The U.S. Geological Survey (USGS) as part of the Department of Interior WaterSmart Program compiled published estimates of groundwater discharge to streams in the Upper Colorado River Basin into a dataset and developed a geospatial database. For the purpose of this compilation, groundwater discharge to streams consists of base-flow, and may include contributions from groundwater discharge from various flow paths, lateral seepage, hyporheic flow, and irrigation return flow. Stream reaches from the National Hydrography Dataset (NHD) where there was groundwater discharge estimates were delineated in the geospatial database. Attributes describing the methods used for estimating groundwater discharge were created. Feature class attributes associated with each stream reach include: groundwater discharge (acre-ft/yr), method of measurement, report reference, defined reach, base flow index estimate (acre-ft/yr), and 8-digit HUC(s) (hydrologic unit code(s) for the reach). In addition, groundwater discharge estimates were calculated using attributes from a flow characteristics dataset (Wolock, 2003), the average annual base-flow index (BFI) value and the average daily streamflow value. The calculated groundwater discharge estimates were included in the database as separate attributes and were compared to reported estimates of groundwater discharge. Groundwater discharge estimates calculated using BFI were greater than reported groundwater discharge estimates. References cited: Wolock, D., 2003, Flow Characteristics at U.S. Geological Survey Streamgages in the Conterminous United States: U.S. Geological Survey Open-File Report 2003-146, accessed July 2, 2012 at https://water.usgs.gov/GIS/metadata/usgswrd/XML/qsitesdd.xml

This USGS data release, supporting USGS Scientific Investigations Report 2020-5075, Estimates of Groundwater Discharge by Evapotranspiration, Stump Spring and Hiko Springs, Clark County, Southern Nevada, 2016–18, consists of five datasets - Normalized Difference Vegetation Indexes (NDVI) and a mapped groundwater discharge areas (GDA) for two spring areas, and a two-class land cover classification for Stump Springs and the Area of Critical Environmental Concern (ACEC) adjacent to Stump Springs. The mapped GDAs are the area within each spring’s riparian area where discharge from evaporation by open water or bare soil and transpiration from phreatophytic plants exceeds the volume of water contributed by precipitation. The GDAs were delineated from visual interpretation of 2015 National Agricultural Imagery Program (NAIP) imagery and 2016 and 2017 WorldView 2 imagery. The WorldView 2 imagery, NDVI based on the Worldview 2 imagery, and two-class land cover classification each were used to estimate the area of riparian vegetation within the GDA.

This USGS data release, supporting USGS Scientific Investigations Report 2020-5075, Estimates of Groundwater Discharge by Evapotranspiration, Stump Spring and Hiko Springs, Clark County, Southern Nevada, 2016–18, consists of five datasets - Normalized Difference Vegetation Indexes (NDVI) and a mapped groundwater discharge areas (GDA) for two spring areas, and a two-class land cover classification for Stump Springs and the Area of Critical Environmental Concern (ACEC) adjacent to Stump Springs. The mapped GDAs are the area within each spring’s riparian area where discharge from evaporation by open water or bare soil and transpiration from phreatophytic plants exceeds the volume of water contributed by precipitation. The GDAs were delineated from visual interpretation of 2015 National Agricultural Imagery Program (NAIP) imagery and 2016 and 2017 WorldView 2 imagery. The WorldView 2 imagery, NDVI based on the Worldview 2 imagery, and two-class land cover classification each were used to estimate the area of riparian vegetation within the GDA.

This data release supports U.S. Geological Survey Scientific Investigations Report 2023-5106, Groundwater Discharge by Evapotranspiration from the Amargosa Wild and Scenic River and Contributing Areas, Inyo and San Bernardino Counties, California. Geospatial datasets presented are two polygon shapefiles representing the groundwater discharge areas and evapotranspiration units for the Amargosa Wild and Scenic River and contributing areas, and a raster dataset representing the vegetation index corresponding to the vegetated evapotranspiration unit.

This data release supports U.S. Geological Survey Scientific Investigations Report 2023-5106, Groundwater Discharge by Evapotranspiration from the Amargosa Wild and Scenic River and Contributing Areas, Inyo and San Bernardino Counties, California. Geospatial datasets presented are two polygon shapefiles representing the groundwater discharge areas and evapotranspiration units for the Amargosa Wild and Scenic River and contributing areas, and a raster dataset representing the vegetation index corresponding to the vegetated evapotranspiration unit.

