This U.S. Geological Survey (USGS) data release provides the data used to predict areas with the greatest probability of ephemeral stream channel instability on north side of the Grand Valley in western Colorado, during 2018-20. The USGS developed a method for automatically extracting channel cross-section geometry from existing remotely sensed terrain models. Based on estimated flood stage and surrogate streamflows, hydraulic characteristics were calculated. The channel geometries and hydraulic characteristics were used to estimate channel stability using a statistical model. Cross-section stabilities were determined from a stream channel stability assessment for a subset of 1,406 visited (field observed) locations out of a needed 13,415 cross sections, which were delineated from remotely sensed terrain models. Specifically, this data release includes delineated stream channels, automatically extracted cross-section profiles, survey data, estimated stream flows, Manning roughness coefficients, digital images, channel geometry characteristics and hydraulics, and channel stabilities. This data release contains subset entity zipped folders, each contains a specific metadata file.

Identifying long-term trends in water availability, including surface water quantity, is a key part of the U.S. Geological Survey (USGS) Integrated Water Availability Assessments (IWAAs) mission. This data release includes input and output data used in Mann-Kendall trend analyses to characterize streamflow conditions at 124 USGS streamgages in the Upper Colorado River Basin for water years 1982 through 2021. The Upper Colorado Riven Basin is defined here as the basin area upstream of USGS streamgage Colorado River above Lee's Ferry, AZ (USGS site number 09380000). Input data included annual (111 streamgages), seasonal (119 streamgages), and monthly (121 streamgages) streamflow metrics, calculated from daily mean streamflow data from the USGS National Water Information System (NWIS) database. Annual streamflow metrics include mean and median annual streamflow, 1-day, 7-day, and 30-day maximum annual streamflow; 1-day, 7-day, and 30-day minimum annual streamflow; and the date of the center of volume (the date on which 50 percent of the annual streamflow has passed by a streamgage). Seasonal metrics were calculated for Fall (October-December), Winter (January-March), Spring (April-June), and Summer (July-September) and include mean and median seasonal streamflow, 1-day and 7-day maximum seasonal streamflow, and 1-day and 7-day minimum seasonal streamflow. Monthly metrics include mean and median monthly streamflow, 1-day and 7-day maximum monthly streamflow, and 1-day and 7-day minimum monthly streamflow. Trend analyses using the Mann-Kendall test were completed on the annual, seasonal, and monthly metrics, which were passed through a series of data completeness filters to ensure robust trend analyses. Trend analyses were conducted for climate years 1982 through 2021 for low-flow metrics (where each climate year represents April – March), and trend analyses were conducted for water years 1982 through 2021 for all other metrics (where each water year represents October – September).

Identifying long-term trends in water availability, including surface water quantity, is a key part of the U.S. Geological Survey (USGS) Integrated Water Availability Assessments (IWAAs) mission. This data release includes input and output data used in Mann-Kendall trend analyses to characterize streamflow conditions at 124 USGS streamgages in the Upper Colorado River Basin for water years 1982 through 2021. The Upper Colorado Riven Basin is defined here as the basin area upstream of USGS streamgage Colorado River above Lee's Ferry, AZ (USGS site number 09380000). Input data included annual (111 streamgages), seasonal (119 streamgages), and monthly (121 streamgages) streamflow metrics, calculated from daily mean streamflow data from the USGS National Water Information System (NWIS) database. Annual streamflow metrics include mean and median annual streamflow, 1-day, 7-day, and 30-day maximum annual streamflow; 1-day, 7-day, and 30-day minimum annual streamflow; and the date of the center of volume (the date on which 50 percent of the annual streamflow has passed by a streamgage). Seasonal metrics were calculated for Fall (October-December), Winter (January-March), Spring (April-June), and Summer (July-September) and include mean and median seasonal streamflow, 1-day and 7-day maximum seasonal streamflow, and 1-day and 7-day minimum seasonal streamflow. Monthly metrics include mean and median monthly streamflow, 1-day and 7-day maximum monthly streamflow, and 1-day and 7-day minimum monthly streamflow. Trend analyses using the Mann-Kendall test were completed on the annual, seasonal, and monthly metrics, which were passed through a series of data completeness filters to ensure robust trend analyses. Trend analyses were conducted for climate years 1982 through 2021 for low-flow metrics (where each climate year represents April – March), and trend analyses were conducted for water years 1982 through 2021 for all other metrics (where each water year represents October – September).

