A request for preference to use ground water to cool a proposed power plant on the reservation was denied. State Engineer Hugh Ricci said he cannot decide if there is enough deep water available for the tribe's request. The tribe and the Calpine Corp. of Pleasanton, Calif., vow to continue seeking permits to secure 7,000 acre-feet of ground water to operate a 750-megawatt facility that could serve power needs of 100,000 people. In a Dec. 26 letter, Ricci noted ground water could come from interconnected basins, where water deposited by rain has accumulated deep under the ground for about 10,000 years, geologists say. But information is insufficient to declare its use for a power plant, Ricci said. The Paiutes, whose reservation is 45 miles northeast of Las Vegas, are battling Nevada Power Co., the Las Vegas Valley Water District and the Moapa Valley Water District. Calpine would build the 750-megawatt generating station and needs water to cool plant generators. The plant also would provide jobs and income for those on the poverty-stricken reservation. Besides requesting permission to reserve ground water, the tribe claimed it has ancestral rights to the water dating back at least 1,000 years. Ricci will set a conference on the applications for mid-February.