Risk Assessment and the Identification of

Infrastructure Renewal Needs for the Town of

Cochrane, AB

Presented by:Nicolas Abarca, M.Sc., P.Eng.

Collaborators:Lynda Cooke, P.Eng., Urban Systems

Troy Sylvestre, Town of Cochrane

2

Presentation Outline Background Information. 2013 Water and Wastewater Master Plan Update. System Analysis and Assessments:

Modeling Work System Failure Risk Capital Projects Identified

Moving Forward.

About the Town of Cochrane Located at the base of Big Hill

in the Bow River Valley. One of the fastest growing

municipalities since the 1990’s.

Approximately 30% growth since 2006, to 17,580 people in 2011.

Expected population of 40,000 in a 20-year time frame

Wastewater and Water Infrastructure

Prior to 1998, the Town relied on sewage lagoons.

Wastewater pumped to the City of Calgary.

New 8ML water treatment plant in 1998 with regular upgrades.

Water Conservation initiatives required due to Bow River moratorium.

Water Conservation in Cochrane Outdoor water guidelines and

bylaws established. Toilet Rebate and other water

conservation programs. The 2012 rebate program issued

213 rebates = 3.75 ML in water savings.

Water Utility Bylaw updated in 2013 to reflect advancements in toilet technology.

6

2013 Water and Wastewater Master Plan Update

OBJECTIVES: Establish service delivery goals Analyze the performance of existing

infrastructure and future requirements. Undertake risk assessments on a multiple

accounts basis. Provide recommendations for utility management

and infrastructure planning.

7

Water Distribution System Analysis and Assessments

Performance Goals: Alberta Environment Standard for

operating pressure. FUS for fire protection

System Modeling: Peak Hour Demand Maximum Day Demand + FF

Identified capital projects

8

Water Distribution System Failure Risk

Identify and plan for other capital works not related to performance.

Analysis completed in ArcGIS, and for pipe elements only.

Quality of analysis depends on quality of available information.

Ranking methodology based on: Likelihood of failure Consequence of failure

9

Likelihood of Failure (Condition Ranking) Ranking based on pipe material and age. Life expectancy based on pipe material:

45 years for cast iron, concrete, VCT, asbestos cement, steel , ductile iron and copper

75 years for PVC and HDPE

Criteria Failure Rank

End of asset life expectancy within 10 years 5

End of asset life expectancy within 20 years 4

End of asset life expectancy within 30 years 3

End of asset life expectancy within 40 years 2

End of asset life expectancy over 40 years 1

10

Consequence of Failure

Modified consequence for larger sized mains

Criteria Failure Rank

River crossing or single feed out of a reservoir 5

Single feed to a reservoir 4

Railway or Highway crossing or easement between houses 3

Located along collector road standard road or higher 2

Other non-impactful location 1

Original Failure Ranking 1 2 3 4 5Modified Failure Ranking 3 3 4 5 5

11

Additional Capital Projects IdentifiedLikelihood of Failure:

Age: 37 years (Installed 1976) Material: Ductile Iron (45 year life expectancy. End of life expectancy: 8 years SCORE = 5

Consequence of Failure: Pipe located along easement between

houses. SCORE = 3

Overall Ranking: 60% likelihood, 40% Consequence

PIPE PRIORITY RANKING = 4.2

12

Sanitary System Analysis and Assessments

Original modeling (SANSYS) completed in 1998.

Updates in 2001 and 2005. New model developed in PCSWMM V.4.3 Demands allocated based on water meter

records for each parcel. Irrigation months were excluded.

Capacity concerns were identified based on service delivery goals.

13

Sanitary System Failure Risk

Likelihood of failure based on pipe material and age.

Capacity concerns:

Criteria Failure Rank

Pipe Capacity equal or greater than 90% 5

Pipe Capacity between 70% and 90% 4

Pipe Capacity between 50% and 70% 3

Pipe Capacity between 30% and 50% 2

Pipe Capacity less than 30% 1

14

Consequence of Failure

Modified consequence for larger sized mains

Original Failure Ranking 1 2 3 4 5Modified Failure Ranking 3 3 4 5 5

Criteria Failure Rank

River / Creek Crossing 5

Within 100 m of a water course 4

Main access difficult (between houses, no encasement, siphon/ forcemain without access points) 3

Located in arterial or collector road 2

Other 1

15

Sanitary Capital Projects Identified based on Capacity

Capacity Ranking: Percent full: 100% SCORE = 5

Consequence of Failure: Pipe located on collector road SCORE = 2

PIPE PRIORITY RANKING = 3.8

16

Passive Replacements – Next 20 Years

17

Conclusions

First step towards the development of a comprehensive asset renewal program.

Performance, risk of failure and consequence of failure were taken into account in the analysis.

Conservative and personalized approach in regards to life expectancy of the assets.

Launch point for a more refined analysis.

18

Moving Forward

Development of an infrastructure renewal strategy that: Adds additional complexity to the analysis. Investigates further the service life of different

materials. Coordinate activities with the Town’s road

replacement program. Accounts for budgetary constraints. Considers alternative construction methods.

19

QUESTIONS?