For the 2010-11 run-off year, the LADWP wants to pump 86,000 acre feet. The DWP Annual Operation Plan just out also reveals that flaws in the water agreement could lead to excessive pumping.
Inyo Water Director Bob Harrington said that he and his department will look at what DWP has proposed, evaluate what the pumping plan would do to the water table and vegetation and make a response. Harrington said his response must go to DWP by April 30th.
Harrington did note that the pumping rate last year was 63,450 acre feet. The run-off forecast this year is 95% of normal, higher than last year and the best run-off since 2006. The Water Director did say that because the pumping rate is nearly 23,000 acre feet higher this year, he and his staff will take a close look. They will use computer models to predict what the pumping rate would do to the groundwater table.
Harrington also pointed to another part of DWP’s plan. The City’s plan lists the available pumping capacity in the Owens Valley well-fields. Harrington said their figure of 163,793 acre feet was arrived at by the Water Agreement on/off provisions for pumping. Harrington said this high number illustrates why the Green Book of pumping rules needs to be fixed. Harrington said, “Pumping 163,793 acre feet would be quite harmful to vegetation and any remaining springs.”
The Inyo-LA Water Agreement spells out steps and formulas to determine available pumping. Harrington said, “We’ve always wanted to revise that. It allows too much pumping to meet vegetation goals in the Water Agreement.” The Water Director summed it up by saying that the current on/off pumping mechanism conflicts with the goals in the Agreement for vegetation conditions.
Over the last three years or more, Inyo and LADWP staff have privately worked over the pumping rules to revise them but have failed to arrive at a new set of protective rules.