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At least 703 records · Page 39Linked to original sources
USGS2004

A summary of the scientific literature on the effects of fire on the concentration of nutrients in surface waters

This paper provides a detailed review of the chemical changes that occur in soil during a fire, the pathways by which nutrients are transferred from soil to surface-water bodies following a fire, and the temporal and spatial effects of fires on the concentration of nutrients in surface-water bodies during and following a fire that have been reported in the scientific literature. Thirty-nine papers from the scientific literature that represent studies that (1) were done in a variety of environments (savannas, grasslands, temperate forests, alpine forests, and so forth); (2) had a range of sampling frequency and duration, such as during and immediately following a fire (from the start of fire to 1 year later), short-term sampling (from end of fire to 3 years later), and long term-sampling (sampling for greater than 3 years following a fire); and (3) incorporated watersheds with various burn intensities, severities, and histories were reviewed and summarized. The review of the scientific literature has revealed that measurable effects of fires on streamwater quality are most likely to occur if the fire was severe enough to burn large amounts of organic matter, if windy conditions were present during the fire, if heavy rain occurred following the fire, and if the fire occurred in a watershed with steep slopes and soils with little cation-exchange capacity. Measurable effects of fires on lake- and reservoir-water quality are most likely to occur if, in addition to the factors listed for streams, the lake or reservoir is oligotrophic or mesotrophic and the residence time of water in the lake or reservoir is short relative to the length of time elevated concentrations of nutrients occur in runoff. Knowledge of whether a lake or reservoir is nitrogen or phosphorus limited is important because eutrophication of nitrogen-limited lakes may occur following a fire due to increasing nitrogen:phosphorus ratios caused by prolonged increases of nitrogen concentrations, especially nitrate.

Open-File Report↗
USGS2022

Sedimentary record of annual-decadal timescale reservoir dynamics: Anthropogenic stratigraphy of Lake Powell, Utah, U.S.A.

The tributaries of Lake Powell were impounded following construction of Glen Canyon Dam, resulting in deposition of reservoir sediment over a ∼650 km2 area since 1963. These units have been exposed through erosion as water storage in Lake Powell has decreased since 2000. This anthropogenic sedimentary record reflects the complex interplay among wet and dry periods of Colorado River runoff and the reservoir operating rules of Lake Powell. The relevant sedimentary exposures are mapped at reconnaissance level over 300 river-km above Glen Canyon Dam in canyons of the Colorado, San Juan, Escalante, and Dirty Devil Rivers. A detailed reference section measured in Calf Canyon, a tributary to the Colorado River, preserves more than 12 m of lacustrine, mainstem Colorado River, and local tributary sediment in an up-river location and elevation that is determined to have been inundated only during the highest reservoir level periods. At Calf Canyon, exposed reservoir sediment is comprised of cyclic sand-mud interbeds that record periods of deposition when reservoir level was at or above full pool. Six depositional cycles are identified in Calf Canyon, and each of these is interpreted to represent rapid sand deposition during Colorado River flood events (likely related to spring snowmelt runoff) followed by deposition of lacustrine mud while reservoir levels were high. The lacustrine mud units display significant pedogenic modification, indicating exposure and colonization dominated by tamarisk plants, prior to deposition of the next sand unit. High-precision elevation surveys of the 6 main lacustrine marker beds in Calf Canyon are correlated to multiple lake level highstands between 1975 and 2000. Preliminary observations suggest that age-equivalent strata are widespread within the reservoir-affected zones of all major tributaries including the Colorado and San Juan River arms as well as the Escalante and Dirty Devil Rivers. We predict that future map- ping in other Lake Powell side canyons will demonstrate strong local control on sediment provenance, dictated by side canyon lithology, as well as time-transgressive deposition (and erosion) moving up and down the main canyons.

