https://data.amerigeoss.org/dataset/17d8e1da-dbd5-4e61-9aea-cc25e3ae3ee4
type: Dataset
description: Nonstationary streamflow due to environmental and human-induced causes can affect water quality over time, yet these effects are poorly accounted for in water-quality trend models. This data release provides instream water-quality trends and estimates of two components of change, for sites across the Nation previously presented in Oelsner et al. (2017). We used previously calibrated Weighted Regressions on Time, Discharge, and Season (WRTDS) models published in De Cicco et al. (2017) to estimate instream water-quality trends and associated uncertainties with the generalized flow normalization procedure available in EGRET version 3.0 (Hirsch et al., 2018a) and EGRETci version 2.0 (Hirsch et al., 2018b). The procedure allows for nonstationarity in the flow regime, whereas previous versions of EGRET assumed streamflow stationarity. Water-quality trends of annual mean concentrations and loads (also referred to as fluxes) are provided as an annual series and the change between the start and end year for four trend periods (1972-2012, 1982-2012, 1992-2012, and 2002-2012). Information about the sites, including the collecting agency and associated streamflow gage, and information about site selection and the data screening process can be found in Oelsner et al. (2017). This data release includes results for 19 water-quality parameters including nutrients (ammonia, nitrate, filtered and unfiltered orthophosphate, total nitrogen, total phosphorus), major ions (calcium, chloride, magnesium, potassium, sodium, sulfate), salinity indicators (specific conductance, total dissolved solids), carbon (alkalinity, dissolved organic carbon, total organic carbon), and sediment (total suspended solids, suspended-sediment concentration) at over 1,200 sites. Note, the number of parameters with data varies by site with most sites having data for 1-4 parameters. Each water-quality trend was parsed into two components of change: (1) the streamflow trend component (QTC) and (2) the watershed m…
issued: 2025-11-20T04:52:18.357199
modified: 20200821
spatial: Location
title: 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
contact point: Organization
  fn: Jennifer C Murphy
keyword: amerigeo
keyword: amerigeoss
keyword: biota
keyword: carbon
keyword: ckan
keyword: concentration
keyword: contiguous-united-states-and-puerto-rico
keyword: geo
keyword: geoss
keyword: loads-fluxes
keyword: major-ions
keyword: national
keyword: north-america
keyword: nutrients
keyword: rivers
keyword: salinity
keyword: sediment
keyword: streams
keyword: surface-water-quality
keyword: united-states
keyword: usgs-589e392ce4b099f50d3a07a3
keyword: water-quality-trends
theme: {geospatial}

Original Metadata
type: Distribution
description: The metadata original format
format: XML
issued: 2022-08-07T07:04:27.961225
modified: 2025-11-20T04:52:18.345348
access URL: https://data.usgs.gov/datacatalog/metadata/USGS.589e392ce4b099f50d3a07a3.xml
media type: text/xml

Digital Data
type: Distribution
description: Landing page for access to the data
format: XML
issued: 2022-08-07T07:04:27.961232
modified: 2025-11-20T04:52:18.345750
access URL: https://doi.org/10.5066/F7TQ5ZS3
media type: application/http

US Migrating
type: Agent