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USGS2007

Contrasting water quality from paired domestic/public supply wells, central High Plains

Closely located domestic and public supply wells were sampled using identical sampling procedures to allow comparison of water quality associated with well type. Water samples from 15 pairs of wells with similar screened intervals completed in the central High Plains regional aquifer in parts of Kansas, Oklahoma, and Texas were analyzed for more than 200 water quality constituents. No statistically significant differences were observed between the concentrations of naturally-derived constituents (major ions, trace elements, and radon) in paired wells. However, differences in water quality between paired wells were observed for selected anthrepogenic compounds (pesticides and tritium), in that some public supply wells produced water that was more recently recharged and contained constituents derived from surface activities. The presence of recently recharged water and compounds indicative of anthrepogenic activities in some public supply wells was likely due to operational variations (pumping rate and pumping cycles), as demonstrated in a particle tracking simulation. Water containing surface-derived anthropogenic compounds from near the water table was more quickly drawn to high volume public supply wells (less than five years) than domestic wells (greater than 120 years) with small pumping rates. These findings indicate that water quality samples collected from different well types in the same area are not necessarily directly comparable. Sampling domestic wells provides the best broad-scale assessment of water quality in this aquifer setting because they are less susceptible to localized contamination from near the water table. However, sampiing public supply wells better represents the quality of the used resource because of the population served.

Kansas, Oklahoma, Texas↗

USGS2017

Decreased runoff response to precipitation, Little Missouri River Basin, northern Great Plains, USA

High variability in precipitation and streamflow in the semiarid northern Great Plains causes large uncertainty in water availability. This uncertainty is compounded by potential effects of future climate change. We examined historical variability in annual and growing season precipitation, temperature, and streamflow within the Little Missouri River Basin and identified differences in the runoff response to precipitation for the period 1976-2012 compared to 1939-1975 ( n = 37 years in both cases). Computed mean values for the second half of the record showed little change (<5%) in annual or growing season precipitation, but average annual runoff at the basin outlet decreased by 22%, with 66% of the reduction in flow occurring during the growing season. Our results show a statistically significant ( p < 0.10) 27% decrease in the annual runoff response to precipitation (runoff ratio). Surface-water withdrawals for various uses appear to account for <12% of the reduction in average annual flow volume, and we found no published or reported evidence of substantial flow reduction caused by groundwater pumping in this basin. Results of our analysis suggest that increases in monthly average maximum and minimum temperatures, including >1°C increases in January through March, are the dominant driver of the observed decrease in runoff response to precipitation in the Little Missouri River Basin.

Montana, North Dakota, South Dakota, Wyoming↗

USGS2007

Nitrate concentrations in Illinois rivers 1967 to 1974: Comparison among reporting agencies

Long term data on surface water quality can sometimes be assembled by combining data collected by different agencies at different times and assuming that between agency differences in data quality are insignificant. The objective of this paper was to assess the quality of riverine nitrate (NO3) concentrations in Illinois measured and reported by four agencies from 1967 to 1974 by comparing median values for similar sampling locations and periods. A total of 17 river reaches were identified for which two agencies reported NO3 concentrations during similar periods. Nonparametric comparison of median values and analysis of covariance with discharge as a covariant produced similar results. Nitrate concentrations reported by the U.S. Geological Survey (USGS) from 1967 to 1971 were not statistically (P > 0.05) different from values reported by the Illinois State Water Survey (ISWS) for two of three river reaches. Additionally, NO3 concentrations reported by USGS from 1972 to 1974 were not statistically different than concentrations reported by the Illinois Environmental Protection Agency (IEPA) for four of five river reaches. From 1969 to 1971, NO3 concentrations reported by the Illinois Department of Public Heath and the Illinois Environmental Protection Agency (IDPH/IEPA) were less than one-fourth the magnitude of values reported by ISWS. The median NO3 concentrations measured by the Central Illinois Public Service (CIPS) were significantly greater than those measured by USGS and IDPH/IEPA in the three comparable sampling locations. The use of NO 3 concentrations measured by CIPS and IDPH/IEPA prior to 1972 is not recommended.

