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<br />16 <br /> <br />PAONIA PlWJECT,\ COLORADO <br /> <br />tions. The consumptive use, as determined from local seasonal tem- <br />peratures using the Johnson-Lowry curve for consumptive use, is 2;00 <br />acre-feet an acre for the growing season. Records show that the <br />winter water requirement will be supplied from precipitation. After <br />taking into account normal summer precipitation for upper and lower <br />project lands, the annual consumptive use to be supplied by irrigation <br />is reduced from the total of 2.00 feet to 1.75 feet for the Fire Mountain <br />la:Qds and 1.66 feet for Leroux Oreek lands. Oombined water losses, <br />including canal and ll!cteral losses and farm wastes, are estimated to <br />total 62 percent of the stream diversion for lands under the. Fire <br />Mountain canal and 53 percent for diversions from Leroux Oreek. <br />The estimated total-diversion requirements, properly distributed <br />throughout the irrigation season, therefore amounts to 4.60 acre-feet <br />an acre for lands under the Fire Mountain canal and 3.50 acre-feet an <br />acre for the Leroux Oreek lands. T.hese water requirements are com- <br />parable to the water. used on a number of operating irrigation projects <br />in western Oolorado. <br /> <br />Present water supply <br />Records show that annual diversions to the Fire Mountain canal <br />plus wat~r supplied to lands thereunder from Leroux Oreek sources <br />averaged 5.17 acre-feet an acre for the years 1934 to 1942, inclusive. <br />This appears high for land reported to be in need of additional water. <br />The .amount, however, includes large amounts of flood water diverted <br />early in the season without corresponding irrigation benefits. Growing <br />crops are damaged and in many instances the soils are leached of <br />valuable plant food by the application of excessive quantities of <br />irrigation water in the spring and early summer months when stream <br />flow is plentiful. This practice of excessive early irrigation is carried <br />on in the hope that ground storag~ will lessen the heavy late season <br />shortages. . In most years severe shortages are experienced after the <br />middle of July. . . <br />Annual diversions to the Leroux Oreek lands are much less than the <br />diversion to lands under the Fire Mountain canal, and average only <br />2.77 acre-feet an acre for the period 1934 to 1942. A similar practice <br />of overirrigation during the high early season run-off period exists in <br />this area but shortages in water supply extend over a longer period. <br />Development of the project will supplement the present supply with <br />late season water and will not in anyway restrict the availability of <br />the present water supplies. <br /> <br />Project water supply <br />Development of the project will increase the irrigation water supply <br />available to the Fire Mountain canal from the main stream of the <br />North Fork River by an average of 18,000 acre-feet annually. This <br />increase in supply represents usable water within the seasonal irriga- <br />tion requirement of the lands to be served by the enlarged and extended <br />canal. Of this total increase, approximately 10,200 acre-feet is <br />natural flow water from the North Fork River made available by the <br />increase in diversion capacity of the Fire Mountain canal. The <br />balance, or an average of 7,800 acre-feet, represents the average <br />useful storage yield of the 9,000 acre-feet of capacity in the Spring <br />Oreek Reservoir provided for project lands. <br />This new supply of water, together with existing diversion from <br />the North Fork River, will provide a full irrigation supply for all <br />irrigable land in the service area of the enlarged and extended Fire <br />