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At least 289 records · Page 16Linked to original sources
USGS1963

Methods of collecting and interpreting ground-water data

Because ground water is hidden from view, ancient man could only theorize as to its sources of replenishment and its behavior. His theories held sway until the latter part of the 17th century, which marked the first experimental work to determine the source and movement of ground water. Thus founded, the science of ground-water hydrology grew slowly and not until the 19th century is there substantial evidence of conclusions having been based on observational data. The 20th century has witnessed tremendous advances in the science in the methods of field investigation and interpretation of collected data, in the methods of determining the hydrologic characteristics of water-bearing material, and in the methods of inventorying ground-water supplies. Now, as is true of many other disciplines, the science of ground-water hydrology is characterized by frequent advancement of new ideas and techniques, refinement of old techniques, and an increasing wealth of data awaiting interpretation. So that its widely scattered staff of professional hydrologists could keep abreast of new ideas and advances in the techniques of groundwater investigation, it has been the practice in the U.S. Geological Survey to distribute such information for immediate internal use. As the methods become better established and developed, they are described in formal publications. Six papers pertaining to widely different phases of ground-water investigation comprise this particular contribution. For the sake of clarity and conformity, the original papers have been revised and edited by the compiler.

Water Supply Paper↗
USGS1963

Salt-water encroachment, geology, and ground-water resources of Savannah area, Georgia and South Carolina

The Savannah area consists of about 2,300 square miles of the Coastal Plain along the coast of eastern Georgia and southeastern South Carolina. Savannah is near the center of the area. Most of the large ground-water developments are in or near Savannah. About 98 percent of the approximately 60 mgd of ground water used is pumped from the principal artesian aquifer, which is composed of about 600 feet of limestone of middle Eocene, Oligocene, and early Miocene ages. Industrial and other wells of large diameter yield as much as 4,200 gpm from the principal artesian aquifer. Pumping tests and flow-net analyses show that the coefficient of transmissibility averages about 200,000 gpd per ft in the immediate Savannah area. The specific capacity of wells in the principal artesian aquifer generally is about 50 gpm per ft of drawdown. The coefficient of storage of the principal artesian aquifer is about 0.0003 in the Savannah area. Underlying the Savannah area are a series of unconsolidated and semiconsolidated sediments ranging in age from Late Cretaceous to Recent. The Upper Cretaceous, Paleocene, and lower Eocene sediments supply readily available and usable water in other parts of the Coastal Plain, but although the character and physical properties of these formations are similar in the Savannah area to the same properties in other areas, the hydraulic and structural conditions appear to be different. Deep test wells are needed to evaluate the ground-water potential of these rocks. The lower part of the sediments of middle Eocene age acts as a confining layer to the vertical movement of water into or out of the principal artesian aquifer. Depending on the location and depth, the principal artesian aquifer consists of from one to five geologic units. The lower boundary of the aquifer is determined by a reduction in permeability and an increase in salt-water content. Although the entire limestone section is considered water bearing, most of the ground water used in the area comes from the upper part of the Ocala limestone of late Eocene age and the limestones of Oligocene age. The greatest volume of water comes from the upper part of the Ocala limestone, but the greatest number of wells are supplied from the rocks of Oligocene age. The Tampa limestone and Hawthorn formation of early Miocene age are generally water bearing; the amount and quality of the water depends on the location. The water from some wells in the Tampa and most of the water from the Hawthorn is high in hydrogen sulfide. In the northeastern part of the area the principal artesian aquifer is close to the land surface. Here the confining layer is thin and in some of the estauaries it may be completely cut through by the scouring action of the streams during tidal fluctuations. In this part of the area artesian groundwater at one time discharged from the aquifer as submarine springs. Now a reverse effect may be occurring; ocean and river water may be entering the aquifer. The silts, clays, and very fine sands of the upper Miocene and Pliocene ( ?) series generally have low permeabilities and form the upper confining layer for the principal artesian aquifer. Although all the sediments overlying the principal artesian aquifer are considered to be part of the confining layer, locally some of the upper units are water bearing. The uppermost geologic units in the Savannah area are sediments of Pliocene ( ?) to Recent age and consist of sands, silts, and clays with shell and gravel beds which are a source of water for shallow wells. The first large ground-water supply from the principal artesian aquifer was developed in 1886 by the city of Savannah. Additional municipal and industrial supplies have been developed since that time. Pumpage progressively increased to a peak of 62 mgd in 1957. Outside of the city and industrial area the 1957 pumpage was about 9 mgd. In 1958 the total pumpage in the Savannah area was about 68 mgd or about 3 mgd less th

