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.

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.

This data release provides water-quality trends for rivers and streams in the Delaware River Basin determined using the Weighted Regressions on Time, Discharge, and Season (WRTDS) model and the Seasonal Kendall Trend (SKT) test. Sixteen water-quality parameters were assessed, including nutrients (ammonia, nitrate, filtered orthophosphate, total nitrogen, total phosphorus, and unfiltered orthophosphate), major ions (calcium, chloride, magnesium, potassium, sodium, and sulfate), salinity indicators (total dissolved solids and specific conductance), and sediment (total suspended solids and suspended sediment concentration). The child items include the input and output data used in the modeling and testing of water-quality trends. The attached files include the scripts used in these analyses, a readMe files for these scripts and tables summarizing information about the sites used in the analysis. These trends build off the national efforts of Oelsner and others (2017) and Murphy and others (2018), with some variations in data screening and processing. One major divergence from these previous efforts was that screened site-parameter combinations were screened for the longest period of record that passed various temporal and seasonal criteria ("maximum calibration" approach) instead of screening by pre-defined trend periods. An additional difference was that water-quality data were combined from multiple monitoring locations and collecting organizations using hierarchical clustering based on the distance between monitoring locations on the same stream reach (as determined by the National Hydrography Dataset comid). Data that were a part of these "cluster sites" were manually reviewed prior to running SKT and WRTDS. Input data for SKT includes 124 sites (including individual sites and cluster sites) and 1,208 site-parameter combinations. Input data for WRTDS, which required additional screening beyond those used for the SKT test and a paired streamflow gage, includes 62 sites and 476 site-parameter combinations. For both methods, some site-parameter combinations were not run due to the amount of censored data, or the results were rejected due to poor model fit. Trends are reported for four trend periods (1978-2018, 1998-2018, 2003-2018, and 2008-2018), as the available screened data allow, and for the entire screened period of record for each parameter at each site. This collection of trend results leverages the monitoring efforts of many collecting organizations across the Delaware River Basin and can serve to better understand changing water-quality conditions across this basin. References Cited: Murphy, J.C., Farmer, W.H., Sprague, L.A., De Cicco, L.A., and Hirsch, R.M., 2018, Water-quality trends and trend component estimates for the Nation's rivers and streams using Weighted Regressions on Time, Discharge, and Season (WRTDS) models and generalized flow normalization, 1972-2012: U.S. Geological Survey data release, https://doi.org/10.5066/F7TQ5ZS3. Oelsner, G.P., Sprague, L.A., Murphy, J.C., Zuellig, R.E., Johnson, H.M., Ryberg, K.R., Falcone, J.A., Stets, E.G., Vecchia, A.V., Riskin, M.L., De Cicco, L.A., Mills, T.J., Farmer, W.H., 2017, Water-quality trends in the Nation’s rivers and streams 1972–2012—Data preparation, statistical methods, and trend results: U.S. Geological Survey Scientific Investigations Report, http://dx.doi.org/10.3133/sir20175006. 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.

This data release provides water-quality trends for rivers and streams in the Delaware River Basin determined using the Weighted Regressions on Time, Discharge, and Season (WRTDS) model and the Seasonal Kendall Trend (SKT) test. Sixteen water-quality parameters were assessed, including nutrients (ammonia, nitrate, filtered orthophosphate, total nitrogen, total phosphorus, and unfiltered orthophosphate), major ions (calcium, chloride, magnesium, potassium, sodium, and sulfate), salinity indicators (total dissolved solids and specific conductance), and sediment (total suspended solids and suspended sediment concentration). The child items include the input and output data used in the modeling and testing of water-quality trends. The attached files include the scripts used in these analyses, a readMe files for these scripts and tables summarizing information about the sites used in the analysis. These trends build off the national efforts of Oelsner and others (2017) and Murphy and others (2018), with some variations in data screening and processing. One major divergence from these previous efforts was that screened site-parameter combinations were screened for the longest period of record that passed various temporal and seasonal criteria ("maximum calibration" approach) instead of screening by pre-defined trend periods. An additional difference was that water-quality data were combined from multiple monitoring locations and collecting organizations using hierarchical clustering based on the distance between monitoring locations on the same stream reach (as determined by the National Hydrography Dataset comid). Data that were a part of these "cluster sites" were manually reviewed prior to running SKT and WRTDS. Input data for SKT includes 124 sites (including individual sites and cluster sites) and 1,208 site-parameter combinations. Input data for WRTDS, which required additional screening beyond those used for the SKT test and a paired streamflow gage, includes 62 sites and 476 site-parameter combinations. For both methods, some site-parameter combinations were not run due to the amount of censored data, or the results were rejected due to poor model fit. Trends are reported for four trend periods (1978-2018, 1998-2018, 2003-2018, and 2008-2018), as the available screened data allow, and for the entire screened period of record for each parameter at each site. This collection of trend results leverages the monitoring efforts of many collecting organizations across the Delaware River Basin and can serve to better understand changing water-quality conditions across this basin. References Cited: Murphy, J.C., Farmer, W.H., Sprague, L.A., De Cicco, L.A., and Hirsch, R.M., 2018, Water-quality trends and trend component estimates for the Nation's rivers and streams using Weighted Regressions on Time, Discharge, and Season (WRTDS) models and generalized flow normalization, 1972-2012: U.S. Geological Survey data release, https://doi.org/10.5066/F7TQ5ZS3. Oelsner, G.P., Sprague, L.A., Murphy, J.C., Zuellig, R.E., Johnson, H.M., Ryberg, K.R., Falcone, J.A., Stets, E.G., Vecchia, A.V., Riskin, M.L., De Cicco, L.A., Mills, T.J., Farmer, W.H., 2017, Water-quality trends in the Nation’s rivers and streams 1972–2012—Data preparation, statistical methods, and trend results: U.S. Geological Survey Scientific Investigations Report, http://dx.doi.org/10.3133/sir20175006. 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.