Utah↗
USGS2001

Water resources data, Pennsylvania, water year 2000. Volume 3. Ohio and St. Lawrence River Basins

Introduction The Water Resources Division of the U.S. Geological Survey, in cooperation with State, municipal, and Federal agencies, collects a large amount of data pertaining to the water resources of Pennsylvania each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, these data are published annually in this report series entitled "Water Resources Data - Pennsylvania, Volumes 1, 2, and 3." Volume 1 contains data for the Delaware River Basin; Volume 2, the Susquehanna and Potomac River Basins; and Volume 3, the Ohio and St. Lawrence River Basins. This report, Volume 3, contains: (1) discharge records for 58 continuous-record streamflow-gaging stations, 5 partial-record stations, and 12 special study and miscellaneous streamflow sites; (2) elevation and contents records for 11 lakes and reservoirs; (3) water-quality records for 1 streamflow gaging station and 8 ungaged streamsites; and (4) water-level records for 15 ground-water network observation wells and. Additional water data collected at various sites not involved in the systematic data-collection program may also be presented. Publications similar to this report are published annually by the Geological Survey for all States. For the purpose of archiving, these official reports have an identification number consisting of the two-letter State abbreviation, the last two digits of the water year, and the volume number. For example, this volume is identified as "U.S. Geological Survey Water-Data Report PA-00-3." These water-data reports, beginning with the 1971 water year, are for sale as paper copy or microfiche by the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161. The annual series of Water Data Reports for Pennsylvania began with the 1961 water-year report and contained only data relating to quantities of surface water. With the 1964 water year, a companion report (part 2) was introduced that contained only data relating to water quality. Beginning with the 1975 water year the report was changed to three volumes (by river basin), with each volume containing data on quantities of surface water, quality of surface and ground water, and ground-water levels. Prior to the introduction of this series and for several years concurrent with it, water-resources data for Pennsylvania were published in U.S. Geological Survey Water-Supply Papers. Data on stream discharge and stage, and on lake or reservoir contents and stage, through September 1960, were published annually under the title "Surface-Water Supply of the United States," which was released in numbered parts as determined by natural drainage basins. For the 1961-70 water years, these data were published in two 5-year reports. Data prior to 1961 are included in two reports: "Compilation of Records of Surface Waters of the United States through 1950," and "Compilation of Records of Surface Waters of the United States, October 1950 to September 1960." Data for Pennsylvania are published in Parts 1, 3, and 4. Data on chemical quality, temperature, and suspended sediment for the 1941-70 water years were published annually under the title "Quality of Surface Waters of the United States," and ground-water levels for the 1935-74 water years were published annually under the title "Ground-Water Levels in the United States." The above mentioned Water-Supply Papers may be consulted in the libraries of the principal cities of the United States and may be purchased from the U.S. Geological Survey, Information Services, Box 25286, Denver, CO 80225. Information for ordering specific reports may be obtained from the Pennsylvania District Office at the address on the back of the title page or by phoning the Scientific and Technical Products Section at (717) 730-6940. Information on the availability of unpublished data or statistical analyses may be obtained from the District Information Specialist by telephone at (717) 730-6916 or by FAX at (717) 730-6997.

Water Data Report↗
USGS2001

Water resources data, Pennsylvania, water year 2000, Volume 1. Delaware River Basin

The Water Resources Division of the U.S. Geological Survey, in cooperation with State, municipal, and Federal agencies, collects a large amount of data pertaining to the water resources of Pennsylvania each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, these data are published annually in this report series entitled "Water Resources Data - Pennsylvania, Volumes 1, 2, and 3." Volume 1 contains data for the Delaware River Basin; Volume 2, the Susquehanna and Potomac River Basins; and Volume 3, the Ohio River and St. Lawrence River Basins. This report, Volume 1, contains: (1) discharge records for 76 continuous-record streamflow-gaging stations, 7 partial-record stations, and 13 special study and miscellaneous streamflow sites; (2) elevation and contents records for 14 lakes and reservoirs; (3) water-quality records for 28 gaging stations and 14 ungaged streamsites; (4) water-quality records for 77 special-study stations; (5) water-level records for 53 network observation wells; and (6) water-quality analyses of ground water from 101 ground-water wells. Additional water data collected at various sites not involved in the systematic data-collection program may also be presented. Publications similar to this report are published annually by the Geological Survey for all States. For the purpose of archiving, these official reports have an identification number consisting of the two-letter State abbreviation, the last two digits of the water year, and the volume number. For example, this volume is identified as "U.S. Geological Survey Water-Data Report PA-00-1." These water data reports, beginning with the 1971 water year, are for sale as paper copy or microfiche by the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161. The annual series of Water Data Reports for Pennsylvania began with the 1961 water-year report and contained only data relating to quantities of surface water. With the 1964 water year, a companion report (part 2) was introduced that contained only data relating to water quality. Beginningwith the 1975 water year the report was changed to its present format of three volumes (by river basin), with each volume containing data on quantities of surface water, quality of surface and ground water, and ground-water levels. Prior to the introduction of this series and for several years concurrent with it, water-resources data for Pennsylvania were published in U.S. Geological Survey Water-Supply Papers. Data on stream discharge and stage, and on lake or reservoir contents and stage, through September 1960, were published annually under the title "Surface-Water Supply of the United States," which was released in numbered parts as determined by natural drainage basins. For the 1961-70 water years, these data were published in two 5-year reports. Data prior to 1961 are included in two reports: "Compilation of Records of Surface Waters of the United States through 1950," and "Compilation of Records of Surface Waters of the United States, October 1950 to September 1960." Data for Pennsylvania are published in Parts 1, 3, and 4. Data on chemical quality, temperature, and suspended sediment for the 1941-70 water years were published annually under the title "Quality of Surface Waters of the United States," and ground-water levels for the 1935-74 water years were published under the title "Ground-Water Levels in the United States." The above mentioned Water-Supply Papers may be consulted in the libraries of the principal cities of the United States and may be purchased from the U.S. Geological Survey, Information Services, Box 25286, Denver, CO 80225. Information for ordering specific reports may be obtained from the Pennsylvania District Office at the address given on the back of the title page or by phoning the Scientific and Technical Products Section, at (717) 730-6940. Information on the availability of unpublished data or statistical analyses may be obtained from the District Information Specialist by telephone at (717) 730-6916 or by FAX at (717) 730-6997.

