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Nancy J. Hornewer

Publications and source records attributed to Nancy J. Hornewer.

12 recordsLinked to original sources
USGS2015

In situ densimetric measurements as a surrogate for suspended-sediment concentrations in the Rio Puerco, New Mexico

Surrogate measurements of suspended-sediment concentration (SSC) are increasingly used to provide continuous, high-resolution, and demonstrably accurate data at a reasonable cost. Densimetric data, calculated from the difference between two in situ pressure measurements, exploit variations in real-time streamflow densities to infer SSCs. Unlike other suspendedsediment surrogate technologies based on bulk or digital optics, laser, or hydroacoustics, the accuracy of SSC data estimated using the pressure-difference (also referred to as densimetric) surrogate technology theoretically improves with increasing SCCs. Coupled with streamflow data, continuous suspended-sediment discharges can be calculated using SSC data estimated in real-time using the densimetric technology. The densimetric technology was evaluated at the Rio Puerco in New Mexico, a stream where SSC values regularly range from 10,000-200,000 milligrams per liter (mg/L) and have exceeded 500,000 mg/L. The constant-flow dual-orifice bubbler measures pressure using two precision pressure-transducer sensors at vertically aligned fixed locations in a water column. Water density is calculated from the temperature-compensated differential pressure and SSCs are inferred from the density data. A linear regression model comparing density values to field-measured SSC values yielded an R² of 0.74. Although the application of the densimetric surrogate is likely limited to fluvial systems with SSCs larger than about 10,000 mg/L, based on this and previous studies, the densimetric technology fills a void for monitoring streams with high SSCs.

New Mexico↗
USGS2014

Sediment and water chemistry of the San Juan River and Escalante River deltas of Lake Powell, Utah, 2010-2011

Recent studies have documented the presence of trace elements, organic compounds including polycyclic aromatic hydrocarbons, and radionuclides in sediment from the Colorado River delta and from sediment in some side canyons in Lake Powell, Utah and Arizona. The fate of many of these contaminants is of significant concern to the resource managers of the National Park Service Glen Canyon National Recreation Area because of potential health impacts to humans and aquatic and terrestrial species. In 2010, the U.S. Geological Survey began a sediment-core sampling and analysis program in the San Juan River and Escalante River deltas in Lake Powell, Utah, to help the National Park Service further document the presence or absence of contaminants in deltaic sediment. Three sediment cores were collected from the San Juan River delta in August 2010 and three sediment cores and an additional replicate core were collected from the Escalante River delta in September 2011. Sediment from the cores was subsampled and composited for analysis of major and trace elements. Fifty-five major and trace elements were analyzed in 116 subsamples and 7 composited samples for the San Juan River delta cores, and in 75 subsamples and 9 composited samples for the Escalante River delta cores. Six composited sediment samples from the San Juan River delta cores and eight from the Escalante River delta cores also were analyzed for 55 low-level organochlorine pesticides and polychlorinated biphenyls, 61 polycyclic aromatic hydrocarbon compounds, gross alpha and gross beta radionuclides, and sediment-particle size. Additionally, water samples were collected from the sediment-water interface overlying each of the three cores collected from the San Juan River and Escalante River deltas. Each water sample was analyzed for 57 major and trace elements. Most of the major and trace elements analyzed were detected at concentrations greater than reporting levels for the sediment-core subsamples and composited samples. Low-level organochlorine pesticides and polychlorinated biphenyls were not detected in any of the samples. Only one polycyclic aromatic hydrocarbon compound was detected at a concentration greater than the reporting level for one San Juan composited sample. Gross alpha and gross beta radionuclides were detected at concentrations greater than reporting levels for all samples. Most of the major and trace elements analyzed were detected at concentrations greater than reporting levels for water samples.

