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At least 325 records · Page 18Linked to original sources
USGS2005

Estimation of stream salamander (Plethodontidae, Desmognathinae and Plethodontinae) populations in Shenandoah National Park, Virginia, USA

Stream salamanders in the family Plethodontidae constitute a large biomass in and near headwater streams in the eastern United States and are promising indicators of stream ecosystem health. Many studies of stream salamanders have relied on population indices based on counts rather than population estimates based on techniques such as capture-recapture and removal. Application of estimation procedures allows the calculation of detection probabilities (the proportion of total animals present that are detected during a survey) and their associated sampling error, and may be essential for determining salamander population sizes and trends. In 1999, we conducted capture-recapture and removal population estimation methods for Desmognathus salamanders at six streams in Shenandoah National Park, Virginia, USA. Removal sampling appeared more efficient and detection probabilities from removal data were higher than those from capture-recapture. During 2001-2004, we used removal estimation at eight streams in the park to assess the usefulness of this technique for long-term monitoring of stream salamanders. Removal detection probabilities ranged from 0.39 to 0.96 for Desmognathus, 0.27 to 0.89 for Eurycea and 0.27 to 0.75 for northern spring (Gyrinophilus porphyriticus) and northern red (Pseudotriton ruber) salamanders across stream transects. Detection probabilities did not differ across years for Desmognathus and Eurycea, but did differ among streams for Desmognathus. Population estimates of Desmognathus decreased between 2001-2002 and 2003-2004 which may be related to changes in stream flow conditions. Removal-based procedures may be a feasible approach for population estimation of salamanders, but field methods should be designed to meet the assumptions of the sampling procedures. New approaches to estimating stream salamander populations are discussed.

Alytes↗
USGS2002

Assessing mine drainage pH from the color and spectral reflectance of chemical precipitates

The pH of mine impacted waters was estimated from the spectral reflectance of resident sediments composed mostly of chemical precipitates. Mine drainage sediments were collected from sites in the Anthracite Region of eastern Pennsylvania, representing acid to near neutral pH. Sediments occurring in acidic waters contained primarily schwertmannite and goethite while near neutral waters produced ferrihydrite. The minerals comprising the sediments occurring at each pH mode were spectrally separable. Spectral angle difference mapping was used to correlate sediment color with stream water pH (r2=0.76). Band-center and band-depth analysis of spectral absorption features were also used to discriminate ferrihydrite and goethite and/or schwertmannite by analyzing the 4T1??? 6A1 crystal field transition (900-1000 nm). The presence of these minerals accurately predicted stream water pH (r2=0.87) and provided a qualitative estimate of dissolved SO4 concentrations. Spectral analysis results were used to analyze airborne digital multispectral video (DMSV) imagery for several sites in the region. The high spatial resolution of the DMSV sensor allowed for precise mapping of the mine drainage sediments. The results from this study indicate that airborne and space-borne imaging spectrometers may be used to accurately classify streams impacted by acid vs. neutral-to-alkaline mine drainage after appropriate spectral libraries are developed.

Pennsylvania↗
USGS1986

Traveltime and longitudinal dispersion in Illinois streams

Twenty-seven measurements of traveltime and longitudinal dispersion in 10 Illinois streams made from 1975 to 1982 provide data needed for estimating traveltime of peak concentration of a conservative solute, traveltime of the leading edge of a solute cloud, peak concentration resulting from injection of a given quantity of solute, and passage time of solute past a given point on a stream. These four variables can be estimated graphically for each stream from distance of travel and either discharge at the downstream end of the reach or flow-duration frequency. From equations developed from field measurements, the traveltime and dispersion characteristics also can be estimated for other unregulated streams in Illinois that have drainage areas less than about 1,500 square miles. For unmeasured streams, traveltime of peak concentration and of the leading edge of the cloud are related to discharge at the downstream end of the reach and to distance of travel. For both measured and unmeasured streams, peak concentration and passage time are best estimated from the relation of each to traveltime. In measured streams, dispersion efficiency is greater than that predicted by Fickian diffusion theory. The rate of decrease in peak concentration with traveltime is about equal to the rate of increase in passage time. Average velocity in a stream reach, given by the velocity of the center of solute mass in that reach, can be estimated from an equation developed from measured values. The equation relates average reach velocity to discharge at the downstream end of the reach. Average reach velocities computed for 9 of the 10 streams from available equations that are based on hydraulic-geometry relations are high relative to measured values. The estimating equation developed from measured velocities provides estimates of average reach velocity that are closer to measured velocities than are those computed using equations developed from hydraulic-geometry relations.