The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating more than 4.5 million acres of farmland, and generating about 12 billion kilowatt hours of hydroelectric power annually. Planning for the sustainable management of the Colorado River in future climates requires an understanding of the Upper Colorado River Basin groundwater system. The Upper Colorado River Basin, encompassing more than 110,000 square miles (mi2), contains the headwaters of the Colorado River and is an important source of snowmelt runoff to the River. Groundwater discharge also is an important source of water in the River and its tributaries, with estimates ranging from 21 to 58 percent of streamflow in the upper basin. A study by Castle and others (2014) using remotely sensed gravity observations from the NASA Gravity Recovery and Climate Experiment (GRACE) mission found that UCRB groundwater was depleted by more than 17 million acre-feet (ft) from December 2004 to November 2013. Understanding groundwater-budget components, including groundwater recharge, is important to sustainably manage both groundwater and surface-water supplies in the Colorado River Basin.

The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating more than 4.5 million acres of farmland, and generating about 12 billion kilowatt hours of hydroelectric power annually. Planning for the sustainable management of the Colorado River in future climates requires an understanding of the Upper Colorado River Basin groundwater system. The Upper Colorado River Basin, encompassing more than 110,000 square miles (mi2), contains the headwaters of the Colorado River and is an important source of snowmelt runoff to the River. Groundwater discharge also is an important source of water in the River and its tributaries, with estimates ranging from 21 to 58 percent of streamflow in the upper basin. A study by Castle and others (2014) using remotely sensed gravity observations from the NASA Gravity Recovery and Climate Experiment (GRACE) mission found that UCRB groundwater was depleted by more than 17 million acre-feet (ft) from December 2004 to November 2013. Understanding groundwater-budget components, including groundwater recharge, is important to sustainably manage both groundwater and surface-water supplies in the Colorado River Basin.

This dataset was created in support of a study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a complex aquifer system comprised of both unconsolidated and bedrock formations covering an area of approximately 110,000 square miles. The aquifer system is situated in the eastern portion of the Great Basin Province of the western United States. The eastern Great Basin is experiencing rapid population growth and has some of the highest per capita water use in the Nation. These factors, combined with the arid setting, have levied intensive demand upon current groundwater resources and, thus, predictions of future shortages. Because of the large regional extent of the aquifer system, rapid growth in the region, and the reliance upon groundwater for urban populations, agriculture, and native habitats, the GBCAAS was selected by the U.S. Geological Survey (USGS) Water Resources program as part of the National Water Census Initiative to evaluate the Nation's groundwater availability. These data represent areas within the GBCAAS study area where groundwater discharge may occur as a result of evapotranspiration. The data were compiled from previously published groundwater discharge areas in the Great Basin.

This dataset was created in support of a study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a complex aquifer system comprised of both unconsolidated and bedrock formations covering an area of approximately 110,000 square miles. The aquifer system is situated in the eastern portion of the Great Basin Province of the western United States. The eastern Great Basin is experiencing rapid population growth and has some of the highest per capita water use in the Nation. These factors, combined with the arid setting, have levied intensive demand upon current groundwater resources and, thus, predictions of future shortages. Because of the large regional extent of the aquifer system, rapid growth in the region, and the reliance upon groundwater for urban populations, agriculture, and native habitats, the GBCAAS was selected by the U.S. Geological Survey (USGS) Water Resources program as part of the National Water Census Initiative to evaluate the Nation's groundwater availability. These data represent areas within the GBCAAS study area where groundwater discharge may occur as a result of evapotranspiration. The data were compiled from previously published groundwater discharge areas in the Great Basin.

This data release supports U.S. Geological Survey (USGS) Scientific Investigations Report 2023-5106, Groundwater Discharge by Evapotranspiration from the Amargosa Wild and Scenic River and Contributing Areas, Inyo and San Bernardino Counties, California. It consists of two comma-separated values (CSV) files containing data collected at two USGS atmospheric monitoring locations (USGS site identification numbers 355846116160401 and 355918116161801) beginning in January 2018 and lasting for approximately 1 year. The data include 30-minute values for cumulative normalized flux for 6 circular areas around each site and 30-minute values for unadjusted total evapotranspiration. The radii of the circular areas are 25, 50, 75, 100, 200, and 300 meters. More data from the USGS monitoring locations can be found in the USGS National Water Information System (U.S. Geological Survey, 2020): Amargosa River Shrub ET Station (USGS site identification number 355846116160401) https://waterdata.usgs.gov/monitoring-location/355846116160401 Amargosa River Wetland ET Station (USGS site identification number 355918116161801) https://waterdata.usgs.gov/monitoring-location/355918116161801 Reference Cited: U.S. Geological Survey, 2020, USGS water data for the Nation: U.S. Geological Survey database, accessed April 20, 2020, at http://doi.org/10.5066/F7P55KJN.