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Research about California, Nevada

Source-linked reports with geographic coverage including California, Nevada.

At least 271 records · Page 15Linked to original sources
USGS1988

Effect of water quality on survival of Lahontan cutthroat trout eggs in the Truckee River, west-central Nevada and eastern California

The U.S. Fish and Wildlife Service has an ongoing program to assess the feasibility of reestablishing naturally spawning populations of Lahontan cutthroat trout in the Truckee River-Pyramid Lake system in Nevada. Previous in situ egg-survival studies have documented a 100 percent mortality of cutthroat trout eggs artificially planted in potential spawning gravels in the Truckee River downstream from Reno. The relation between ambient river-quality conditions and the observed mortality of eggs, however, has not been adequately documented. This study was designed to monitor the quality of surface and intragravel water during a trout-egg incubation period that began March 10, 1980. Five sites were monitored: two upstream from Reno (background sites), one near Reno, and two downstream from Wadsworth. After an incubation period of about 30 days, poor egg survival was recorded at all sites, including an unexpected high mortality at the upstream background sites. Analyses of the data indicated that the principal cause of egg mortality at the two downstream sites was low concentrations (less than 5 milligrams per liter) of intragravel dissolved oxygen. Low water temperatures, rather than degraded water-quality conditions, largely contributed to the poor survival at the upstream sites. Based on the results of this study, the following were considered unlikely to be mortality factors during the incubation period: (1) high water temperatures; (2) toxicity due to ammonia, nitrite, nitrate, arsenic, cadmium, copper, iron, lead, manganese, mercury, and zinc; and (3) decreasing intragravel dissolved oxygen caused by inflow of oxygen-poor ground water.

California, Nevada↗
USGS1987

Bouguer gravity anomaly and isostatic residual gravity maps of the Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada

The accompanying gravity anomaly maps are part of a folio of maps of the Walker Lake 1° by 2° quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The quadrangle encompasses an area of about 19,500 km 2 along and to the east of the east flank of the Sierra Nevada (fig. 1). The Bouguer gravity anomaly map of the Walker Lake quadrangle was prepared by interpolating gravity values among 3,447 gravity stations established in the quadrangle and additional stations from adjacent quadrangles. An isostatic residual gravity map was prepared in order to reduce the effect; of interfering gravity gradients associated with the isostatic root of the Sierra Nevada. Methods of data reduction and factors that limit the accuracy of the gravity values are discussed in the following sections of this report. The geologic interpretation of the gravity maps is based on previous studies, sample measurements, and correlation with other maps of the folio including a geologic map (Stewart and others, 1982) and a map showing Mesozoic plutonic rocks (John, 1983). The purpose of the interpretative part of this report is to demonstrate the correlation between gravity anomalies and the mapped geology, to assess the continuation of exposed geologic units beneath the surface, and to suggest the location of concealed subsurface bodies with mineral resource potential. A three-dimensional model of the Little Walker caldera (fig. 6) is used to illustrate a possible quantitative interpretation of a gravity anomaly. A concealed 25 by 75-km Cenozoic batholith along the east flank of the Sierra Nevada with possible lateral extensions is suggested in this report. A possible magmatic mechanism is discussed to augment contemporary explanations for the extensional origin of valleys. The possibility of lower gravity anomalies indicating thinner roof rocks in the basement beneath mountain ranges also is discussed. Furthermore, interpretation of gravity anomalies was applied in discussions with W.D. Menzie (oral commun. , 1982) as one of the criteria used to identify and to delineate areas of mineral resource potential.

California, Nevada↗
USGS1987

Analytical results and sample locality map of stream-sediment, heavy mineral-concentrate, rock, and water samples from the Skedaddle (CA-020- 612) and Dry Valley Rim (CA-020-615) Wilderness Study Areas, Lassen County, California, and Washoe County, Nevada

In the summer of 1985, the U.S. Geological Survey conducted a reconnaissance geochemical survey of the Skedaddle (CA-020-612) and Dry Valley Rim (CA-020-615) Wilderness Study Areas in Lassen County, California, and Washoe County, Nevada. Skedaddle and Dry Valley Rim are contiguous wilderness study areas (WSA) located in the eastern part of the Modoc Plateau in Lassen County, northeastern California, and Washoe County, northwestern Nevada (fig. 1). The Skedaddle study area encompasses 39,420 acres and the Dry Valley Rim study area encompasses 54,480 acres of Bureau of Land Management administered public land about 25 mi east of Susanville, California. The Skedaddle study area is bounded on the east by the Skedaddle road, on the north by the Smoke Creek Road, on the south by the Wendel road, and on the west by the rim west of Wendel Canyon. The Dry Valley Rim study area is bounded on the east by the lower Smoke Creek road, the Dry Valley road, and the Pipe Springs Road. The northern boundary is the Smoke Creek Ranch road, the southern boundary the Wendel road, and the western boundary the east-side Skedaddle road. Access to the study areas is provided by several light-duty dirt roads and ways that join the boundary roads. Elevations range from 3,800 (1158 m) to 7,552 ft (2302 m). Steep rim rock walls and talus-covered canyons are common in the eastern third of the Dry Valley Rim study area, and the western third of the Skedaddle study area, while the majority of both study areas is gradually sloping, covered only by sparse sagebrush. Existing geologic maps that cover the two study areas consist of Lydon and others (I960), Bonham (1969), and Diggles and others (1986). The Skedaddle Wilderness Study Area consists of two parallel ridges, the Skedaddle Mountains and the Amedee Mountains. The ridges bound the Wendel and Spencer basins, an area of bleached and silicified rocks. Dry Valley Rim is a 17-mi (5.2 m)-long north-south-trending fault block that is situated 1,500 ft (457 m) above the Smoke Creek Desert to the east. The rim provides good exposure of the thick sequences of volcanic rocks that underlie the wilderness study area. The rocks of the study areas consist mostly of Tertiary basalt, andesite, and lahar with minor amounts of rhyolitic ash-flow tuff, rhyolite, and dacite. Surficial deposits consist of colluvium, alluvium, and talus, as well as aeolian, lacustrine, and fluvial deposits.