Illinois↗
USGS2008

Heat as a tracer to determine streambed water exchanges

This work reviews the use of heat as a tracer of shallow groundwater movement and describes current temperature-based approaches for estimating streambed water exchanges. Four common hydrologic conditions in stream channels are graphically depicted with the expected underlying streambed thermal responses, and techniques are discussed for installing and monitoring temperature and stage equipment for a range of hydrological environments. These techniques are divided into direct-measurement techniques in streams and streambeds, groundwater techniques relying on traditional observation wells, and remote sensing and other large-scale advanced temperature-acquisition techniques. A review of relevant literature suggests researchers often graphically visualize temperature data to enhance conceptual models of heat and water flow in the near-stream environment and to determine site-specific approaches of data analysis. Common visualizations of stream and streambed temperature patterns include thermographs, temperature envelopes, and one-, two-, and three-dimensional temperature contour plots. Heat and water transport governing equations are presented for the case of transport in streambeds, followed by methods of streambed data analysis, including simple heat-pulse arrival time and heat-loss procedures, analytical and time series solutions, and heat and water transport simulation models. A series of applications of these methods are presented for a variety of stream settings ranging from arid to continental climates. Progressive successes to quantify both streambed fluxes and the spatial extent of streambeds indicate heat-tracing tools help define the streambed as a spatially distinct field (analogous to soil science), rather than simply the lower boundary in stream research or an amorphous zone beneath the stream channel.

Water Resources Research↗
USGS2007

Factors controlling nitrogen release from two forested catchments with contrasting hydrochemical responses

Quantifying biogeochemical cycles of nitrogen (N) and the associated fluxes to surface waters remains challenging, given the need to deal with spatial and temporal variability and to characterize complex and heterogeneous landscapes. We focused our study on catchments S14 and S15 located in the Adirondack Mountains of New York, USA, which have similar topographic and hydrologic characteristics but contrasting stream nitrate ($\hbox{NO}_{3}^{-}$) concentrations. We characterized the mechanisms by which $\hbox{NO}_{3}^{-}$ reaches the streams during hydrological events in these catchments, aiming to reconcile our field data with our conceptual model of factors that regulate nutrient exports from forested catchments. Combined hydrometric, chemical and isotopic (δ$\hbox{NO}_{3}^{-}$) data showed that the relative contributions of both soil and ground water sources were similar between the two catchments. Temporal patterns of stream chemistry were markedly different between S14 and S15, however, because the water sources in the two catchments have different solute concentrations. During late summer/fall, the largest source of $\hbox{NO}_{3}^{-}$ in S14 was till groundwater, whereas shallow soil was the largest $\hbox{NO}_{3}^{-}$ source in S15. $\hbox{NO}_{3}^{-}$ concentrations in surface water decreased in S14, whereas they increased in S15 because an increasing proportion of stream flow was derived from shallow soil sources. During snowmelt, the largest sources of $\hbox{NO}_{3}^{-}$were in the near‐surface soil in both catchments. Concentrations of $\hbox{NO}_{3}^{-}$ increased as stream discharge increased and usually peaked before peak discharge, when shallow soil water sources made the largest contribution to stream discharge. The timing of peaks in stream $\hbox{NO}_{3}^{-}$concentrations was affected by antecedent moisture conditions. By elucidating the factors that affect sources and transport of N, including differences in the soil nutrient cycling and hydrological characteristics of S14 and S15, this study contributes to the overall conceptualization of $\hbox{NO}_{3}^{-}$ release from temperate forested catchments.

