Streamflow and phosphorus concentrations were monitored in the Assabet River in central Massachusetts in order to evaluate concentrations and loads in the river before, during, and after changes in the amount of total phosphorus that was discharged to the river from three wastewater-treatment plants. At four locations the U.S. Geological Survey collected weekly flow-proportional, composite samples of water from the Assabet River for analysis of concentrations of total phosphorus and orthophosphate. Streamflow and concentration data were used to estimate total phosphorus and orthophosphate loads in the river and compare them with total phosphorus load outputs from three wastewater-treatment plants. Data were collected from October 2008 through April 2014. The data are analyzed in a report that describes changes in phosphorus concentrations and loads during the study period. This data release consists of tables of (1) instream daily streamflow, concentrations of total phosphorus and orthophosphate from weekly composite samples, and daily load estimates for the four monitoring stations on the Assabet River; (2) daily outflow, daily measured and estimated total phosphorus and concentrations, and daily total phosphorus load estimates from the three wastewater-treatment plants; and (3) concentrations of total phosphorus and orthophosphate, and associated daily mean streamflows, for quality-control samples collected for the project.

This data release contains simulated orthophosphate concentrations (milligrams per liter) as a function of year, season, and flow for 53 monitoring stations in the Chesapeake Bay watershed. These data were generated for a study published in Science of the Total Environment (https://doi.org/10.1016/j.scitotenv.2018.10.062). They were extracted from the Weighted Regressions in Time, Discharge and Season (WRTDS; Hirsch et al. 2010) models developed for each monitoring station using two functions in the EGRET R package: the flowDuration function and the plotConcTimeSmooth function. The flowDuration function in the EGRET package (Hirsch and DeCicco, 2015) was used to quantify the 5th and 95th percentile flows to represent low and high flows, respectively, for each season at each watershed. These discharge values are then used as input for the plotConcTimeSmooth function, along with a date to represent the midpoint of each calendar year season (January-March = winter, etc.). The midpoints for the seasons were 15-February, 15-May, 15-August, and 15-November for the winter, spring, summer, and fall seasons, respectively. The plotConcTimeSmooth function provides estimates of concentration for those dates at those flows for all years included in the analysis. Simulated concentrations for the years 2006 and 2014 were extracted from this output, and are the only years included in this data release. Sources: Hirsch, R.M., Moyer, D.L., and Archfield, S.A., 2010, Weighted regressions on time, discharge, and season (WRTDS), with an application to Chesapeake Bay river inputs: Journal of the American Water Resources Resources Association, v. 46, no. 5, p. 857-880 Hirsch, R.M. and De Cicco, Laura, 2015, User guide to Exploration and Graphics for RivEr Trends (EGRET) and dataRetrieval: R packages for hydrologic data (version 2.0, February 2015): U.S. Geological Survey Techniques and Methods book 4, chap. A10, 93 p., http://dx.doi.org/10.3133/tm4A10.(accessed May 24, 2018)

This data release contains simulated orthophosphate concentrations (milligrams per liter) as a function of year, season, and flow for 53 monitoring stations in the Chesapeake Bay watershed. These data were generated for a study published in Science of the Total Environment (https://doi.org/10.1016/j.scitotenv.2018.10.062). They were extracted from the Weighted Regressions in Time, Discharge and Season (WRTDS; Hirsch et al. 2010) models developed for each monitoring station using two functions in the EGRET R package: the flowDuration function and the plotConcTimeSmooth function. The flowDuration function in the EGRET package (Hirsch and DeCicco, 2015) was used to quantify the 5th and 95th percentile flows to represent low and high flows, respectively, for each season at each watershed. These discharge values are then used as input for the plotConcTimeSmooth function, along with a date to represent the midpoint of each calendar year season (January-March = winter, etc.). The midpoints for the seasons were 15-February, 15-May, 15-August, and 15-November for the winter, spring, summer, and fall seasons, respectively. The plotConcTimeSmooth function provides estimates of concentration for those dates at those flows for all years included in the analysis. Simulated concentrations for the years 2006 and 2014 were extracted from this output, and are the only years included in this data release. Sources: Hirsch, R.M., Moyer, D.L., and Archfield, S.A., 2010, Weighted regressions on time, discharge, and season (WRTDS), with an application to Chesapeake Bay river inputs: Journal of the American Water Resources Resources Association, v. 46, no. 5, p. 857-880 Hirsch, R.M. and De Cicco, Laura, 2015, User guide to Exploration and Graphics for RivEr Trends (EGRET) and dataRetrieval: R packages for hydrologic data (version 2.0, February 2015): U.S. Geological Survey Techniques and Methods book 4, chap. A10, 93 p., http://dx.doi.org/10.3133/tm4A10.(accessed May 24, 2018)

