Water-quality and streamflow datasets used in Weighted Regressions on Time, Discharge, and Season (WRTDS) models to determine trends in the Nation’s rivers and streams, 1972-2017 (output data)

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.

Tags: alkalinity, ammonia, bromide, calcium, chloride, dissolved-organic-carbon, environment, fluoride, magnesium, major-ions, nitrate, nutrient-content-water, orthophosphate-filtered, orthophosphate-unfiltered, particulate-organic-carbon, potassium, puerto-rico, salinity, sodium, specific-conductance, sulfate, suspended-material-water, suspended-sediment-concentration, total-dissolved-solids, total-nitrogen, total-organic-carbon, total-phosphorus, total-suspended-solids, united-states, usgs-60e61aafd34e2a7685cf637b, water-quality, water-quality-trends, weighted-regressions-on-time-discharge-and-season-wrtds
Organization: Department of the Interior