Hydrological Processes↗
USGS2017

Measuring fish and their physical habitats: Versatile 2D and 3D video techniques with user-friendly software

Applications of video in fisheries research range from simple biodiversity surveys to three-dimensional (3D) measurement of complex swimming, schooling, feeding, and territorial behaviors. However, researchers lack a transparently developed, easy-to-use, general purpose tool for 3D video measurement and event logging. Thus, we developed a new measurement system, with freely available, user-friendly software, easily obtained hardware, and flexible underlying mathematical methods capable of high precision and accuracy. The software, VidSync, allows users to efficiently record, organize, and navigate complex 2D or 3D measurements of fish and their physical habitats. Laboratory tests showed submillimetre accuracy in length measurements of 50.8 mm targets at close range, with increasing errors (mostly <1%) at longer range and for longer targets. A field test on juvenile Chinook salmon ( Oncorhynchus tshawytscha ) feeding behavior in Alaska streams found that individuals within aggregations avoided the immediate proximity of their competitors, out to a distance of 1.0 to 2.9 body lengths. This system makes 3D video measurement a practical tool for laboratory and field studies of aquatic or terrestrial animal behavior and ecology.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1946

Artificial recharge of productive ground-water aquifers in New Jersey

Artificial recharge by water spreading is practiced in several places in New Jersey. Rates of recharge ranging from 3,000 to 125,000 gallons per acre per day have been measured at the Perth Amboy Water Works, where artificial recharge of the Old Bridge sand, of upper Cretaceous age, has been practiced for more than 40 years. At the Duhernal development, which also draws from the Old Bridge sand, four or five million gallons daily is now derived from artificial recharge. This rate will probably increase with further lowering of the water table near the lake. For many years the Princeton Water Company has pumped water from a stream for recharging the Stockton sandstone, of Triassic age. The Lake Mohawk-Sparta Water Company spreads water underground by means of covered, gravel-filled ditches to recharge a shallow aquifer in its well field. The City of East Orange spreads the water from several small streams over parts of the intake area of the Quaternary beds supplying its wells. The estimated total recharge there is about two million gallons daily. Closely related to artificial recharge are those instances wherein well sites are chosen to take advantage of potential recharge from existing bodies of surface water. At the Borough of Manville no water spreading operations are conducted, but about three quarters of the water from its wells is derived by recharge from the Raritan River. The silting of water spreading areas may impair their effectiveness considerably. In some instances the growth of aquatic vegetation seems to reduce the ill effects of silting.

New Jersey↗
USGS2012

Tectonic influences on the preservation of marine terraces: Old and new evidence from Santa Catalina Island, California

The California Channel Islands contain some of the best geologic records of past climate and sea-level changes, recorded in uplifted, fossil-bearing marine terrace deposits. Among the eight California Channel Islands and the nearby Palos Verdes Hills, only Santa Catalina Island does not exhibit prominent emergent marine terraces, though the same terrace-forming processes that acted on the other Channel Islands must also have occurred on Santa Catalina. We re-evaluated previous researchers' field evidence and examined new topographic, bathymetric, and stream-profile data in order to find possible explanations for the lack of obvious marine terrace landforms or deposits on the island today. The most likely explanation is associated with the island's unresolved tectonic history, with evidence for both recent uplift and subsidence being offered by different researchers. Bathymetric and seismic reflection data indicate the presence of submerged terrace-like landforms from a few meters below present sea level to depths far exceeding that of the lowest glacial lowstand, suggesting that the Catalina Island block may have subsided, submerging marine terraces that would have formed in the late Quaternary. Similar submerged marine terrace landforms exist offshore of all of the other California Channel Islands, including some at anomalously great depths, but late Quaternary uplift is well documented on those islands. Therefore, such submarine features must be more thoroughly investigated and adequately explained before they can be accepted as definitive evidence of subsidence. Nevertheless, the striking similarity of the terrace-like features around Santa Catalina Island to those surrounding the other, uplifting, Channel Islands prompted us to investigate other lines of evidence of tectonic activity, such as stream profile data. Recent uplift is suggested by disequilibrium stream profiles on the western side of the island, including nickpoints and profile convexities. Rapid uplift is also indicated by the island's highly dissected, steep topography and abundant landslides. A likely cause of uplift is a restraining bend in the offshore Catalina strike-slip fault. Our analysis suggests that Santa Catalina Island has recently experienced, and may still be experiencing, relatively rapid uplift, causing intense landscape rejuvenation that removed nearly all traces of marine terraces by erosion. A similar research approach, incorporating submarine as well as subaerial geomorphic data, could be applied to many tectonically active coastlines in which a marine terrace record appears to be missing.

