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This USGS Data Release supports USGS Scientific Investigations Report (SIR) 2017-5079. Following is the 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...
Evapotranspiration rates and the ground water component of evapotranspiration at a site in Colorado's San Luis Valley that is dominated by shrubby phreatophytes (greasewood and rabbitbrush) were compared before and after a water table drawdown. Evapotranspiration (ET) rates at the site were first measured in 1985–1987 (pre-drawdown) when the mean water table depth was 0.92 m. Regional ground water pumping has since lowered the water table by 1.58 m, to a mean of 2.50 m. We measured ET at the same site in 1999–2003 (post-drawdown), and assessed physical and biological factors affecting the response of ET to water table drawdown. Vegetation changed markedly from the pre-drawdown to the post-drawdown period as phreatophytic...
Evapotranspiration determined using the energy-budget method at a semi-permanent prairie-pothole wetland in east-central North Dakota, USA was compared with 12 other commonly used methods. The Priestley-Taylor and deBruin-Keijman methods compared best with the energy-budget values; mean differences were less than 0.1 mm d−1, and standard deviations were less than 0.3 mm d−1. Both methods require measurement of air temperature, net radiation, and heat storage in the wetland water. The Penman, Jensen-Haise, and Brutsaert-Stricker methods provided the next-best values for evapotranspiration relative to the energy-budget method. The mass-transfer, deBruin, and Stephens-Stewart methods provided the worst comparisons;...
In dryland ecosystems, the timing and magnitude of precipitation pulses drive many key ecological processes, notably soil water availability for plants and soil microbiota. Plant available water has frequently been viewed simply as incoming precipitation, yet processes at larger scales drive precipitation pulses, and the subsequent transformation of precipitation pulses to plant available water are complex. We provide an overview of the factors that influence the spatial and temporal availability of water to plants and soil biota using examples from western USA drylands. Large spatial- and temporal-scale drivers of regional precipitation patterns include the position of the jet streams and frontal boundaries, the...
Non-native shrub species in the genus Tamarix (saltcedar, tamarisk) have colonized hundreds of thousands of hectares of floodplains, reservoir margins, and other wetlands in western North America. Many resource managers seek to reduce saltcedar abundance and control its spread to increase the flow of water in streams that might otherwise be lost to evapotranspiration, to restore native riparian (streamside) vegetation, and to improve wildlife habitat. However, increased water yield might not always occur and has been substantially lower than expected in water salvage experiments, the potential for successful revegetation is variable, and not all wildlife taxa clearly prefer native plant habitats over saltcedar....
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The evapotranspiration (ET) datasets were created under contract for this study by the University of Idaho. A high-resolution remote sensing technique known as Mapping Evapotranspiration at High Resolution and Internalized Calibration (METRIC) was used to create estimates of the spatial distribution of ET. The METRIC technique uses thermal infrared Landsat imagery to quantify actual evapotranspiration at a 30-meter resolution that can be related to individual irrigated fields. Because evaporation uses heat energy, ground surfaces with large ET rates are left cooler as a result of ET than ground surfaces that have less ET. As a consequence, irrigated fields appear in the Landsat images as cooler than nonirrigated...
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The data set consists of evapotranspiration measurements made at the USGS Dead River forested wetland climate station beginning November 21, 2009 and ending February 29, 2016. Annual ET rates corrected to a near-surface energy-budget varied from 1448 mm (2012) to 1614 mm (2010). The eddy-covariance method was used, with high-frequency sensors installed above the forest canopy to measure sensible and latent heat fluxes. Ancillary meteorological data are also included in the data set: net radiation, soil temperature and moisture, air temperature, relative humidity, wind speed and direction, rainfall, and ground-water levels. Data were collected at 30-minute resolution, with evapotranspiration corrected to the near-surface...
Summary Human activities have historically affected hydrology in the upper Midwestern United States, specifically through the conversion of forests and prairie grasslands to agricultural uses. The hydrologic impacts of land-use change due to settlement on the water balance of three Great Lakes states: Minnesota, Wisconsin, and Michigan were analyzed using the Variable Infiltration Capacity (VIC) large-scale hydrology model, and changes in the spatial distribution of vegetation types were studied. Point model simulations demonstrated that the VIC model simulated changes in average annual and monthly evapotranspiration (ET) and total runoff response were in the same direction and had similar magnitudes to values from...
