importance of the inspection and assessment program and

– The benefits to be derived.

• Update your constituents regularly with current information.

– We brief our Stormwater Committee (includes Council Liaisons, Citizens, and staff) bi-monthly

– We advise staff and superiors monthly


84

8/8/2014

29

• Investigate what your neighboring localities and other involved agencies are doing to avoid their implementation issues (Don’t repeat them).

– Talk with your counterparts and visit their operation

– Talk to your suppliers and consultants

– Get the equipment that best fits your needs. Don’t be sold on anything less


85

One last learning item!

Cement matrix from exposed aggregate

driveway (since removed by replacing pipe)

86

And just one other last learning item!

87

8/8/2014

30

Questions?

Pete Fortin, PE, CSM

[email protected] (757) 382-3321

Ken Eyre, PE, PACP [email protected]

(571) 581-3011

Thank you

greeley-hansen.com

Documents

More on Things that Go Bump in the Pipe: Implementing ... · the Pipe: Implementing municipal storm sewer pipe condition rating ... approach such as NASSCO PACP / MACP ... Sewerage