Water Data Report↗
USGS2000

Water resources data, Pennsylvania, water year 2000. Volume 2. Susquehanna and Potomac River Basins

Introduction The Water Resources Division of the U.S. Geological Survey, in cooperation with State, municipal, and Federal agencies, collects a large amount of data pertaining to the water resources of Pennsylvania each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, these data are published annually in this report series entitled "Water Resources Data - Pennsylvania, Volumes 1, 2, and 3." Volume 1 contains data for the Delaware River Basin; Volume 2, the Susquehanna and Potomac River Basins; and Volume 3, the Ohio and St. Lawrence River Basins. This report, Volume 2, contains: (1) discharge records for 83 continuous-record streamflow-gaging stations, 16 partial-record stations, and 24 special study and miscellaneous streamflow sites; (2) elevation and contents records for 12 lakes and reservoirs; (3) water-quality records for 11 streamflow gaging stations and 70 partial-record and project stations; and (4) water-level records for 30 ground-water network observation wells and water-quality analyses of ground water from 8 wells; and (5) water-quality analyses at 60 special study ground-water wells. Additional water data collected at various sites not involved in the systematic data-collection program may also be presented. Publications similar to this report are published annually by the Geological Survey for all States. For the purpose of archiving, these official reports have an identification number consisting of the two-letter State abbreviation, the last two digits of the water year, and the volume number. For example, this volume is identified as "U.S. Geological Survey Water-Data Report PA-00-2." These water-data reports, beginning with the 1971 water year, are for sale as paper copy or microfiche by the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161. The annual series of Water Data Reports for Pennsylvania began with the 1961 water-year report and contained only data relating to quantities of surface water. With the 1964 water year, a companion report (part 2) was introduced that contained only data relating to water quality. Beginning with the 1975 water year the report was changed to three volumes (by river basin), with each volume containing data on quantities of surface water, quality of surface and ground water, and ground-water levels. Prior to the introduction of this series and for several years concurrent with it, water-resources data for Pennsylvania were published in U.S. Geological Survey Water-Supply Papers. Data on stream discharge and stage, and on lake or reservoir contents and stage, through September 1960, were published annually under the title "Surface-Water Supply of the United States," which was released in numbered parts as determined by natural drainage basins. For the 1961-70 water years, these data were published in two 5-year reports. Data prior to 1961 are included in two reports: "Compilation of Records of Surface Waters of the United States through 1950," and "Compilation of Records of Surface Waters of the United States, October 1950 to September 1960." Data for Pennsylvania are published in Parts 1, 3, and 4. Data on chemical quality, temperature, and suspended sediment for the 1941-70 water years were published annually under the title "Quality of Surface Waters of the United States," and ground-water levels for the 1935-74 water years were published annually under the title "Ground-Water Levels in the United States." The above mentioned Water-Supply Papers may be consulted in the libraries of the principal cities of the United States and may be purchased from the U.S. Geological Survey, Information Services, Box 25286, Denver, CO 80225. Information for ordering specific reports may be obtained from the Pennsylvania District Office at the address on the back of the title page or by phoning the Scientific and Technical Products Section at (717) 730-6940. Information on the availability of unpublished data or statistical analyses may be obtained from the District Information Specialist by telephone at (717) 730-6916 or by FAX at (717) 730-6997.