Georgia, South Carolina↗
USGS1960

Geology and ground water in the Platte-Republican Rivers watershed and the Little Blue River basin above Angus, Nebraska, with a section on chemical quality of the ground water

This report describes an area of about 7,300 square miles in south-central Nebraska. Approximately one-fourth of the area, largely at its east end, consists of an undissected southeastward-sloping upland plain and is almost wholly irrigable; the remainder is in various stages of dissection and only parts of it are suitable for irrigation. Although some of the deeper lying bedrock formations are potential sources of water supply, they are not likely to be tapped in the near future because abundant supplies are available at shallower depth from semiconsolidated and unconsolidated deposits. The Ogallala formation of Tertiary (Pliocene) age consists of gravel, sand, silt, and volcanic ash, some layers of which are partly cemented. It was deposited by eastward-flowing streams, which formed a constructional plain above a surface into which the streams had previously eroded broad valleys. In turn, valleys were cut into the surface of the Ogallala before the overlying deposits of gravel, sand, silt, and clay of Quaternary (Pleistocene) age were laid down, also forming a constructional plain. During Recent time, streams have dissected the older deposits and have deposited thin alluvium in their valleys; also, several parts of the area have become mantled by wind-deposited sand. Because during Tertiary and Quaternary time the area repeatedly was the site of deposition and erosion, the thickness of all the stratigraphic units differs markedly from place to place. In general, however, the Ogallala formation thins eastward and in the central and eastern parts of the area is overlain by the eastward-thickening deposits of Pleistocene age. The maximum thickness of the Ogallala formation is about 500 feet, and the maximum thickness of the Pleistocene deposits is a little more than 300 feet. Each thins to a featheredge and is completely absent in parts of the area. The water-bearing part of the combined Tertiary and Pleistocene deposits is considered to be a single zone of saturation because the ground water, as it percolates southeastward beneath the area, moves out of the Tertiary and into the Quaternary deposits without apparent hindrance. The water that enters the area as underflow from the west is augmented within the area by water that infiltrates from the land surface. The principal sources of irrigating water are precipitation, seepage from canals and reservoirs, and applied irrigation water. Except for the water withdrawn through wells or discharged by natural processes where valleys have been cut into the zone of saturation, ground water leaves the area as underflow into the Platte River valley on the north, the Blue River drainage basin on the east, or the Republican River valley on the south. Part of the water used for irrigation and watering livestock and all the water used in rural and urban homes, in public buildings, and for industrial purposes is obtained from wells, To date (1952) there is no indication that the supply of ground water is being depleted faster than it is being replenished; instead, studies indicate that greater quantities can be withdrawn without causing an excessive decline of the water table. An increase of ground-water withdrawals to a sustainable maximum, however, will be possible only if the points of withdrawal are scattered fairly uniformly. It is estimated that annual withdrawals per township should not exceed 2,100 acre-feet where infiltrating precipitation is the only source of recharge, or 3,000 acre-feet where other sources of recharge are significant. Although perennial withdrawals of this amount could be sustained indefinitely, they would cause some lowering of the water table and eventually a decrease in the amount of water discharged from the area by natural means. The ground water is of the calcium bicarbonate type. In much of the area it is hard or very hard, and in places it contains excessive amounts of iron. In all other respects the water is chemically suitable for domesti