Utah↗
USGS2008

Bathymetric Survey and Storage Capacity of Upper Lake Mary near Flagstaff, Arizona

Upper Lake Mary is a preferred drinking-water source for the City of Flagstaff, Arizona. Therefore, storage capacity and sedimentation issues in Upper Lake Mary are of interest to the City. The U.S. Geological Survey, in cooperation with the City of Flagstaff, collected bathymetric and land-survey data in Upper Lake Mary during late August through October 2006. Water-depth data were collected using a single-beam, high-definition fathometer. Position data were collected using real-time differential global position system receivers. Data were processed using commercial software and imported into geographic information system software to produce contour maps of lakebed elevations and for the computation of area and storage-capacity information. At full pool (spillway elevation of 6,828.5 feet above mean sea level), Upper Lake Mary has a storage capacity of 16,300 acre-feet, a surface area of 939 acres, a mean depth of 17.4 feet, and a depth near the dam of 39 feet. It is 5.6 miles long and varies in width from 308 feet near the central, narrow portion of the lake to 2,630 feet in the upper portion. Comparisons between this survey and a previous survey conducted in the 1950s indicate no apparent decrease in reservoir area or storage capacity between the two surveys.

Open-File Report↗
USGS2007

Flow Velocity and Sediment Data Collected During 1990 and 1991 at National Canyon, Colorado River, Arizona

During 1990 and 1991, a series of research flows were released from Glen Canyon Dam. Data collected at the streamflow-gaging station on the Colorado River above National Canyon near Supai from that period have been compiled and entered into the U.S. Geological Survey database. The data consist of measurements of suspended-sediment concentration and sand sizes in suspension, sand sizes of streambed sediment, and velocity of the Colorado River above National Canyon near Supai streamflow-gaging site. Velocity and sediment data are available upon request from the Arizona Water Science Center and from the U.S. Geological Survey water-quality database (http://waterdata.usgs.gov/az/nwis/qw).

Data Series↗
USGS2003

Variations in sand storage measured at monumented cross sections in the Colorado River between Glen Canyon Dam and Lava Falls Rapid, northern Arizona, 1992-99

Bed elevations were measured at 131 monumented cross sections in the Colorado River between Glen Canyon Dam and Lava Falls Rapid from June 1992 to September 1999 to provide data on channel sand storage. This report documents the location of the 131 monumented cross sections, dates of measurements for all cross sections, methods of data collection and processing, and spatial and temporal variation and variability in changes in cross-sectional area for selected cross sections. Additionally, data were analyzed to determine if changes in sediment storage could be related to main channel flow conditions and tributary sediment inputs. Most of the cross sections showed a limited capacity, both in terms of amount and residence time, to store sediment. Data for 83 of the 131 cross sections were comprehensive and complete, and were used for analyses in this report. This data set is referred to as the primary data set. Of these 83 cross sections, 19 had a net gain in stored sediment, 61 had a net loss of stored sediment, and 3 had no change in stored sediment for the period of data collection, excluding data collected during the high release from Glen Canyon Dam in 1996. A subset of the primary data set consisting of the sections downstream from the Paria and Little Colorado Rivers with measurements made on or nearly on the same day, referred to as the matching-date data set, was used to explore the effects of controlled flows and tributary flows on the changes in cross-sectional area. The matching-date data set consists of data from 57 cross sections. Of these 57 cross sections, 1 had a net gain in stored sediment, 55 had a net loss of stored sediment, and 1 had no change in stored sediment. Results of the analysis did not show that changes in cross-sectional area were strongly related to main channel flow conditions or tributary sediment inputs.