Water Data Report↗
USGS2001

Water Resources Data, Pennsylvania, Water Year 2001, Volume 2. Susquehanna and Potomac River Basins

Introduction The Water Resources Division of the U.S. Geological Survey, in cooperation with State, municipal, and Federal agencies, collects a large amount of data pertaining to the water resources of Pennsylvania each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, these data are published annually in this report series entitled "Water Resources Data - Pennsylvania, Volumes 1, 2, and 3." Volume 1 contains data for the Delaware River Basin; Volume 2, the Susquehanna and Potomac River Basins; and Volume 3, the Ohio and St. Lawrence River Basins. This report, Volume 2, contains: (1) discharge records for 83 continuous-record streamflow-gaging stations, 15 partial-record stations, and 24 special study and miscellaneous streamflow sites; (2) elevation and contents records for 12 lakes and reservoirs; (3) water-quality records for 9 streamflow gaging stations and 73 partial-record and project stations; and (4) water-level records for 36 ground-water network observation wells and water-quality analyses of ground water from 8 wells; (5) water-quality analyses at 123 special study ground-water wells; and, (6) miscellaneous water-level measurements at 80 special study ground-water wells. Additional water data collected at various sites not involved in the systematic data-collection program may also be presented. Publications similar to this report are published annually by the Geological Survey for all States. For the purpose of archiving, these official reports have an identification number consisting of the two-letter State abbreviation, the last two digits of the water year, and the volume number. For example, this volume is identified as "U.S. Geological Survey Water-Data Report PA-01-2." These water-data reports, beginning with the 1971 water year, are for sale as paper copy or microfiche by the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161. The annual series of Water Data Reports for Pennsylvania began with the 1961 water-year report and contained only data relating to quantities of surface water. With the 1964 water year, a companion report (part 2) was introduced that contained only data relating to water quality. Beginning with the 1975 water year the report was changed to three volumes (by river basin), with each volume containing data on quantities of surface water, quality of surface and ground water, and ground-water levels. Prior to the introduction of this series and for several years concurrent with it, water-resources data for Pennsylvania were published in U.S. Geological Survey Water-Supply Papers. Data on stream discharge and stage, and on lake or reservoir contents and stage, through September 1960, were published annually under the title "Surface-Water Supply of the United States," which was released in numbered parts as determined by natural drainage basins. For the 1961-70 water years, these data were published in two 5-year reports. Data prior to 1961 are included in two reports: "Compilation of Records of Surface Waters of the United States through 1950," and "Compilation of Records of Surface Waters of the United States, October 1950 to September 1960." Data for Pennsylvania are published in Parts 1, 3, and 4. Data on chemical quality, temperature, and suspended sediment for the 1941-70 water years were published annually under the title "Quality of Surface Waters of the United States," and ground-water levels for the 1935-74 water years were published annually under the title "Ground-Water Levels in the United States." The above mentioned Water-Supply Papers may be consulted in the libraries of the principal cities of the United States and may be purchased from the U.S. Geological Survey, Information Services, Box 25286, Denver, CO 80225. Information for ordering specific reports may be obtained from the Pennsylvania District Office at the address on the back of the title page or by phoning the Scientific and Technical Products Section at (717) 730-6940. Information on the availability of unpublished data or statistical analyses may be obtained from the District Information Specialist by telephone at (717) 730-6916 or by FAX at (717) 730-6997.