Nebraska↗
USGS2018

Evaluation of the Source and Transport of High Nitrate Concentrations in Ground Water, Warren Subbasin, California

Ground water historically has been the sole source of water supply for the Town of Yucca Valley in the Warren subbasin of the Morongo ground-water basin, California. An imbalance between ground-water recharge and pumpage caused ground-water levels in the subbasin to decline by as much as 300 feet from the late 1940s through 1994. In response, the local water district, Hi-Desert Water District, instituted an artificial recharge program in February 1995 using imported surface water to replenish the ground water. The artificial recharge program resulted in water-level recoveries of as much as 250 feet in the vicinity of the recharge ponds between February 1995 and December 2001; however, nitrate concentrations in some wells also increased from a background concentration of 10 milligrams per liter to more than the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 44 milligrams per liter (10 milligrams per liter as nitrogen). The objectives of this study were to: (1) evaluate the sources of the high-nitrate concentrations that occurred after the start of the artificial-recharge program, (2) develop a ground-water flow and solute-transport model to better understand the source and transport of nitrates in the aquifer system, and (3) utilize the calibrated models to evaluate the possible effect of a proposed conjunctive-use project. These objectives were accomplished by collecting water-level and water-quality data for the subbasin and assessing changes that have occurred since artificial recharge began. Collected data were used to calibrate the ground-water flow and solute-transport models. Data collected for this study indicate that the areal extent of the water-bearing deposits is much smaller (about 5.5 square miles versus 19 square miles) than that of the subbasin. These water-bearing deposits are referred to in this report as the Warren ground-water basin. Faults separate the ground-water basin into five hydrogeologic units: the west, the midwest, the mideast, the east and the northeast hydrogeologic units. Water-quality analyses indicate that septage from septic tanks is the primary source of the high-nitrate concentrations measured in the Warren ground-water basin. Water-quality and stable-isotope data, collected after the start of the artificial recharge program, indicate that mixing occurs between imported water and native ground water, with the highest recorded nitrate concentrations in the midwest and the mideast hydrogeologic units. In general, the timing of the increase in measured nitrate concentrations in the midwest hydrogeologic unit is directly related to the distance of the monitoring well from a recharge site, indicating that the increase in nitrate concentrations is related to the artificial recharge program. Nitrate-to-chloride and nitrogen-isotope data indicate that septage is the source of the measured increase in nitrate concentrations in the midwest and the mideast hydrogeologic units. Samples from four wells in the Warren ground-water basin were analyzed for caffeine and selected human pharmaceutical products; these analyses suggest that septage is reaching the water table. There are two possible conceptual models that explain how high-nitrate septage reaches the water table: (1) the continued downward migration of septage through the unsaturated zone to the water table and (2) rising water levels, a result of the artificial recharge program, entraining septage in the unsaturated zone. The observations that nitrate concentrations increase in ground-water samples from wells soon after the start of the artificial recharge program in 1995 and that the largest increase in nitrate concentrations occur in the midwest and mideast hydrogeologic units where the largest increase in water levels occur indicate the validity of the second conceptual model (rising water levels). The potential nitrate concentration resulting from a water-level rise in the midwest and mideast hydrogeologic units was estimated using a simple mixing-cell model. The estimated value is within the range of concentrations measured in samples from wells, further indicating the validity of the second conceptual model. A ground-water flow model and a solute-transport model were developed for the Warren ground-water basin for the period 1956-2001. MODFLOW-96 was used for the ground-water flow model and MOC3D was used for the solute-transport model. The model cell size is about 500 feet by 500 feet and the models were discretized vertically into three layers. The models were calibrated using a trial-and-error approach using water-level and nitrate-concentration data collected between 1956-2001. In order to better match the measured data, low fault hydraulic characteristic values were required, thereby compartmentalizing the ground-water basin. In addition, it was necessary to parameterize the specific yield distribution for the top model layer where unconfined ground-water conditions occur into three homogeneous zones. Separate sets of specific- yield values were needed to simulate the drawdown and subsequent water-level recovery. In addition, the calibrated natural recharge was about 83 acre-feet per year. The entrainment of unsaturated-zone septage was simulated as recharge having an associated nitrate concentration. The volume of recharge was a function of the measured water-level rise between 1994-98 and the moisture content of the unsaturated zone. The nitrate concentration of the recharge water was a weighted function of the assumed nitrate concentration in the infiltrating water associated with the overlying land use. The simulated hydraulic head and nitrate concentration results were in good agreement with the measured data indicating that the mechanism for the increase in nitrate concentrations was rising water levels entraining high-nitrate septage in the unsaturated-zone. The calibrated models were used to simulate the possible effects of a planned conjunctive-use project in the western part of the ground-water basin. The simulated project included the addition of a new recharge pond and a new extraction well. In addition, recharge at two existing recharge ponds was increased and three existing production wells were pumped, treated in a nitrate-removal facility, and used for water supply. The simulated hydraulic heads increased in the west, the mideast, and parts of the east hydrogeologic units; however, the simulated hydraulic heads decreased in the midwest and northeast hydrogeologic units. The simulated nitrate concentrations increased to above the MCL of 44 milligrams per liter (10 milligrams per liter as nitrogen) in parts of the west as a result of the increase in simulated hydraulic head. The simulated nitrate concentrations decreased in part of the midwest hydrogeologic unit as a result of the artificial recharge and pumping from the nitrate-removal wells. The simulated nitrate concentrations increased to above the MCL of 44 milligrams per liter in part of the mideast and parts of the east hydrogeologic units beneath commercial land-use areas.

