AgdaPkt 2013-02-11 - Laserfiche WebLink

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6.1.B. - Page 1 RE PO RT To the Honorable Mayor and City Council From the Cit Mana er February 11, 2013 SUBJECT Professional Services Agreement with JDH Corrosion Consultants, Inc. for the Cathodic Protection Assessment of the Highline Water Transmission Pipeline. RECOMMENDATION By motion, approve and authorize the City Manager to execute the Agreement for consulting services with JDH Corrosion Consultants, Inc. of Concord, CA, for the Cathodic Protection Assessment of the Highline Water Transmission Pipeline for $125,970.00. BACKGROUND The Highline Water Transmission Pipeline, which is comprised of approximately 14,500 linear feet of below grade water mains, supplies the Emerald Hills water distribution system in addition to supplying water to the Main City zone under certain emergency conditions. The existing pipes are12-inch and 16-inch ductile iron and cast iron and transport water from the Hetch-Hetchy waterline connection at Edgewood Road throughout Emerald Hills by means of pumps, water tanks, and direct connections. The pipeline is a vital source of water conveyance for the City. After review of as-built records and existing field conditions, staff concludes that the pipeline lacks necessary corrosion protection mechanisms. A condition assessment of the pipeline has not been performed since its installation in 1965 and, due to known and potentially unknown areas of highly corrosive soils throughout the alignment, certain pipe sections may be susceptible to corrosion failure, which can lead to untimely shutdowns, loss of water storage, and costly emergency repairs. ANALYSIS Because the Highline Transmission Pipeline is critical to the City's water supply, it is important to take a proactive approach and analyze the condition of the watermain to mitigate the risk of corrosion failure. The initial step of the analysis will measure the soil's corrosiveness along the length of pipeline. The data from the soil analysis will be used to determine locations along the alignment to perform a secondary surface survey. Based on the results of the survey, several locations will be selected to perform direct assessment of the pipeline by excavating and examining the pipe. This analysis will provide the City with an accurate assessment of the condition of the water main, identify weak spots and propose appropriate protection to extend the life of the pipe.