California↗
USGS1996

Nitrate in groundwater and water sources used by riparian trees in an agricultural watershed: A chemical and isotopic investigation in southern Minnesota

This study evaluates processes that affect nitrate concentrations in groundwater beneath riparian zones in an agricultural watershed. Nitrate pathways in the upper 2 m of groundwater were investigated beneath wooded and grass-shrub riparian zones next to cultivated fields. Because trees can be important components of the overall nitrate pathway in wooded riparian zones, water sources used by riparian trees and possible effects of trees on nitrate concentrations in groundwater were also investigated. Average nitrate concentrations in shallow groundwater beneath the cultivated fields were 5.5 mg/L upgradient of the wooded riparian zone and 3.5 mg/L upgradient of the grass-shrub zone. Shallow groundwater beneath the fields passed through the riparian zones and discharged into streams that had average nitrate concentrations of 8.5 mg/L (as N). Lateral variations of δD values in groundwater showed that mixing among different water sources occurred beneath the riparian zones. In the wooded riparian zone, nitrate concentrations in shallow groundwater were diluted by upwelling, nitrate-poor, deep groundwater. Upwelling deep groundwater contained ammonium with a δ 15 N of 5‰ that upon nitrification and mixing with nitrate in shallow groundwater caused nitrate δ 15 N values in shallow groundwater to decrease by as much as 19.5‰. Stream water penetrated laterally beneath the wooded riparian zone as far as 19 m from the stream's edge and beneath the grass-shrub zone as far as 27 m from the stream's edge. Nitrate concentrations in shallow groundwater immediately upgradient of where it mixed with stream water averaged 0.4 mg/L in the wooded riparian zone and 0.8 mg/L near the grass-shrub riparian zone. Nitrate concentrations increased toward the streams because of mixing with nitrate-rich stream water. Because nitrate concentrations were larger in stream water than shallow groundwater, concentrated nitrate in the streams cannot have come from shallow groundwater at these sites. Water sources of riparian trees were identified by comparing δD values of sap water, soil water, groundwater, and stream water. Soil water was the main water source for trees in the outer 4 to 6 m of one part of the wooded riparian zone and outer 10 m of another part. Groundwater was a significant water source for trees closer to the streams where the water table was less than about 2.1 to 2.7 m below the surface. No evidence was found in the nitrate concentration profiles that trees close to the streams that took up groundwater through their roots also took up nitrate from groundwater. The lack of such evidence is attributed to the nitrate concentration profiles being insufficiently sensitive indicators of nitrate removal by trees.

Minnesota↗
USGS2025

Evaluating episodic sediment deposition zones in freshwater mussel habitats across Missouri, USA

Point-source sedimentation, such as spills from construction-related activities, can introduce substantial sediments into streams in the short term, potentially leading to mussel burial. To estimate downstream areas where freshwater mussels might face threats from sediment burial within the mussel habitats of Missouri streams and rivers, we examined 49 reaches where both field measurements and gaging data are available. We established empirical relationships for three flow classes to represent general flow conditions of all reaches. Using these hydraulic data, we employed a Lagrangian particle tracking model to simulate sediment transport under each condition, employing two sediment size ranges covering very fine sands to small gravels, resulting in 72 simulated scenarios. The model results indicate that sediments with diameters exceeding a critical value, ranging from 0.041 to 1.975 mm for varying velocities (ranging from 0.124 to 2.191 m/s) and depths (ranging from 1 to 12 m), settle in downstream locations. Potential settling sites span from tens to hundreds of meters downstream. The mode, median, and mean of sediment distribution generally fall within the range of 10–200 m based on particle count, while these values typically range from 1 to 100 m based on sediment mass.