IMPORTANT NOTE: This dataset includes spatial locations where streamflow permanence observations (continuous flow, discontinuous flow, and dry) were recorded using the FLOwPER (FLOw PERmanence) field survey available in the Survey 123 mobile data collection application. Additional information to describe the field conditions are included as part of the survey. Field observations in the FLOwPER Database have not been processed for quality control including spatial data accuracy or association with a stream network such as the National Hydrography Dataset. Streamflow permanence observations are collected from several governmental and non-governmental organizations on a continuing basis. This data release is formatted as a shapefile that includes streamflow permanence observations with associated information. Photographs associated with FLOwPER data observations are included. The spatial extent of this dataset is the western United States and includes the following states: Oregon, Washington, Idaho, Nevada, California, Colorado, Maryland, Montana, Virginia, Wisconsin, and Wyoming.

IMPORTANT NOTE: This dataset includes spatial locations where streamflow permanence observations (continuous flow, discontinuous flow, and dry) were recorded using the FLOwPER (FLOw PERmanence) field survey available in the Survey 123 mobile data collection application. Additional information to describe the field conditions are included as part of the survey. Field observations in the FLOwPER Database have not been processed for quality control including spatial data accuracy or association with a stream network such as the National Hydrography Dataset. Streamflow permanence observations are collected from several governmental and non-governmental organizations on a continuing basis. This data release is formatted as a shapefile that includes streamflow permanence observations with associated information. Photographs associated with FLOwPER data observations are included. The spatial extent of this dataset is the western United States and includes the following states: Oregon, Washington, Idaho, Nevada, Arizona, Utah, Alabama, and Alaska.

This dataset provides watershed delineations for 1,703 U.S. Geological Survey (USGS) streamgaging stations (gages) for geospatial statistical study of peak streamflows in and near Texas. These streamgaging stations are in Texas, Oklahoma, and New Mexico (east of the Great Continental Divide) with some of the watersheds associated with the 1,703 streamgaging stations extending into several surrounding states or into Mexico. Watershed characteristics are indexed by using the National Hydrography Dataset (NHD) version 2.2.1 Indexing was accomplished by using the Permanent Identifier (PERMID; a string that uniquely identifies each feature in the NHD) and by using the USGS identification number for the streamgaging station (gage). The following watershed characteristics are included: watershed centroid, area, perimeter, basin shape index, sinuosity, drainage area, contributing drainage area, functional drainage area, summed values per watershed from the National Inventory of Dams (NID), mean watershed slope, main-channel slope, 10-85 slope, streamgaging station point elevation, mean elevation per watershed, mean annual precipitation per streamgaging station, mean annual and monthly precipitation per watershed, mean annual and monthly solar radiation per streamgaging station, mean annual and monthly solar radiation per watershed, hydrologic soil groups per watershed, land cover per watershed, and multi order hydrologic position of streamgaging stations and stream segments. The watershed characteristics in this dataset are used to describe the point at the USGS streamgaging station, the full watershed that defines each site, and the main channel segment of each watershed.

This dataset provides watershed delineations for 1,703 U.S. Geological Survey (USGS) streamgaging stations (gages) for geospatial statistical study of peak streamflows in and near Texas. These streamgaging stations are in Texas, Oklahoma, and New Mexico (east of the Great Continental Divide) with some of the watersheds associated with the 1,703 streamgaging stations extending into several surrounding states or into Mexico. Watershed characteristics are indexed by using the National Hydrography Dataset (NHD) version 2.2.1 Indexing was accomplished by using the Permanent Identifier (PERMID; a string that uniquely identifies each feature in the NHD) and by using the USGS identification number for the streamgaging station (gage). The following watershed characteristics are included: watershed centroid, area, perimeter, basin shape index, sinuosity, drainage area, contributing drainage area, functional drainage area, summed values per watershed from the National Inventory of Dams (NID), mean watershed slope, main-channel slope, 10-85 slope, streamgaging station point elevation, mean elevation per watershed, mean annual precipitation per streamgaging station, mean annual and monthly precipitation per watershed, mean annual and monthly solar radiation per streamgaging station, mean annual and monthly solar radiation per watershed, hydrologic soil groups per watershed, land cover per watershed, and multi order hydrologic position of streamgaging stations and stream segments. The watershed characteristics in this dataset are used to describe the point at the USGS streamgaging station, the full watershed that defines each site, and the main channel segment of each watershed.

