BENEFITS OF THE LARGEST EARTH/ROCKFILL DAM PROJECT IN U.S. HISTORY

摘要

In early 2000, the Metropolitan Water District of Southern California completed construction of the largest earth/rockfill dam project in United States history: the $2.1-billion (US) Eastside Reservoir Project in Southern California. The 1 x109 cubic-meter (800 000 acre-foot) reservoir is formed by three earth/ rockfill dams: two 7.2 kilometers (4.5 miles) apart to close both ends of a valley and one at a low saddle in a mountain rim. Planning for the project started in 1987. The purpose of the reservoir, along with comprehensive groundwater management, conservation, and reclamation programs already implemented, is to ensure the reliable delivery of water to member public agencies currently serving 16 million people and expected to increase to 21.5 million by 2030. The role of reservoir storage in Metropolitan's integrated water delivery system is to regulate fluctuating sources of supply and variable demands to provide assured water service, even under adverse circumstances. The project will benefit Metropolitan's customers by: (1) providing emergency reserves for times when a major earthquake might damage imported water supply lines and interrupt water deliveries; (2) providing carryover (drought) storage as a reliable reserve against shortages when supply sources are limited during periods of low precipitation; (3) storing water during the winter to meet annual summer demands; (4) preserving operational reliability by allowing preventive maintenance to occur without consumer shortages; and (5) optimizing groundwater storage programs with short-term impoundment of imported water for later delivery to groundwater recharge areas.