Water-Resources Investigations Report↗
USGS2002

Monitoring and analysis of combined sewer overflows, Riverside and Evanston, Illinois, 1997-99

The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, collected and analyzed flow data in combined sewer systems in Riverside and Evanston, northeastern Illinois, from March 1997 to December 1999. Continuous 2- and 5-minute stage and velocity data were collected during surcharged and nonsurcharged conditions at 12 locations. Mass balances were calculated to determine the volume of water flowing through the tide-gate openings to the Des Plaines River and the North Shore Channel and to determine the volume of water flowing past the sluice gate to the deep tunnel. The sewer systems consist of circular pipes ranging in diameter from 0.83 feet to 10.0 feet, elliptical siphon pipes, ledges, and tide and sluice gates. Pipes were constructed of either brick and mortar or concrete, and ranged from having smooth surfaces to rough, pitted and crumbling surfaces. One pipe was noticeably affected by water infiltration from saturated ground. During data analysis, many assumptions were necessary because of the complexity of the flow data and sewer-system configurations. These assumptions included estimating the volume of water entering an interceptor sewer at the ''Gage Street pipe'' at Riverside, the effect of infiltration on the ''brick pipe'' at Riverside, and the minimum velocity required for the meter to make an accurate velocity determination. Other factors affecting the analysis of flow data included possible non-instrumented sources of inflow, and backwater conditions in some pipes, which could have caused error in the data analysis. Variations of these assumptions potentially could cause appreciable changes to the final massbalance calculations. Mass-balance analysis at Riverside indicated a total inflow volume into chamber 3 of approximately 721,000 cubic feet (ft3) during April 22-26, 1999. Outflow volume to the Des Plaines River at Riverside through the tide gate was approximately 132,000 ft3; outflow volume to the deep tunnel through the sluice gate was approximately 267,000 ft3. The mass-balance analysis at Evanston indicated a total inflow volume into chamber 3 of approximately 5,970,000 ft3 during April 21-26, 1999. The outflow volume to the North Shore Channel through the tide gates at Evanston was approximately 2,920,000 ft3; outflow volume to the deep tunnel through the sluice gates was approximately 3,050,000 ft3.

Water-Resources Investigations Report↗
USGS2000

Methodology, data collection, and data analysis for determination of water-mixing patterns induced by aerators and mixers

The U.S. Geological Survey collected and analyzed data to describe mixing patterns induced by aerators and mixers to aid in the calibration and verification of a three-dimensional hydrodynamic model. During September 1995, three-dimensional water-velocity profiles were collected during the operation of fine-bubble and coarse-bubble aerators in a test tank at the U.S. Army Corps of Engineers Waterways Experiment Station. Three-dimensional water velocity, water-temperature, pH, dissolved oxygen concentration, and specific conductivity profiles were collected during operation of a coarse-bubble aerator in a reservoir in Schaumburg, Illinois, during summer 1996 and summer 1997, during strongly stratified and weakly stratified conditions. The effects of a submersible mixer alone and in combination with coarse-bubble aerators and a surface mixer alone also were investigated during summer 1997. The mixing patterns induced by the operation of aerators, submersible mixers, and surface mixers were described and compared with mixing patterns predicted by model simulations. Bubble-plume characteristics during tests in strongly stratified and weakly stratified conditions in the reservoir were documented and compared with characteristics simulated by different models. Lemckert and Imberger?s model simulates an entrainment rate similar to the rate measured during a test in the reservoir under strongly stratified conditions, whereas Schladow?s one-dimensional model appears to underestimate the total entrainment rate by about 50 percent. Schladow?s model was accurate during weak stratification but underestimated the radius of the plume during strong stratification. For 5 days during daylight hours, water temperature profiles were collected continuously during the operation of four aerators. Water temperatures in the reservoir were significantly affected by the operation of the aeration system. These changes were compared to simulations from a one-dimensional Dynamic Lake Model (DLM) simulation. DLM accurately simulated changes as a result of aeration, including daily changes. On the basis of temporal and spatial dissolved oxygen measurements, the volumetric quantity of oxygen in the reservoir was quantified before and after operation of a submersible mixer. A net loss of oxygen was calculated. This net loss may have resulted from a net warming of water throughout the reservoir or submerged supersaturated water releasing oxygen when the water came in contact with the atmosphere.