California↗
USGS1954

Geology and ground-water resources of the Fort Berthold Indian Reservation, North Dakota, with a section on chemical quality of the ground water

The Fort Berthold Indian Reservation occupies about 1,000 square miles in west- central North Dakota. The Missouri and Little Missouri Rivers flow through the area and form part of its boundaries. Garrison Dam, which is under construction on the Missouri River 30 miles downstream from the east boundary of the reservation, will impound water in Garrison Reservoir and flood the valleys of both rivers throughout the area. The reservoir will divide the reservation into five parts, herein referred to as the eastern, northeastern, northern, western, and southern segments. Rock formations ranging in age from Paleocene to Recent are exposed. The Fort Union formation of Paleocene age underlies the entire reservation, and it crops out along the Missouri and Little Missouri Rivers. Relatively thin glacial till and outwash deposits of late Pleistocene age mantle much of the upland in all of the segments. The glacial de. posits commonly are less than 10 feet thick; in many places they consist only of scattered boulders on the bedrock surface. The major valleys have terrace deposits of Pleistocene and Recent age and alluvium of Recent age. The principal mineral resources of the reservation are lignite, sand, and gravel. The lignite beds range in thickness from a few inches to about 30 feet. At least four separate beds, which range in thickness from 4 feet to more than 7 feet, are mined locally. Although many mines will be flooded after Garrison Dam is completed, many suitable mine sites will remain above the proposed reservoir level. Sand and gravel deposits are found in glacial outwash and in stream-terrace deposits. On upland areas of the reservation ground water is available principally from the lignite and the associated fine- to medium-grained sandstone beds of the Fort Union formation. Few wells on the reservation are known to produce water from glacial material, although the recessional moraines are possible sources of shallow-water supplies. Small quantities of ground water are available from thin alluvial deposits in some places on the upland. Most wells in the valleys produce water from the alluvium or the terrace deposits. However, several wells penetrate the underlying Fort Union formation. A few flowing wells in the Missouri River valley near Elbowoods produce water from either the lower part of the Fort Union formation or from the Cannonball formation, also of Paleocene age. The chemical character of water from the Fort Union formation and the outwash and river gravels was determined from analyses of 39 samples from wells and springs. Water from bedrock may be either hard or soft, and it is moderately to highly mineralized. Water from the surficial deposits is uniformly hard, but it is less mineralized. Shallow wells in the eastern and northeastern segments produce water of good quality. Wells in these segments, and several springs in the western segment, could be used satisfactorily as domestic supplies. Spring water from lignite deposits on the reservation generally is colored and contains objectionable amounts of iron. Treatment of the water would improve its quality for domestic use. The filling of Garrison Reservoir will cause a rise of the water levels in wells that tap aquifers now discharging below the operating level of the reservoir. All the permeable strata below this level will become saturated, and ground-water bodies that are now separated will become hydraulically united. In addition to providing subsurface information, the drilling program of the U. S. Bureau of Indian Affairs provided wells for domestic and stock-water supplies. All test holes that tapped an adequate supply of potable water were reamed to a larger diameter, equipped with casing and well screen, and gravel-packed. The test-drilling program was completed in 1951; however, the drilling of domestic wells was continued under the supervision of the U. S. Geological Survey.