Illinois↗

USGS2010

Constructing an interdisciplinary flow regime recommendation

It is generally agreed that river rehabilitation most often relies on restoring a more natural flow regime, but credibly defining the desired regime can be problematic. I combined four distinct methods to develop and refine month-by-month and event-based flow recommendations to protect and partially restore the ecological integrity of the Cache la Poudre River through Fort Collins, Colorado. A statistical hydrologic approach was used to summarize the river's natural flow regime and set provisional monthly flow targets at levels that were historically exceeded 75% of the time. These preliminary monthly targets were supplemented using results from three Poudre-specific disciplinary studies. A substrate maintenance flow model was used to better define the high flows needed to flush accumulated sediment from the river's channel and help sustain the riparian zone in this snowmelt-dominated river. A hydraulic/habitat model and a water temperature model were both used to better define the minimum flows necessary to maintain a thriving cool water fishery. The result is a range of recommended monthly flows and daily flow guidance illustrating the advantage of combining a wide range of available disciplinary information, supplemented by judgment based on ecological principles and a general understanding of river ecosystems, in a highly altered, working river. ?? 2010 American Water Resources Association.

Journal of the American Water Resources Associatio↗

USGS2007

Detectability of step trends in the rate of atmospheric deposition of sulfate

A method is presented to assist policy makers in determining the combination of number of sampling stations and number of years of sampling necessary to state with a given probability that a step reduction in atmospheric deposition rates of a given magnitude has occurred at a pre-specified time. This pre-specified time would typically be the time at which a sulfate emission control program took effect, and the given magnitude of reduction is some percentage change in deposition rate one might expect to occur as a result of the emission control. In order to determine this probability of detection, a stochastic model of sulfate deposition rates is developed, based on New York State bulk collection network data. The model considers the effect of variation in precipitation, seasonal variations, serial correlation, and site-to-site (cross) correlation. A nonparametric statistical test which is well suited to detection of step changes in such multi-site data sets is developed. It is related to the Mann-Whitney Rank-Sum test. The test is used in Monte Carlo simulations along with the stochastic model to derive statistical power functions. These power functions describe the probability of detecting (α=0.05) a step trend in deposition rate as a function of the size of the step-trend, record length before and after the step-trend, and the number of stations sampled. The results show that, for an area the size of New York State, very little power is gained by increasing the number of stations beyond about eight. The results allow policy makers to determine the tradeoff between the cost of monitoring and time required to detect a step-trend of a given magnitude with a given probability.

New York↗

USGS2019

A multi-scale soil moisture monitoring strategy for California: Design and validation

A multi‐scale soil moisture monitoring strategy for California was designed to inform water resource management. The proposed workflow classifies soil moisture response units (SMRUs) using publicly available datasets that represent soil, vegetation, climate, and hydrology variables, which control soil water storage. The SMRUs were classified, using principal component analysis and unsupervised K‐means clustering within a geographic information system, and validated, using summary statistics derived from measured soil moisture time series. Validation stations, located in the Sierra Nevada, include transect of sites that cross the rain‐to‐snow transition and a cluster of sites located at similar elevations in a snow‐dominated watershed. The SMRUs capture unique responses to varying climate conditions characterized by statistical measures of central tendency, dispersion, and extremes. A topographic position index and landform classification is the final step in the workflow to guide the optimal placement of soil moisture sensors at the local‐scale. The proposed workflow is highly flexible and can be implemented over a range of spatial scales and input datasets can be customized. Our approach captures a range of soil moisture responses to climate across California and can be used to design and optimize soil moisture monitoring strategies to support runoff forecasts for water supply management or to assess landscape conditions for forest and rangeland management.

