AgdaPkt 2003-05-12 - Laserfiche WebLink

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V. A -4 DRAFT URBAN WATER MANAGEMENT PLAN and structural work are performed as needed. Several tanks have recently been recoated on the interior and exterior, an d seismically retrofitted. All storage tanks have cathodic protection to prevent corrosion. The storage facilities are in excellent condition and are properly secured against unauthorized entry. Most recently, one steel tank was constructed to replace two redwood tanks of the same total capacity at Easter Cross. The City has 10 pump stations located throughout the system. Four stations have permanent standby generators. The City also has four portable generators for emergency use. Most pump stations are housed. The City plans to eventually build housing around the remaining pump stations to protect them from weathering and vandalism. The City can meet maximum day demand as long as the SFPUC pipelines are in service. In the event of a loss of the SFPUC supply, the City would be able to supply all but four of the 17 pressure zones in the system for an extended period. Those four pressure zones are not currently connected to other pressure zones and do not have storage facilities. In order to provide water to those four zones when the SFPUC supply is not available, the City has connected the four zones to storage tanks that normally supply the Main City pressure zone. The City connected Altamont, Femside North, and Fernside South pressure zones to Carson Reservoir for emergency use only, and constructed a permanent connection from Cordilleras pressure zone to the Sequoia Tanks. In addition, the City may add storage facilities to serve remote services areas; such as Seaport and Friendly Acres areas, susceptible to low service pressures during prolonged interruptions. 4.2 Leak Detection The City's unaccounted -for water rate is about 4 %. This is an excellent rate and is significantly below most other water agencies. The City monitors its unaccounted -for rate continually and repairs system leaks immediately when found. The City purchased an electronic leak detector unit and its crews have participated in AWWA sponsored Leak Detection training, surveying at least 15 miles of main and service lines per year on an on -going basis. 4.3 Water Quality Monitoring Monitoring of the imported Hetch Hetchy supply is conducted by the SFPUC. The SFPUC treats the Hetch Hetchy supply by lime addition at Rock River for corrosion control and chlorination at Tesla Portal for disinfection, but does not filter prior to delivery. Bay Area reservoir waters receive complete treatment of filtration and disinfection at either the Sunol or the Harry Tracy filtration plants. Filtered water from these treatment plants may be co- mingled with unfiltered Hetch Hetchy water in bay area transmission pipelines. The SFPUC and the agencies that serve water from the SFPUC Hetch Hetchy supply previously applied for and were granted filtration avoidance for that supply under the Federal regulations. The Department adopted revisions to the Surface Water Treatment Regulations ( "SWTR "), Chapter 17, Title 22, California Code of 31