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USGS1966

Geological Survey Research 1966, Chapter A

'Geological Survey Research 1966' is the seventh annual review of the econamic and scientific work of the U.S. Geological Survey. As in previous years the purpose of the volume is to make available promptly to the public the highlights of Survey investigations. This year the volume consists of 4 chapters (A through D) of Professional Paper 550. Chapter A contains a summary of significant results, and the remaining chapters are made up of collections of short technical papers. Many of the results summarized in chapter A are discussed in greater detail in the short papers or in reports listed in 'Publications in Fiscal Year 1966,' beginning on page A265. The tables of contents for chapters B through D are listed on pages A259-A264. Numerous Federal, State, county, and municipal agencies listed on pages A211-A215 cooperated financially with the Geological Survey during fiscal 1966 and have contributed significantly to the results reported here. They are identified where appropriate in the short technical papers that have appeared in Geological Survey Research and in papers published cooperatively, but generally are not identified in the brief statements in chapter A. Many individuals on the staff of the Geological Survey have contributed to 'Geological Survey Research 1966.' Reference is made to only a few. Frank W. Trainer, Water Resources Division, was responsible for organizing and assembling chapter A and for critical review of papers in chapters B-D, assisted by Louis Pavlides, Geologic Division. Marston S. Chase, Publications Division, was in charge of production aspects of the series, assisted by Jesse R. Upperco in technical editing, and William H. Elliott and James R. Hamilton in planning and preparing illustrations. The volume for next year, 'Geological Survey Research 1967,' will be published as chapters af Professional Paper 5715. Previous volumes are listed below, with their series designations. Gealagical Survey Research 1960-Prof. Paper 400 Gealagical Survey Research 1961-Prof. Paper 424 Gealagical Survey Research 1962-Prof. Paper 450 Gealagical Survey Research 1963-Prof. Paper 475 Gealagical Survey Research 1964-Prof. Paper 501 Gealagical Survey Research 1965-Prof. Paper 525