Water-Resources Investigations Report↗
USGS1998

Rainfall in and near Du Page County, Illinois, October 1991-September 1995

Twenty-four hour rainfall data are presented for 11 rain gages in and near Du Page County, Illinois. Daily rainfall totals were recorded from October 1, 1991, to September 30, 1995. Station descriptions include site identifiers, locations, drainage basins, types of instrumentation, accuracy, and periods of record. Missing and partial rainfall data, and precipitation totals affected by snowfall have been noted for the periods of record.

Open-File Report↗
USGS1997

Sources of contamination in an urban basin in Marquette, Michigan and an analysis of concentrations, loads, and data quality

The concentrations of contaminants generated from discrete source areas are critical to urban nonpoint Source Load and Management Model (SLAMM) loading calculations to Lake Superior. This study summarizes data-collection efforts during 12 storms in October 1993 and from May through August 1994, in which stormwater data were collected concurrently at 33 sites representing the eight major source areas in a 117-hectare urban basin in Marquette, Mich. For the 12 storms, commercial rooftops produced the highest geometric mean concentrations of dissolved metals such as lead (20 mg/L), zinc (263 mg/L), cadmium (0.71 mg/L), and copper (17.8 mg/L). Parking lots produced the highest concentration for all of the individual polycyclic aromatic hydrocarbon (PAH) compounds (summation equal to 64 mg/L). Residential lawns generated the highest concentrations of total kjeldahl nitrogen (9.3 mg/L) and total phosphorus (2.3 mg/L). A mass-budget approach, in which summed source area loads are compared to those measured at the basin outlet for individual storms, provided the basis for an error analysis to identify unreliable concentration data. Of the 611 concentration samples used in the mass budgets, 59 were identified as unreliable. Seventy-six percent of the unreliable samples came from collection bottles that were filled prior to the end of runoff. These full bottles may have captured a first-flush effect or acted as a sediment trap. The relative importance of an individual source-area load to the overall basin-outlet load varied according to the individual constituent. Parking lots were a major contributor of total zinc (30 percent), total cadmium (25 percent), total copper (22 percent), and all the PAH compounds (=64 percent); whereas low-traffic streets were a major producer of total suspended solids (27 percent), nitrate plus nitrite (21 percent), and total cadmium (25 percent). Grass areas were a major producer of total kjeldahl nitrogen (31 percent) and total phosphorus (26 percent), even though the water volume generated from grass areas was low (5.8 percent of the total water volume generated).

Michigan↗
USGS1996

Contaminant concentrations in stormwater from eight lake Superior basin cities, 1993-94

The U.S. Geological Survey collected Stormwater samples from eight Lake Superior Basin cities to determine the quality of urban runoff entering Lake Superior from urban areas. The samples were collected during July 1993-September 1994 from storm sewers in Ishpeming, Negaunee, Sault Ste. Marie, and Houghton, Michigan; Virginia and Ribbing, Minnesota; and Ashland and Hurley, Wisconsin. Automated samplers were installed in manholes draining the selected sewers within each city. Water samples were collected for analyses of total recoverable metals, nutrients, and poly cyclic aromatic hydrocarbons. Concentrations of these constituents for each site are listed in data tables.

Michigan, Minnesota, Wisconsin↗
USGS1993

Sources of pollutants in Wisconsin stormwater

Rainfall runoff samples were collected from streets, parking lots, roofs, driveways, and lawns. These five source areas are located in residential, commercial, and industrial land uses in Madison, Wisconsin. Solids, phosphorus, and heavy metals loads were determined for all the source areas using measured concentrations and runoff volumes estimated by the Source Load and Management Model. Source areas with relatively large contaminant loads were identified as critical source areas for each land use. Streets are critical source areas for most contaminants in all the land uses. Parking lots are critical in the commercial and industrial land uses. Lawns and driveways contribute large phosphorus loads in the residential land use. Roofs produce significant zinc loads in the commercial and industrial land uses. Identification of critical source areas could reduce the amount of area needing best-management practices in two areas of Madison, Wisconsin. Targeting best-management practices to 14% of the residential area and 40% of the industrial area could significantly reduce contaminant loads by up to 75%.

Wisconsin↗