The dataset includes total phosphorus and ortho-phosphate concentrations in water. This dataset is associated with the following publication: Baek, S., S.H. Joo, D. Linne, S. Leon, C. Luciano, C. Bariley, C. Su, and Y. Wan. Pilot-Scale Application of Shotblast Dust for Phosphorus Removal. Journal AWWA. American Water Works Association, Denver, CO, USA, 110(11): 64-68, (2018).

The dataset contains estimates for total phosphorus flux from wastewater treatment plants that discharge to surface water within the Red River of the North Basin in the United States and subbasins. Shapefiles defining the subbasins are available as part of the same data release in which these data are published. Estimates of wastewater treatment plant total phosphorus flux (or load) were calculated by Tammy Ivanhnenko for the years 1978, 1980, 1982, 1984, 1986, 1988, 1990, 1992, 1996, 2000, 2004, 2008, and 2012. Flux estimates were based on the average discharge from the wastewater treatment plants and treatment level, both reported as part of the U.S. Environmental Protection Agency's Clean Watershed Needs Survey, https://www.epa.gov/cwns. The treatment level concentrations used for total phosphorus are based on data from a 2000 U.S. Environmental Protection Agency report (table 2-17; Tetra Tech, Inc. and Andrew Stoddard & Associates, 2000). Tetra Tech, Inc. and Andrew Stoddard & Associates, 2000, Progress in water quality-An evaluation of the National investment in municipal wastewater treatment: U.S. Environmental Protection Agency Technical Report EPA-832-R-00-008, 452 p., accessed November 5, 2015, at http://water.epa.gov/polwaste/wastewater/treatment/benefits.cfm.

The dataset contains estimates for total phosphorus flux from wastewater treatment plants that discharge to surface water within the Red River of the North Basin in the United States and subbasins. Shapefiles defining the subbasins are available as part of the same data release in which these data are published. Estimates of wastewater treatment plant total phosphorus flux (or load) were calculated by Tammy Ivanhnenko for the years 1978, 1980, 1982, 1984, 1986, 1988, 1990, 1992, 1996, 2000, 2004, 2008, and 2012. Flux estimates were based on the average discharge from the wastewater treatment plants and treatment level, both reported as part of the U.S. Environmental Protection Agency's Clean Watershed Needs Survey, https://www.epa.gov/cwns. The treatment level concentrations used for total phosphorus are based on data from a 2000 U.S. Environmental Protection Agency report (table 2-17; Tetra Tech, Inc. and Andrew Stoddard & Associates, 2000). Tetra Tech, Inc. and Andrew Stoddard & Associates, 2000, Progress in water quality-An evaluation of the National investment in municipal wastewater treatment: U.S. Environmental Protection Agency Technical Report EPA-832-R-00-008, 452 p., accessed November 5, 2015, at http://water.epa.gov/polwaste/wastewater/treatment/benefits.cfm.

This data release contains the R source code, inputs, and selected outputs associated with the turbidity-based regression models used to estimate total phosphorus concentrations and loads for the Missouri River at St. Joseph and Hermann, Missouri, for water years 2008–22. Additionally, the R source code, inputs, and selected outputs for LOADEST models used to estimate daily total phosphorus loads for the study period are included, as these loads were used for days when turbidity data was unavailable.

