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1.Analysis of the maximum, minimum a nd average temperatures, and precipitation <br />records for the period 1970-90. <br />2.Review of a map provided by Colorado St ate University's IDS group. The map shows <br />the locations of the weather stations and th e irrigated areas in the Dolores-San Miguel <br />River basins. <br />3.Review of the USGS topographic maps. <br />It is recommended that if the elevation of the irrigate d area is different than the elevation of the weather <br />station, the temperatures used to calculate consum ptive use be adjusted using appropriate adiabatic <br />lapse rates. <br />3.0RESULTS AND CONCLUSIONS <br />The recommended changes for each hydrologic unit and county are summarized in Table 4 and <br />discussed in the following text. In hydrologic un its and counties where more than one weather station is <br />recommended, the weighting factor for each station was determined by the CSU IDS group using GIS <br />technology. <br />Hydrologic Unit 14030001, Mesa County <br />The USBR recommended changing from the Fruita sta tion to the Gateway station because the Gateway <br />station is closer. Based upon an analysis of precipitation, topography , and the location of irrigated <br />lands, it is recommended that the temperature at Fru ita and the precipitation at Gateway be used. The <br />Little Dolores and Little Dolores 5 NE stations are lo cated near the irrigated acreage. However, data is <br />only available for 1948-55 and 1961-66, respectively. Gateway's precipitation more closely <br />approximates that recorded at the Little Dolores st ations. The difference in average annual precipitation <br />at Gateway (10.98 inches) and at Fruita (8.40 inches) may be due to local orographic effects. Fruita's <br />temperature more closely approximates that at the Little Dolores stations. Fruita is located in an a rural <br />area where the topography and fetch is similar to that of the irrigated areas. Whereas, the area <br />surrounding Gateway is heavily eroded canyon country. <br />Hydrologic Unit 14030002, Dolores County <br />For this unit, the USBR recommended using the Nort hdale station. However , based upon an analysis of <br />precipitation, topography, and the location of irri gated lands, it is recommended that two weather <br />stations be used in this unit. The Northdale st ation should be used for the irrigated lands in the <br />Disappointment Creek drainage and irrigated lands downstream of the Dolores River and West Dolores <br />confluence. <br />The Rico station should be used for estimating crop consumptive use for irrigated areas upstream of the <br />Dolores River and West Dolores confluence. The topography surrounding Rico is similar to that <br />surrounding irrigated lands in this area. <br />2 <br />12..3.96 12.09-16 - Walter <br />