Selected evapotranspiration data were collected from 7/5/2011 to 1/1/2017 at the Amargosa Desert Research Site (ADRS, https://nevada.usgs.gov/adrs/) in support of ongoing research to improve the understanding of hydrologic and contaminant-transport processes in arid environments. The data presented in this data release includes 30-minute and daily evapotranspiration and associated energy-balance fluxes, precipitation, soil water content, air and soil temperature, wind speed and direction, humidity, and photosynthetically active radiation. Data methods follow those described in Moreo and others (2017). This is the third in a series of three releases of evapotranspiration data, which has been measured continuously at the ADRS since 2002.

Abstract from SIR 2017-5079: This report documents methodology and results of a study to evaluate groundwater discharge by evapotranspiration (GWET) in sparsely vegetated areas of Amargosa Desert and improve understanding of hydrologic-continuum processes controlling groundwater discharge. Evapotranspiration and GWET rates were computed and characterized at three sites over 2 years using a combination of micrometeorological, unsaturated zone, and stable-isotope measurements. One site (Amargosa Flat Shallow [AFS]) was in a sparse and isolated area of saltgrass (Distichlis spicata) where the depth to groundwater was 3.8 meters (m). The second site (Amargosa Flat Deep [AFD]) was in a sparse cover of predominantly shadscale (Atriplex confertifolia) where the depth to groundwater was 5.3 m. The third site (Amargosa Desert Research Site [ADRS]), selected as a control site where GWET is assumed to be zero, was located in sparse vegetation dominated by creosote bush (Larrea tridentata) where the depth to groundwater was 110 m. Results indicated that capillary rise brought groundwater to within 0.9 m (at AFS) and 3 m (at AFD) of land surface, and that GWET rates were largely controlled by the slow but relatively persistent upward flow of water through the unsaturated zone in response to atmospheric-evaporative demands. Greater GWET at AFS (50 ± 20 millimeters per year [mm/yr]) than at AFD (16 ± 15 mm/yr) corresponded with its shallower depth to the capillary fringe and constantly higher soil-water content. The stable-isotope dataset for hydrogen (δ2H) and oxygen (δ18O) illustrated a broad range of plant-water-uptake scenarios. The AFS saltgrass and AFD shadscale responded to changing environmental conditions and their opportunistic water use included the time- and depth-variable uptake of unsaturated-zone water derived from a combination of groundwater and precipitation. These results can be used to estimate GWET in other areas of Amargosa Desert where hydrologic conditions are similar.

Abstract from SIR 2017-5079: This report documents methodology and results of a study to evaluate groundwater discharge by evapotranspiration (GWET) in sparsely vegetated areas of Amargosa Desert and improve understanding of hydrologic-continuum processes controlling groundwater discharge. Evapotranspiration and GWET rates were computed and characterized at three sites over 2 years using a combination of micrometeorological, unsaturated zone, and stable-isotope measurements. One site (Amargosa Flat Shallow [AFS]) was in a sparse and isolated area of saltgrass (Distichlis spicata) where the depth to groundwater was 3.8 meters (m). The second site (Amargosa Flat Deep [AFD]) was in a sparse cover of predominantly shadscale (Atriplex confertifolia) where the depth to groundwater was 5.3 m. The third site (Amargosa Desert Research Site [ADRS]), selected as a control site where GWET is assumed to be zero, was located in sparse vegetation dominated by creosote bush (Larrea tridentata) where the depth to groundwater was 110 m. Results indicated that capillary rise brought groundwater to within 0.9 m (at AFS) and 3 m (at AFD) of land surface, and that GWET rates were largely controlled by the slow but relatively persistent upward flow of water through the unsaturated zone in response to atmospheric-evaporative demands. Greater GWET at AFS (50 ± 20 millimeters per year [mm/yr]) than at AFD (16 ± 15 mm/yr) corresponded with its shallower depth to the capillary fringe and constantly higher soil-water content. The stable-isotope dataset for hydrogen (δ2H) and oxygen (δ18O) illustrated a broad range of plant-water-uptake scenarios. The AFS saltgrass and AFD shadscale responded to changing environmental conditions and their opportunistic water use included the time- and depth-variable uptake of unsaturated-zone water derived from a combination of groundwater and precipitation. These results can be used to estimate GWET in other areas of Amargosa Desert where hydrologic conditions are similar.

This data release describes micrometeorological and soil-moisture data collected from January 1, 2012 through December 31, 2016 at the Amargosa Desert Research Site adjacent to a low-level radioactive waste and hazardous chemical waste facility near Beatty, Nevada. Micrometeorological data include precipitation, solar radiation, net radiation, air temperature, relative humidity, saturated and ambient vapor pressure, wind speed and direction, barometric pressure, near-surface soil temperature, soil-heat flux, and soil-water content. Soil-moisture data include periodic measurements of volumetric water-content at four experimental sites that represent vegetated native soil, devegetated native soil, and two simulated waste disposal trenches—maximum measurement depths range from 5.25 to 29.25 meters. All data are compiled in electronic spreadsheets that are included with this release.

This data release describes micrometeorological and soil-moisture data collected from January 1, 2012 through December 31, 2016 at the Amargosa Desert Research Site adjacent to a low-level radioactive waste and hazardous chemical waste facility near Beatty, Nevada. Micrometeorological data include precipitation, solar radiation, net radiation, air temperature, relative humidity, saturated and ambient vapor pressure, wind speed and direction, barometric pressure, near-surface soil temperature, soil-heat flux, and soil-water content. Soil-moisture data include periodic measurements of volumetric water-content at four experimental sites that represent vegetated native soil, devegetated native soil, and two simulated waste disposal trenches—maximum measurement depths range from 5.25 to 29.25 meters. All data are compiled in electronic spreadsheets that are included with this release.