California↗

USGS2022

Quantifying streamflow depletion from groundwater pumping: A practical review of past and emerging approaches for water management

Groundwater pumping can cause reductions in streamflow (“streamflow depletion”) that must be quantified for conjunctive management of groundwater and surface water resources. However, streamflow depletion cannot be measured directly and is challenging to estimate because pumping impacts are masked by streamflow variability due to other factors. Here, we conduct a management-focused review of analytical, numerical, and statistical models for estimating streamflow depletion and highlight promising emerging approaches. Analytical models are easy to implement, but include many assumptions about the stream and aquifer. Numerical models are widely used for streamflow depletion assessment and can represent many processes affecting streamflow, but have high data, expertise, and computational needs. Statistical approaches are a historically underutilized tool due to difficulty in attributing causality, but emerging causal inference techniques merit future research and development. We propose that streamflow depletion-related management questions can be divided into three broad categories (attribution, impacts, and mitigation) that influence which methodology is most appropriate. We then develop decision criteria for method selection based on suitability for local conditions and the management goal, actionability with current or obtainable data and resources, transparency with respect to process and uncertainties, and reproducibility.

Journal of the American Water Resources Associatio↗

USGS2007

Use of streamflow data to estimate base flowground-water recharge for Wisconsin

The average annual base flow/recharge was determined for streamflow-gaging stations throughout Wisconsin by base-flow separation. A map of the State was prepared that shows the average annual base flow for the period 1970-99 for watersheds at 118 gaging stations. Trend analysis was performed on 22 of the 118 streamflow-gaging stations that had long-term records, unregulated flow, and provided aerial coverage of the State. The analysis found that a statistically significant increasing trend was occurring for watersheds where the primary land use was agriculture. Most gaging stations where the land cover was forest had no significant trend. A method to estimate the average annual base flow at ungaged sites was developed by multiple-regression analysis using basin characteristics. The equation with the lowest standard error of estimate, 9.5%, has drainage area, soil infiltration and base flow factor as independent variables. To determine the average annual base flow for smaller watersheds, estimates were made at low-flow partial-record stations in 3 of the 12 major river basins in Wisconsin. Regression equations were developed for each of the three major river basins using basin characteristics. Drainage area, soil infiltration, basin storage and base-flow factor were the independent variables in the regression equations with the lowest standard error of estimate. The standard error of estimate ranged from 17% to 52% for the three river basins. ?? 2007 American Water Resources Association.

Journal of the American Water Resources Associatio↗

USGS1984

Analysis of potential yield per recruit for striped bass produced in Chesapeake Bay

The yield of striped bass ( Morone saxatilis ) in biomass and numbers was estimated for constant recruitment of young fish into the population on the basis of vital statistics of the Maryland stock. Separate computations were performed for males, females, and sexes combined. Yield in biomass per individual entering the population was highest when the minimum legal length was in the range of 80-90 cm fork length and no upper size limits were imposed. The yield would increase at these size limits in both the Bay and Coastal fisheries, although the Coastal fishery would gain a slight relative advantage because the escapement of immature females from the Bay would increase. The most significant negative effect associated with an increase in the size limits would be the elimination of the traditional fisheries that focus on panfish (male and immature female striped bass 28-40 cm long). Although the length limits recommended in an existing Interstate Fisheries Management Plan for Striped Bass will increase yield per recruit, more stringent regulations would further increase the yield.

Maryland↗

USGS2002

Predictive evaluation of size restrictions as management strategies for tennessee reservoir crappie fisheries

We evaluated the potential effect of minimum size restrictions on crappies Pomoxis spp. in 12 large Tennessee reservoirs. A Beverton-Holt equilibrium yield model was used to predict and compare the response of these fisheries to three minimum size restrictions: 178 mm (i.e., pragmatically, no size limit), 229 mm, and the current statewide limit of 254 mm. The responses of crappie fisheries to size limits differed among reservoirs and varied with rates of conditional natural mortality (CM). Based on model results, crappie fisheries fell into one of three response categories: (1) In some reservoirs (N = 5), 254-mm and 229-mm limits would benefit the fishery in terms of yield if CM were low (30%); the associated declines in the number of crappies harvested would be significant but modest when compared with those in other reservoirs. (2) In other reservoirs (N = 6), little difference in yield existed among size restrictions at low to intermediate rates of CM (30-40%). In these reservoirs, a 229-mm limit was predicted to be a more beneficial regulation than the current 254-mm limit. (3) In the remaining reservoir, Tellico, size limits negatively affected all three harvest statistics. Generally, yield was negatively affected by size limits in all populations at a CM of 50%. The number of crappies reaching 300 mm was increased by size limits in most model scenarios: however, associated declines in the total number of crappies harvested often outweighed the benefits to size structure when CM was 40% or higher. When crappie growth was fast (reaching 254 mm in less than 3 years) and CM was low (30%), size limits were most effective in balancing increases in yield and size structure against declines in the total number of crappies harvested. The variability in predicted size-limit responses observed among Tennessee reservoirs suggests that using a categorical approach to applying size limits to crappie fisheries within a state or region would likely be a more effective management strategy than implementing a single, areawide regulation.

