how the city of raleigh, nc is improving asset … · works? asset management age (40%) other gis...

Chris Nesbit, PE, BCEECDM Smith

John Sorrell, PECity of Raleigh2015 NC AWWA WEA Spring Conference

How the City of Raleigh, NC is Improving Asset Management of

Water Pipe Infrastructure

2015 NC AWWA WEA Spring Conference

City of Raleigh, NC –One of America’s Coolest Cities

• 2 WTPs

– Serving approximately 180,000 customers

– 2,200 miles of aging pipe

– Delivering approximately 50 mgd on an average day

• Initial Water System Built in 1887


ECM

City Works

?

Asset Management

Age (40%)

Other GIS Data

Gaps

Where We Started From in Asset Management in 2013


Recommended R & R Program Requires Continuous Data Updates to Support Decisions


Implementing a Defensible Water Main Rehabilitation & Replacement (R&R) Program

• Long Term Funding Needs and KANEW model

• Risk-Based Approach to Setting Priorities

• Refining the Data with Unique and Combined Data Sources

• Proceeding with Assessment Projects

• Summary


Long-Term Sustainable R&R Needs – How Much?

• Goal: Estimate annual pipe R&R needs expected in future years

• Benefit: Planning R&R CIP budgets in near term and long term and any increased funding needed to reach sustainable levels in the long term.

• Modeled using KANEW software based on age and material of pipe and service life expectancy curves of different materials

• Considered continued replacement of the “replaced” pipe as well as 1% new growth in pipe footage.


Long Term R&R Needs

0

20

40

60

80

100

120

140

2013 2033 2053 2073 2093 2113 2133

New Growth and ContinuedReplacement

Continued Replacement ofExisting Pipe

Existing Pipe ReplacementMile

s o

f P

ipe

Year


Water Distribution System Results

0

10

20

30

40

50

60

70

80

20

15

20

25

20

35

20

45

20

55

20

65

20

75

20

85

20

95

21

05

21

15

21

25

21

35

21

45

21

55

21

65

21

75

Mile

s o

f P

ipe

Future Renewal Year

W_PVC

W_PCCP

W_GALV

W_DIP

W_CO

W_CI

W_AC

W_REP

W_NEW

KANEWTarget

2015 Through 2025


Water Distribution Pipe Renewal CIP Compared to KANEW

0

5

10

15

20

25

2015 2016 2017 2018 2019 2020 2021 2022 2023 2024

Tota

l (M

illo

n $

)

Fiscal Year

Water R&R in CIP

Initial KANEW Results

KANEW Target

Annual Increase 2.51%


Condition and Criticality Ratings Determine Risk and the Recommended Course of Action

Criticality = Consequences of Failure

Co

nd

itio

n =

Pro

bab

ility

of

Failu

re

1 2 3 4 5

5

Mid Priority

Program

Rehab

High Priority

Program

Rehab

High Priority

Program

Rehab

Highest

Priority Action

Highest

Priority Action

4

Mid Priority

Program

Rehab

Mid Priority

Program

Rehab

High Priority

Program

Rehab

Highest

Priority Action

Highest

Priority Action

3 Low Priority Low Priority

Regular

Monitoring

Frequent

Assessment

Frequent

Assessment


Regular

Monitoring

Frequent

Assessment

Frequent

Assessment


Regular

Monitoring

Regular

Monitoring

Regular

Monitoring C

on

dit

ion

Criticality


Condition Factors – Water Distribution Pipes

Condition

CategoryCondition Factor

Condition

Age

Material

Water Main Breaks

C-Values

Water Quality Complaints

Pipe Operating Pressure

Capacity

ConditionExisting or Future Capacity Issues


Overall Results – Probability of Failure

Level % of Total Pipe Length

1 32%

2 34%

3 19%

4 10%

5 5%

• Percentage of the system in each category by length


Criticality Factors – Water Distribution Pipes

CriticalityCategory CriticalityFactor

Hydraulic CriticalityNumber of model junctions with pressure below 40 PSI when a pipe breaks

Critical User Service Interruption

Pipes nearest to critical users that when they fail will most likely effect the service to a critical user due to repair isolation

Critical User FloodingProximity to schools, hospitals, dialysis centers, large customers and industrial customers

Flooding/DisruptionsSelect pipes within distance of areas of known sensitivityBaseline flooding differential based on pipe diameter

Transportation Impact Crossing/proximity to roadways ranked based on speed

Crossing/proximity to railways

Ease of Emergency Repair

Pipes in know areas with difficulty of emergency repair

Pipes under lakes

Proximity to utility easements (i.e. transmission lines, etc.)