The datasets provided here are the output from the Seasonal Kendall Trend (SKT) test and Weighted Regressions on Time, Discharge, and Season (WRTDS) model that characterize changes in water quality in rivers and streams across the Delaware River Basin. SKT results are compiled in "skt_out.csv" for all combinations of site, water-quality parameter, and trend period. WRTDS results are compiled in four datasets. If unspecified, generalized flow normalization (GFN) results are reported. Stationary flow normalization (SFN) results are indicated in the datasets. "wrtds_out_annResults.csv" contains the annual estimates of mean concentration and load and GFN and SFN estimates by site and parameter for the entire calibration period. "wrtds_out_annResultsCIs.csv" gives confidence intervals for GFN annual estimates. "wrtds_out_bootOut.csv" gives the results of the bootstrap trend test by site, parameter, and trend period. "wrtds_out_pairsOut.csv" gives the trend component estimates (concentration-discharge trend component (CQCT, also referred to as the "management" trend component (MTC)) and discharge trend component (QTC)) and related information, by site, parameter, trend period, and estimate type (i.e. concentration or load). Finally, the "eList" for each WRTDS model (site-parameter combination) is available in the zipped folder. References Cited: Hirsch, R.M., and De Cicco, L.A., 2015, User guide to Exploration and Graphics for RivEr Trends (EGRET) and dataRetrieval: R packages for hydrologic data (version 2.0, February 2015): U.S. Geological Survey Techniques and Methods book 4, chap. A10, 93 p., https://doi.org/10.3133/tm4A10.

The datasets provided here are the input data used to run the Seasonal Kendall Trend (SKT) tests and Weighted Regressions on Time, Discharge, and Season (WRTDS) models. SKT tests use "annualSamplingFreqs_allSites.csv" and "wqData_screenedSitesAll.csv" which includes, for all site-parameter combinations, information on annual sampling frequencies and the screened water-quality data, respectively. The WRTDS models use "DRB.wqdata.20200521.csv", "DRB.flow.20200610.zip", and "DRB.info.20200521.csv" for calibration which includes, for all site-parameter combinations, the water-quality data, streamflow data (as separate .csv files for each site), model specifications and site information, respectively. The multisource data used in these analyses are from Shoda and others (2019), which were originally retrieved from the Water Quality Portal (www.waterqualitydata.us). References Cited: Shoda, M.E., Murphy, J.C., Falcone, J.A., and Duris, J.W., 2019, Multisource surface-water-quality data and U.S. Geological Survey streamgage match for the Delaware River Basin: U.S. Geological Survey data release, https://doi.org/10.5066/P9PX8LZO. National Water Quality Monitoring Council, Water Quality Portal (WQP), https://www.waterqualitydata.us/. Accessed 2020-11-03.

The datasets provided here are the output from the Seasonal Kendall Trend (SKT) test and Weighted Regressions on Time, Discharge, and Season (WRTDS) model that characterize changes in water quality in rivers and streams across the Delaware River Basin. SKT results are compiled in "skt_out.csv" for all combinations of site, water-quality parameter, and trend period. WRTDS results are compiled in four datasets. If unspecified, generalized flow normalization (GFN) results are reported. Stationary flow normalization (SFN) results are indicated in the datasets. "wrtds_out_annResults.csv" contains the annual estimates of mean concentration and load and GFN and SFN estimates by site and parameter for the entire calibration period. "wrtds_out_annResultsCIs.csv" gives confidence intervals for GFN annual estimates. "wrtds_out_bootOut.csv" gives the results of the bootstrap trend test by site, parameter, and trend period. "wrtds_out_pairsOut.csv" gives the trend component estimates (concentration-discharge trend component (CQCT, also referred to as the "management" trend component (MTC)) and discharge trend component (QTC)) and related information, by site, parameter, trend period, and estimate type (i.e. concentration or load). Finally, the "eList" for each WRTDS model (site-parameter combination) is available in the zipped folder. References Cited: Hirsch, R.M., and De Cicco, L.A., 2015, User guide to Exploration and Graphics for RivEr Trends (EGRET) and dataRetrieval: R packages for hydrologic data (version 2.0, February 2015): U.S. Geological Survey Techniques and Methods book 4, chap. A10, 93 p., https://doi.org/10.3133/tm4A10.