North Dakota↗
USGS2000

Hydrogeologic setting, water budget, and preliminary analysis of ground-water exchange at Lake Starr, a seepage lake in Polk County, Florida

Lake Starr, a 134-acre seepage lake of multiple-sinkhole origin on the Lake Wales Ridge of central Florida, was the subject of a detailed water-budget study from August 1996 through July 1998. The study monitored the effects of hydrogeologic setting, climate, and ground-water pumping on the water budget and lake stage. The hydrogeologic setting of the Lake Starr basin differs markedly on the two sides of the lake. Ground water from the surficial aquifer system flows into the lake from the northwest side of the basin, and lake water leaks out to the surficial aquifer system on the southeast side of the basin. Lake Starr and the surrounding surficial aquifer system recharge the underlying Upper Floridan aquifer. The rate of recharge to the Upper Floridan aquifer is determined by the integrity of the intermediate confining unit and by the downward head gradient between the two aquifers. On the inflow side of the lake, the intermediate confining unit is more continuous, allowing ground water from the surficial aquifer system to flow laterally into the lake. Beneath the lake and on the southeast side of the basin, breaches in the intermediate confining unit enhance downward flow to the Upper Floridan aquifer, so that water flows both downward and laterally away from the lake through the ground-water flow system in these areas. An accurate water budget, including evaporation measured by the energy-budget method, was used to calculate net ground-water flow to the lake, and to do a preliminary analysis of the relation of net ground-water fluxes to other variables. Water budgets constructed over different timeframes provided insight on processes that affect ground-water interactions with Lake Starr. Weekly estimates of net ground-water flow provided evidence for the occurrence of transient inflows from the nearshore basin, as well as the short-term effects of head in the Upper Floridan aquifer on ground-water exchange with the lake. Monthly water budgets showed the effects of wet and dry seasons, and provided evidence for ground-water inflow generated from the upper basin. Annual water budgets showed how differences in timing of rainfall and pumping stresses affected lake stage and lake ground-water interactions. Lake evaporation measurements made during the study suggest that, on average, annual lake evaporation exceeds annual precipitation in the basin. Rainfall was close to the long-term average of 51.99 inches per year for the 2 years of the study (50.68 and 54.04 inches, respectively). Lake evaporation was 57.08 and 55.88 inches per year for the same 2 years, making net precipitation (rainfall minus evaporation) negative during both years. If net precipitation to seepage lakes in this area is negative over the long-term, then the ability to generate net ground-water inflow from the surrounding basin plays an important role in sustaining lake levels. Evaporation exceeded rainfall by a similar amount for both years of the study, but net ground-water flow differed substantially between the 2 years. The basin contributed net ground-water inflow to the lake in both years, however, net ground-water inflow was not sufficient to make up for the negative net precipitation during the first year, and the lake fell 4.9 inches. During the second year, net ground-water inflow exceeded the difference between evaporation and rainfall and the lake rose by 12.7 inches. The additional net ground-water inflow in the second year was due to both an increase in the amount of gross ground-water inflow and a decrease in lake leakage (ground-water outflow). Ground-water inflow was greater during the second year because more rain fell during the winter, when evaporative losses were low, resulting in greater ground-water recharge. However, decreased lake leakage during this year was probably at least as important as increased ground-water inflow in explaining the difference in net ground-water flow to the lake between the 2 years. Estimates of lake leakage based on a relation between net ground-water flow and head in the Upper Floridan aquifer could easily account for the differences in net ground-water exchange with the lake in the 2 years of the study. The relation between net ground-water flow and head in the Upper Floridan aquifer implied that an estimated 1-foot increase in the average Upper Floridan aquifer head from the first to the second year could account for reduced leakage of about 8.5 million cubic feet of water from Lake Starr, or an additional 17 inches of lake stage over a year. The first year of the study was representative of typical rainfall patterns, where most of the rainfall occurs during the summer. If rainfall and lake evaporation in the first year reflect long-term average conditions, the stage of Lake Starr will decrease unless ground-water inflow increases, or leakage decreases, compared to that year.

