Water main pipeline and seated cutoff valves

[UNVERIFIED CONTENT] Utility workers repairing a broken water main at Division st and 10th st in SoMa district (San Francisco).The contractors installed two large cut-off valves on an old bypass water pipe that exploded on December 13th, 2009, causing a huge sink-hole in Division Street.The water main is part of the Hetch Hetchy Water System, that brings drinking water from the Sierra Nevada mountains.Other keywords: fixing, working, safety jackets, reflector vests, water pipe, sink hole, water department, infrastructure, construction workers, welders, safety helmets, seated valves, cut-off valves, gate valves, C515 SFPUC, AWWA C515.