Water Data Report↗
USGS1963

Fluvial sediments a summary of source, transportation, deposition, and measurement of sediment discharge

This paper presents a broad but undetailed picture of fluvial sediments in streams, reservoirs, and lakes and includes a discussion of the processes involved in the movement of sediment by flowing water. Sediment is fragmental material that originates from the chemical or physical disintegration of rocks. The disintegration products may have many different shapes and may range in size from large boulders to colloidal particles. In general, they retain about the same mineral composition as the parent rocks. Rock fragments become fluvial sediment when they are entrained in a stream of water. The entrainment may occur as sheet erosion from land surfaces, particularly for the fine particles, or as channel erosion after the surface runoff has accumulated in streams. Fluvial sediments move in streams as bedload (particles moving within a few particle diameters of the streambed) or as suspended sediment in the turbulent flow. The discharge of bedload varies with several factors, which may include particle size and a type of effective shear on the surface of the streambed. The discharge of suspended sediment depends partly on concentration of moving sediment near the streambed and hence on discharge of bedload. However, the concentration of fine sediment near the streambed varies widely, even for equal flows, and, therefore, the discharge of fine sediment normally cannot be computed theoretically. The discharge of suspended sediment also depends on velocity, turbulence, depth of flow, and fall velocity of the particles. In general, the coarse sediment transported by a stream moves intermittently and is discharged at a rate that depends on properties of the flow and of the sediment. If an ample supply of coarse sediment is available at the surface of the streambed, the discharge of the coarse sediment, such as sand, can be roughly computed from properties of the available sediment and of the flow. On the other hand, much of the fine sediment in a stream usually moves nearly continuously at about the velocity of the flow, and even low flows can transport large amounts of fine sediment. Hence, the discharge of fine sediments, being largely dependent on the availability of fine sediment upstream rather than on the properties of the sediment and of the flow at a cross section, can seldom be computed from properties, other than concentrations based directly on samples, that can be observed at the cross section. Sediment particles continually change their positions in the flow; some fall to the streambed, and others are removed from the bed. Sediment deposits form locally or over large areas if the volume rate at which particles settle to the bed exceeds the volume rate at which particles are removed from the bed. In general, large particles are deposited more readily than small particles, whether the point of deposition is behind a rock, on a flood plain, within a stream channel, or at the entrance to a reservoir, a lake, or the ocean. Most samplers used for sediment observations collect a water-sediment mixture from the water surface to within a few tenths of a foot of the streambed. They thus sample most of the suspended sediment, especially if the flow is deep or if the sediment is mostly fine; but they exclude the bedload and some of the suspended sediment in a layer near the streambed where the suspended-sediment concentrations are highest. Measured sediment discharges are usually based on concentrations that are averages of several individual sediment samples for a cross section. If enough average concentrations for a cross section have been determined, the measured sediment discharge can be computed by interpolating sediment concentrations between sampling times. If only occasional samples were collected, an average relation between sediment discharge and flow can be used with a flow-duration curve to compute roughly the average or the total sediment discharges for any periods of time for which the flow-duration c

Bulletin↗
USGS1996

Water Resources Data, Nevada, Water Year 1995

Water resources data published herein for the 1995 water year comprise the following records: Water discharge for 178 gaging stations on streams, canals and drains. Discharge for 113 peak-flow stations and miscellaneous sites, and 46 springs. Stage and contents for 22 lakes and reservoirs. Water-quality data for 171 stream, lake, canal, spring, precipitation, and drain sites, and 111 wells. Precipitation totals for 58 stations. Water levels for 17 continuous record wells, and 1022 observation wells. Additional water-data, collected at various sites that are not part of the systematic data-collection program, are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Nevada.

Nevada↗
USGS1982

Water-quality assessment of White River between Lake Sequoyah and Beaver Reservoir, Washington County, Arkansas

The Arkansas Department of Pollution Control and Ecology and U.S. Geological Survey conducted a water quality assessment be made of the White River and, that a steady-state digital model be calibrated and used as a tool for simulating changes in nutrient loading. The city of Fayetteville 's wastewater-treatment plant is the only point-source discharger of waste effluent to the river. Data collected during synoptic surveys downstream from the wastewater-treatment plan indicate that temperature, dissolved oxygen, dissolved solids, un-ionized ammonia, total phosphorus, and floating solids and depositable materials did not meet Arkansas stream standards. Nutrient loadings below the treatment plant result in dissolved oxygen concentrations as low as 0.0 milligrams per liter. Biological surveys found low macroinvertebrate organism diversity and numerous dead fish. Computed dissolved oxygen deficits indicate that benthic demands are the most significant oxygen sinks in the river downstream from the wastewater-treatment plant. Benthic oxygen demands range from 2.8 to 11.0 grams per meter squared per day. Model projections indicate that for 7-day, 10-year low-flow conditions and water temperature of 29 degrees Celsius, daily average dissolved oxygen concentrations of 6.0 milligrams per liter can be maintained downstream from the wastewater-treatment plant if effluent concentrations of ultimate carbonaceous biochemical oxygen demand and ammonia nitrogen are 7.5 (5.0 5-day demand) and 2 milligrams per liter respectively. Model sensitivity analysis indicate that dissolved oxygen concentrations were most sensitive to changes in stream temperature. (USGS)

