Laserfiche WebLink
<br />f' <br />0) <br />0) <br /> <br />c <br /> <br />Irrigation Supplies and Requirements <br /> <br />&>urces of Data <br /> <br />No detailed studies have been made of irrigation requirements on the 3nith <br />Fork project. However, several comprehensive studies include estimates of <br />irrigation requirements in the general vicinity of this project. Among <br />these studies are: (1) Appendix B of the Record of the Upper Colorado River <br />Basin Compact Commission; (2) Consumptive Use and Irrigation Water Requirements <br />of Crops in Colorado, by Harry F. Blaney and Wa;yne D. Criddle; and 0) <br />Consumptive Use of Water in the Irri gated Areas of the Upper Colorado River <br />Basin, by Blaney and Criddle. Additional related information is contained <br />in the Water Supply Papers of the U.S. Geological Survey, Climatological <br />Data by the U.S. Weather Bureau, Colorado Heat and Moisture Indexes for use <br />in Land Capabili ty Classification by the Soil Conservation Service, and <br />other publications. These and all other available related reports were <br />carefully reviewed for the purpose of this study. In addition, information <br />was supplied by techni cians of the Agricultural Research Servi ce, Colorado <br />State University, U.S. Bureau of Reclamation, and others familiar wi th the <br />area. <br /> <br />Analysis of Data <br /> <br />Consumptive use requirements for the principal crops in the area Were <br />estimated by the Blaney-G:riCldJ.le procedures. Based on projected crop <br />acreage distribution, the average seasonal consumptive use and farm water <br />supply requirements for the project were estimated. (Table 4) <br /> <br />The water supply for the 3ni th Fork project comes principally from the flow <br />of the 3nith Fork River. Historically, the flow of this river varies <br />widely with the seasons. The water supply is quite large during the spring <br />snowmelt period which usually extends through M~ and part of June. During <br />this period there is usually more water available than can be used, and the <br />excess flows downstream past the project. Later in the SUIDIIler when crop <br />water requirements are higher, the stream flow diminishes to an amount that <br />is insufficient to meet crop needs on lands that are presently irrigated, <br />with a consequent reduction in crop yields. The water supply shortages <br />thus actually occur during the critical crop months of July, August, and <br />September. These shortages have ranged from about 24' percent to 70 percent, <br />averaging approximately 45 percent of crop needs during these months. As <br />shown in table 4, the shortages will be reduced under project operating <br />condi tion to an average of four percent of seasonal requirements. <br /> <br />With the installation of the project works, consisting primarily of the <br />Crawford Reservoir and the enlarged and extended Aspen Canal, storage <br />capaci ~ will be provided to meet late-season water demands for the <br />presently irri gated lands. Additional water will be available to meet <br />the requirements of nonirrigated lands proposed for irrigation under the <br />project plan. The availabili ty of adequate late-season water wi 11 permi t <br />better seasonal distribution than has been possible by direct diversion of <br />unregulated stream flows. <br /> <br />- 14 - <br />