Proximity to Endangered Species Areas

Coinciding with Other Construction/Street Improvements

Proximity to scheduled paving projects


Overall Results – Consequence of Failure

• Percentage of the system in each category by length

Level % of Total Pipe Length

1 20%

2 18%

3 24%

4 21%

5 17%


Recommended Actions Matrix

1 2 3 4 5

5

Mid Priority

Program

Rehab

High Priority

Program

Rehab

High Priority

Program

Rehab

Highest

Priority Action

Highest

Priority Action

4

Mid Priority

Program

Rehab

Mid Priority

Program

Rehab

High Priority

Program

Rehab

Highest

Priority Action

Highest

Priority Action


Regular

Monitoring

Frequent

Assessment

Frequent

Assessment


Regular

Monitoring

Frequent

Assessment

Frequent

Assessment


Regular

Monitoring

Regular

Monitoring

Regular

Monitoring C

on

dit

ion

Criticality


Water Pipes - Recommended Action

Action% of Total Pipe

Length

Highest Priority Action6%

High Priority Program Rehab

5%

Frequent Assessment 23%

Mid Priority Program Rehab

3%

Regular Monitoring 29%


Prioritized Project Lists Developed for Highest Priority Action Pipes

• First step = data validation and/or condition assessment to confirm place on highest priority list of projects.

• Projects where the condition is field verified as poor or very poor will then proceed to R&R.

• Program is cyclical with annual condition assessment performed to verify condition and the R&R project list continuously updated and re‐prioritized based on the matrix framework.


Next Steps for Highest Priority Action Pipes


Refining the Data with Unique Sources and Efforts

• We found some great data sources…

Four Departmental Paper Plan Archives

Eight

Digital Plan Archives

Six Merger Community

Archives

Two Microfilm Archives


Digging for Age Data

• We found some great data sources…

• And realized that we had a multi-year project to catalog them get the information into GIS!

• We needed a strategy to quickly get enough information to proceed with our assessment/rehab projects.

• Still no age data for anything between 1887 and 1930

Four Departmental Paper Plan Archives

Eight

Digital Plan Archives

Six Merger Community

Archives

Two Microfilm Archives


Looking Outside the City

North Carolina State Archives

Annual Reports:

1887 Design Criteria

System Maps

Sanborn Maps

Local museums/ libraries

1887 Water map

1921 Water map

Local Engineering Firms

1928 Water map

1945 Water map

1958 Water map

1968 Water map


Detailed information from Overall maps

• Overall System Maps from 1887, 1914, 1921, 1928, 1945, 1958, 1968

– Identifies what decade a pipe was installed.

– Identifies main replacements when diameter changes between maps.


Critical Assets and Critical Records

• Searched every archive looking for documents related to PCCP and Cast Iron transmission mains. -> full GIS Update

• Searched every archive looking for documents related to replacement, rehabilitation or redevelopment. -> full GIS Update


Proceeding With Confirmed Assessment Projects – Gravity Sewer Main Assessment

• Assess critical sewer mains

• Assess sewer mains adjacent to old watermains in streets soon to be paved.

• Assess sewer mains adjacent to highest priority water in the same street/area


Proceeding With Confirmed Assessment Projects –Raw Water Main Highest Priority Action Project

• 36,000 ft parallel 36-inch and 54-inch pipes


Proceeding With Confirmed Assessment Projects – PCCP Water Transmission Main Projects

• Hillsborough Street

• 5500 ft 36-inch

• Pullen

• 4000 ft of 24-inch

• East Street

• 11200 ft of 30-inch PCCP


Summary and Conclusions

• An effective R&R plan studies both the macro level (entire system/long term needs) and the micro level (prioritizing pipe segments & projects).

• Important to move forward even with existing gaps.

• A risk-based approach is essential to identify priorities.

• In the early stages it’s important to locate all records and plan how to use them efficiently.


Summary and Conclusions (cont.)

• Improving our ability to communicate a defensible program to community leaders can lead to increasing the overall funding level for infrastructure rehabilitation

• Commitment to Important versus Urgent

Questions

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