North American Journal of Fisheries Management↗

USGS2011

Estimation of suspended-sediment concentration from total suspended solids and turbidity data for Kentucky, 1978-1995

Suspended sediment is a constituent of water quality that is monitored because of concerns about accelerated erosion, nonpoint contamination of water resources, and degradation of aquatic environments. In order to quantify the relationship among different sediment parameters for Kentucky streams, long‐term records were obtained from the National Water Information System of the U.S. Geological Survey. Suspended‐sediment concentration (SSC), the parameter traditionally measured and reported by the U.S. Geological Survey, was statistically compared to turbidity and total suspended solids (TSS), two parameters that are considered surrogate data. A linear regression of log‐transformed observations was used to estimate SSC from TSS; 72% of TSS observations were less than coincident SSC observations; however, the estimated SSC values were almost as likely to be overestimated as underestimated. The SSC‐turbidity relationship also used log‐transformed observations, but required a nonlinear, breakpoint regression that separated turbidity observations ≤6 nephelometric turbidity units. The slope for these low turbidity values was not significantly different than zero, indicating that low turbidity observations provide no real information about SSC; in the case of the Kentucky sediment record, this accounts for 30% of the turbidity observations.

Kentucky↗

USGS2007

A triangular model of dimensionless runoff producing rainfall hyetographs in Texas

A synthetic triangular hyetograph for a large data base of Texas rainfall and runoff is needed. A hyetograph represents the temporal distribution of rainfall intensity at a point or over a watershed during a storm. Synthetic hyetographs are estimates of the expected time distribution for a design storm and principally are used in small watershed hydraulic structure design. A data base of more than 1,600 observed cumulative hyetographs that produced runoff from 91 small watersheds (generally less than about 50 km2) was used to provide statistical parameters for a simple triangular shaped hyetograph model. The model provides an estimate of the average hyetograph in dimensionless form for storm durations of 0 to 24 hours and 24 to 72 hours. As a result of this study, the authors concluded that the expected dimensionless cumulative hyetographs of 0 to 12 hour and 12 to 24 hour durations were sufficiently similar to be combined with minimal information loss. The analysis also suggests that dimensionless cumulative hyetographs are independent of the frequency level or return period of total storm depth and thus are readily used for many design applications. The two triangular hyetographs presented are intended to enhance small watershed design practice in applicable parts of Texas.

Texas↗

USGS1999

Effects of temephos (Abate? 4E) on fiddler crabs (Uca pugnax and Uca minax) on a Delaware salt marsh

The non-target effects of temephos (as Abate 4E, 44.6% active ingredient) on fiddler crabs were examined on the salt marsh at Bombay Hook National Wildlife Refuge (NWR), near Dover, DE. Six 170 x 170 m plots were established; 3 were sprayed on 4 occasions at a rate of 1.5 fl oz/acre (0.054 kg active ingredient/ha) and 3 were controls. On each plot, marsh fiddler crab (Uca pugnax) populations were monitored by repeatedly counting the number of burrow holes in 2 counting areas marked out along tidal guts. One half of each counting area was covered with bird netting to evaluate sublethal toxic effects, which, if present, could result in increased susceptibility to bird predation. A statistically significant linear association was established between the number of holes and the number of crabs. No significant differences were found in the numbers of holes (or crabs) in the sprayed vs. control plots and in the covered vs. uncovered sections. However, survival of juvenile crabs in in situ bioassays was significantly reduced (16% lower) by the spraying. Median acetylcholinesterase activity in claw muscle of red-jointed fiddler crabs (U. minax) collected 2 days after an operational spray with Abate 4E was significantly reduced (28% lower) compared to unsprayed crabs. In view of the toxicity to juvenile crabs and the cholinesterase inhibition, we recommend continued monitoring and research for non-target impacts of Abate 4E on fiddler crabs to establish whether the reported level of cholinesterase inhibition results in acute or chronic toxicity.

