Laserfiche WebLink
<br />. <br /> <br />. <br /> <br />. <br /> <br />~.... <br />CD <br />r" <br />~.J <br /> <br />2 <br /> <br />GEOGRAPHIC DESCRIPTION <br /> <br />STUDY REGIONS, SUBREGIONS, WAUs, AND SUBUNITS <br /> <br />The Upper Colorado River Regioa (hE'reinafter called the "Region") <br />occupies about 45 percent of the Colorado River Basin. Using the U.S. <br />Water Resources Council (WRC) definition, the Region includes the Great <br />Divide Basin--a closed basin--and a total drainage area comprising 113,496 <br />square miles. (72,600,000 acres). Dimensionally, the Region extends about <br />550 miles north-south and about 350 miles east-west to encompass portions <br />of the states of Wyoming, Colorado, .New Hexico, Arizona, and Utah. <br /> <br />The Region is largely bounded by rugged mountains. On the north, the <br />Green River Basin is surrounded by the Wyoming and Gros Ventre mountain <br />ranges. To the east, the Region is bounded by the Continental Divide; the <br />Wasatch Hountains form the western boundary. The southern boundary, <br />as delineated by the 1922 Colorado River Compact, is at Lees Ferry, <br />Arizona. <br /> <br />For purposes of this assessment, the Region has been subdivided into <br />a number of smaller units. The first level of disaggregation consists <br />of eight subregions, which are identified by four-digit numbers beginning <br />with 1401, the prefix 14 indicating the Colorado River Basin of the <br />National Water Data Network Accounting Units of the WRC. The subregions <br />are then disaggregated into water accounting units (WAUs) with six-digit <br />codes (e.g., 140401 represents the Upper Green River Basin). Fin311y, <br />this assessment disaggregates WAUs into "study subunits" which are iden- <br />tified by letters suffixed to the appropriate WAU numeric designation (see <br />Table 2.1). For example, l40500A is that portion of the Little Snake <br />River Basin which lies within Wyoming (Fig. 2.1). This level of regional i- <br />zation conforms to state boundaries in instances where such a division is <br />important. <br /> <br />The Region can also be characterized by political boundaries. The <br />Upper Colorado Region Comprehensive Framework Study (1971) divided the <br />Region into thr"ee "economic subregions." These subregions are coterminous <br />with the three "aggregated subareas" (ASAs 1401, 1402, and 1403) \lsed in <br />the WRC's '75 Water Assessment (Fig. 2.2). Therefore, ASA 1401 includes <br />a block of counties which approximate the Green River Basin, ASA 1402 <br />approximates the Upper Hain Stem of the Colorado River, and 1403, the <br />San Juan River. ASAs will be used throughout this report for various <br />descriptive purposes. <br /> <br />2-1 <br />