Filters: Tags: unsaturated zone (X)
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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...
Categories: Data;
Types: Citation;
Tags: Amargosa Desert,
Amargosa Flat,
Evapotranspiration,
Groundwater levels,
Nevada,
Various processes within the unsaturated zone affect ground-water availability and portability, as well as concentrations of water vapor and trace gases in the atmosphere. The rate at which precipitation or applied irrigation water infiltrates, its redistribution following infiltration, and the partitioning of the redistributed soil moisture between ground-water recharge and evapotranspiration affect the rate at which the ground-water reservoir is replenished and the degree to which ground water might be contaminated by chemical applications, spills, or disposal. Consequently, knowledge of and methods to quantitatively measure and predict these processes are needed to determine the impact of such societal practices...
The NRP had its beginnings in the late 1950's. Since that time, the program has grown to encompass a broad spectrum of scientific investigations. The sciences of hydrology, mathematics, chemistry, physics, ecology, biology, geology, and engineering are used to gain a fundamental understanding of the processes that affect the availability, movement, and quality of the Nation's water resources. Results of NRP's long-term research investigations often lead to the development of new concepts, techniques, and approaches that are applicable not only to the solution of current water problems, but also to future issues that may affect the Nation's water resources. Basic tools of hydrology that have been developed by the...
Categories: Project;
Types: ScienceBase Project;
Tags: Acid Mine Drainage,
Aquatic Habitat,
Arid Land Hydrology,
Carbon Cycle,
Contaminant Reactions and Transport,
Movement of toxic and radioactive substances in aquifer systems occurs in all three phases and is controlled by both hydrologic and chemical forces. Solute movement can be greatly affected not only by physical dispersion, but by other factors such as exchange sorption, chemical kinetics, and ionic distributions. Movement of gases and particulate material in the unsaturated zone are controlled by many additional factors. Knowledge of how these physical and geochemical factors affect prediction of movement of toxic and radioactive wastes is only generally known for ideal systems. This project's objective is to develop field methods and techniques that will yield values for physical and geochemical factors of regional...
Categories: Project;
Tags: Groundwater Flow and Transport,
Radioisotopes,
Solute Transport,
Unsaturated Zone
The National Hydrologic Model (NHM) is a modeling framework which has been applied to the continental United States through the Precipitation Runoff Modeling System (PRMS). The PRMS model of Puerto Rico extends the NHM and allows the simulation of rainfall-driven hydrologic conditions in the Commonwealth. Calibration of the NHM Puerto Rico model involved an initial manual calibration to understand the important processes and develop a basic representation of the hydrology. This is followed by an automated calibration procedure using the Let Us CAlibrate (LUCA) multi-objective function model calibration tool. A four-step procedure is used in Luca to separately calibrate parameters for solar radiation, evapotranspiration,...
The overarching objective of my research is to integrate hydrology, pedology, chemistry, and physics to develop an improved process-level understanding of fluid, solute, and heat transport in unsaturated zones with applications ranging from geologic hazards to carbon storage in soils. I try to develop multi-disciplinary understanding of unsaturated zones in diverse settings with respect to groundwater-recharge and contaminant-transport determining processes, soil formation, and soil-water-plant-atmospheric interactions. I lead teams and work with others to generate individual and multidisciplinary synthesis products that address long-standing problems of fundamental importance to water resources, such as groundwater...
Categories: Project;
Tags: Climate Change,
Contaminants,
Groundwater Flow and Transport,
Unsaturated Zone
To measure, predict, and understand the flow of water through the soil and rock of the unsaturated zone. Specifically to advance (1) knowledge of aquifer recharge rates for improved management of water resources, (2) the assessment and quantification of hazards from contaminants near the earth's surface, and (3) the understanding of soil moisture processes in relation to ecological habitat. Results are directed toward large-scale problems of water quality, water availability, land-use evaluation, and environmental impacts of climate change.
This metadata record documents 8 comma delimitated files that support the USGS Scientific Investigations Report 2018-5020 on field studies in the Bucks Branch watershed and the Andover Branch watershed. Data were collected from two fields at two locations and include: groundwater, soil water, soils and plant tissue chemistry. Data also include sulfur hexafluoride and dissolved gas concentrations used in age dating of groundwater.
Categories: Data;
Tags: Agriculture,
Chesapeake Bay Watershed,
Coastal Plain,
Cover Crop,
Delmarva Peninsula,
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...
Categories: Data;
Tags: Amargosa Desert,
Armagosa Desert Research Site,
Climatology,
Mojave Desert,
Nevada,
Plan and conduct research on flow in the unsaturated zone with emphasis on development of experimental techniques and theory to describe the effects of soil physical factors, preferential flow paths, and other physical and chemical parameters of environmental importance on contamination of groundwater.