In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project. One of the major goals of the NAWQA project was to determine how river water quality has changed over time. To support that goal, long-term consistent and comparable monitoring has been conducted by the USGS on streams and rivers throughout the Nation. Outside of the NAWQA project, the USGS and other Federal, State, and local agencies also have collected long-term water-quality data to support their own assessments of changing water quality. In 2017, data from these multiple sources were combined to support one of the most comprehensive assessments to date of water-quality trends in the United States (Oelsner and others., 2017; De Cicco and others, 2017). This data release updates these water quality trends, which ended in 2012, with 5 more years of data and now end in 2017. The three zipped folders below contain the input data used to calibrate the WRTDS trend models for three separate runs on the Yeti supercomputer. The initial run contained the majority of the screened sites and parameters and later runs included additional sites and reruns for sites with corrected data. The output from later runs always superseded earlier runs for any site-parameter combination that was run more than once. The data used in each run is contained in a zipped folder, each of which contains a "data" folder with 2 files and 1 folder with the same beginning part of the filename and same formatting. "WRTDS_2017data...csv" contains discrete water quality data. "WRTDS_2017info...csv" contains site information and model specifications. The folder "flowScaled" contains individual "Q_....csv" files of daily mean streamflow for each trend site. This metadata describes the format of those 3 objects within the zipped folders.

In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project. One of the major goals of the NAWQA project was to determine how river water quality has changed over time. To support that goal, long-term consistent and comparable monitoring has been conducted by the USGS on streams and rivers throughout the Nation. Outside of the NAWQA project, the USGS and other Federal, State, and local agencies also have collected long-term water-quality data to support their own assessments of changing water quality. In 2017, data from these multiple sources were combined to support one of the most comprehensive assessments to date of water-quality trends in the United States (Oelsner and others, 2017; De Cicco and others, 2017). This data release updates these water quality trends, which ended in 2012, with 5 more years of data and now end in 2017. These datasets contain the output from the WRTDS trend models that characterize changes in water quality in rivers and streams across the Nation. The "compiledResults_final" folder contains 3 output tables: "allAnnualResults.csv", "bootOut.csv", and "parisOut.csv". "allAnnualResults.csv" contains several types of estimates of annual mean concentration and fluxes for the entire calibration period for each combination of site and parameter. These estimates include "true condition" estimates determined using the original implementation of WRTDS ("_orig" suffix). "true condition" estimates determined using WRTDS_K (i.e. using a Kalman filter: "_K" suffix), flow normalized (FN) trend estimates ("FN prefix"), lower and upper 90% confidence intervals of FN trend estimates ("FN" prefix with "Low" or "High" suffix), and FN trend estimates assuming a stationary flow regime ("SFN" suffix). Water quality changes were calculated for up to six trend periods (1972-2017, 1982-2017, 1992-2017, 2002-2017, and 2007-2017) per site and parameter. "bootOut.csv" gives the results of the bootstrap trend test, including uncertainty estimates, by site parameter and trend period. "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 flux). Finally, the "eList" for each WRTDS model (site-parameter combination) is available in the zipped folder according to whether the model was accepted or rejected; "outLists_accepted.zip" and "outLists_rejected.zip", respectively. The output tables in "compiledResults_final.zip" contain results only for models that had acceptable fits, as determined by an estimated probability of acceptance or by manual evaluation of residual and diagnostic plots. eLists are compiled according to whether the model was accepted or rejected.

