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R. B. Zelt

Publications and source records attributed to R. B. Zelt.

10 recordsLinked to original sources
USGS2007

Simulation and mapping of soil-water conditions in the Great Plains

Soil-water conditions provide valuable insight into the hydrologic system in an area. A soil-water balance quantitatively summarizes soil-water conditions and is based on climatic, soil, and vegetation characteristics that vary spatially and temporally. Soil-water balances in the Great Plains of the central United States were simulated for 1951-1980. Results of the simulations were mean annual estimates of infiltration, runoff, actual evapotranspiration, potential recharge, and consumptive water and irrigation requirements at 152 climatic data stations. A method was developed using a geographic information system to integrate and map the simulation results on the basis of spatially variable climatic, soil, and vegetation characteristics. As an example, simulated mean annual potential recharge was mapped. Mean annual potential-recharge rates ranged from less than 0.5 inch in much of the north-central and southwestern Great Plains to more than 10 inches in parts of eastern Texas and southwestern Arkansas.

Water Resources Bulletin↗
USGS2007

Identifying fecal sources in a selected catchment reach using multiple source-tracking tools

Given known limitations of current microbial source-tracking (MST) tools, emphasis on small, simple study areas may enhance interpretations of fecal contamination sources in streams. In this study, three MST tools - Escherichia coli repetitive element polymerase chain reaction (rep-PCR), coliphage typing, and Bacteroidales 16S rDNA host-associated markers - were evaluated in a selected reach of Plum Creek in sooth-central Nebraska. Water-quality samples were collected from six sites. One reach was selected for MST evaluation based on observed patterns of E. coli contamination. Despite high E. coli concentrations, coliphages were detected only once among water samples, precluding their use as a MST tool in this setting. Rep-PCR classification of E. coli isolates from both water and sediment samples supported the hypothesis that cattle and wildlife were dominant sources of fecal contamination, with minor contributions by horses and humans. Conversely, neither ruminant nor human sources were detected by Bacteroidales markers in most water samples. In bed sediment, ruminant- and human-associated Bacteroidales markers were detected throughout the interval from 0 to 0.3 m, with detections independent of E. coli concentrations in the sediment. Although results by E. coli-based and Bacteroidales-based MST methods led to similar interpretations, detection of Bacteroidales markers in sediment more commonly than in water indicates that different tools to track fecal contamination (in this case, tools based on Bacteroidales DNA and E. coli isolates) may have varying relevance to the more specific goal of tracking the sources of E. coli in watersheds. This is the first report of simultaneous, toolbox approach application of a library-based and marker-based MST analyses to lowing surface water. ?? ASA, CSSA, SSSA.

Journal of Environmental Quality↗
USGS1999

Element concentrations in bed sediment of the Yellowstone River basin, Montana, North Dakota, and Wyoming — A retrospective analysis

Chemical data for bed sediment were analyzed as part of the U.S. Geological Survey National Water-Quality Assessment Program investigation of the Yellowstone River Basin in parts of Montana, North Dakota, and Wyoming. The primary data set consisted of about 13,000 samples collected during 1974-79 for the National Uranium Resource Evaluation program. Data were available for 50 elements, although not all samples were analyzed for all elements. Element concentrations varied spatially and were associated with geologic settings or ecoregions. Factor analysis indicated three groups of associated elements: factor 1 elements were strongly correlated with basaltic rocks, factor 2 elements were strongly correlated with granitic rocks, and factor 3 elements were strongly correlated with carbonate rocks. Scores for factor 1 were highest for bed-sediment samples associated with volcanic rocks of Tertiary and Cretaceous age in the Absaroka volcanic field and crystalline rocks of Precambrian age in the Beartooth Mountains. Scores for factor 2 were highest for samples associated with volcanic rocks of Quaternary age on the Yellowstone Plateau, crystalline rocks of Precambrian age, and sedimentary rocks of Tertiary age in the Wyoming Basin ecoregion. Scores for factor 3 were highest in samples associated with sedimentary rocks of Paleozoic age and volcanic rocks of Cretaceous and Tertiary age. Descriptive statistics are presented to serve as a baseline for element concentrations in bed sediment associated with eight geologic settings or ecoregions in the study unit. Some of the concentrations of chromium, copper, lead, nickel, and zinc in bed-sediment samples from areas of crystalline rocks in the Beartooth Mountains and other formations in the western part of the study unit exceeded sediment-quality assessment values associated with toxic effects to aquatic life.

Idaho, Montana, North Dakota, South Dakota, Wyomin↗
USGS1998

Water quality in the central Nebraska basins, Nebraska, 1992-95

This report is intended to summarize major findings that emerged between 1992 and 1995 from the water-quality assessment of the Central Nebraska Basins Study Unit and to relate these findings to water-quality issues of regional and national concern. The information is primarily intended for those who are involved in waterresource management. Indeed, this report addresses many of the concerns raised by regulators, water-utility managers, industry representatives, and other scientists, engineers, public officials, and members of stakeholder groups who provided advice and input to the USGS during this NAWQA Study-Unit investigation. Yet, the information contained here may also interest those who simply wish to know more about the quality of water in the rivers and aquifers in the area where they live.