Missouri↗
USGS2022

Ephemeral stream network extraction from lidar-derived elevation and topographic attributes in urban and forested landscapes

Under-representations of headwater channels in digital stream networks can result in uncertainty in the magnitude of headwater habitat loss, stream burial, and watershed function. Increased availability of high-resolution (<2 m) elevation data makes the delineation of headwater channels more attainable. In this study, elevation data derived from light detection and ranging was used to predict ephemeral stream networks across a forested and urban watershed in the Maryland Piedmont USA. A method was developed using topographic openness (TO) and wetness index to remotely predict the extent of stream networks. Predicted networks were compared against a comprehensive field survey of the ephemeral network in each watershed to evaluate performance. Comparisons were also made to the U.S. Geological Survey National Hydrography Dataset (NHD) and a flow accumulation approach where a single drainage area threshold defined channel initiation. Although the NHD and flow accumulation methods resulted in low commission errors, omission errors were highest in these networks. The TO-based networks detected a larger number of ephemeral channels, but with higher commission error. Small ephemeral channels with less defined banks or originating at groundwater seeps were difficult to detect in all methods. Comparisons between forested and urban watersheds also highlight the difficulty of identifying headwater channels using topographic attributes in human-modified landscapes.

Maryland↗
USGS2001

Sources of salinity near a coal mine spoil pile, north-central Colorado

A small (1 km 2 ) salt-affected stream drainage on the High Plains north of Denver, Colorado was sampled to determine the near-surface dispersion of soluble salts and metals from low-sulfur coal mining waste (spoil). Surface waters collected along the 0.8-km stream reach, and aqueous leachates of spoil and naturally saline local soil, were analyzed for chemical constituents and sulfur isotopes. In this semiarid setting with abundant carbonate-bearing surficial sediments, the limited, mildly acidic drainage from the spoil pile is quickly neutralized, restricting the mobility of many elements. However, some spoil-derived constituents were clearly traceable within the upper 0.4 km of the stream reach. Spoil leachates and surface water near the spoil pile have distinctive compositions of major anions and cations, and elevated levels of dissolved nitrate compared with downstream waters. Spoil-derived sulfate was traceable because it has generally positive values of δ 34 S that contrasted with generally negative values of δ 34 S in soil leachates and evaporite salts from the surrounding area. Spatial–chemical sampling of surface water showed an abrupt increase in dissolved U, Se, B, Li, and Mn in the lower 0.4 km of the stream reach where shallow ground water from surrounding irrigated fields contributed to surface flow. The downstream evolution of surface water chemistry and sulfur isotopic composition is consistent with mixing between spoil-affected upstream water and irrigation-return water. The methods described should be applicable at other sites in similar settings where the environmental effect of low-sulfur coal mining waste must be assessed and where access to samples of shallow ground water is limited.

Colorado↗
USGS1979

Potential hydrologic effects of peat mining in the Red Lake Peatlands, north-central Minnesota— A project plan

Peat is being considered for fuel in Minnesota. This study will investigate the potential effects of large-scale surface mining of peat on the hydrology and water quality of Upper Red Lake and the Tamarac River. The major aspects of the study are the characterization of the surface-water and groundwater hydrology and water quality, including the trace-metal content of the peat. Data will be collected to construct two- and three-dimensional digital models to simulate the movement of ground water and its relation to surface water in the peatlands, streams, and lakes. After the model is calibrated with field data, it will be used to evaluate the effect of mining peat on the hydrology and water quality of the Upper Red Lake and Tamarac River.

