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David W. Clark

Publications and source records attributed to David W. Clark.

11 recordsLinked to original sources
USGS2017

Rapid late Pleistocene/Holocene uplift and coastal evolution of the southern Arabian (Persian) Gulf

The coastline along the southern Arabian Gulf between Al Jubail, Kingdom of Saudi Arabia, and Dubai, UAE, appears to have risen at least 125 m in the last 18,000 years. Dating and topographic surveying of paleo-dunes (43–53 ka), paleo-marine terraces (17–30 ka), and paleo-marine shorelines (3.3–5.5 ka) document a rapid, > 1 mm/a subsidence, followed by a 6 mm/a uplift that is decreasing with time. The mechanism causing this movement remains elusive but may be related to the translation of the coastal area through the backbasin to forebulge hinge line movement of the Arabian plate or, alternatively, by movement of the underlying Infracambrian-age Hormuz salt in response to sea-level changes associated with continental glaciation. Independent of the mechanism, rapid and episodic uplift may impact the design of engineering projects such as nuclear power plants, airports, and artificial islands as well as the interpretation of sedimentation and archeology of the area.

Quaternary Research↗
USGS2006

A graphical modeling tool for evaluating nitrogen loading to and nitrate transport in ground water in the mid-Snake region, south-central Idaho

A flow and transport model was created with a graphical user interface to simplify the evaluation of nitrogen loading and nitrate transport in the mid-Snake region in south-central Idaho. This model and interface package, the Snake River Nitrate Scenario Simulator, uses the U.S. Geological Survey's MODFLOW 2000 and MOC3D models. The interface, which is enabled for use with geographic information systems (GIS), was created using ESRI's royalty-free MapObjects LT software. The interface lets users view initial nitrogen-loading conditions (representing conditions as of 1998), alter the nitrogen loading within selected zones by specifying a multiplication factor and applying it to the initial condition, run the flow and transport model, and view a graphical representation of the modeling results. The flow and transport model of the Snake River Nitrate Scenario Simulator was created by rediscretizing and recalibrating a clipped portion of an existing regional flow model. The new subregional model was recalibrated with newly available water-level data and spring and ground-water nitrate concentration data for the study area. An updated nitrogen input GIS layer controls the application of nitrogen to the flow and transport model. Users can alter the nitrogen application to the flow and transport model by altering the nitrogen load in predefined spatial zones contained within similar political, hydrologic, and size-constrained boundaries.

Scientific Investigations Report↗
USGS1996

Quality of ground water and surface water in intermontane basins of the northern Rocky Mountains, Montana and Idaho

The Regional Aquifer-System Analysis (RASA) program is a series of studies by the U.S. Geological Survey (USGS) to analyze regional ground-water systems that compose a major portion of the Nations water supply (Sun, 1986). The Northern Rocky Mountains Intermontane Basins is one of the study regions in this national program. The main objectives of the RASA studies are to: (1) describe the ground-water systems as they exist today, (2) analyze the known changes that have led to the system's present condition, (3) combine results of previous studies in a regional analysis, where possible, and (4) provide means by which effects of future ground-water development can be estimated. The purpose of this study, which began in 1990, was to increase understanding of the hydrogeology of the intermontane basins of the Northern Rocky Mountains area. This report is Chapter C of a three-part series and describes the quality of ground water and surface water in the study area. Chapter A (Tuck and others, 1996) describes the geologic history and generalized hydrogeologic units. Chapter B (Briar and others, 1996) describes the general distribution of ground-water levels in basin-fill deposits. Water-quality data illustrated in this report represent the distribution of concentrations and composition of dissolved solids in ground water and surface water in the intermontane areas. The chemistry of ground and surface water in the intermontane areas is influenced by the chemical and physical nature of the rocks in the basin deposits of the valleys and surrounding bedrock in the mountains.

Hydrologic Atlas↗
USGS1991

Ground-water resources and simulated effects of withdrawals in the Bountiful area, Utah

Ground-water resources in the Bountiful area, Utah, were studied to document changes in ground-water conditions and to simulate the effects of increased ground-water withdrawals and changes in recharge. The aquifer system is in basin-fill deposits and is primarily a confined system with unconfined parts along the mountain front. Recharge to the aquifer system was estimated to range from about 22,000 to 32,000 acre-feet per year during 1947-85. Discharge was estimated to range from 26,000 to 30,000 acre-feet per year during 1947-85. Long-term trends of ground-water levels indicate a steady decline at most observation wells from 1952 to 1962. Importation of surface water for irrigation in 1962 resulted in decreased ground-water withdrawals, causing water levels to rise. Water levels fluctuated from 1962 to 1985, depending on changes in withdrawals and precipitation. A computer model of the aquifer system was constructed and calibrated using water-level data from 1946 and changes in ground-water withdrawals from 1947-86. Simulations of aquifer responses to projected withdrawals were based on a 50-percent increase in the 1981-85 rate of municipal and industrial withdrawals for 20 years using both average and less-than-average recharge rates. The simulations indicated water-level declines between 5 and 50 feet; a decrease in natural discharge to drains, by evapotranspiration, and to Great Salt Lake; and a decrease of ground water in storage after 20 years between 25,000 acre-feet using the average recharge rate, and 70,000 acre-feet using the less-than-average recharge rate.