Nebraska↗
USGS1996

Basin-level habitat characteristics of selected streams in central Nebraska

The goal of stream habitat characterization is to use identified relations between habitat and other physical, chemical, or biological factors in interpreting water-quality conditions. Basin-level characterization of habitat is one component of the spatially hiearchial approach to stream habitat description adopted by the U.S. Geological Survey's National Water-Quality Assessment Program. The Central Nebraska Basins study unit is about 78,000 km2 in area and includes the Loup and Elkhorn River Basins as well as basins of smaller tributaries to the Platte River. Stream-basin habitat characteristics associated with nine fixed-sampling stations were computed from conventional and digital map data. Geographic information systems software was the principal analytical tool used. Basin characterizations generally were limited to only that part of each stream basin contained within the study unit. Habitat characteristics analyzed included basin size and shape, elevation, relief, drainage network characteristics, geology, physiography, soils, land use and cover, climate, runoff, and streamflow characteristics. The report presents a tabular summary of the basin-level habitat characteristics determined for the nine selected stream basins.

Open-File Report↗
USGS1995

Land-cover sampling designs, data-collection procedures, and land-cover data for the Central Nebraska Basins, 1993-94

Within the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program, land-cover data are used in characterizing drainage areas upstream from surface-water sampling sites and areas selected for spatially distributed ground-water sampling. During the period of time when the initial 20 NAWQA study study-unit investigations were evaluating existing land-cover data, a Prototype 190 Conterminous U.S. land Cover Characteristics Data Set was produced by the Survey's EROS Data Center in Sioux Falls, South Dakota. As part of the Central Nebraska Basins (CNB) study-unit investigation, a method was developed to estimate the areal extent of the principal land-cover types within selected seasonally distinct land-cover (SDLC) regions defined in the 1990 prototype data set. This report describes the sampling designs and methods used to collect land-cover data in the CNB study unit. Data collected at 309 sampling sites during the summers of 1993 and 1994 are presented and statistically summarized. Eleven land-cover categories were quantified, including major field crops and broad noncropland cover types.

Open-File Report↗
USGS1995

Isopachs of Quaternary deposits, Fremont 1- by 2- degree Quadrangle and part of Omaha Quadrangle, Nebraska, digitized from a published 1:250,000-scale geologic map

A geologic map showing the isopachs of Quaternary deposits in the Fremont and part of the Omaha, Nebraska, 1- by 2-degree quadrangles was published at a scale of 1:250,000 in 1975 (Burchett and others, 1975). This report describes the conversion of Quaternary thickness data into a digital geographic data set. A film separation of the published isopachs was scan-digitized and processed to produce digital geographic data. Geographic feature attributes and data-set documentation also are included in the digital data set. The digital data set are formatted for distribution with accordance with the Spatial Data Transfer Standard approved by the U.S. National Institute of Standards and Technology.

Open-File Report↗
USGS1994

Water-level changes in the High Plains aquifer -- Predevelopment to 1992

Changes in water levels in the High Plains aquifet underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming result from the variability of precipitation, land use, and ground-water withdrawals. From the beginning of development of the High Plains aquifer to 1980, water levels declined throughout much of the area; the declines exceeded 100 feet in parts of the central and southern High Plains. From 1980 to 1992, water levels continued to decline in these same areas, but at a slightly slower overall annual rate. This slower rate of decline was associated, in part, with a decrease in ground-water application for irrigated agriculture and above normal precipitation throughout the High Plains during 1980-91. Declines exceeding 20 feet were common from 1980 to 1992 in areas of intense irrigation development in Kansas, New Mexico, Oklahoma, and Texas. In the northern High Plains, declines of 10 to 20 feet from 1980 to 1992 were widespread in northeastern Colorado, southwestern Nebraska, and the Nebraska Panhandle. Water levels were generally stable from 1980 to 1992 in most other areas of the High Plains. In a large area in the southern High Plains of Texas, however, water-level rises exceeded 20 feet. Also, scattered rises of 5 to 10 feet occurred in eastern Nebraska. The estimated average area-weighted water-level change, from 1991 to 1992 was -0.55, even though precipitation was well-above normal in 1991 in the High Plains. Water- level declines of 3 to 5 feet were widespread in the intensively irrigated areas of southwestern Kansas and the northern part of the Southern High Plains of Texas. These large declines were not closely related to 1991 precipitation patterns in those areas. Declines of 1 to 3 feet were common throughout the intensively irrigated areas of the Northern High Plains and the less intensively irrigated areas of the Central and Southern High Plains. Water levels continued to rise, generally 1 to 3 feet in the extreme Southern High Plains of Texas. Rises of 1 to 3 feet also occurred in parts of northeastern and central Nebraska.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗
USGS1993

Water-quality assessment of the central Nebraska basins; summary of data for recent conditions through 1990

Among the first activities undertaken in each National Water-Quality Assessment (NAWQA) program study-unit investigation are compilation, screening, and statistical summary of available data concerning recent, general water-quality conditions in the study unit. This report (1) identifies which of the existing water-quality data are suitable for characterizing general conditions in a nationally consistent manner and (2) describes, to the extent possible, recent, general water-quality conditions in the Central Nebraska Basins. The study unit con- sists of the area drained by the Platte River between the confluence of the North Platte and South Platte Rivers near North Platte downstream to its confluence with the Missouri River south of Omaha. The report includes (1) a description of the sources and characteristics of water-quality data that are available, (2) a description of the approach used for screening data to identify a subset of the data suitable for summary and comparisons, (3) a presen- tation of the results of statistical and graphical summaries of recent, general water-quality con- ditions, and (4) comparisons of recent, general water-quality conditions to established national water-quality criteria, where applicable. Stream- and lake-water data are summarized for selected sampling sites, and data are summarized by major subunits of the study unit (the Sandhills, Loess Hills, Glaciated Area, and Platte Valley subunits) for streambed-sediment, fish-tissue, aquatic- ecological, and ground-water data. The summaries focus on the central tendencies and typical variation in the data and use nonparametric statistics such as frequencies and percentile values.

Open-File Report↗