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Synopsis: This study analyzed the effects of vegetation change on hydrological fluctuations in the Columbia River basin over the last century using two land cover scenarios. The first scenario was a reconstruction of historical land cover vegetation, c. 1900. The second scenario was more recent land cover as estimated from remote sensing data for 1990. The results show that, hydrologically, the most important vegetation-related change has been a general tendency towards decreased vegetation maturity in the forested areas of the basin. This general trend represents a balance between the effects of logging and fire suppression. In those areas where forest maturity has been reduced as a result of logging, wintertime...
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Final Report - Executive Summary: This final project report is prepared to summarize the research project titled “Assessing evapotranspiration rate changes for proposed restoration of the forested uplands of the Desert Landscape Conservation Cooperatives (LCC)” for the Desert LCC of the Bureau of Reclamation as a requirement for closing out the project. This report includes the scope of work, summary of research project, results, and conclusions.Among all of the components of the terrestrial water cycle, evapotranspiration (ET) consumes the largest amount of water. Accurate estimation of ET is very important to understand the influence of ET to the hydrologic response of recharge and runoff processes in the water...
Categories: Data, Publication; Types: Citation, Map Service, OGC WFS Layer, OGC WMS Layer, OGC WMS Service; Tags: 2012, ATMOSPHERE, ATMOSPHERE, ATMOSPHERIC WATER VAPOR, ATMOSPHERIC WATER VAPOR, All tags...
Increases in the abundance or density of woody plants in historically semiarid and arid grassland ecosystems have important ecological, hydrological, and socioeconomic implications. Using a simplified water-balance model, we propose a framework for conceptualizing how woody plant encroachment is likely to affect components of the water cycle within these ecosystems. We focus in particular on streamflow and the partitioning of evapotranspiration into evaporation and transpiration. On the basis of this framework, we suggest that streamflow and evaporation processes are affected by woody plant encroachment in different ways, depending on the degree and seasonality of aridity and the availability of subsurface water....
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The data set consists of evapotranspiration measurements made at the USGS Dead River forested wetland climate station beginning November 21, 2009 and ending February 29, 2016. Annual ET rates corrected to a near-surface energy-budget varied from 1448 mm (2012) to 1614 mm (2010). The eddy-covariance method was used, with high-frequency sensors installed above the forest canopy to measure sensible and latent heat fluxes. Ancillary meteorological data are also included in the data set: net radiation, soil temperature and moisture, air temperature, relative humidity, wind speed and direction, rainfall, and ground-water levels. Data were collected at 30-minute resolution, with evapotranspiration corrected to the near-surface...
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The data set consists of monthly sums of 30-minute evapotranspiration measurements made at the USGS Starkey pasture climate station beginning May 1, 2003 and ending April 30, 2016. Annual evapotranspiration rates corrected to a near-surface energy-budget for the 12 calendar years of record at this site (2004-2015) varied from 718 millimeters (2007) to 903 millimeters (2010). The eddy-covariance method was used, with high-frequency sensors installed above the pasture to measure sensible and latent heat fluxes. Ancillary meteorological data are also included in the data set: rainfall and ground-water levels. Data were collected at 30-minute resolution, with evapotranspiration corrected to the near-surface energy-budget...
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The release of the saltcedar beetle (Diorhabda carinulata) has resulted in the periodic defoliation of tamarisk (Tamarix spp.) along more than 1000 river km in the upper Colorado River Basin and is expected to spread along many other river reaches throughout the upper basin, and possibly into the lower Colorado River Basin. Identifying the impacts of these release programs on tamarisk water use and subsequent water cycling in arid riparian systems are largely unknown, due in part to the difficulty of measuring water fluxes in these systems. We used lab-calibrated, modified heat-dissipation sap flux sensors to monitor tamarisk water use (n = 20 trees) before, during and after defoliation by the saltcedar leaf beetle...
Physiological activity and structural dynamics in arid and semi-arid ecosystems are driven by discrete inputs or "pulses" of growing season precipitation. Here we describe the short-term dynamics of ecosystem physiology in experimental stands of native (Heteropogon contortus) and invasive (Eragrostis lehmanniana) grasses to an irrigation pulse across two geomorphic surfaces with distinctly different soils: a Pleistocene-aged surface with high clay content in a strongly horizonated soil, and a Holocene-aged surface with low clay content in homogenously structured soils. We evaluated whole-ecosystem and leaf-level CO2 and H2O exchange, soil CO2 efflux, along with plant and soil water status to understand potential...