Utah↗
USGS1990

Ground-water resources and simulated effects of withdrawals in the East Shore area of Great Salt Lake, Utah

The ground-water resources in the East Shore area of Great Salt Lake, Utah, were studied to better define the ground-water system; to document changes in ground-water levels, quality, and storage; and to simulate effects of an increase in ground-water withdrawals. The East Shore aquifer system is in basin-fill deposits, and is primarily a confined system with unconfined parts near the mountain front. Recharge to and discharge from the East Shore aquifer system were estimated to average about 160,000 acre-feet per year during 1969-84, with minor amounts of water being removed from storage during that period. Major sources of ground-water recharge are seepage from surface water in natural channels and irrigation canals, and subsurface inflow from consolidated rock to the basin-fill deposits. Discharge of ground water is primarily to wells, water courses, springs, and as diffuse seepage to Great Salt Lake. Average annual surface-water inflow to the study area was estimated to be 860,000 acre-feet for the period 1969-84. Annual withdrawal of ground water for municipal and industrial use increased from about 10,000 acre-feet in 1960 to more than 30,000 acre-feet in 1980 to supply a population that increased from 175,000 in 1960 to 290,000 in 1980. Long-term trends of ground-water levels indicate a steady decline at most observation wells since 1952, despite near normal or increased precipitation since the late 1960's. Water levels declined as much as 50 feet near the principal pumping center in the east-central part of the study area. They declined as much as 35 feet more than five miles from the pumping center. The increase in withdrawals and subsequent water-level declines have caused about 700 wells within 30 square miles to cease flowing since 1954. A numerical model of the East Shore aquifer system in the Weber Delta area was constructed and calibrated using water-level data and changes in ground-water withdrawals for 1955-85. Predictive simulations were made based on doubling the 1980-84 rate of municipal and industrial withdrawals for 20 years, and using both average and below-average recharge rates. The simulations indicated water-level declines of an additional 35 to 50 feet near the principal pumping center; a decrease in natural discharge to drains, evapotranspiration, and Great Salt Lake; and a decrease in ground-water storage of 80,000 to 115,000 acre-feet after 20 years.

Utah↗
USGS1985

Selected hydrologic data from wells in the East Shore area of the Great Salt Lake, Utah, 1985

This report contains hydrologic data for wells collected in the East Shore area of the Great Salt Lake, Utah. It includes water-quality data, discharge measurements, water levels, and drillers* logs. The East Shore area (plate 1) includes about 430 square miles, bounded by the Wasatch Range on the east and the Great Salt Lake on the west. The first section line north of the town of Willard is the northern boundary, whereas the Davis-Salt Lake County line is the southern boundary. Most of the data in this report were collected from 1983 to 1985 by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights. Some of the data were previously published by Smith (1961) or Bolke and Waddell (1972). The purpose of this report is to provide ground-water data for use by officials managing water resources and the general public and to supplement an interpretive report for the area that will be published later. From tables 1- 5 of this report, determinations can be made for the depth to water-bearing units, water levels in wells, well yields, or chemical quality of ground water at the sites shown on plate 1.

Utah↗
USGS1985

Developing a state water plan: Ground-water conditions in Utah, spring of 1985

This is the twenty-second in a series of annual reports that describe ground-water conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Division of Water Resources, provide data to enable interested parties to keep abreast of changing ground-water conditions. This report, like the others in the series, contains information on well construction, ground-water withdrawals from wells, water-level changes, and related changes in precipitation and streamflow. Supplementary data such as graphs showing chemical quality of water and maps showing ground-water level contours are included in reports of this series only for those years or areas for which applicable data are available and are important to a discussion of changing ground-water conditions. This report includes individual discussions of selected major areas of ground-water development in the State for the calendar year 1984. Water-level fluctuations, however, are described from the spring of 1984 to the spring of 1985. Much of the data used in this report were collected by the U.S. Geological Survey in cooperation with the Division of Water Rights, Utah Department of Natural Resources.

Utah↗
USGS1984

Developing a state water plan: Ground-water conditions in Utah, spring of 1984

This is the twenty-first in a series of annual reports that describe ground-water conditions in Utah. Reports in this series, published cooperatively by the U.S. Geological Survey and the Utah Division of Water Resources, provide data to enable interested parties to keep abreast of changing ground-water conditions. This report, like the others in the series, contains information on well construction, ground-water withdrawals from wells, water-level changes, and related changes in precipitation and streamflow. Supplementary data such as graphs showing chemical quality of water and maps showing ground-water level contours are included in reports of this series only for those years or areas for which applicable data are available and are important to a discussion of changing ground-water conditions. This report includes individual discussions of selected major areas of ground-water development in the State for the calendar year 1983. Water-level fluctuations, however, are described from the spring of 1983 to the spring of 1984. Much of the data used in this report were collected by the U.S. Geological Survey in cooperation with the Division of Water Rights, Utah Department of Natural Resources.

Utah↗