An innovative solution for replacement of the Lake Mathews Outlet Facilities

The Metropolitan Water District of Southern California is one of the world’s largest water wholesalers and serves over 18 million people. The primary sources of Metropolitan’s water supply are the Colorado River Aqueduct and the California State Water Project. Lake Mathews is the terminus reservoir of the CRA, and is the distribution source of CRA water for 90% of Metropolitan’s service area. The Lake Mathews Outlet Tower, constructed in 1938, is incapable of resisting forces imposed by the maximum credible earthquakes that could be expected from three nearby major faults. No feasible modifications to strengthen the existing tower could be found, and initial cost estimates to replace the tower ranged from $100 to over $150 million. As a public agency, Metropolitan must not only consider the need to maintain system reliability, but the cost and funding of projects of this kind as well. This paper will describe Metropolitan’s preliminary study effort to develop a constructable and cost effective project to replace the Lake Mathews Outlet Facilities, while also ensuring that sufficient funding will be available when needed for this and other major capital improvement projects.