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UUiJJ-='~ ,;.~j . ' ., I. Introduction: The Water ConseIVation Act of 1991, HB 91-1154, contained a provision directing the Colorado Water ConseIVation Board (Board) to conduct an analysis of water salvage which may result from federal programs, including salinity controL." Section 37-60-106.5, C.R.S. During discussions of that analysis the Board recognized that the General Assembly's interest in water salvage arose, at least in part, from a complex water supply situation in the Grand Valley reach of the Colorado River near Grand Junction, Colorado. Representative Foster's bill, HB 91-1110, sought to address one aspect of this situation - "saved" water resulting from improved irrigation efficiency. The Board directed that this situation be examined specifically, separate and apart from a more comprehensive, or "global" analysis of water salvage and conseIVation on a statewide basis. This report addresses the Grand Valley issues. II. Overview of Grand Valley Water Issues Several very senior water rights diverting from the Colorado River several miles above its confluence with the Gunnison River near Grand Junction effectively "control" water use in the basin. Collectively these rights are known as the "Cameo Call". There are no significant diversions in Colorado downstream of these rights. Due to the seniority of these rights the users in the Grand Valley normally receive a full supply of water, sufficient for all their needs. The Cameo Call consists of water rights decreed for a total of 2,374 cfs wilh priority dates between 1882 and 1918, however due to size limits in various structures a maximum of 2,260 cfs can be diverted at anyone time. A list of these rights and a map showing the location of major features in the Grand Valley is attached as table 1 and figure 1. Except for a 400 cfs hydropower right and 270 cfs used for pumping irrigation water at Orchard Mesa the remainder (1,700 cfs) of these rights are used for irrigation. Rights of 1,730 cfs are diverted at a common point, the Grand ValIt?y Diversion Dam, and delivered in an extensive interconnected system of canals known as the Grand Valley Project and built with federal reclamation assistance. The remaining 640 cfs, including the most senior 520 cfs, is diverted by the Grand Valley Irrigation Company (GVIC) at a separate diversion dam, 8 miles downstream, near the town of Palisade. GVIC is a privately built and operated system with approximately 3,000 shareholders. The Orchard Mesa "Check" allows delivery of a portion of the Grand Valley Project diversions into the GVIC system. The bedrock and soils of the Grand Valley are of marine origin and contain high amounts of salt. When irrigated these salts leach out the soil and bedrock, creating saline return flows to the Colorado, making the Grand Valley a large contributor of salt to the river. In the early 1970s the seven Colorado River Basin states and the United States recognized that salinity of the Colorado River was a major water quality problem. In 1