LOCAL WELL NEEDS UP FOR DEBATE LIQUID AMOUNT REQUIRED UNCLEAR.

Byline: Karen Maeshiro Staff Writer

PALMDALE - How much water is pumped annually from Antelope Valley wells, and how much annually is replenished by rainfall and other sources?

No one knows for certain.

But that issue - last a concern at the tail end of the valley's 1980s population boom - could become the focus of 5-year-old litigation that has pitted farming companies against most of the Antelope Valley's public water agencies.

``It's got to be one of the contentious items in the litigation. There is not a consensus. There are several different positions on that,'' Antelope Valley-East Kern Water Agency General Manager Russ Fuller said. ``It's a very difficult thing to measure whether you are actually in overdraft or not. There are a lot of variables. There will be lot of studies and numbers determined by different parties. The judge will decide who's right.''

Lawsuits filed by two Kern County farming companies in 1999 and 2001 seek priority rights to the water under their Antelope Valley farmland.

A Riverside County Superior Court judge presiding over the case has urged the farmers and local public water agencies to negotiate a settlement, but those efforts have so far been unsuccessful.

Experts consulted by Los Angeles County, which is one of the defendants, estimate that 140,000 to 170,000 acre-feet a year is pumped annually, which county officials say far exceeds the amount the groundwater table can lose without lowering dramatically.

A U.S. Geological Survey report from 2003 concluded that annual pumping from the Antelope Valley groundwater basin averaged 81,700 acre-feet per year between 1991 and 1995, after the housing boom of the 1980s but also at a time when agriculture had fallen sharply from its peak in the 1950s.

Pumping averaged more than 350,000 acre-feet during the peak years in the late 1940s and early 1950s, the report said.

Groundwater storage by 1995 had declined more than 8.5 million acre-feet since 1915, when well use intensified through the introduction of engine-powered pumps.

The annual recharge, the report said, in the early 1990s was 68,100 acre-feet per year - from rainfall, treated sewage and irrigation water soaking back down into the water table.

``Groundwater-level declines of more than 200 feet in some parts of the groundwater basin have resulted in an increase in pumping lifts, reduced well efficiency and land subsidence of more than six feet in some areas,'' the report said.

``Future urban growth and limits on the supply of imported water may continue to increase reliance on groundwater,'' the report said.

Water officials said determining how much water is going out compared with how much is going in is a difficult task.

Palmdale Water District General Manager Dennis LaMoreaux said experts are working in conjunction with the lawsuits to determine how much groundwater is pumped annually.

``I would agree that an unmanaged basin like we've got here, with all the urban growth that's occurring, plus the increase in agriculture usage, is definitely going to be trouble, if it isn't already, without some kind of overall management,'' LaMoreaux said.

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Photo:

A field of alfalfa is watered at 50th Street East near Avenue M in Lancaster.

Jeff Goldwater/Staff Photographer