Protecting drinkign water-supply sources: san francisco's water quality vulnerability zones

摘要

Water utilities are facing increasing challenges in meeting drinkign water treatmetn regulations because of the discovery of new patheogens in raw waters and the difficulties in balancing disinfectint usage.A greater emphasis is therefore placed on soruce portection of dinking water supplies.The U.S.EPA's Source Water Assessment Program (Safe Drinkign Water Act Smendments of 1996) reinforces the impoortance of source protection.A unique mehtodology was devleoped for the cityu and County of San Francisco Publich Utilities Commission to aid in the delineation of its local watersheds and spatially define kwater qualtiy vulnerability zones iwthin the watersheds.