California, Nevada↗
USGS1986

Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Sweetwater Roadless Area, Mono County, California and Lyon and Douglas Counties, Nevada

The Sweetwater Roadless Area lies between Yerington, Nevada, and Bridgeport, California, along the California-Nevada boundary. The area encompasses approximately 72,240 acres in Toiyabe National Forest in Mono County, California, and Lyon and Douglas Counties, Nevada. This roadless area, which lies just east of the Sierra Nevada range, exhibits rugged topography. Elevations range from about 6,160 feet near Devil's Gate to 11,673 feet at Mount Patterson. Geochemical sampling was conducted during 1978, 1979, and 1980. This report summarizes the results of that investigation and provides details of the geochemical evaluation used in producing the final mineral resource assessment of the study area (Brem and others, 1984). Map A shows the locations of all sites where rock samples were collected for this report and the distributions of anomalous concentrations for 12 elements in the 127 rock samples collected. In a similar manner, map B shows the collection sites for 59 samples of minus-60-mesh stream sediment, and 59 samples of nonmagnetic heavy-mineral concentrate derived from stream sediment and also shows the distributions of anomalous concentrations for 13 elements in the stream-sediment samples and 17 elements in the concentrate samples. Map C shows outlines of those drainage basins containing samples of stream sediment and concentrate with anomalous element concentrations and also shows weighted values for each outlined basin based on the number of elements with anomalous concentrations in each stream-sediment and concentrate sample and on the degree to which these concentrations are anomalous in each sample.

California, Nevada↗
USGS1986

Reconnaissance surficial geologic map of northern Death Valley, California and Nevada

Sedimentary deposits of northern Death Valley include units of alluvial, eolian, lacustrine, and spring origin. The alluvial deposits, which include both fan and pediment deposits, predominate. Fan deposits are divided into four major units; locally one of these is further divided into three subunits. Pediment deposits may be divided into two subunits. Hyphenated map symbols (for example, Qf 4-3 ) are used where two deposits cannot be separated at the map scale; symbols separated by a slash indicate areas where thin veneers of younger deposits overlie old deposits (for example, Qf 3 /Qp 2 ).

California, Nevada↗
USGS1986

River-quality assessment of the Truckee and Carson River system, California and Nevada: Hydrologic characteristics

A study of the Truckee and Carson Rivers was begun in October 1978 to assess the cause and effect relations between human and natural actions, and the quality of water at different times and places along the rivers. This report deals with the compilation of basic hydrologic data and the presentation of some of the new data collected during the study. Topographic, flow, and chemical data, data from recent time-of-travel studies, and new data on river mileages and drainage areas that were determined using new , high-resolution maps, are included. The report is a guide to locating maps, aerial photographs, computer files, and reports that relate to the rivers and their basins. It describes methods for compiling and expressing hydrologic information for ease of reading and understanding by the many users of water-related data. Text, tabular data, and colored plates with detailed maps and hydrographs are extensively cross referenced.

California, Nevada↗
USGS1986

Geohydrology and simulated response to ground-water pumpage in Carson Valley, a river-dominated basin in Douglas County, Nevada, and Alpine County, California

A numerical model was used to simulate the effect of development of the groundwater reservoir in Carson Valley on Carson River outflow, evapotranspiration, and groundwater levels and storage. The basin-fill groundwater reservoir consists of: (1) confined and unconfined sedimentary deposits of Quaternary age that underlie the valley floor, and (2) sedimentary deposits of Tertiary age that are exposed mainly on the east side of the valley. Water levels indicate the presence of two confined aquifer systems: one < 100 ft deep, and the other, generally deeper than 200 ft. The basin-fill reservoir is surrounded by bedrock that transmits recharge to the basin through weathered and fractured zones near the contact between bedrock and valley fill. Estimates were made of the distribution of hydraulic properties of aquifer materials, and of the components of inflow to and outflow from the basin-fill reservoir. Inflow components consisted of the following approximate quantities, in acre-ft/yr: (1) mainstem Carson River flow, 360,000; (2) direct precipitation, 70,000; (3) runoff from perennial and ephemeral streams, 24,000: and (4) subsurface inflow, 38,000. Approximate estimates of outflow components were, in acre-ft/yr; (1) mainstem Carson River flow, 291,000; (2) potential evapotranspiration, 200,000. Both inflow and outflow totaled about 490,000 acre-ft/yr. These flow volumes show that the hydrologic regimen of the basin is dominated by surface water flow of the Carson River. Steady-state and transient calibration of the model provided an unacceptable fit of observed versus simulated groundwater level fluctuations and storage, and surface water outflow from the valley. These values provide a reasonable balance for the simulated steady-state water budget. Simulations show that surface water flow is the ultimate source of about 75% of pumped water for six scenarios of possible future ground-water development. Model simulations indicate that changes from agricultural to urban land uses could decrease the loss of Carson River outflow to pumpage when streamflow is not used for flood irrigation in that area.

California, Nevada↗