Open-File Report 2006–1311
U.S. GEOLOGICAL SURVEY
Open-File Report 2006–1311
The U.S. Geological Survey (USGS), in cooperation with Southern Nevada Water Authority and Nevada Division of Water Resources (NDWR), operates and maintains a surface-water network of 6 continuous-record stream-gaging stations and 11 partial-record stations in the Warm Springs area near Moapa, Nevada. Permanent land-surface bench marks were installed in the Warm Springs area by the Las Vegas Valley Water District, the Southern Nevada Water Authority, and the USGS to determine water-surface elevations at these gaging-stations. Vertical datum elevations and horizontal coordinates were established for all bench marks through a series of Differential Global Positioning System (DGPS) surveys. DGPS vertical datums were transferred to reference marks and points installed at each monitoring site using optical theodolite surveys. All surveys were completed by June 2004, and water-surface elevations were measured on August 17, 2004. Water-surface elevations ranged from 1,810.33 ft at Pederson Spring to 1,706.31 ft at Muddy River near Moapa.
All USGS discharge and water-quality data published through September 30, 2004, for the Warm Springs area were compiled for this study. Additional discharge and water-quality data were provided by other agencies that manage, regulate, study, or use the water resources of the area. Periodic water-level readings for 10 flumes were provided by NDWR. U.S. Fish and Wildlife Service provided discharge data for springs within the Moapa Valley National Wildlife Refuge. Additional water-quality data were provided by the Moapa Valley Water District (MVWD), Desert Research Institute (DRI), and Converse Consultants.
Chronologies of water-resources development and hydrologic data collection are included in this report to illustrate the relation of the hydrologic monitoring network with historical and contemporary land- and water-use changes in the Warm Springs area. Prior to 1950, the Warm Springs area consisted of a few ranches that derived their water from individual springs or wells. From the 1950s to the late 1960s, most of the small ranches eventually merged into one working ranch with large land areas watered by an intricate network of irrigation ditches. Recreational facilities were established to take advantage of the warm spring waters for year-round aquatic and outdoor activities. The first exportation of water from springs in the study area was for supply to a nearby power plant and to growing communities to the south. As a result of these activities, flumes were installed near the major spring groups to monitor effects of water withdrawals and diversions.
Toward the late 1970s, environmental concerns resulted in the creation of the Moapa Valley National Wildlife Refuge that eventually terminated two of the three recreational developments. Additional hydrologic monitoring was started to characterize the water resources within the refuge for the protection and management of the Moapa dace. During the 1980s, additional ground-water and surface-water sources were tapped to meet the growing capacity of the powerplant. To provide better monitoring of the effects of water withdrawals, additional gages were installed and existing flumes were upgraded. In the 1990s, the wildlife refuge was expanded and additional monitoring sites were established.
In the past 4 years, two new recording gages were installed and major improvements were made to an existing site. With the completion of the water-surface surveys and the compilation of discharge and water quality data, this upgraded network will help identify potential effects on the water resources as a result of (1) changes in vegetation within the former agricultural lands, (2) changes within the Wildlife Refuge due to restoration activities, (3) continued withdrawal of ground water within the valley, and (4) potential withdrawals of ground water from adjacent basins.
U.S.
Department of the Interior | U.S. Geological
Survey
Persistent URL: http://pubs.water.usgs.gov/ofr20061311
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