Florida↗
USGS2008

GSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)

The need to assess the effects of variability in climate, biota, geology, and human activities on water availability and flow requires the development of models that couple two or more components of the hydrologic cycle. An integrated hydrologic model called GSFLOW (Ground-water and Surface-water FLOW) was developed to simulate coupled ground-water and surface-water resources. The new model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Ground-Water Flow Model (MODFLOW). Additional model components were developed, and existing components were modified, to facilitate integration of the models. Methods were developed to route flow among the PRMS Hydrologic Response Units (HRUs) and between the HRUs and the MODFLOW finite-difference cells. This report describes the organization, concepts, design, and mathematical formulation of all GSFLOW model components. An important aspect of the integrated model design is its ability to conserve water mass and to provide comprehensive water budgets for a location of interest. This report includes descriptions of how water budgets are calculated for the integrated model and for individual model components. GSFLOW provides a robust modeling system for simulating flow through the hydrologic cycle, while allowing for future enhancements to incorporate other simulation techniques.

Techniques and Methods↗
USGS1978

Summary appraisals of the nation's ground-water resources – Tennessee region

Ground water is an abundant and little-used resource in the Tennessee Region, a 41,000 square mile area dominated by the Tennessee River system and including parts of Alabama, Georgia, Kentucky, Mississippi, North Carolina, Tennessee, and Virginia. One-fifth to one-fourth of the precipitation that falls on the region enters the ground-water reservoirs. During the year approximately the same amount of water leaves the ground-water system, sustaining the dry-weather flow of streams. Recharge for the region is about 22,000 million gallons per day or 0.5 million gallons per day per square mile. The major types of aquifers in the region are unconsolidated material (including sand and regolith), carbonate rocks, and fractured noncarbonate rocks. One or more of these aquifer types occurs in each of the six physiographic subdivisions of the region. The productivity of these aquifers depends on their hydraulic properties and on the distribution of these properties. The unconsolidated sand aquifers are the most homogeneous in composition and most predictable in occurrence. These aquifers commonly yield 200 to 600 gallons per minute per well depending on the thickness of sand penetrated. The most difficult aquifers to predict in regard to depth and yield are the carbonate rocks. In these aquifers it is possible to drill dry holes within a few hundred feet of wells capable of producing several thousand gallons per minute. However, with an adequate reconnaissance study to determine the occurrence of ground water and a planned test drilling program, yields of up to 300 gallons per minute per well can be expected in the carbonate aquifers. Potential yields from the fractured noncarbonate aquifers are lower than in the carbonate rocks. The chemical and physical properties of ground water in the Tennessee Region are usually within the limits recommended by the Environmental Protection Agency for drinking water, and the ground water in all but some very shallow aquifers tends to be free of pathogenic microorganisms. Saline water is not known to occur in significant quantities in the region. In 1970, 173 million gallons per day of ground water were used in the Tennessee Region. This was less than 8 percent of the total quantity of water used in the region and only 0.8 percent of the estimated ground-water recharge. Ground water is used chiefly as a source of water supply for rural areas and small towns. A lesser amount is used by industries and commercial establishments located beyond the limits of municipal water-supply systems. However, there is potential for significantly increased use in order to augment surface-water supplies and to utilize the total water resource more efficiently. Hydrologic studies and adequate test drilling would greatly increase the chances of locating large amounts of ground water, especially in the nine-tenths of the Tennessee Region that is underlain by either carbonate rocks or fractured noncarbonate rocks which have highly variable water-bearing properties. Collectively, such studies are useful in developing a concept of the hydrologic system which would permit the development of criteria for selecting well sites in other areas with a similar geological and hydrological setting. Hydrologic studies that include test drilling have been conducted in all parts of the region except the Cumberland Plateau. Some of the basic data necessary for hydrologic studies, such as geologic maps, well records, and streamflow records are available throughout the region. However, detailed information on groundwater levels, ground-water quality, and aquifer characteristics are not equally available throughout the region. This type of information cannot be obtained quickly when it is needed; it must be the product of a continuing program of studies designed to evaluate the Tennessee Region's ground-water resource. Because of the interdependence of ground water and surface water, water management efforts can be fully effective only if they involve the whole water resource. In the Tennessee Region, surface water is highly controlled, but there is at present no regionwide water-resources management plan that includes ground water.