Water-Resources Investigations Report↗
USGS2006

Complementary population dynamics of exotic and native Daphnia in North American reservoir communities

During its invasion of North America, the exotic Daphnia lumholtzi has rapidly colonized numerous reservoirs, natural lakes, and large rivers. In the current study, we examine the overlap between D. lumholtzi and native Daphnia species through analysis of two data sets: co-occurrence in reservoirs of the south-central United States and population dynamics in one reservoir. In 171 reservoirs and oxbow lakes, D. lumholtzi was among the most prevalent species and its distribution was independent of other Daphnia species. Over a 28-month period in Stockton Lake, Missouri, D. lumholtzi was abundant only in late summer, a period when the epilimnion was warm (25-30??C) and cyanobacteria were common. Native Daphnia (D. mendotae, D. parvula, and D. retrocurva) complemented this pattern, being generally rare in summer and most abundant during winter and spring. Peak densities and average fecundities of native Daphnia during the cooler months were typically greater than densities and fecundities of D. lumholtzi in summer. The complementary population dynamics between native and exotic species may be significant for the food webs in warm reservoirs, with D. lumholtzi providing another food resource when the abundance of large zooplankton is ordinarily low. ?? 2006 E. Schweizerbart'sche Verlagsbuchhandlung.

Archiv fur Hydrobiologie↗
USGS2017

Season, molt, and body size influence mercury concentrations in grebes

We studied seasonal and physiological influences on mercury concentrations in western grebes (Aechmophorus occidentalis) and Clark's grebes (A. occidentalis) across 29 lakes and reservoirs in California, USA. Additionally, at three of these lakes, we conducted a time series study, in which we repeatedly sampled grebe blood mercury concentrations during the spring, summer, and early fall. Grebe blood mercury concentrations were higher among males (0.61 ± 0.12 μg/g ww) than females (0.52 ± 0.10 μg/g ww), higher among Clark's grebes (0.58 ± 0.12 μg/g ww) than western grebes (0.51 ± 0.10 μg/g ww), and exhibited a strong seasonal pattern (decreasing by 60% from spring to fall). Grebe blood THg concentrations exhibited a shallow, inverse U-shaped pattern with body size, and was lowest among the smallest and largest grebes. Further, the relationship between grebe blood mercury concentrations and wing primary feather molt exhibited a shallow U-shaped pattern, where mercury concentrations were highest among birds that had not yet begun molting, decreased approximately 24% between pre-molt and late molt, and increased approximately 19% from late molt to post-molt. Because grebes did not begin molting until mid-summer, lower grebe blood mercury concentrations observed in late summer and early fall were consistent with the onset of primary feather molt. However, because sampling date was a much stronger predictor of grebe mercury concentrations than molt, other seasonally changing environmental factors likely played a larger role than molt in the seasonal variation in grebe mercury concentrations. In the time series study, we found that seasonal trends in grebe mercury concentrations were not consistent among lakes, indicating that lake-specific variation in mercury dynamics influence the overall seasonal decline in grebe blood mercury concentrations. These results highlight the importance of accounting for sampling date, as well as ecological processes that may influence mercury concentrations, when developing monitoring programs to assess site-specific exposure risk of mercury to wildlife.

California↗
USGS2019

Stochastic model for simulating Souris River Basin regulated streamflow upstream from Minot, North Dakota