Minnesota↗
USGS2020

Quality of data from the U.S. Geological Survey National Water Quality Network for water years 2013–17

Water samples from 122 sites in the U.S. Geological Survey National Water Quality Network were collected in 2013–17 to document ambient water-quality conditions in surface water of the United States and to determine status and trends of loads and concentrations for nutrients, contaminants, and sediment to estuaries and streams. Quality-control (QC) samples collected in the field with environmental samples were combined with QC samples from laboratory processing to provide information and documentation about the quality of the environmental data. Quality assurance for inorganic and organic compounds assessed in the National Water Quality Network includes collection of field blanks to determine contamination bias and field replicates to determine variability bias. No contamination bias was found for 6 of the 13 nutrient compounds analyzed, and some potential contamination bias for some years was found for the other 7 nutrient compounds. Contamination bias was not found for carbon compounds or ultraviolet-absorbance measurements and was not assessed for sediment. All major ions and trace elements except potassium and lithium showed moderate contamination bias for at least 1 water year; generally, this bias was not at environmentally relevant concentrations. All compounds in the nutrient, carbon, and sediment group and in the major ions and trace elements group had low variability both in detection frequency and in concentration. Exceptions to this low variability were total particulate inorganic carbon and sediment for 2015, both of which are particulate substances with intrinsically high sampling variability. The risk of contamination bias for pesticides in National Water Quality Network samples was low, as indicated by very few detections in field blanks. Sixteen pesticide compounds showed potential contamination bias based on unexpected detections in third-party blind spikes (false-positive results for compounds that are not included in the spike mixture of a sample, where the identity as a QC sample is unknown to the analyst), and 47 different compounds (out of 225 pesticide compounds) showed potential contamination bias from laboratory blanks. However, when timing and relative magnitudes of detections in blank samples, environmental samples, and benchmark concentrations are considered, most of this potential contamination is not relevant to interpretation of published pesticide results. Overall variability in detection frequency for pesticides from field replicates was low or moderate. Also based on field replicates, 55 pesticides had overall high variability in concentrations for at least 1 water year, although these assessments likely overestimate high variability. At least 1 QC issue was found for 87 pesticides; however, most of the QC issues had no or little effect on the interpretation of environmental results because the U.S. Geological Survey National Water Quality Laboratory addressed the QC issue before publishing the environmental results, environmental results were almost entirely nondetections, concentrations of environmental results were higher than potential contamination bias, or benchmark concentrations were orders of magnitude higher than all environmental results. Eight compounds affected by two QC issues had a benchmark less than 100 nanograms per liter and warranted careful consideration of timing and magnitude of QC results in relation to surface-water results before interpretive use.

Scientific Investigations Report↗
USGS2005

A field test of the extent of bias in selection estimates after accounting for emigration

Question: To what extent does trait-dependent emigration bias selection estimates in a natural system? Organisms: Two freshwater cohorts of Atlantic salmon (Salmo salar) juveniles. Field site: A 1 km stretch of a small stream (West Brook) in western Massachusetts. USA from which emigration could be detected continuously. Methods: Estimated viability selection differentials for body size either including or ignoring emigration (include = emigrants survived interval, ignore = emigrants did not survive interval) for 12 intervals. Results: Seasonally variable size-related emigration from our study site generated variable levels of bias in selection estimates for body size. The magnitude of this bias was closely related with the extent of size-dependent emigration during each interval. Including or ignoring the effects of emigration changed the significance of selection estimates in 5 of the 12 intervals, and changed the estimated direction of selection in 4 of the 12 intervals. These results indicate the extent to which inferences about selection in a natural system can be biased by failing to account for trait-dependent emigration. ?? 2005 Benjamin H. Letcher.

Evolutionary Ecology Research↗
USGS2002

A flood early warning system for southern Africa

Sizeable areas of the Southern African Region experienced widespread flooding in 2000. Deployment of hydrologic models can help reduce the human and economic losses in the regions by providing improved monitoring and forecast information to guide relief activities. In this study, we describe a hydrologic model developed for wide-area flood risk monitoring for the Southern African region. The model is forced by daily estimates of rainfall and evapotranspiration derived from remotely sensed data and assimilation fields. Model predictive skills were verified with data observed stream flow data from locations within the Limpopo basin. The model performed well in simulating the timing and magnitude of the stream flow during a recent episode of flooding in Mozambique in 2000.