In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project. One of the major goals of the NAWQA project was to determine how river water quality has changed over time. To support that goal, long-term consistent and comparable monitoring has been conducted by the USGS on streams and rivers throughout the Nation. Outside of the NAWQA project, the USGS and other Federal, State, and local agencies also have collected long-term water-quality data to support their own assessments of changing water quality. In 2017, data from these multiple sources were combined to support one of the most comprehensive assessments to date of water-quality trends in the United States (Oelsner and others, 2017; De Cicco and others, 2017). This data release updates these water quality trends, which ended in 2012, with 5 more years of data and now end in 2017. These datasets contain the output from the WRTDS trend models that characterize changes in water quality in rivers and streams across the Nation. The "compiledResults_final" folder contains 3 output tables: "allAnnualResults.csv", "bootOut.csv", and "parisOut.csv". "allAnnualResults.csv" contains several types of estimates of annual mean concentration and fluxes for the entire calibration period for each combination of site and parameter. These estimates include "true condition" estimates determined using the original implementation of WRTDS ("_orig" suffix). "true condition" estimates determined using WRTDS_K (i.e. using a Kalman filter: "_K" suffix), flow normalized (FN) trend estimates ("FN prefix"), lower and upper 90% confidence intervals of FN trend estimates ("FN" prefix with "Low" or "High" suffix), and FN trend estimates assuming a stationary flow regime ("SFN" suffix). Water quality changes were calculated for up to six trend periods (1972-2017, 1982-2017, 1992-2017, 2002-2017, and 2007-2017) per site and parameter. "bootOut.csv" gives the results of the bootstrap trend test, including uncertainty estimates, by site parameter and trend period. "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 flux). Finally, the "eList" for each WRTDS model (site-parameter combination) is available in the zipped folder according to whether the model was accepted or rejected; "outLists_accepted.zip" and "outLists_rejected.zip", respectively. The output tables in "compiledResults_final.zip" contain results only for models that had acceptable fits, as determined by an estimated probability of acceptance or by manual evaluation of residual and diagnostic plots. eLists are compiled according to whether the model was accepted or rejected.

In 1991, the U.S. Geological Survey (USGS) began a study of more than 50 major river basins across the Nation as part of the National Water-Quality Assessment (NAWQA) project. One of the major goals of the NAWQA project was to determine how river water quality has changed over time. To support that goal, long-term consistent and comparable monitoring has been conducted by the USGS on streams and rivers throughout the Nation. Outside of the NAWQA project, the USGS and other Federal, State, and local agencies also have collected long-term water-quality data to support their own assessments of changing water quality. In 2017, data from these multiple sources were combined to support one of the most comprehensive assessments to date of water-quality trends in the United States (Oelsner and others, 2017; De Cicco and others, 2017). This data release updates these water quality trends, which ended in 2012, with 5 more years of data and now end in 2017. These datasets contain the output from the WRTDS trend models that characterize changes in water quality in rivers and streams across the Nation. The "compiledResults_final" folder contains 3 output tables: "allAnnualResults.csv", "bootOut.csv", and "parisOut.csv". "allAnnualResults.csv" contains several types of estimates of annual mean concentration and fluxes for the entire calibration period for each combination of site and parameter. These estimates include "true condition" estimates determined using the original implementation of WRTDS ("_orig" suffix). "true condition" estimates determined using WRTDS_K (i.e. using a Kalman filter: "_K" suffix), flow normalized (FN) trend estimates ("FN prefix"), lower and upper 90% confidence intervals of FN trend estimates ("FN" prefix with "Low" or "High" suffix), and FN trend estimates assuming a stationary flow regime ("SFN" suffix). Water quality changes were calculated for up to six trend periods (1972-2017, 1982-2017, 1992-2017, 2002-2017, and 2007-2017) per site and parameter. "bootOut.csv" gives the results of the bootstrap trend test, including uncertainty estimates, by site parameter and trend period. "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 flux). Finally, the "eList" for each WRTDS model (site-parameter combination) is available in the zipped folder according to whether the model was accepted or rejected; "outLists_accepted.zip" and "outLists_rejected.zip", respectively. The output tables in "compiledResults_final.zip" contain results only for models that had acceptable fits, as determined by an estimated probability of acceptance or by manual evaluation of residual and diagnostic plots. eLists are compiled according to whether the model was accepted or rejected.