Journal of the American Mosquito Control Associati↗

USGS2019

Reduced soil macropores and forest cover reduce warm-season baseflow below ecological thresholds in the upper Delaware River Basin

We examined the impacts of changes in land cover and soil conditions on the flow regime of the upper Delaware River Basin using the Water Availability Tool for Environmental Resources (WATER). We simulated flows for two periods, circa 1600 and 1940, at three sites using the same temperature and precipitation conditions: the East Branch (EB), West Branch (WB), and mainstem Delaware River at Callicoon, NY. The 1600 period represented pristine forest and soils. The 1940 period included reduced forest cover, increased agriculture, and degraded soils with reduced soil macropore fractions. A model-sensitivity test examined the impact of soil macropore and land cover change separately. We assessed changes in flow regimes between the 1600 and 1940 periods using a variety of flow statistics, including established ecological limits of hydrologic alteration (ELOHA) thresholds. Reduced forest soil macropore fraction significantly reduced summer and fall base flows. The 1940 period had significantly lower Q50 flows (50% exceedance) than the 1600 period, as well as summer and fall Q90 and Q75-90 flows below the ELOHA thresholds. The 1- to 7-day minimum flows were also lower for the 1940 period, by 17% on the mainstem. 1940 flows were 6% more likely than the 1600 period to fall below the low-flow threshold for federally endangered dwarf wedgemussel (Alasmidonta heterodon) habitat. In contrast, the 1940 period had higher flows than the 1600 period from late fall to early winter.

New York, Pennsylvania↗

USGS2007

Spatial variability in water-balance model performance in the conterminous United States

A monthly water-balance (WB) model was tested in 44 river basins from diverse physiographic and climatic regions across the conterminous United States (U.S.). The WB model includes the concepts of climatic water supply and climatic water demand, seasonality in climatic water supply and demand, and soil-moisture storage. Exhaustive search techniques were employed to determine the optimal set of precipitation and temperature stations, and the optimal set of WB model parameters to use for each basin. It was found that the WB model worked best for basins with: (1) a mean elevation less than 450 meters or greater than 2000 meters, and/or (2) monthly runoff that is greater than 5 millimeters (mm) more than 80 percent of the time. In a separate analysis, a multiple linear regression (MLR) was computed using the adjusted R-square values obtained by comparing measured and estimated monthly runoff of the original 44 river basins as the dependent variable, and combinations of various independent variables [streamflow gauge latitude, longitude, and elevation; basin area, the long-term mean and standard deviation of annual precipitation; temperature and runoff; and low-flow statistics (i.e., the percentage of months with monthly runoff that is less than 5 mm)]. Results from the MLR study showed that the reliability of a WB model for application in a specific region can be estimated from mean basin elevation and the percentage of months with gauged runoff less than 5 mm. The MLR equations were subsequently used to estimate adjusted R-square values for 1,646 gauging stations across the conterminous U.S. Results of this study indicate that WB models can be used reliably to estimate monthly runoff in the eastern U.S., mountainous areas of the western U.S., and the Pacific Northwest. Applications of monthly WB models in the central U.S. can lead to uncertain estimates of runoff.

Conterminous United States↗

USGS2021

OpenET: Filling a critical data gap in water management for the western United States