Professional Paper↗
USGS1976

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

Most people in the California Region live in a semiarid or arid climate, with precipitation less than the potential evapotranspiration- environments of perennial water deficiency. The deficiency becomes most onerous during the characteristically rainless summers and during recurrent droughts that may continue for 10--20 years. However, water from winter rain and snow can be stored for use during the dry summer months, and water stored during a wet climatic period can be used in a succeeding dry period; moreover, perennial deficiency can be overcome by bringing water from areas of perennial surplus. Ground-water reservoirs have especial significance in arid and semiarid regions as repositories where water is stored or can be stored with minimum loss by evaporation. Nearly all the ground-water reservoirs of the California Region are in alluvial sediments of valleys and plains that flank the mountain ranges. The largest, underlying the vast Central Valley, occupies 10 percent of the area of the region, has an estimated usable capacity exceeding 100 million acre-feet (125 cubic kilometres), and has an annual pumpage from wells of about 13 million acre-feet (16 cubic kilometres). Another 10 percent of the region is occupied by 55 developed ground-water reservoirs that are widely distributed; aggregate annual pumpage from them is about 3 1/2 million acre-feet (4 cubic kilometres). In the southeastern desert about 60 ground-water reservoirs occupy still another 10 percent of the region; these have been explored only enough to show that most have some usable water, but current use is negligible. In northeastern California and adjacent Oregon and Nevada, ground-water reservoirs are identified only in valleys and lowlands where wells are feasible, but basaltic rocks of the Cascade Range and Modoc Plateau are excellent aquifers distributed over an area constituting about 15 percent of the region. In sum, slightly less than half the California Region is underlain by ground-water reservoirs, either in valley fill or in volcanic rocks, which can yield significant quantities of water to wells. The rest of the California Region includes the mountains, canyons, slopes, and foothills of the Sierra Nevada, Coast Ranges, and Basin Ranges, whose consolidated rocks and products of their weathering may be permeable locally but are not generally so. Here, the prevailing method of ground-water development is still mostly trial and error, and while in many places a well can yield enough water for a family, some families might have to do without amenities such as flush toilets and automatic washers. For more than half a century the California Region has led all others in North America in pumping of ground water as well as in the area, variety, yield, and export of crops irrigated by water from wells. It has led in the development and use of deep-well turbine pumps for large yield and in the drilling of water wells to great depths. At the same time, such developments have resulted in the elimination of artesian pressures that produced thousands of flowing wells in the 19th century and led to the wide distribution of "falling water tables." Also, California was first to induce encroachment of seawater into wells (in 1906); first to recognize subsidence of land caused by pumping from wells (in 1933), generating news about land sinking in San Jose, Long Beach, and along the Delta-Mendota and Friant-Kern Canals; and first to experience pollution of ground-water reservoirs by brines, chemicals, industrial wastes, and petroleum byproducts including gasoline. The region has led in research in several fields leading to solution of many of these problems. Ground-water problems developed rapidly after World War II with booming population, agriculture, industry, and water demand during several years of regionwide drought. Water levels in wells trended downward almost everywhere as a natural effect of the drought and at accelerated rates in areas of pumping for new enterprises or to supplement subnormal surface-water supplies. The declines in many pumping areas exceeded 100 feet (30 metres), and in some confined aquifers the potentiometric surface was drawn down more than 330 feet (100 metres). The depletion of ground-water storage has had "permanent" side effects, including subsidence of the land exceeding 10 feet (3 metres) in extensive areas, and seawater intrusion that ended the useful lives of many wells along the coast and as much as 6 miles (10 kilometres) inland. Some problems have been solved, but these solutions have at times created other problems. Many ground-water reservoirs have gone through one or more stages - exploration for productive aquifers, exploitation and development for use of the water, restriction to the perennial supply or "safe" yield, importation of surface water, artificial recharge of ground water, conjunctive use of surface and ground water, protection of water quality, and integrated management of use and disposal of water. This evolutionary sequence is unique for each reservoir, and so generalizations become difficult in a regional appraisal; also, the changes with time are significant and varied, and knowledge of prior events is a prerequisite in an appraisal of the resource in a specific year. As of 1970, water levels in many wells had risen significantly from the minimum levels of record reached during the 1960's or earlier; only in areas of new development and in desert areas of long-continued "mining" of nonreplenished water was ground-water storage still being depleted. Land subsidence has continued at diminishing rates and practically has come to a halt in some areas; invading seawater has been stopped or nudged back in most places where problems were significant. The current, favorable situation has been helped by climatic variations, from drought in 1945-52 and exceedingly dry years in 1959 and 1961 to above-normal precipitation in 1969 and 1970; but most of the serious problems have been solved by human efforts, including especially the implementation of the California Water Plan, transporting water from areas of perennial surplus to areas where it is used in lieu of ground water or for ground-water replenishment. All major urban areas now import water to supplement or replace the water pumped from wells. Extensive agricultural areas that formerly were irrigated solely by ground water now obtain some of their water from surface reservoirs and canals, especially in the Central Valley. With surface water available as an alternative supply, well owners can view their ground water with complacency. But complacency can lead to neglect and carelessness and consequent deterioration of the ground-water resource by pollution. Claiming heritage from the English Common Law, the existing California law grants to the landowner (riparian) and private enterprise (appropriator) rights to the water stored in ground-water reservoirs or discharged from them, including the base flow of streams. Ground-water development has been by private and local enterprise, and the California legislature has protected and encouraged local responsibility, control, and management of ground water. As to surface water, a constitutional amendment in 1928 limited riparian rights to the quantities of water that were "reasonably required for the beneficial use to be served." The surpluses have become public waters which are collected, stored, transported, and delivered under various contracts by Federal, State, and other agencies. The agencies have not stored water underground because of uncertainty as to their rights, but some local agencies have been encouraged with favorable pricing schedules to undertake the artificial recharge and management of ground-water reservoirs. Thus, conjunctive use of surface and ground water has become a matter of interagency negotiation. Of all the constraints on effective use of ground-water reservoirs, the most formidable may be the attitudes of people. Assurance of water supply is vital in areas of water deficiency, and Government has assumed increasing responsibility for the welfare of people in these areas. Unfortunately, when Government provides this assurance, most beneficiaries demand continued subsidy to the exclusion of perhaps cheaper private development. Indeed, as the water resources are presently segregated-with private rights predominant in ground water and public interest dominant in surface water-ground-water development has suffered for lack of public concern. The region has the scientific and technologic capability for effective use of groundwater reservoirs, as shown by the achievements and programs of several districts, but many districts are not organized or staffed for such comprehensive management and will need assistance and scientific expertise available from State and Federal agencies. Those agencies, in turn, may not have the scientific data that are essential to prevent haphazard activities and to enable programs to be organized for the most effective and attractive utilization of the water resources. In these days of increasing concern over pollution, existing data are generally inadequate to assess the natural deterioration of ground waters as a basis for defining pollution.

