City Council

Agenda Request

Agenda Of:

06-15-10

Agenda Request No:

vii-c

Initiated By:

SuEllen Staggs, Director of Utilities

Responsible Department:

Utilities

Presented By:

SuEllen Staggs, Director of Utilities

Department Head:

SuEllen Staggs, Director of Utilities

 

 

Additional Department. Head (s):

N/A

Subject / Proceeding:

Risk Based Infrastructure Management Program

Review and Discuss

Exhibits:

N/A

Clearances

Approval

Legal:

N/A

Executive Director:

N/A

Purchasing:

N/A

Asst. City Manager:

Karen Daly 

Budget:

N/A

City Manager:

Allen Bogard

Budget

Expenditure Required:  $

N/A

Current Budget:  $

N/A

Additional Funding:  $

N/A

Recommended Action

 

Review and discuss the Risk Based Infrastructure Management Program for wastewater collection system.

 

Executive Summary

 

As part of the City’s continued efforts to proactively manage our infrastructure, the Utilities Department has development a GIS-centric Risk Based Analysis Forecasting Tool. Since it is difficult to determine the condition of underground infrastructure such as water and wastewater lines, the tool was developed to help forecast what underground infrastructure should be targeted for further review and eventually rehabilitation or replacement.  The tool will also ensure we spend our limited dollars in the most cost effective way to extend the useful life of the collection system.

 

Infrastructure asset management is a practice of placing records of all your assets into a structured database that can be queried and manipulated.  The benefit of easily managed data is the ability to create decision-making processes for the future of the infrastructure. An Infrastructure Management System, and its forecasting capability, is an essential tool that can be used to develop long-range strategies for infrastructure maintenance, rehabilitation and replacement.  The most difficult piece to ascertain for underground infrastructure is its condition.

 

To ascertain the condition of each sewer pipe section, the Utilities Department first looked at inflow and infiltration (I&I) as an indicator of sanitary sewer line degradation.  This analysis targeted lift station basins with high I&I so 49 lift station service areas with significant flows to WW plant were identified. After collecting data for 60 days, it was determined the City’s collection system is very tight and that I&I will not be a good indicator for potential line replacement or failure.

 

Consequently, it was decided to concentrate on the gravity sewer system because of several expensive line failures over the last two years.  The City’s robust GIS database contains data on each line segment in the City so five factors were used to help determine the risk of failure.  The five factors of each line segment used in the analysis were:

·                     Material

·                     Age

·                     Remaining useful life

·                     Diameter

·                     Depth

 

The factors were then used to create three categories, Impact, Condition, and Criticality.  These categories are typical infrastructure asset management criteria used to provide a forecasting method that will enable flexible and dynamic financial modeling to maximize the life of our sanitary sewer system.

 

The Utilities Department will review the development of the forecasting tool and the analysis’ recommendations.

 

Exhibits

 

N/A