|
Major Rivers, Lakes, and Reservoirs
Nevada contains 14 river basins and hydrographic regions (Figure 2-3). Five contain major rivers. Except for the Colorado River, Nevada's perennial rivers are comparatively small. Only the streams in the Snake River Basin (e.g., Owyhee, Bruneau, Goose, and Jarbidge) and Colorado River Basin flow to the ocean. All other streams discharge into alluvial fans along the mountains or into terminal sinks, which may contain lakes, playas, or wetlands. The major river systems in Nevada are the Colorado, Walker, Carson, Truckee, and Humboldt. Major lakes and reservoirs are listed in Table 2-4.
The Carson River flows in two main forks from the eastern slopes of the Sierra Nevada Range in California, into Carson Valley where the forks join. The main stem flows through other populated valleys - Eagle (Carson City), Dayton, and Lahontan before the 184-mile long river empties into the Carson Sink (California Department of Water Resources, 1991a). Several small, regulated lakes and storage reservoirs located high in the basin help prolong the irrigation season. Waters of the Carson River are used primarily for agriculture. Important fisheries, wildlife, and water based recreation uses occur also, most prominently in the upper river reaches. Municipal and industrial users are supplied by groundwater. Lahontan Reservoir, located in the lower river, stores water for use in the state's agricultural oasis and large wetland complexes in the Lahontan Valley. In lower river reaches, water sinks into the ground, leaving dry reaches, as happens in many streams in Nevada. These wetlands, which are part of the Western Hemispheric Shorebird Reserve Network, provide vital feeding, breeding, and resting habitat for hundreds of thousand of migratory and resident birds.
 Carson River Photos
Photos of Lahontan Reservior
 Carson River Monitoring Data
The Colorado River is the largest river in Nevada, receiving water from many western states, including Wyoming, Colorado, Utah, New Mexico, Arizona, California, as well as Nevada. Along its 1,400-mile course to the Gulf of California, the Colorado River Basin drains an area of about 240,000 square miles - about one-twelfth the area of the contiguous United States. The Colorado River and tributaries in Nevada (i.e., Muddy, Virgin, and White rivers) provide a majority of the drinking water supply to the Las Vegas area. The river also provides hydroelectric power and recreation opportunities at Lake Mead and Lake Mohave, and water for agriculture. Nevada receives a 300,000 acre-feet annual allotment of the river's water under the Colorado River Compact, the smallest portion among the seven states and Mexico. Fortunately, Las Vegas is located close to Lake Mead so southern Nevada water utilities can economically pump from the Colorado River system to meet municipal and industrial needs. Nevada is allowed a "return-flow" credit for all water returned to Lake Mead. Water treated and returned to Lake Mead is accounted for and Nevada has "earned" as much as an additional 151,000 acre-feet annually in return-flow credits.
Colorado River -- Monitoring Data
The Humboldt River is the longest river entirely within Nevada. The Humboldt River originates in the Ruby, East Humboldt, Independence, and Jarbidge Mountains and flows 310 miles westward to terminate in the Humboldt Sink. Higher elevation watersheds north and south of the main stem feed seven tributaries that help sustain flow. A majority of the Humboldt River system water is used for agriculture. There are only a few flow-regulating reservoirs in the basin, the largest (Rye Patch Reservoir) being near the end of the system. Extensive reaches of the lower half of the river lose water to the ground and also evaporation. As a result, late season irrigation water shortages are commonplace throughout much of the area above Rye Patch Reservoir.
Humboldt River -- Monitoring Data Photos
The Truckee River begins at a modestly sized dam located at the northern end of Lake Tahoe, in California. It flows down a narrow, winding canyon until the channel enters the Truckee Meadows where the cities of Reno and Sparks are located. The 145 mile long river terminates at Pyramid Lake (California Department of Water Resources, 1991(b)). Pyramid is one of only two sizable lakes surviving the desiccation of ancient Lake Lahontan. With numerous upstream reservoirs, mostly in California, the Truckee River is the most regulated river  system in Nevada (Figure 7). Along its course, water is diverted to meet the needs of municipal and industrial, agricultural, and hydropower users. In response to greater use and dependency on Truckee River water, a new river operating agreement is being prepared. The Truckee River Operating Agreement is intended to provide modified operational criteria of reservoirs to conserve the endangered and threatened fishes of Pyramid Lake (i.e., cui-ui and Lahontan cutthroat trout) and to provide for future municipal and industrial water demands during droughts (U.S. Bureau of Reclamation, 1998). A portion of the Truckee River flow is diverted at Derby Dam and then conveyed via canal to Lahontan Reservoir in the Carson River Basin. Reservoir water is distributed to irrigate 50,000 to 60,000 acres in the Newlands Reclamation Project and large wetlands in Lahontan Valley.
Truckee River -- Monitoring Data
The Walker River: Like the Carson and Truckee, the Walker River rises in California. The river flows into Nevada through large irrigated valleys, the most prominent being Bridgeport and Antelope in California, and Smith and Mason in Nevada. The terminus is Walker Lake. Walker Lake is the only other surviving descendant of ancient Lake Lahontan, which covered 8,000 square miles in northern Nevada when mountain glaciers were melting and the climate was wetter several thousand years ago (California Department of Water Resources, 1992). Most of the Walker River streamflow originates in California and is used almost exclusively for a variety of agricultural uses in Nevada and California. The two largest reservoirs on the system are Topaz Lake, straddling the Nevada/California border, and Bridgeport Reservoir in California. Both are owned and operated by the Walker River Irrigation District to supply irrigation water to district members. Small lakes and reservoirs in the Sierra Nevada Range and nearby valleys help sustain stream flow into the autumn months during all but the driest years.
Walker River Monitoring Data
Photos of Walker Lake
Real-Time Water Data for Nevada -- USGS
 Next Page -- Climate
Back to Table of Contents
|
|
