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.. f~ ..... . n00833 PROBLEM Continued growth of the population in Nor1;hern Nevada and also around Lake Tahoe on the Truckee River created more demands on the water supplies of these two rivers for municipal use, Even with additional storage reservoirs on the Truckee River, the amount of water available was not adequate to meet demands. In 1967 the cui- ui, a fish species endemic to Pyramid Lake, which is the terminal lake for the Truckee River, was listed as endangered. It was determined that these fish must spawn in the Truckee River in order to survive. However, due to the existing demands already placed on the river, there was not enough flow in the river to allow them to spawn except in years of above average runoff. In an effort to make sure that the cui-ui did not become extinct, the Federal Government began issuing Operating Criteria and Procedures rOCAP) for the Newlands Project. The purpose of OCAP was to reduce diversions from the Truckee River, and therefore, provide more water for the endangered species. The first OCAP was issued in 1967. Several interim OCAP were issued during ensuing years with a final or permanent OCAP being issued in April of 1988. The basic premise of the final OCAP is the reduction of diversions from the Truckee River by increasing the efficiency of the project"s irrigation delivery system. Since the Truckee River is, used to supplement the water available from the Carson River, any water saved as a result of increased efficiencies will result in less water being diverted-from the Truckee River. Extensive litigation over the waters of the Carson and Truckee Rivers in previous years had resulted in a. water duty being established by the courts for the lands within the Newlands Project. This water duty cannot be changed except for natural drought periods. Therefore, water savings through efficiency improvements must come from the delivery system. alone, since the individual user cannot be required to increase on-farm efficiency. Prior to issuance of the final OCAP in 1988, the project irrigation delivery system was being operated at approximately 55%. The final OCAP defines the efficiency of the delivery system as, the sum of water deliv~red to the headgates of all users divided by the total amount of water diverted to the project. The OCAP requires the project operating entity, the Truckee-Carson Irrigation District (District), to increase the efficiency of the delivery system approximately 12% during the five year period from 1988 to 1993. This would result in an efficiency of over 67% which will result in a savings of approximately 58 million m' (47,000 acre-feet) of water each year. The primary crops of the project are alfalfa hay and small grains which are of relatively low value. Therefore, the water users are 3