This data release contains an inventory of 1,358 major surface water diversion structures with associated daily time series withdrawal records (1980-2022) for structures within the Upper Colorado River and Little Colorado River Basins. Diversion structures were included in this dataset if they were determined to have the capacity to divert water at rates greater than 10 cubic feet per second. Since those river basins encompasses portions of five states, water use data are dispersed among numerous federal and state agency databases and there is no centralized dataset that documents surface water use within the entire UCOL at a fine spatial and temporal resolution. Diversion structures and locations were identified from a mix of state reports, maps, and satellite imagery. A Python script was developed to automate retrieval of daily time series withdrawal records from multiple state and federal databases. The script was also used to process, filter, and harmonize the diversion records to remove outlier values and estimate missing data. The original withdrawal data, the processed datasets, and the Python script are included in this data release.

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).

The U.S. Geological Survey developed a coupled groundwater and surface-water flow (GSFLOW) model to represent the aquifers of the Colorado Plateau and Upper Colorado River Basin. The study area covers approximately 142,000 square miles and includes parts of Arizona, Colorado, New Mexico, Utah, and Wyoming. To support this modeling effort, groundwater well withdrawal volume data were needed from January 01, 1980 to September 30, 2022. These data were retrieved from online state databases. In addition to withdrawal-volume data, well-construction data including depths and/or perforated casing intervals were recorded when available from the databases and/or scanned driller’s logs. Arizona groundwater-withdrawal volume and well-construction data were downloaded from the Arizona Department of Water Resources. Colorado groundwater-withdrawal volume and well-construction data were accessed via the Colorado Department of Natural Resources Decision Support Systems. New Mexico groundwater-withdrawal volume and well-construction data were downloaded from the New Mexico Office of the State Engineer’s New Mexico Water Rights Reporting System (NMWRRS). Utah groundwater-withdrawal volume and well-construction data were accessed via the Utah Division of Water Rights Water Use Data Portal and Utah's State Geographic Information Database (SGID). Wyoming groundwater-withdrawal volume and well-construction data were retrieved from the Wyoming Water Development Office Public Water System Surveys and Wyoming State’s Engineer Office. Because of the different state databases, each state has slightly different information (see Supplemental Information).

The U.S. Geological Survey developed a coupled groundwater and surface-water flow (GSFLOW) model to represent the aquifers of the Colorado Plateau and Upper Colorado River Basin. The study area covers approximately 142,000 square miles and includes parts of Arizona, Colorado, New Mexico, Utah, and Wyoming. To support this modeling effort, groundwater well withdrawal volume data were needed from January 01, 1980 to September 30, 2022. These data were retrieved from online state databases. In addition to withdrawal-volume data, well-construction data including depths and/or perforated casing intervals were recorded when available from the databases and/or scanned driller’s logs. Arizona groundwater-withdrawal volume and well-construction data were downloaded from the Arizona Department of Water Resources. Colorado groundwater-withdrawal volume and well-construction data were accessed via the Colorado Department of Natural Resources Decision Support Systems. New Mexico groundwater-withdrawal volume and well-construction data were downloaded from the New Mexico Office of the State Engineer’s New Mexico Water Rights Reporting System (NMWRRS). Utah groundwater-withdrawal volume and well-construction data were accessed via the Utah Division of Water Rights Water Use Data Portal and Utah's State Geographic Information Database (SGID). Wyoming groundwater-withdrawal volume and well-construction data were retrieved from the Wyoming Water Development Office Public Water System Surveys and Wyoming State’s Engineer Office. Because of the different state databases, each state has slightly different information (see Supplemental Information).

This data release contains two sets of estimated values at selected sites within the Colorado River Basin: 1) daily specific conductance at 143 sites in the Upper Basin and 3 sites in the Lower Basin (WY 1980-2022); and 2) daily baseflow discharge at 100 sites in the Upper Basin and 3 sites in the Lower Basin (WY 1980-2022). The estimates of daily baseflow discharge will be used as input to an application of the USGS GSFLOW model, which is a coupled groundwater and surface-water flow model based on the integration of the USGS Precipitation-Runoff Modeling System (PRMS-V) and the USGS Modular Groundwater Flow Model (MODFLOW).

This data release contains two sets of estimated values at selected sites within the Colorado River Basin: 1) daily specific conductance at 143 sites in the Upper Basin and 3 sites in the Lower Basin (WY 1980-2022); and 2) daily baseflow discharge at 100 sites in the Upper Basin and 3 sites in the Lower Basin (WY 1980-2022). The estimates of daily baseflow discharge will be used as input to an application of the USGS GSFLOW model, which is a coupled groundwater and surface-water flow model based on the integration of the USGS Precipitation-Runoff Modeling System (PRMS-V) and the USGS Modular Groundwater Flow Model (MODFLOW).

This data release contains two sets of estimated values at selected sites within the Colorado River Basin: 1) daily specific conductance at 143 sites in the Upper Basin and 3 sites in the Lower Basin (WY 1980-2022); and 2) daily baseflow discharge at 100 sites in the Upper Basin and 3 sites in the Lower Basin (WY 1980-2022). The estimates of daily baseflow discharge will be used as input to an application of the USGS GSFLOW model, which is a coupled groundwater and surface-water flow model based on the integration of the USGS Precipitation-Runoff Modeling System (PRMS-V) and the USGS Modular Groundwater Flow Model (MODFLOW).

This data release contains measured stream discharge and total dissolved solids (TDS) data and estimated values for daily stream TDS loads, daily baseflow discharge, and daily baseflow TDS loads for 205 locations in the Upper Colorado River Basin. The estimated values, which represent conditions between 10/1/1985 and 9/30/2020, were obtained using the Weighted Regressions on Time, Discharge, and Season (WRTDS) program and a previously published method for hydrograph separation.

This data release contains measured stream discharge and total dissolved solids (TDS) data and estimated values for daily stream TDS loads, daily baseflow discharge, and daily baseflow TDS loads for 205 locations in the Upper Colorado River Basin. The estimated values, which represent conditions between 10/1/1985 and 9/30/2020, were obtained using the Weighted Regressions on Time, Discharge, and Season (WRTDS) program and a previously published method for hydrograph separation.