The Souris River Basin is a 24,000 square-mile basin in the Provinces of Saskatchewan and Manitoba in Canada, and the State of North Dakota in the United States. Above-average snowpack during the winter of 2010–11, along with record-setting rains in May and June of 2011, led to record flooding that caused extensive damage to Minot, North Dakota, and numerous smaller communities in Saskatchewan, Manitoba, and North Dakota. As a result, the International Souris River Board created the Souris River Flood Task Force to evaluate potential reservoir operation changes and flood control measures to manage future floods and droughts. Part of this evaluation involved identifying a need for a stochastic streamflow model to estimate the likelihood of future flooding or drought. A stochastic natural (unregulated) streamflow simulation model described in a previous report was built upon in this report to include the effects of regulation of four reservoirs (Rafferty, Alameda, and Boundary Reservoirs and Lake Darling) and their operation guidelines. First, a regulated reservoir storage/streamflow routing model was developed and calibrated from when all four reservoirs were in operation until the end of the reconstructed natural streamflow dataset provided by the U.S. Army Corps of Engineers (1992–2011). The regulated reservoir storage/streamflow routing model then was combined with the stochastic natural (unregulated) streamflow model to provide a stochastic regulated streamflow simulation model for the Souris River Basin upstream from Minot, North Dakota. The stochastic regulated streamflow simulation model was used to estimate regulated flood frequency curves, which are useful for feasibility and design of critical structures such as levees or bridges. Three potential future climatic conditions were considered in this analysis: condition A (wet equilibrium), representing wet (similar to 1970–2017) climatic conditions; condition B (transition), representing transition from wet to dry (similar to 1912–69) climatic conditions; and condition C (dry equilibrium), representing dry climatic conditions. Comparison of the estimated flood frequency curves for regulated flow among the three climatic conditions indicated large differences in flood magnitudes for the more extreme (1-percent or less) annual exceedance probabilities. The estimated 0.2-percent annual exceedance probability flood magnitude for the Souris River upstream from Minot, N. Dak., was 29,300 cubic feet per second for condition A (wet equilibrium), compared to 14,800 cubic feet per second for condition C (dry equilibrium). For comparison, the recorded peak streamflow for 2011 for the Souris River upstream from Minot, N. Dak., was 26,900 cubic feet per second. Although it is not possible to predict how long the current (1970–2017) wet climatic conditions may persist, flood risk for at least the next 25 years, or until about 2040, may be represented best by climatic condition A.

North Dakota↗
USGS2002

Water resources data, Nevada, water year 2001

Water resources data published herein for the 2001 water year comprise the following records: o Water discharge for 168 gaging stations on streams, canals and drains. o Discharge for 146 peak-flow stations and miscellaneous sites, and 14 springs. o Stage and contents for 20 lakes and reservoirs. o Water-quality data for 95 stream, lake, canal, spring, and drain sites, and 53 wells. o Water levels for 97 primary/continuous record wells, and 654 secondary observation wells. o Water withdrawals for 12 wells o Precipitation totals for 31 stations. Additional water-data, collected at various sites that are not part of the systematic data-collection program, are published as miscellaneous measurements. These data represent that part of the National Water Information System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Nevada.

Nevada↗
USGS1998

Water resources data, Nevada, water year 1997

Water resources data published herein for the 1997 water year comprise the following records: o Water discharge for 173 gaging stations on streams, canals and drains. o Discharge for 170 peak-flow stations and miscellaneous sites, and 6 springs. o Stage and contents for 21 lakes and reservoirs. o Water-quality data for 64 stream, lake, canal, spring, and drain sites, and 115 wells. o Precipitation totals for 36 stations. o Water levels for 34 continuous record wells, and 924 observation wells. o Water withdrawals for 14 wells Additional water-data, collected at various sites that are not part of the systematic data-collection program, are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Nevada.

Nevada↗
USGS2009

Rehabilitation of Delavan Lake, Wisconsin

A comprehensive rehabilitation plan was developed and implemented to shift Delavan Lake , Wisconsin, from a hypereutrophic to a mesotrophic condition. The plan was threefold: (1) reduce external phosphorus (P) loading by applying Best Management Practices in the watershed, enhance an existing wetland, and short-circuit the inflows through the lake , (2) reduce internal P loading by treating the sediments with alum and removing carp, and (3) rehabilitate the fishery by removing carp and bigmouth buffalo and adding piscivores (biomanipulation). The first and second parts of the plan met with only limited success. With only minor reductions in internal and external P loading, P concentrations in the lake returned to near pre-treatment concentrations. The intensive biomanipulation and resulting trophic cascade (increased piscivores, decreased planktivores, increased large zooplankton populations, and reduced phytoplankton populations) eliminated most of the original problems in the lake (blue-green algal blooms and limited water clarity). However, now there is extensive macrophyte growth and abundant filamentous algae. Without significantly reducing the sources of the problems (high P loading) in Delavan Lake , the increased water clarity may not last. With an improved understanding of the individual components of this rehabilitation program, better future management plans can be developed for Delavan Lake and other lakes and reservoirs with similar eutrophication problems.

