The Owens Valley Monitor 2002-2003

LADWP’s Eastern Sierra Water Exports

In its 2002-2003 annual pumping program, LADWP projected that its water exports from the Eastern Sierra between April 1, 2002, and March 31, 2003, would be 243,400 acre-feet. According to LADWP, this amount of water is worth about $90 million, based on the current cost to LADWP of water purchased from the Metropolitan Water District.
     LADWP’s primary source of export is surface water runoff from the Owens Valley, Long Valley, and the Mono Basin. Groundwater pumping from the Owens Valley provides an additional, but much smaller, water source.
     Based on its April 1, 2002, snow survey, LADWP estimated potential Eastern Sierra surface water runoff for April 2002-March 2003. LADWP predicted runoff from Owens Valley and Long Valley streams would be 302,100 acre-feet, with an additional 93,100 acre-feet from the Mono Basin. Actual runoff was probably less than predicted since LADWP assumed in its estimates that runoff would be 76% of average. Runoff during 2002-2003 was actually 67% of average.
     LADWP exports to Los Angeles are reduced by the amount of water that remains in the Eastern Sierra. Local uses include irrigation and stockwater supplies to LADWP land and water supplies to environmental enhancement projects (see Table 4). Dust control on Owens Lake currently requires about 40,000 acre-feet of water per year, though this number could ultimately rise to 67,000 acre-feet per year. In the Mono Basin, LADWP water exports are currently limited to 16, 000 acre-feet per year by an order issued by the State Water Resources Control Board.
     LADWP has exported water from the Eastern Sierra since 1913. During that time, the city derived a vast amount of water, and wealth, from the region. In the last 30 years, court decisions and settlements have shifted the balance somewhat, leaving more water in the Eastern Sierra to protect the environment.
     More water left in its area of origin for such things as controlling dust on Owens Lake, rewatering the Lower Owens River, preserving irrigated lands and protecting groundwater-dependent native vegetation in the Owens Valley, and providing flows to Mono Lake will reduce LADWP’s water exports.
     Still, in its most recent Urban Water Management Plan (2000), LADWP estimated its median annual exports from the Eastern Sierra over the next 20 years will be 321,000 acre-feet.

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