– The following letter was written by James G. Yannotta, Manager Of Aqueduct, Los Angeles Department of Water Power:
The Los Angeles Department of Water and Power (LADWP) is providing this letter to the editor in response to the May 5, 2013 Sierra Wave story titled “Inyo officials concerned about environment, water agreement” because the story includes comments and misconceptions on how LADWP manages groundwater pumping, vegetation conditions in the Owens Valley, and the Water Agreement. Concerns are often expressed about low groundwater levels and vegetation damage, but across the Owens Valley this is generally not the case.
LADWP remains committed to all provisions of the Water Agreement, a document that was forged from over 25 years of negotiations involving representatives from both Inyo County and Los Angeles. The Water Agreement is clear in stating that management of water resources in the Owens Valley must balance providing a reliable supply of water for Inyo County and Los Angeles, while avoiding significant changes in vegetation and the environment that cannot be mitigated. Although this past winter was the second very low precipitation year in a row, conditions in the Owens Valley are relatively stable considering the dry conditions. While this year’s Owens River Basin runoff is just 47% of normal, LADWP is working diligently to meet its water supply obligations in the Eastern Sierra.
Currently, based on vegetation parcels monitored by LADWP throughout the Owens Valley, total live vegetation cover in LADWP’s wellfields is approximately 34% compared to 35% in these same parcels during 1984-87, which is a period of time which is used for comparison according to the Water Agreement. Vegetation cover values should also be considered in the context of the ambient conditions at the time. Precipitation immediately preceding and during the 1984-87 period was unusually high in the Eastern Sierra. Snowpack runoff between 1982 and 1987 averaged about 135% of normal. Abundant water was available in the Owens Valley that provided very favorable conditions for native vegetation.
Reviewing groundwater pumping, precipitation runoff, vegetation cover inventory, and depth to groundwater from the 1991 to the present shows that LADWP has conscientiously and carefully considered important factors before establishing annual pumping plans. LADWP has a good track record over the last 20 years on how it has managed the over 300,000 acres of City-owned land and the Owens Valley Groundwater Basin, despite what some people may have been led to believe. All wellfields have groundwater levels that are higher than when the Water Agreement was enacted.
This year, LADWP anticipates pumping in the range of 71,000 to 79,000 acre-feet. Last year groundwater pumping was just under 89,000 acre-feet. Comparing this to past groundwater pumping which duringi 984-87 averaged 112,000 acre-feet per year shows that LADWP is being responsible with groundwater pumping in the Owens Valley.
LADWP continues to be attentive to problem areas such as Laws. Blackrock is performing as expected 21 years ago and was mitigated for by providing a fish hatchery and the Lower Owens River Project. LADWP is willing to work jointly with Inyo County to resolve any issues at Blackrock.
Most of the groundwater pumped and surface water diverted by LADWP stays in the Owens Valley for agriculture, irrigation, enhancement and mitigation projects, town supplies, and other uses. This year LADWP expects to supply over 104,000 acre-feet for Owens Valley uses, not including Owens Lake, while exporting much less, only about 67,000 acre-feet, for Los Angeles’ municipal supply, which is the by far the lowest amount ever exported to Los Angeles.
James G Yannotta
Manager of Aqueduct
Los Angeles Department of Water and Power