Wisconsin↗
USGS1982

Water resources data, Louisiana, water year 1982: Volume 1. Central and northern Louisiana

Water resources data for the 1982 water year for Louisiana consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. This report, in two volumes, contains records for water discharge at 77 gaging stations (including stage for 65 of these stations); stage only for 64 gaging stations and 9 lakes; contents for 1 reservoir; water quality for 104 surface-water stations (including 31gaging stations) 20 miscellaneous sites, and 8 lakes, and 223 wells; and water levels for 526 observation wells. Also included are data for 209 cres-stage and flood-profile partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program, and are published as miscellaneous measurements. Records for a few pertinent stations in bordering states are also included in this report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Louisiana.

Louisiana↗
USGS2011

Hypolimnetic dissolved-oxygen dynamics within selected White River reservoirs, northern Arkansas-southern Missouri, 1974-2008

Dissolved oxygen is a critical constituent in reservoirs and lakes because it is essential for metabolism by all aerobic aquatic organisms. In general, hypolimnetic temperature and dissolved-oxygen concentrations vary from summer to summer in reservoirs, more so than in natural lakes, largely in response to the magnitude of flow into and release out of the water body. Because eutrophication is often defined as the acceleration of biological productivity resulting from increased nutrient and organic loading, hypolimnetic oxygen consumption rates or deficits often provide a useful tool in analyzing temporal changes in water quality. This report updates a previous report that evaluated hypolimnetic dissolved-oxygen dynamics for a 21-year record (1974-94) in Beaver, Table Rock, Bull Shoals, and Norfork Lakes, as well as analyzed the record for Greers Ferry Lake. Beginning in 1974, vertical profiles of temperature and dissolved-oxygen concentrations generally were collected monthly from March through December at sites near the dam of each reservoir. The rate of change in the amount of dissolved oxygen present below a given depth at the beginning and end of the thermal stratification period is referred to as the areal hypolimnetic oxygen deficit. Areal hypolimnetic oxygen deficit was normalized for each reservoir based on seasonal flushing rate between April 15 and October 31 to adjust for wet year and dry year variability. Annual cycles in thermal stratification within Beaver, Table Rock, Bull Shoals, Norfork, and Greers Ferry Lakes exhibited typical monomictic (one extended turnover period per year) characteristics. Flow dynamics drive reservoir processes and need to be considered when analyzing areal hypolimnetic oxygen deficit rates. A nonparametric, locally weighted scatter plot smooth line describes the relation between areal hypolimnetic oxygen deficit and seasonal flushing rates, without assuming linearity or normality of the residuals. The results in this report are consistent with earlier findings that oxygen deficit rates and flushing-rate adjusted areal hypolimnetic oxygen deficit in Beaver and Table Rock Lakes were decreasing between 1974 and 1994. The additional data (1995-2008) demonstrate that the decline in flushing-rate adjusted areal hypolimnetic oxygen deficit in Beaver Lake has continued, whereas that in Table Rock Lake has flattened out in recent years. The additional data demonstrate the flushing-rate adjusted areal hypolimnetic oxygen deficit in Bull Shoals and Norfork Lakes have declined since 1995 (improved water quality), which was not indicated in earlier studies, while Greers Ferry Lake showed little net change over the period of record. Given the amount of data (35 years) for these reservoirs, developing an equation or model to predict areal hypolimnetic oxygen deficit and, therefore, areal hypolimnetic oxygen content, on any given day during future stratification seasons may be useful for reservoir managers.

Missouri;Arkansas↗
USGS1979

Water resources data for Louisiana, water year 1979, volume 1. Central and northern Louisiana

Water resources data for the 1979 water year for Louisiana consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. This report, in three volumes, contains records for water discharge at 78 gaging stations (including stage for 72 of these stations); stage only for 42 gaging stations and 10 lakes; contents for 1 reservoir; water quality for 146 surface-water stations (including 22 gaging stations, 52 miscellaneous sites, and 24 lakes), and 335 wells; and water levels for 685 observation wells. Also included are data for 212 crest-stage and flood-profile partial record stations. Additional water data were collected at various sites not involved in the systematic data-collection program, and are published as miscellaneous measurements. Records for a few pertinent stations in bordering States are also included in this report. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Louisiana.

Louisiana↗