Open-File Report 2006–1311
U.S. GEOLOGICAL SURVEY
Open-File Report 2006–1311
The Warm Springs area, located in the northwestern end of Moapa Valley, Nev., (fig. 1) consists of a network of springs and seeps that form the headwaters of the Muddy River. Over time, this area has been home to the Anasazi and the Southern Paiute Indian tribes, outlaws, prospectors, Mormon settlers, and others (Baxter and Haworth, 1996; U.S. Fish and Wildlife, 1991). The availability of water has provided past and current inhabitants with the resource necessary to sustain life in a desert setting. In addition, nearby entities, such as the Moapa River Indian Reservation, the Moapa Valley Water District (MVWD), and the Nevada Power Company (NPC), use water obtained from the area. The Warm Springs area is home to the Moapa Valley National Wildlife Refuge. The refuge was established in 1979 to protect and secure the riparian habitat of an endangered native minnow, the Moapa dace (Moapa coriacea) (U.S. Fish and Wildlife, 1991). A brief history of water-resources development in the Warm Springs area is included in Appendix A.
The Warm Springs area is located approximately 60 mi northeast of Las Vegas, which is one of the fastest growing metropolitan areas in the country. For more than 50 years, Las Vegas has used Lake Mead as its main source of drinking water. The ongoing growth of Las Vegas and the effects of the recent drought on the Colorado River have prompted water-resource managers to seek out and investigate additional sources of water. Presently (2006), the Nevada State Engineer is considering numerous applications to develop ground-water resources in basins adjacent to the upper Moapa Valley that would provide additional water to Las Vegas and Moapa Valley. It is not known what effects these proposed ground-water withdrawals will have on the riparian habitats and springs that form the Warm Springs area. Efforts are underway to acquire additional data to monitor for potential effects of these ground-water withdrawals.
As part of these efforts, the U.S. Geological Survey (USGS), in cooperation with the Southern Nevada Water Authority (SNWA), has completed a survey of water-surface elevations in the Warm Springs area. Bench marks (BMs), reference marks (RMs), reference points (RPs), and staff plates were established that will provide resource managers with tools to determine water-surface elevations at numerous monitoring sites in the area. These data will be used to assist in the efforts to determine what effects, if any, nearby ground-water withdrawals may have on the springs within the Warm Springs area.
The primary purposes of this study are (1) to determine water-surface elevations in spring-fed pools and channels that currently are monitored by the USGS, and (2) to compile existing discharge and water-quality data within the Warm Springs area. For the purposes of this report, the Warm Springs area is defined as the area of the upper Moapa Valley upstream of the Muddy River Bridge at Warm Springs Road. The principle areas include the Muddy River flood plain and all the springs and seeps that are generally bounded by State Highway 168 and Warm Springs Road (fig. 2).
Permanent RMs and staff plates were installed near each of the hydrologic monitoring sites so that water-surface elevations could easily be obtained and related to land-surface datum. Land-surface datums used in this study were derived from permanent BMs established by the Las Vegas Valley Water District (LVVWD), SNWA, and USGS adjacent to the major spring groups and other monitoring sites. The elevations of these BMs were determined from a series of Differential Global Positioning System (DGPS) surveys. The elevations were transferred to the monitoring sites by optical theodolite surveys.
Existing discharge and water-quality data compiled for the Warm Springs area include data collected by the USGS and other agencies that manage, regulate, study, or use the water resources of the area. These data are included in this report, with measurements of water-surface elevations throughout the Warm Springs area made during this study, to support studies relating the condition of the springs to the regional ground-water flow system. Evaluation of the quality-assurance procedures for data collection by the other agencies is beyond the scope of this study. As a result, the USGS cannot verify the accuracy of the data provided.
As a supplement to data compilation, compendiums of water-resources development and data-collection networks are presented. Historical perspectives were based on (1) available data and references, (2) telephone interviews with many government and municipal officials, and (3) personal interviews with long-term residents within the Warm Springs area. Inclusion of the two compendiums in this report is intended to relate the historical development of the hydrologic monitoring network with land- and water-use changes in Moapa Valley.
The Warm Springs area, also known as the Muddy Springs area, is a network of springs and seeps that are located along the northeast slope of the Arrow Canyon Range (fig. 1). The area is bounded by Highway 168 to the north and northeast, Battleship Wash to the south, and Warm Springs Road to the west and southeast (fig. 1). There are six major spring groups within the study area that are generally aligned in a northwest-southeast direction: Cardy Lamb, Baldwin, Apcar, Muddy, Pederson, and Plummer (fig. 2). An unnamed spring area is located adjacent to Highway 168 near L.D.S. East well (fig 2, site 18); however, flow from this area discharges only intermittently.
The Warm Springs area is located near the southern boundary of the White River ground-water flow system (Prudic and others, 1995). Discharge from the springs and seeps of the Warm Springs area is believed to be the largest and most southerly outflow from this ground-water system (Eakin, 1966). The physiography of the study area is characterized by north-trending mountains to the west and a broad alluvial basin to the east. The topography consists of normal-faulted terrains that form complex, heterogeneous geologic settings with unique local and regional characteristics.
The primary aquifers in the area generally are made up of carbonate rocks of Paleozoic age and sedimentary rocks of Tertiary age. The carbonate rocks form complex aquifers whose extents and thicknesses are largely unknown. These aquifers interconnect with aquifers of other rock types and, where deformed or fractured, have the potential to transmit ground water (Prudic and others, 1995).
The climate of the area is semiarid to arid with approximately 5 in. of annual precipitation, low humidity, and high evapotranspiration rates (Eakin, 1966; Mozejko, 1981). Recharge to the ground-water system supplying the Warm Springs area is primarily from precipitation in the high mountain ranges in east-central Nevada (Eakin, 1966). Ground-water discharge within the Warm Springs area is from evaporation, transpiration by plants, and flow from the springs.
The discharge channels of springs in the area and the main stem of the Muddy River primarily are meandering and shallow and contain moderate amounts of fine silt and organic debris. Vegetation within and along the channel banks include cattails (Typha spp.), willows (Salix spp.), mesquite (Prosopis pubescens), reeds, and non-native palm trees (Washingtonia filifera and Phoenix dactylifera) and Tamarisk (Tamarix spp.). Aquatic plants such as algae, spike rush (Eleocharis spp.), water nymph (Najas spp.), watercress (Nasturtium spp.), pondweed (Potamogeton spp.), and non-native eel grass (Vallisneria spp.) are abundant in most spring pools and slack water areas (Mozejko, 1981; U.S. Fish and Wildlife Service, 1995).
The Warm Springs area is home to numerous birds, mammals, and reptiles, including quail (Callipepla gambelii), roadrunners (Geococcyx californianus), songbirds, shorebirds, cottontail rabbits (Sylvilagus spp.), coyotes (Canis latrans), foxes, spiny soft-shell turtles (Amyda spinifera), and snakes. In addition to the aforementioned endangered Moapa dace, several other species in the area’s waterways are listed as sensitive. These include the Moapa White River springfish (Crenichthys baileyi moapae), Moapa pebblesnail (Fluminicola avernalis), and the Moapa Warm Spring riffle beetle (Stenelmis moapa) (U.S. Fish and Wildlife Service, 1991, 1995).
U.S.
Department of the Interior | U.S. Geological
Survey
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