Inyo Supes consider DWP pumping plan
The Inyo County Board of Supervisors convened in a special meeting on Monday to deliberate over the Los Angeles Department of Water and Power (LADWP) proposed Owens Valley pumping plan for the 2013-2014 runoff year. Because this runoff year comes after 2 consecutive drought years, the LADWP released not the typical 12-month plan, but a 6-month pumping plan for April-September of 2013. The LADWP proposed pumping between 47,370-54,660 acre-feet for those 6 months, with a projected 70,000 acre-feet pumped over the course of the full runoff year.
Board Supervisors expressed concern about the impact of this pumping plan on vegetation and groundwater tables in the Owens Valley. In a comment letter submitted to the LADWP prior to the meeting, Inyo County Water Department Director Bob Harrington articulated his support for a smaller range of pumping in several key well fields to help preserve vegetation and groundwater already impacted by prior years of pumping.
Sally Manning, former Inyo Water Department plant expert, now Big Pine Tribal Environmental Director, attested to the necessity of protecting these areas at Monday’s meeting. “The pumping is happening faster than the Valley is being recharged,” she said, according to a news report from Sierra Wave. She also noted that the Valley has yet to fully recover from the extreme pumping conducted during the ‘80s, which reached a peak of 209,000 acre-feet in 1987.
The resulting erosion of vegetation and groundwater supply will affect not only the environment of the Owens Valley, she argued, but also those residents who make their living from the land. Ranchers in particular may be threatened by the pumping plan, which calls for a 20% reduction in irrigation in Laws and Independence, and a 10% reduction in irrigation Valley-wide.
“For the DWP to do that under the [Inyo/Los Angeles Long Term] Water Agreement, they need the agreement of the Board of Supervisors,” explained Bob Harrington. The Board, which has not reached a definitive conclusion regarding the LADWP’s request for reduced irrigation, will attend the Standing Committee meeting on May 20. “It’s a tough decision, to weigh the pumping versus the needs of the ranchers for irrigation water,” said Harrington. “I honestly don’t have a sense of what their decision will be.”
Supervisor Linda Arcularius also refused to speculate on the Board’s final decision. “The Board certainly gave [the pumping plan] a lot of thought,” she said. “It’s a difficult year.” The Board did agree overall with Harrington’s letter, which asked for a reduction in pumping from the LADWP’s projected 47,370-54,660 are-feet to 46,825-49,585 acre-feet. The lower numbers are the result of site-specific reductions in pumping in Big Pine, Taboose-Aberdeen and Symmes-Shepherd well fields.
The LADWP pumping plan proposed pumping 11,550-12,900 acre-feet in Big Pine; Harrington’s Inyo County comment letter proposed 10,800. In Taboose-Aberdeen, the LADWP proposed pumping 4,200-7,380 acre-feet, compared to Inyo County’s recommended 5,200. And in Symmes-Shepherd, the LADWP plans to pump 3,100 acre-feet to Inyo’s desired 2,305.
As Harrington’s letter noted, last year the LADWP pumped 26,451 acre-feet from Big Pine, resulting in an overall 1 to 2-foot decline in the water table at monitoring sites and indicator monitoring wells. Indicator monitoring wells were 2.7-5.3 feet below their baseline water levels. The end result: 3 vegetation parcels displayed a negative impact, with the LADWP’s own independent vegetation data for the well field indicating a decline from 2011-2012, and average vegetation cover below baseline.
Meanwhile, last year the LADWP pumped 12,734 acre-feet from Taboose-Aberdeen, which resulted in water table declines ranging from 0.73 to 1.86 feet. Water levels ranged from 1.4 to 5.9 feet below baseline water levels. The LADWP’s data indicated a decline from 2011 to 2012, and average vegetation cover below baseline. Harrington’s letter projected that the LADWP’s proposed maximum well field pumping for the 2013-2014 runoff year would result in water table declines ranging from 0.2 to 1.3 feet in indicator wells, resulting in water tables 0.1 to 6.9 feet below baseline.
But the most dramatic changes could be seen at Symmes-Shepherd, where the LADWP pumped 7,270 acre-feet last year, resulting in water table declines ranging from 0.57 to 5.81 feet. Water table levels range from 2.6 to 22.7 feet below baseline levels. LADWP’s data indicated the average vegetation cover in the well field has declined to below baseline, yet the proposed pumping is predicted to result in water table changes ranging from an increase of 0.4 feet to a decline of 0.6 feet at indicator wells and monitoring sites, resulting in water tables 2.3 to 22.8 feet below baseline.
How Inyo County and the LADWP resolve their differences will be determined in large part by the May 20 Standing Committee meeting in Los Angeles.