The lack of consistent, accurate information on evapotranspiration (ET) and consumptive use of water by irrigated agriculture is one of the most important data gaps for water managers in the western United States (U.S.) and other arid agricultural regions globally. The ability to easily access information on ET is central to improving water budgets across the West, advancing the use of data-driven irrigation management strategies, and expanding incentive-driven conservation programs. Recent advances in remote sensing of ET have led to the development of multiple approaches for field-scale ET mapping that have been used for local and regional water resource management applications by U.S. state and federal agencies. The OpenET project is a community-driven effort that is building upon these advances to develop an operational system for generating and distributing ET data at a field scale using an ensemble of six well-established satellite-based approaches for mapping ET. Key objectives of OpenET include: Increasing access to remotely sensed ET data through a web-based data explorer and data services; supporting the use of ET data for a range of water resource management applications; and development of use cases and training resources for agricultural producers and water resource managers. Here we describe the OpenET framework, including the models used in the ensemble, the satellite, meteorological, and ancillary data inputs to the system, and the OpenET data visualization and access tools. We also summarize an extensive intercomparison and accuracy assessment conducted using ground measurements of ET from 139 flux tower sites instrumented with open path eddy covariance systems. Results calculated for 24 cropland sites from Phase I of the intercomparison and accuracy assessment demonstrate strong agreement between the satellite-driven ET models and the flux tower ET data. For the six models that have been evaluated to date (ALEXI/DisALEXI, eeMETRIC, geeSEBAL, PT-JPL, SIMS, and SSEBop) and the ensemble mean, the weighted average mean absolute error (MAE) values across all sites range from 13.6 to 21.6 mm/month at a monthly timestep, and 0.74 to 1.07 mm/day at a daily timestep. At seasonal time scales, for all but one of the models the weighted mean total ET is within ±8% of both the ensemble mean and the weighted mean total ET calculated from the flux tower data. Overall, the ensemble mean performs as well as any individual model across nearly all accuracy statistics for croplands, though some individual models may perform better for specific sites and regions. We conclude with three brief use cases to illustrate current applications and benefits of increased access to ET data, and discuss key lessons learned from the development of OpenET.

western United States↗

USGS2016

Effects of land use and sample location on nitrate-stream flow hysteresis descriptors during storm events

The U.S. Geological Survey's New Jersey and Iowa Water Science Centers deployed ultraviolet-visible spectrophotometric sensors at water-quality monitoring sites on the Passaic and Pompton Rivers at Two Bridges, New Jersey, on Toms River at Toms River, New Jersey, and on the North Raccoon River near Jefferson, Iowa to continuously measure in-stream nitrate plus nitrite as nitrogen (NO 3 + NO 2 ) concentrations in conjunction with continuous stream flow measurements. Statistical analysis of NO 3 + NO 2 vs . stream discharge during storm events found statistically significant links between land use types and sampling site with the normalized area and rotational direction of NO 3 + NO 2 -stream discharge (N-Q) hysteresis patterns. Statistically significant relations were also found between the normalized area of a hysteresis pattern and several flow parameters as well as the normalized area adjusted for rotational direction and minimum NO 3 + NO 2 concentrations. The mean normalized hysteresis area for forested land use was smaller than that of urban and agricultural land uses. The hysteresis rotational direction of the agricultural land use was opposite of that of the urban and undeveloped land uses. An r 2 of 0.81 for the relation between the minimum normalized NO 3 + NO 2 concentration during a storm vs . the normalized NO 3 + NO 2 concentration at peak flow suggested that dilution was the dominant process controlling NO 3 + NO 2 concentrations over the course of most storm events.

Iowa, New Jersey↗

USGS2007

Water quality in shallow alluvial aquifers, Upper Colorado River Basin, Colorado, 1997

Shallow ground water in areas of increasing urban development within the Upper Colorado River Basin was sampled for inorganic and organic constituents to characterize water-quality conditions and to identify potential anthropogenic effects resulting from development. In 1997, 25 shallow monitoring wells were installed and sampled in five areas of urban development in Eagle, Grand, Gunnison, and Summit Counties, Colorado. The results of this study indicate that the shallow ground water in the study area is suitable for most uses. Nonparametric statistical methods showed that constituents and parameters measured in the shallow wells were often significantly different between the five developing urban areas. Radon concentrations exceeded the proposed USEPA maximum contaminant level at all sites. The presence of nutrients, pesticides, and volatile organic compounds indicate anthropogenic activities are affecting the shallow ground-water quality in the study area. Nitrate as N concentrations greater than 2.0 mg/L were observed in ground water recharged between the 1980s and 1990s. Low concentrations of methylene blue active substances were detected at a few sites. Total coliform bacteria were detected at ten sites; however, E. coli was not detected. Continued monitoring is needed to assess the effects of increasing urban development on the shallow ground-water quality in the study area.

Colorado↗