Early succession aspen and late succession conifer forests have different architecture and physiology affecting hydrologic transfer processes. An evaluation of water pools and fluxes was used to determine differences in the hydrologic dynamics between stands of quaking aspen (Populus tremuloides) and associated stands of mixed conifer consisting of white fir (Abies concolor), Douglas-fir (Pseudotsuga menziesii), and Engelmann spruce (Picea engelmannii). In 2005 and 2006, measurements of snow water accumulation, snow ablation (melt), soil water content, snowpack sublimation, and evapotranspiration (ET) were measured in adjacent aspen and conifer stands. Peak snow water equivalent (SWE) averaged 34–44% higher in...
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The evapotranspiration (ET) datasets were created under contract for this study by the University of Idaho. A high-resolution remote sensing technique known as Mapping Evapotranspiration at High Resolution and Internalized Calibration (METRIC) was used to create estimates of the spatial distribution of ET. The METRIC technique uses thermal infrared Landsat imagery to quantify actual evapotranspiration at a 30-meter resolution that can be related to individual irrigated fields. Because evaporation uses heat energy, ground surfaces with large ET rates are left cooler as a result of ET than ground surfaces that have less ET. As a consequence, irrigated fields appear in the Landsat images as cooler than nonirrigated...
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The evapotranspiration (ET) datasets were created under contract for this study by the University of Idaho. A high-resolution remote sensing technique known as Mapping Evapotranspiration at High Resolution and Internalized Calibration (METRIC) was used to create estimates of the spatial distribution of ET. The METRIC technique uses thermal infrared Landsat imagery to quantify actual evapotranspiration at a 30-meter resolution that can be related to individual irrigated fields. Because evaporation uses heat energy, ground surfaces with large ET rates are left cooler as a result of ET than ground surfaces that have less ET. As a consequence, irrigated fields appear in the Landsat images as cooler than nonirrigated...
In semiarid complex terrain, the landscape creates spatial niches for different types of vegetation through the effects of aspect, slope and curvature on the water and energy balance at the soil surface. The ecohydrology of rangelands is defined by the interaction of soils, plants and climate occurring on a topographic surface. While these interactions have been studied for subtle terrain, little is known about the controls exerted by terrain position, in particular terrain aspect, on ecosystem processes. Furthermore, differential plant establishment can lead to measurable differences in rates of soil development, which in turn can affect soil hydraulic properties and the surface water balance. In this study, we...
map background search result map search result map Sap flux-scaled transpiration by tamarisk (Tamarix spp.) before, during and after episodic defoliation by the saltcedar leaf beetle (Diorhabda carinulata) Effects of land cover change on streamflow in the interior Columbia River Basin (USA and Canada). Evapotranspiration in the Upper Klamath Basin for April 2013 Evapotranspiration in the Upper Klamath Basin for August 2013 Evapotranspiration in the Upper Klamath Basin for October 2013 1. Evapotranspiration (ET) at Dead River forested wetland site, 30-minute data, Hillsborough County, Florida, December 2009 - February 2016 3. Evapotranspiration (ET) at Dead River forested wetland site, monthly data, Hillsborough County, Florida, December 2009 - February 2016 Evapotranspiration at Starkey pasture site, monthly data, Pasco County, Florida, May 2003 - April 2016 Evapotranspiration, Groundwater, and Unsaturated-Zone Data, Amargosa Desert, Nye County, Nevada, 2011-13 Report and Publications: Assessing Evapotranspiration Rate Changes for Proposed Restoration of the Forested Uplands of the DLCC Evapotranspiration at Starkey pasture site, monthly data, Pasco County, Florida, May 2003 - April 2016 1. Evapotranspiration (ET) at Dead River forested wetland site, 30-minute data, Hillsborough County, Florida, December 2009 - February 2016 3. Evapotranspiration (ET) at Dead River forested wetland site, monthly data, Hillsborough County, Florida, December 2009 - February 2016 Evapotranspiration, Groundwater, and Unsaturated-Zone Data, Amargosa Desert, Nye County, Nevada, 2011-13 Sap flux-scaled transpiration by tamarisk (Tamarix spp.) before, during and after episodic defoliation by the saltcedar leaf beetle (Diorhabda carinulata) Evapotranspiration in the Upper Klamath Basin for April 2013 Evapotranspiration in the Upper Klamath Basin for August 2013 Evapotranspiration in the Upper Klamath Basin for October 2013 Report and Publications: Assessing Evapotranspiration Rate Changes for Proposed Restoration of the Forested Uplands of the DLCC Effects of land cover change on streamflow in the interior Columbia River Basin (USA and Canada).