Laserfiche WebLink
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />II. BASIN SETTING <br /> <br />General knowledge about features of a river basin which influence water availability <br /> <br /> <br />is a pre-requisite for a water availability study. The following sections describe <br /> <br />aspects of the Rio Grande Basin which influence water availability and which have <br /> <br /> <br />been incorporated into the Rio Grande Water Supply Study - Phase I. <br /> <br />II.l LOCATION AND PHYSIOGRAPHY <br /> <br />The Rio Grande Basin within Colorado is located in south central Colorado and <br /> <br /> <br />encompasses approximately 7500 square miles (USDA, 1978). The primary feature of <br /> <br />the basin is an open, almost treeless, relatively flat valley floor (known as the <br /> <br />San Luis Valley) surrounded by mountains. The valley ranges in elevation from 7,440 <br /> <br />feet to 8,000 feet and is bounded on the west by the San Juan Mountains and on the <br /> <br />east by the Sangre de Cristo Mountains. <br /> <br />Approximately 3000 square miles (of the 7500 square miles) in the northern part of <br /> <br />the valley (see Figure I-i) is separated from the lest of the valley by a low divide <br /> <br />formed by the alluvial fan of the Rio Grande on the west and alluvial material from <br /> <br />the Sangre de Cristo mountains on the east. This area is known as the Closed Basin. <br /> <br />The Rio Grande mainstem rises in the San Juan Mountains and flows easterly where <br /> <br />it is joined by the South Fork of the Rio Grande at South Fork, Colorado. The <br /> <br /> <br />mainstem continues east to Del Norte where the Rio Grande flows onto the San Luis <br /> <br /> <br />Valley floor and begins flowing in a southeasterly direction. The mainstem <br /> <br />continues this path through Monte Vista and Alamosa until near its confluence with <br /> <br /> <br />the Conejos River, the most significant tributary to the Rio Grande in Colorado. <br /> <br /> <br />The Rio Grande then flows south into the Rio Grande Canyon on its way to the state- <br /> <br /> <br />line. <br /> <br />I I. 2 CL IMATE <br /> <br />Mean monthly temperatures, total monthly precipitation and dates of first and last <br /> <br /> <br />frosts have been collected and placed on the LRCWE computer for the Alamosa, Center <br /> <br /> <br />and Del Norte, weather stations. The valley floor is considered to be a high <br /> <br />13 <br />