County wants DWP to cut pumping in 2021-22

By: 
Register Staff
Staff Writer

Faced with drought conditions and the second straight year of runoff levels far below average, Inyo County is recommending a significant drop in proposed groundwater pumping by the Los Angeles Department of Water and power during the 2021-22 runoff year.
The county is proposing that LADWP drop its planned pumping by 19,603 acre feet, to a total of 59,377 acre feet. The LADWP pumping plan calls for up to 78,980 af of pumping, as outlined in the department’s draft Annual Operations Plan for 2021-22.
The LADWP plan outlines two levels of pumping, with a minimum of 64,600 af and a maximum of 78.980 af (an acre foot of water is about 326,000 gallons, and can supply water to about two families). The Inyo County Water Department pointed out that the higher pumping total projects about 10,000 af of pumping from October to March, “presumably for aqueduct supply” since irrigation season ends in the fall.
In the response letter to the LADWP plan, the county Water Department notes that “LADWP has historically pumped near the maximum proposed amount,” thus the department based is analysis of the impacts of the pumping on the higher, maximum pumping total.
The Water Department analysis states both the lower proposed pumping amount and higher amount would farther drop groundwater levels throughout in the Owens Valley. Those groundwater levels were mostly lower than baseline levels after last year, when pumping hit about 73,000 af.
“Adjusting pumping (in 2021-22) to maintain” water tables with groundwater-dependent vegetation “is necessary to stabilize declines since the onset of the present drought and to potentially avoid impacts” if the valley experiences long-term drought conditions “like those experienced in the past 35 years,” the county letter states.
This year’s runoff was 55% of average. Last year, runoff was 75% of average. Thus, the Water Department’s “recommended pumping amount, 59,377 af, is a more prudent plan for the upcoming drought year which allows multiple goals of the Water Agreement to be met with a more sustainable approach.”
That level of pumping will stabilize groundwater levels and also provide water for in-valley uses and exports to Los Angeles. The in-valley uses include water for mandated irrigation, stock-water, enhancement and mitigation projects, recreation and town water supplies.
“We are pleased to note that despite the lower than normal expected runoff, attempts will be made to meet Type E irrigation and other in-valley use obligations,” the county letter states.
Total “in-valley uses” outlined by LADWP come to 85,380 af of water, allocated as follows: irrigation, 40,760; stock-water, 10,490 af; enhancement and mitigation projects, 7,920 af; the Lower Owens River Project, 17,500 af; The “1600” projects will receive 1,600 af; recreation and wildlife projects will receive about 7,100 af.
However, the county Water Department also notes that water supplied for irrigation and stock-water (a total of 51,250 af) is lower than the historic average, and assumes that low creek and stream levels will limit irrigation in the fall.
In addition, the county adds that the operations plan does not include water used by LADWP for dust control on Owens Lake, which the county would like included in the operations plan since the county is part of the Owens Lake Groundwater Work Group.
Last year’s LADWP pumping total of 73,000 af, which was at the low end of the range of planned pumping totals, was due to the shutdown of the Department of Fish and Wildlife Fish Springs trout hatchery when a virus infected the hatchery trout. The county notes that DFW has informally indicated it might need less groundwater to operate the hatchery when it reopens and in future years. Discussions with DFG are in the early stages regarding any adjustment to the water supplies to the hatchery.
The LADWP draft operations plan outlines the current conditions in the Eastern Sierra.
Runoff in the Eastern Sierra for 2021-22 is just 55% of average. The reduced runoff will limit water exports through the Los Angeles Aqueduct to 108,000 acre feet. Last year, runoff hit 75% and the aqueduct delivered about 188,400 af of water to Los Angles.
This season’s meagre snowpack runoff will deliver about 295,600 acre feet of water moving through the Los Angeles Department of Water and Power’s water gathering operation in the coming year, with 226,800 af coming from the Owens River Basin and 68,800 af from Mono Basin, according to the Draft Operation. The long-term mean (1966 to 2015) runoff for both basins is 528,302 af.
The LADWP draft operations plan and the county’s comments and recommendations will be discussed at the Inyo Los Angeles Technical Group meeting in May.
The complete draft LADWP Owens Valley Operations Plan for Runoff Year 2021-22, the county’s response letter, and details about the upcoming technical group meeting can be found on the Inyo County Water Department webpage at www.inyowater.org.

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