Laserfiche WebLink
Introduction <br />agriculture in the basin, and the key water administration issues for the basin. An overview of DSS <br />technology, in general, and the CRDSS, in particular, is provided, followed by a discussion of the key <br />individuals that were interviewed and the key reports that were identified and reviewed in this study. <br />Finally, the organization of this feasibility study and the resulting report are outlined in this section. <br />1.1 Feasibility Study Purpose <br />The RGDSS feasibility study was conducted to define the purposes for, uses and users of, <br />components of, data requirements for, and costs and schedule for developing such a system. The <br />results of the feasibility study will be used by the CWCB, the CDWR, and the State Information <br />Management Committee (IMC) to recommend the development of the RGDSS to the Colorado <br />General Assembly. In this feasibility study, the term Rio Grande basin is used to describe the area <br />also known as the San Luis Valley in Colorado (i.e., the Rio Grande, Conejos, and the Closed Basin <br />drainages in Colorado). Funding for the RGDSS Feasibility Study was provided by the CWCB from <br />the operational account. <br />1.2 Rio Grande Basin Conditions <br />1.2.1 Basin Setting <br />The Rio Grande basin (Figure 1-1) within Colorado is located in south-central Colorado and <br />encompasses approximately 7,500 square miles (U.S. Department of Agriculture 1978). The primary <br />feature of the basin is an open, almost treeless, relatively flat valley floor (known as the San Luis <br />Valley) surrounded by mountains. The valley floor ranges in elevation from 7,440 feet on the south <br />end to 8,000 feet on the north end, and is bounded on the west by the San Juan Mountains and on the <br />east by the Sangre de Cristo Mountains. <br />Of the 7,500 square miles, there is an area of approximately 3,000 square miles in the northern part of <br />the valley that does not naturally drain into the Rio Grande because it is separated by a low divide in <br />the shallow ground water table formed by the alluvial fan of the Rio Grande on the west and alluvial <br />material from the Sangre de Cristo Mountains on the east. This non-tributary area is known as the <br />Closed Basin. <br />The Rio Grande main stem rises in the San Juan Mountains in the vicinity of Creede, Colorado and <br />flows easterly where it is joined by the South Fork of the Rio Grande at South Fork, Colorado. The <br />main stem continues east to Del Norte where it flows out onto the San Luis Valley floor in a <br />southeasterly direction. The main stem continues this path until it reaches Alamosa, where it abruptly <br />turns south and flows to the state line. <br />1.2.2 Hydrogeologic Setting of the San Luis Valley <br />The San Luis Valley is considered to be a high mountain desert with cool summers and cold winters. <br />Most of the precipitation on the valley floor comes in the form of scattered summer afternoon rain <br />showers. Annual average precipitation ranges from approximately 7 inches at Alamosa to <br />approximately 45 inches at Wolf Creek Pass. However, most streamflow originates from snowmelt in <br />a454/report/fmaUintro.doc 07/2&~OS I-2 <br />