These data comprise the target and non-target VOC measurements collected from 1999 to 2016 from the shallow and deep unsaturated zone at the Amargosa Desert Research Site adjacent to a low-level radioactive waste and hazardous chemical waste facility near Beatty, Nevada. All data are compiled in electronic text files that are included with this release.
To measure, predict, and understand the flow of water through the soil and rock of the unsaturated zone. Specifically to advance (1) knowledge of aquifer recharge rates for improved management of water resources, (2) the assessment and quantification of hazards from contaminants near the earth's surface, and (3) the understanding of soil moisture processes in relation to ecological habitat. Results are directed toward large-scale problems of water quality, water availability, land-use evaluation, and environmental impacts of climate change.
Objectives are quantitative scientific examination of hydrologic processes in the near-stream environment to determine spatial and temporal patterns of stream exchanges with shallow ground, for the purpose of improved understanding of streambed exchanges and resulting impacts on water resources and stream ecology.
Widespread nitrate contamination of groundwater in agricultural areas poses a major challenge to sustainable water resources. Efficient analysis of nitrate fluxes across large regions also remains difficult. This study introduces a method of characterizing nitrate transport processes continuously across regional unsaturated zones and groundwater based on surrogate, machine-learning metamodels of an N flux process-based model. The metamodels used boosted regression trees (BRTs) to relate mappable variables to parameters and outputs of a “vertical flux method” (VFM) applied in the Fox-Wolf-Peshtigo (FWP) area in Wisconsin. In this context, the metamodels are upscaling the VFM results throughout the region, and the...
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...
Categories: Data;
Tags: Amargosa Desert,
Armagosa Desert Research Site,
Climatology,
Hydrogeology,
Mojave Desert,
This dataset represents an aquifer sensitivity rating for the vadose or unsaturated zone in the State of Wyoming. This dataset is specifically to be used within a DRASTIC-type aquifer sensitivity/vulnerability analysis.
Categories: Data;
Types: Downloadable;
Tags: Aquifer,
Aquifer Sensitivity,
Ground Water,
Ground-Water Vulnerability,
Hydrology,
In contrast with the extreme variability expected for water and contaminant fluxes in the unsaturated zone, evidence from 64 field tests of preferential flow indicates that the maximum transport speed V max, adjusted for episodicity of infiltration, deviates little from a geometric mean of 13 m/d. A model based on constant-speed travel during infiltration pulses of actual or estimated duration can predict V max with approximate order-of-magnitude accuracy, irrespective of medium or travel distance, thereby facilitating such problems as the prediction of worst-case contaminant traveltimes. The lesser variability suggests that preferential flow is subject to rate-limiting mechanisms analogous to those that impose...
This data release contains code for computing the filtering properties of cyclical infiltration in a layered vadose zone in Central Valley, California. The code for computing the filtering is described in a manuscript that is under review at Vadose Zone Journal. The updated data contained in this data release are the code to compute the filtering properties of the vadose zone. This code was developed in 2018. The code uses existing data as inputs. The inputs are from a groundwater flow model for Central Valley, California, described by Faunt et al. (2009), and from a soil texture model described by Faunt et al. (2010). The inputs from Faunt et al. (2009) and Faunt et al. (2010) were released in those years and are...
Categories: Data;
Tags: California,
Central Valley,
Hydrogeology,
Soil Sciences,
USGS Science Data Catalog (SDC),
These data comprise air, plant (creosote bush, Larrea tridentata), and unsaturated-zone tritium measurements and plant metrics collected during 2012 to 2016 from three sampling areas at the Amargosa Desert Research Site (ADRS) near Beatty, Nevada: (1) within a low-level radioactive waste facility, (2) buffer area adjacent to the waste facility, and (3) reference area 3 kilometers from the waste facility. Plant metrics include foliage-water content and canopy and stem dimensions. Supporting information includes a list of publications that provide descriptions of methods used to collect the data and results of previous tritium research at the ADRS. All data and supporting information are compiled in an electronic...
Various processes within the unsaturated zone affect ground-water availability and portability, as well as concentrations of water vapor and trace gases in the atmosphere. The rate at which precipitation or applied irrigation water infiltrates, its redistribution following infiltration, and the partitioning of the redistributed soil moisture between ground-water recharge and evapotranspiration affect the rate at which the ground-water reservoir is replenished and the degree to which ground water might be contaminated by chemical applications, spills, or disposal. Consequently, knowledge of and methods to quantitatively measure and predict these processes are needed to determine the impact of such societal practices...
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