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Ray J. Hoffman

Publications and source records attributed to Ray J. Hoffman.

12 recordsLinked to original sources
USGS2017

Devils Hole, Nevada—A photographic story of a restricted subaqueous environment

This report presents selected photographic images taken by the author during U.S. Geological Survey (USGS) research into paleoclimatology and geochemistry in Devils Hole cavern during 1984 to 1993 in cooperation with the National Park Service. The unaltered suite of photographs was prepared by the USGS dive team as an aid to assist nondiving scientists with a visual perspective of the environment where earth-science samples were collected and subsequently analyzed for chemical and isotopic composition.

Nevada↗
USGS1994

Detailed study of irrigation drainage in and near wildlife management areas, west-central Nevada, 1987-90. Part C. Summary of irrigation-drainage effects on water quality, bottom sediment, and biota

This report presents a summary of the detailed scientific study of Stillwater Wildlife Management Area and other nearby wetlands in west-central Nevada during 1987-90. The work was funded by the National Irrigation Water Quality Program of the U.S. Department of the Interior with the overall objectives of determining (1) the extent, magnitude, and effects of selected water-quality constituents associated with irrigation drainage on fish, wildlife, and human health, and (2) the sources and exposure pathways that cause contamination where adverse effects are documented. Much of the information in this report was summarized from two previously published interpretive reports that were completed to fulfill study objectives. Where applicable, data for the study area from other published sources also were utilized. The results of these studies indicate that the aquatic biota in natural wetlands of the Carson Desert are adversely affected by hydrological and geochemical sources and processes in the Newlands Irrigation Project area. Reactions between water and naturally occurring minerals in the shallow alluvial aquifer increase concentrations of potentially toxic constituents in ground water that eventually enters the wetlands. Once in the wetlands, these constituents are furhter concentrated by evaporation and transpiration. Water from some agricultural drains that enter Stillwater WMA was acutely toxic to aquatic organisms. The drains in the agricultural areas, which eventually discharge to the wetlands, were also implicated as sites of uptake of selenium and mercury by aquatic organisms.

Nevada↗
USGS1988

Chronology of diving activities and underground surveys in Devils Hole and Devils Hole Cave, Nye County, Nevada, 1950-86

A Chronology of diving activities and underground surveys in Devils Hole and Devils Hole Cave, southern Nevada, is presented for the period 1950-86. The report acknowledges the efforts of past underwater explorers, scientists, and observers of the cavern system, and provides a historical perspective for comparison with present investigations at that site. (Thacker-USGS, WRD)

Open-File Report↗
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↗
USGS1981

Water-quality assessment of the Merced River, California, in the 1977 water year

Water-quality conditions in the Merced River in California were sampled four times during the 1977 water year at 12 stations on the river and its major impoundments. Samples taken at the record or near-record low flows of the 1976-77 drought, showed that calcium and bicarbonate were the predominant ions in the water. Inflow of irrigation return water to the river caused a threefold to sevenfold increase in specific conductance between river kilometer 42 and the farthest downstream station at kilometer 8. During the four sampling periods, the increase in total nitrogen concentrations was twofold to sixfold in that reach. Upstream of kilometer 42, the river was free of apparent water-quality degradation, with the exception of occasional increases in nitrogen and phosphorus. Measurements of primary productivity and phytoplankton in Lake McClure and at three river stations gave indications of trophic conditions in the river system. (USGS)

Water-Resources Investigations Report↗
USGS1979

Water quality in the Merced River above and below the El Portal sewage treatment plant near Yosemite National Park, California, 1975-77

A study was made to evaluate the effects that treated sewage has on some characteristics of water quality in a reach of the Merced River near Yosemite National Park. Streamflow and water-quality data were collected from July through October 1975 and from July through November 1977 at five stations on the river and at an auxiliary station on the South Fork of the Merced River before and after a sewage treatment plant near El Portal began discharging treated effluent into the river in January 1977. Data collected in 1977 coincided with drought conditions in the Merced River drainage basin. On-site measurements included streamflow, water temperature, specific conductance, pH, total alkalinity, and dissolved oxygen. Diel measurements were made at selected stations to determine the daily fluctuations of dissolved oxygen, temperature, alkalinity, pH, and specific conductance. Water samples were analyzed for nitrogen, phosphorus, and silica. Periphyton samples were collected from artificial substrates for taxonomic and biomass determinations. Chemical analyses of water for plant nutrients indicated (1) an increase in the concentration of inorganic nitrogen immediately below the treated sewage effluent, (2) uniformly low phosphorus concentrations above and below the effluent, and (3) silica concentrations above and below the effluent greatly exceeding the minimum concentrations required for diatom growth and production. Diel measurements of dissolved oxygen in the reach below the effluent showed substantial sag during the night with supersaturation during the day, indicating considerable in-stream primary production. Measured and observed periphyton growth suggest that sufficient quantities of plant nutrients were available to support periphytic diatom blooms in the Merced River prior to the operation of the treatment plant during near-normal flow conditions. Nutrient availability was also sufficient to support both periphytic diatom and green-algal blooms above and below the treated sewage effluent during drought conditions. Greatest algal production was observed in early autumn

