AWWA INF53975

Corrosion-induced failures on metallic water mains have been a chronic problem inWinnipeg, Manitoba, as well as other North American cities. In the early 1980s,Winnipeg experienced a significant rise in leaks on metallic water mains due tocorrosion. The City chose to address this problem through a combination oftraditional methods involving the use of spot repairs and water main renewalcampaigns based on a technical and economic evaluation of the situation. A leakfrequency of five or more repairs per year per kilometer (LF5) was determined asthe economic criterion to support water main renewal. Emergency spot repairscontinued to be performed as leaks occurred. The most critical failure locationswere prioritized and renewed as annual budget cycles permitted. Selectivecathodic protection was initiated in 1992 at repair locations on metallic watermains and locations where new PVC water mains were connected to existing metallicones. The goal of this policy was to minimize, prevent, or further reducecorrosion-induced leaks at the "hot spot" locations and defer the need forrenewal. Advances in information management and asset management provide a meansof optimizing the cost-effectiveness of operating and maintaining Winnipeg'swater distribution system. Ongoing analysis of repair records confirmed thatannual renewal campaigns and "hot spot" cathodic protection were effectivelyreducing leak frequency on metallic water mains. With this understanding, theCity recognized the need to investigate other engineering based solutions thatcould cost-effectively improve reliability and prolong the functional life of theexisting distribution system. A present value economic analysis was performed toevaluate various water main management options and scenarios to provide financialinformation required to make sound economic decisions regarding cost-effectivelife cycle management of the metallic portion of Winnipeg's water maindistribution system. Includes 40 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2001

Number of Pages:

17

File Size:

1 file , 270 KB