Tennessee↗
USGS1994

Ground-water hydrology of Ogden Valley and surrounding area, eastern Weber County, UT, and simulation of ground-water flow in the Valley-fill aquifer system

The ground-water resources in Ogden Valley, eastern Weber County, Utah, were the subject of a study to provide a better understanding of the hydrologic system in the valley and to estimate the hydrologic effects of future ground-water development. The study area included the drainage basin of the Ogden River upstream from Pineview Reservoir dam and the drainage basin of Wheeler Creek. Ogden Valley and the surrounding area are underlain by rocks that range in age from Precambrian to Quaternary. The consolidated rocks that transmit and yield the most water in the area surrounding Ogden Valley are the Paleozoic carbonate rocks and the Wasatch Formation of Tertiary age. Much of the recharge to the consolidated rocks is from snowmelt that infiltrates the Wasatch Formation, which underlies a large part of the study area. Discharge from the consolidated rocks is by streams, evapotranspiration, springs, subsurface outflow, and pumping from wells. Water in the consolidated rocks is a calcium bicarbonate type and has a dissolved-solids concentration of less than 250 milligrams per liter.

Utah↗
USGS1961

Records of wells, water levels, and chemical quality of ground water in the French Prairie-Mission Bottom area, northern Willamette Valley, Oregon

An investigation of the ground-water resources of the northern Willamette Valley was begun in 1960 as a cooperative program between the Ground Water Branch, U.S. Geological Survey, and the Oregon State Engineer. The northern Willamette Valley area is one of the fastest growing areas of ground-water use within the state. The purpose of the investigation is to obtain an understanding of the availability, movement, and chemical quality of the ground-water resources of the area. This information is needed to attain an optimum development of the ground-water resources of the area and to aid in the prevention of problems of overdevelopment and pollution. The first phase of the program was the collection of well records, water level records, and chemical quality data in the central part of this area, which is known as the French Prairie-Mission Bottom area. The records collected in this phase of the study are essential in the preparation of an interpretive report describing the occurrence and movement of ground-water in the French Prairie-Mission Bottom area. These records, which will not be included in the interpretive report that is being prepared at this time, are being made available in this publication to aid in the location and the development of the ground-water resources of the area, and to serve as a supplement to the forthcoming interpretive report.

Oregon↗
USGS1987

Ground-water levels in water years 1984-86 and estimated ground-water pumpage in water years 1984-85, Carson Valley, Douglas County, Nevada

Tabulations of groundwater level measurements made during the water years 1984-86 and summaries of estimated pumpage for water years 1984 and 1985 in Carson valley, Douglas County, Nevada, are included in this report. The data are being collected to provide a record of long-term groundwater changes and pumpage estimates that can be incorporated in a groundwater model change at a later date. (USGS)

Open-File Report↗