Conference Paper↗
USGS2018

Testing a two-scale focused conservation strategy for reducing phosphorus and sediment loads from agricultural watersheds

This study tested a focused strategy for reducing phosphorus (P) and sediment loads in agricultural streams. The strategy involved selecting small watersheds identified as likely to respond relatively quickly, and then focusing conservation practices on high-contributing fields within those watersheds. Two 5,000 ha (12,360 ac) watersheds in the Driftless Area of south central Wisconsin, previously ranked in the top 6% of similarly sized Wisconsin watersheds for expected responsiveness to conservation efforts to reduce high P and sediment loads, were chosen for the study. The stream outlets from both watersheds were monitored from October of 2006 through September of 2016 for streamflow and concentrations of sediment, total P, and, beginning in October of 2009, total dissolved P. Fields and pastures having the highest potential P delivery to the streams in each watershed were identified using the Wisconsin P Index (Good et al. 2012). After three years of baseline monitoring (2006 to 2009), farmers implemented both field- and farm-based conservation practices in one watershed (treatment) as a means to reduce sediment and P inputs to the stream from the highest contributing areas, whereas there were no out-of-the-ordinary conservation efforts in the second watershed (control). Implementation occurred primarily in 2011 and 2012. In the four years following implementation of conservation practices (2013 through 2016), there was a statistically significant reduction in storm-event suspended sediment loads in the treatment watershed compared to the control watershed when the ground was not frozen ( p = 0.047). While there was an apparent reduction in year-round suspended sediment event loads, it was not statistically significant at the 95% confidence level ( p = 0.15). Total P loads were significantly reduced for runoff events ( p < 0.01) with a median reduction of 50%. Total P and total dissolved P concentrations for low-flow conditions were also significantly reduced ( p < 0.01) compared to the control watershed. This study demonstrated that a strategy that first identifies watersheds likely to respond to conservation efforts and then focuses implementation on relatively high-contributing fields within those watersheds can be successful in reducing stream P concentrations and loads.

Wisconsin↗
USGS1996

Selected hydrologic data, through water year 1994, Black Hills Hydrology Study, South Dakota

This report presents water-level, water-quality, and spring data that have been collected or compiled, through water year 1994, for the Black Hills Hydrology Study. This study is a long-term cooperative effort between the U.S. Geological Survey, the South Dakota Department of Environment and Natural Resources, and the West Dakota Water Development District (which represents various local and county cooperators). This report is the second in a series of biennial project data reports produced for the study. Daily water-level data are presented for 39 observation wells and 2 cave sites in the Black Hills area of western South Dakota. The wells are part of a network of observation wells maintained by the Department of Environment and Natural Resources and are completed in various bedrock formations that are utilized as aquifers in the Black Hills area. Both cave sites are located within outcrops of the Madison Limestone. Data presented include site descriptions, hydrographs, and tables of daily water levels. Annual measurements of water levels collected during water years 1993-94 from a network of 20 additional, miscellaneous wells are presented. These wells are part of a Statewide network of wells completed in bedrock aquifers that was operated from 1959 through 1989 in cooperation with the Department of Environment and Natural Resources. Site descriptions and hydrographs for the entire period of record for each site also are presented. Drawdown and recovery data are presented for five wells that were pumped (or flowed) for collection of water-quality samples. These wells are part of the network of observation wells for which daily water-level records are compiled. Water-quality data are presented for 20 surface-water sites and 22 ground-water sites. Data presented include field parameters, bacteria counts, and concentrations of common ions, solids, nutrients, trace elements, radiometrics and isotopes, cyanide, phenols, and suspended sediment. Spring data are presented for 94 springs and 21 stream reaches with significant springflow components. Data presented include site information, discharge, and field water-quality parameters including temperature, specific conductance, dissolved oxygen, and pH.

Open-File Report↗