Ground-water flow and simulated effects of development in Stagecoach Valley, a small, partly drained basin in Lyon and Storey counties, western Nevada

Abstract

The Regional Aquifer-System Analysis (RASA) Program was started in 1978 following a congressional mandate to develop quantitative appraisals of the major groundwater systems of the United States. The RASA Program represents a systematic effort to study a number of the Nation's most important aquifer systems, which in aggregate underlie much of the country and which represent an important component of the Nation's total water supply. In general, the boundaries of these studies are identified by the hydrologic extent of each system and accordingly transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective for each study is to assemble geologic, hydrologic, and geochemical information, to analyze and develop an understanding of the system, and to develop predictive capabilities that will contribute to the effective management of the system. The use of computer simulation is an important element of the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system and the changes brought about in it by human activities, and to provide a means of predicting the regional effects of future pumping or other stresses. The final interpretive results of the RASA Program are presented in a series of U.S. Geological Survey Professional Papers that describe the geology, hydrology, and geochemistry of each regional aquifer system. Each study within the RASA Program is assigned a single Professional Paper number, and where the volume of interpretive material warrants, separate topical chapters that consider the principal elements of the investigation may be published. The series of RASA interpretive reports begins with Professional Paper 1400 and thereafter will continue in numerical sequence as the interpretive products of subsequent studies become available.

Aquifer systems in the Great Basin region of Nevada, Utah, and adjacent states; summary report

“…A ground-water flow model was used to simulate conditions prior to significant pumping and then to evaluate responses to selected developmental scenarios. In Professional Paper 1409-H, Harrill and Preissler (1994) described the hydrology of Stagecoach Valley, a small topographically closed basin in western Nevada that is partly drained by subsurface flow. A ground-water flow model was used to simulate conditions prior to significant pumping and then to evaluate responses to selected developmental scenarios.…”

“…The five hydrographic areas that were selected ( fig. 16) are the Milford Area in Utah and Carson, Paradise, Smith Creek, and Stagecoach Valleys in Nevada (Thomas, Carlton, and Mines, 1989;Harrill and Preissler, 1994;Prudic and Wood, 1995;Prudic and Herman, 1996;Mason, 1998). In general, the Milford area represents a large basin-fill reservoir under sustained development; Carson Valley represents a basin-fill aquifer dominated by a through-flowing river; Paradise Valley represents a basin-fill reservoir having an upgradient part dominated by streams and an arid lower part; Smith Creek Valley represents a topographically closed, arid basin; and Stagecoach Valley represents a small, topographically closed basin that is partly drained by subsurface outflow.…”

Geologic framework and hydrogeology of the middle Carson River Basin, Eagle, Dayton, and Churchill Valleys, West-Central Nevada

“…The map for Stagecoach Valley shows more than 3,000 ft of basin-fill sediments west of Misfits Flat. The geologic map used for this study, however, shows basaltic volcanic rock exposed where the basin-fill thickness of 3,000 ft was estimated by Harrill and Preissler (1994), suggesting their estimate may be in error. For this reason, new estimates of the thickness of basin-fill sediments in the Carson Plains and Stagecoach subbasins and in Churchill Valley and western Lahontan Valley were made for this study.…”

“…Glancy and Katzer (1976) published the first estimates of water-budget components and maps showing the distribution of phreatophytes and irrigated land for Dayton and Churchill Valleys. Harrill and Preissler (1994) Churchill Valley is the least studied in the middle Carson River basin. The geophysical models of Schaefer and Whitney (1992) showed estimated depth to bedrock along two cross sections in Churchill Valley, and maps showing the depth to water, water-level altitude, and groundwater-flow directions for 1982.…”

“…The groundwater and surface-water systems are thought to be well connected in the Carson River basin upstream of Lahontan Reservoir in Dayton and Churchill Valleys (Harrill and Preissler, 1994;Brown and Caldwell, 2004;Maurer and others, 2009). In these valleys, groundwater pumping may cause flow of the Carson River to Lahontan Valley to decrease over time, thereby affecting water users downstream.…”