We projected future streamflow outcomes arising from climate change for the southwestern United States during the 21st century due to climate change under two possible greenhouse gas concentration pathways (RCP4.5 and 8.5). The results inform water managers about the future risks of drought in their water resource regions by providing bounds on the possible locations and extents of streamflow loss. To get to these results, we used downscaled future and historical climate data from seven models to drive a new, calibrated SPAtially Referenced Regression On Watershed attributes (SPARROW) streamflow model (Wise and others, 2019, Miller and others, 2020). Temperature and precipitation data come from the NASA Earth Exchange (NEX) Downscaled Climate Projections (NEX-DCP30, Thrasher and others, 2013 and Thrasher and others, 2015), and actual and potential evapotranspiration come from the NEX-DCP30 temperature and precipitation used in the Monthly Water Balance Model (MWBM, Hostetler and Alder, 2016 and Alder, 2017a,b,c). This data set comprises climate data preprocessing code to convert the gridded, monthly-scale climate data to reach scale multidecadal averages for the intervals 1975-2005, 2020-2049, 2040-2069 and 2070-2099, the model input (data1) and model control files, the model code, model results files, and code to post-process and analyze the streamflow model results. The raw climate data (NEX-DCP30, MWBM), and SPARROW model calibration documentation are publicly available elsewhere and are cross linked with this data release (see crossref section). The full data preparation, modeling, and analysis methods, as well as results are described in Miller and others, (2021)

We projected future streamflow outcomes arising from climate change for the southwestern United States during the 21st century due to climate change under two possible greenhouse gas concentration pathways (RCP4.5 and 8.5). The results inform water managers about the future risks of drought in their water resource regions by providing bounds on the possible locations and extents of streamflow loss. To get to these results, we used downscaled future and historical climate data from seven models to drive a new, calibrated SPAtially Referenced Regression On Watershed attributes (SPARROW) streamflow model (Wise and others, 2019, Miller and others, 2020). Temperature and precipitation data come from the NASA Earth Exchange (NEX) Downscaled Climate Projections (NEX-DCP30, Thrasher and others, 2013 and Thrasher and others, 2015), and actual and potential evapotranspiration come from the NEX-DCP30 temperature and precipitation used in the Monthly Water Balance Model (MWBM, Hostetler and Alder, 2016 and Alder, 2017a,b,c). This data set comprises climate data preprocessing code to convert the gridded, monthly-scale climate data to reach scale multidecadal averages for the intervals 1975-2005, 2020-2049, 2040-2069 and 2070-2099, the model input (data1) and model control files, the model code, model results files, and code to post-process and analyze the streamflow model results. The raw climate data (NEX-DCP30, MWBM), and SPARROW model calibration documentation are publicly available elsewhere and are cross linked with this data release (see crossref section). The full data preparation, modeling, and analysis methods, as well as results are described in Miller and others, (2021)

This data release contains drainage basin characteristics and peak-streamflow trend and change-point results for 2,683 U.S. Geological Survey (USGS) streamgages in the conterminous U.S. Data include streamgage identification number, name, drainage area, latitude, longitude, percent urban land use, dam storage, streamgage classification, record completeness status, lag-1 autocorrelation, trend slopes and significance, peaks-over-threshold counts, trends in the numbers of peaks-over-threshold, and change point years and values for median and scale. Also included is an R script containing the Mann-Kendall trend test for three different null hypotheses of the serial structure of the time-series data: independence, short-term persistence, and long-term persistence. Revised - April 8, 2019 (ver. 3.0).