California↗
USGS1978

Selected water-quality data from the Merced River, California, November 1976 through August 1977

The Merced River originates on the western slope of the Sierra Nevada and flows through Yosemite National Park. The river drains 1,276 square miles before joining the San Joaquin River near Stevinson, Calif. Data were collected to permit descriptions of the river's quality during a hydrologic cycle, the natural and manmade factors in the basin that affect the quality, and the trends that might be used in developing procedures to reduce degradation in the future.

California↗
USGS1978

Observation of water quality in the mixed reach below the confluence of the Sacramento and Feather Rivers, California, August and November 1975

The area near the confluence of the Sacramento and Feather Rivers was selected for study of water-quality changes that occur when two large rivers mix. Water-quality measurements were made during August 13-14 and November 4-5, 1975. Considering the concentrations of most of the properties and constituents measured, the mixing of the Sacramento and Feather Rivers generally occurs as simple dilution. Specific conductance and silica had consistently larger measured Nalues than theoretical values in the mixed reach. Some deviations from the theoretical value for any one characteristic in the mixed water are probably the result of physical forces such as upwelling near the confluence of the two rivers, or the concentrating effect of evaporation as the mixed water in the Sacramento River flows downstream. Other deviations in values of constituent concentrations or other properties may be the result of plant and animal activities in the water. Benthic invertebrates and phytoplanktonic similarity indexes between selected paired sites correspond to the quantity of water common to each site. Paired sites with the least volume of water in common had the lowest similarity indexes.

California↗
USGS1976

Water-quality study of a reach of the Merced River in Yosemite National Park and vicinity, California, April 1973 through September 1974

A 25-mile (40-kilometre) reach of the Merced River was studied to provide the National Park Service with water-quality data prior to the operation of a new sewage-treatment plant. Data were collected periodically at four Merced River and two inflow stations. Discharge varied seasonally with highest flow occurring at the time of spring snowmelt runoff. Lowest flow occurred during late summer, coinciding with high park visitor use and elevated water temperature. Water-quality variables investigated were discharge, temperature, major chemical constituents, selected trace metals, specific conductance, suspended sediment, turbidity, dissolved oxygen, pH, alkalinity, carbon dioxide, total organic carbon, nitrogen, phosphorus, algal growth potential, coliform bacteria, periphyton, and benthic invertebrates. Diel measurements were made at some stations to delineate daily fluctuations in selected water-quality variables. Results indicate that water in the reach of the Merced River studied was of good quality. The river had low concentrations of dissolved solids (8 to 41 milligrams per litre) and low alkalinity values (2 to 24 milligrams per litre of alkalinity as CaCO 3 ). Mean concentrations of nitrogen and phosphorus were highest in the Merced River at Rancheria Flat. Algal growth potential tests showed that phosphorus was limiting algal growth at Happy Isles Bridge, El Capitan Bridge, and South Fork Merced River, whereas nitrogen was limiting growth at Rancheria Flat. Input of excessive nitrogen and phosphorus concentrations in the Merced River during the summer low-flow period, and mixing with warm tributary inflow could cause excessive algal growth and production. The algal types found were diatoms, green algae, and blue-green algae. Biomass/chlorophyll a ratios in the Merced River were low (0.3 to 7.7). Benthic invertebrates consisted chiefly of Diptera, Ephemeroptera, and Plecoptera.

California↗
USGS1976

A reconnaissance of the effects of a forest fire on water quality in Kings Canyon National Park, California

Following two adjacent forest fires in the Roaring River drainage basin, Kings Canyon National Park, a sampling program was undertaken from May to July 1974 to ascertain water-quality changes resulting from the fires. Field measurements included alkalinity, pH, specific conductance, temperature, and discharge. Water samples were analyzed in the laboratory for major dissolved chemical constituents, selected plant nutrients, trace metals, suspended sediment, total organic carbon, and seston. Periphytic algae and benthic invertebrate samples were collected. A noticeable increase in the concentration of nitrogen was found in Roaring River immediately downstream from the Moraine Creek fire. The increase in the concentration of inorganic nitrogen compounds, however, was not great enough to pose a serious threat to the aquatic ecosystem. High total organic nitrogen concentrations may have been due, in part, to factors other than the effect of fire. The results of other water-quality measurements were typical of dilute Sierra Nevada streams and indicate that Roaring River was not adversely affected by the fires.

California↗