This data release describes micrometeorological and soil-moisture data collected from January 1, 2017 through May 31, 2019 at the Amargosa Desert Research Site adjacent to a low-level radioactive waste and hazardous chemical waste facility near Beatty, Nevada. Micrometeorological data include precipitation, solar radiation, air temperature, relative humidity, saturated and ambient vapor pressure, wind speed and direction, barometric pressure, and soil-water content. Soil-moisture data include periodic measurements of volumetric water-content at four experimental sites that represent vegetated native soil, devegetated native soil, and two simulated waste disposal trenches—maximum measurement depths range from 5.25 to 29.25 meters. All data are compiled in electronic spreadsheets that are included with this release.

In cooperation with the Bureau of Reclamation (Lower Colorado Region), the U.S. Geological Survey collected meteorological data from 4/22/2013 to 4/25/2017 at Lake Mead and 4/11/2013 to 9/30/2016 at Lake Mohave. Meteorological monitoring equipment were mounted to a floating platform located at each lake. The data presented in this data release includes 30-minute mean air temperature, relative humidity, wind speed and direction, water surface temperature, net radiation, and incoming solar radiation. Quality assurance consisted of (1) monthly site visits to inspect and clean sensors, (2) recalibrating each sensor as necessary according to manufacturer guidelines, and (3) manual and graphical analysis for out-of-range values and anomalous patterns. Net radiation data were corrected for sensitivity to wind speed (Campbell Scientific, Inc, 2016) and calibrated following the procedures outlined in Moreo and Swancar (2013, p. 7-10). Meteorological data were collected in support of ongoing evaporation research at both lakes.

This U.S. Geological Survey data release presents monthly evaporation estimates from Lake Mead, Nevada and Arizona. Data are updated approximately annually. The spreadsheet includes five worksheets: (1) Read_Me worksheet contains information relevant to understanding the data contained in the rest of the worksheets. (2) Monthly_EC_Met worksheet includes data measured at a land-based station (USGS site identification number 360500114465601) using primarily eddy covariance measurement methods: uncorrected evaporation, latent- and sensible-heat fluxes, net radiation, air temperature, wind speed, and relative humidity. Values are monthly averages computed by averaging daily values except as noted. Monthly values are marked as estimated when a significant portion of daily values are estimated. (3) Monthly_Energy-Budget_Data worksheet includes computed data used to correct measured evaporation for energy balance. Computed data include monthly values for change in stored heat, net advection, turbulent flux, available energy, energy balance ratio, energy balance closure, and Bowen ratio. Change in stored heat was calculated based on methods in Earp and Moreo (2021). Net advection was calculated based on data estimated by the Bureau of Reclamation 24-Month Study (2022). Values are monthly averages or computed from monthly averages. (4) Annual_Energy_Balance worksheet includes annual averages of the Monthly_Energy_Balance data and the annual average values for energy-balance corrected sensible and latent heat fluxes. Values are annual averages or computed from annual averages. (5) Monthly_Evaporation_Estimates worksheet includes measured evaporation, corrected (most probable) evaporation, and energy balance ratio (EBR) adjusted evaporation, in feet. Values are monthly averages or computed from monthly averages. Data were processed according to methods described in Moreo and Swancar (2013) and Earp and Moreo (2021). References Cited: Bureau of Reclamation, Lower Colorado Region website: Operation Plan for Colorado River System Reservoirs (24-Month Study), accessed September 1, 2022 at https://www.usbr.gov/lc/region/g4000/24mo/index.html. Earp, K.J., and Moreo, M.T., 2021, Evaporation from Lake Mead and Lake Mohave, Nevada and Arizona, 2010–2019: U.S. Geological Survey Open-File Report 2021–1022, 36 p., https://doi.org/10.3133/ofr20211022. Moreo, M.T., and Swancar, A., 2013, Evaporation from Lake Mead, Nevada and Arizona, March 2010 through February 2012: U.S. Geological Survey Scientific Investigations Report 2013–5229, 40 p., http://dx.doi.org/10.3133/sir20135229.

Selected evapotranspiration data were collected between 7/8/2010 and 11/2/2012 at two eddy covariance sites and from 6/8/2011 to 11/2/2012 at two additional eddy covariance sites in Kobeh Valley, central Nevada. The data presented in this data release includes 30-minute and daily evapotranspiration and associated energy-balance fluxes, precipitation, soil water content, air and soil temperature, wind speed and direction, humidity, and photosynthetically active radiation data. Data collection and processing methods follow those described in Berger and others (2016). Berger, D.L., Mayers, C.J., Garcia, C.A., Buto, S.G., and Huntington, J.M., 2016, Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12: U.S. Geological Survey Scientific Investigations Report 2016–5055, 83 p., http://dx.doi.org/10.3133/sir20165055 .

Selected evapotranspiration data were collected between 7/8/2010 and 11/2/2012 at two eddy covariance sites and from 6/8/2011 to 11/2/2012 at two additional eddy covariance sites in Kobeh Valley, central Nevada. The data presented in this data release includes 30-minute and daily evapotranspiration and associated energy-balance fluxes, precipitation, soil water content, air and soil temperature, wind speed and direction, humidity, and photosynthetically active radiation data. Data collection and processing methods follow those described in Berger and others (2016). Berger, D.L., Mayers, C.J., Garcia, C.A., Buto, S.G., and Huntington, J.M., 2016, Budgets and chemical characterization of groundwater for the Diamond Valley flow system, central Nevada, 2011–12: U.S. Geological Survey Scientific Investigations Report 2016–5055, 83 p., http://dx.doi.org/10.3133/sir20165055 .