California↗
USGS1979

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

This report summarizes ground-water availability in the lower Colorado region and discusses the potential for greater ground-water development and increased efficiency of water use. The climate in the most highly developed southwestern part of the region is warm and dry and that in the northeastern part is cool and moist to dry. Although the regional average annual precipitation is only about 14 inches and most streambeds are dry during most of the year, about 1.5 billion acre-feet of ground water of moderate to good chemical quality is stored in aquifers of the region. Much of the water use is founded on pumped withdrawal of ground water. However, in most of the southwestern part of the region pumpage and consumptive use are in excess of replenishment, resulting in declining water levels. In the southwestern part of the region, water levels generally are from 200-500 feet below land surface and in large areas are less than 200 feet. Large-diameter water wells in this part of the region commonly produce 500-1 ,500 gallons per minute of water. In the northeastern part of the region, water levels generally are more than 500 feet below land surface, but in some large areas water levels are from 200-500 feet, and locally are less than 200 feet below the surface. In the northeastern part of the region, water wells generally have lower yields than those to the southwest. The yields range from a few to 2,000 gallons per minute, but most wells yield from 10 to less than 500 gallons per minute. In the southwestern part of the region about 1 billion acre-feet of ground water is recoverable from storage from the water table to a depth of 700 feet below the land surface. In the northeast about 150 million acre-feet can be recovered by dewatering a 100-foot-thick section of a typical aquifer (16 million-acre area). The estimated current annual rate of ground-water depletion, occurring almost entirely in the southwestern part of the region, is 2.4-3.2 million acre-feet per year. Almost 6 million acre-feet is pumped each year-about 90 percent for agriculture, 6 percent for public supply, and 3 percent for industrial use. The percentage of use for public supply and industry is increasing each year. The potential for greater development of ground water in the southwestern part of the region is constrained by land subsidence, earth cracks, increasing costs of pumping and transportation, and moderate to poor chemical quality of water. More ground water can be developed in the northeastern part of the region, where the major constraint is pumping cost owing to low to moderate well yields and depth to water. Some benefits can be realized everywhere in the region through changes in current use and greater efficiencies of use. Additional supplies may be made available by capture of natural evapotranspiration. Increasing the efficiency of use is possible hydrologically but, in the near term, is more expensive than increasing groundwater development. Decrease of irrigation, change to water-saving methods of irrigation, use of saline water, decrease of per capita public- supply use, and more reuse of water in almost every type of use could help extend the supply and thereby reduce the current rate of ground-water depletion. Financial problems have not yet caused an overall decrease in pumpage, but, locally, operating costs or partial dewatering of the aquifer has eliminated or decreased withdrawal. Current water laws in all States of the region, except Arizona, control or allocate the use of ground water.

Arizona, California, Nevada, New Mexico, Utah↗
USGS1975

Paleotectonic investigations of the Pennsylvanian System in the United States, Part I: Introduction and regional analyses of the Pennsylvanian System

The Pennsylvanian is the fourth geologic system to be analyzed and synthesized by geologists of the U.S. Geological Survey in the form of a paleotectonic study covering the conterminous United States. Earlier investigations were of the Jurassic, Triassic, and Permian Systems. Results were published as Miscellaneous Geologic Investigation Maps I-175, I-300, and I-450 and in Professional Paper 515. The objective of these investigations is to provide in graphic form the factual basis for recognition of tectonic events of each system on a countrywide scale. The maps in this publication depict rock thickness, generalized lithology, ancient geography, and other regional relations of the Pennsylvanian System. Method of preparation of the maps, the stratigraphic limits of the map units, and various stratigraphic and structural features and their probable tectonic significance are discussed. Pennsylvanian data were largely compiled between 1961 and 196 by 16 geologists, including the late Harold R. Wanless, who covered the five eastern regions and contributed to several of the special studies. The areas of responsibility of the cooperating geologists are indicated in figure 1. Work in Kansas was done by Gary F. Stewart, of the Kansas Geological Survey. Results of this investigation are presented in three units. Part I comprises an introduction and 17 chapters, each describing and discussing one of the regions in which the conterminous United States was divided for purposes of study and mapping. Part II is a synthesis of Pennsylvanian history to accompany interpretive maps of the five divisions of the Pennsylvanian System treated in this publication; it also includes a series of chapters on depositional environments, climatic conditions, and economic products of the system. The final section of part II is devoted to an index of localities and sources used in construction of the principal maps of this publication. Part III consists of the plates on which are presented the major maps and sections.

Professional Paper↗
USGS2007

Louisiana ground-water map no. 22: Generalized potentiometric surface of the Amite aquifer and the "2,800-foot" sand of the Baton Rouge area in southeastern Louisiana, June-August 2006

The Amite aquifer and the “2,800-foot” sand of the Baton Rouge area (hereafter referred to as the “2,800-foot” sand) are principal sources of fresh ground water in southeastern Louisiana. Both the Amite aquifer and the “2,800-foot” sand are part of the Jasper equivalent aquifer system. The Amite aquifer is heavily pumped in the Bogalusa area, and the “2,800-foot” sand is one of the most heavily pumped aquifers in East Baton Rouge Parish. The Baton Rouge fault zone, which acts as a barrier to flow, trends approximately west-northwest from a point just south of The Rigolets through southern West Baton Rouge Parish, and is the approximate southern limit of freshwater in the aquifers. For the purposes of this report, freshwater is defined as water having less than 250 milligrams per liter (mg/L) of chloride, and most of the water withdrawals described in this report were assumed to be fresh. In 2005, about 18 million gallons per day (Mgal/d) was withdrawn from the Amite aquifer, primarily for public-supply use (8.4 Mgal/d) and industrial use (9.6 Mgal/d). During this same period, about 32 Mgal/d was withdrawn from the “2,800-foot” sand, primarily for public-supply use (13 Mgal/d) and industrial use (19 Mgal/d). Public-supply and industrial withdrawals from the Amite aquifer and the “2,800-foot” sand are listed in table 1. According to data from the Louisiana State Census Data Center, some of the largest population increases in the State during the period 1990 to 2000 occurred in St. Tammany (32.4 percent), Livingston (30.2 percent), and Tangipahoa (17.4 percent) Parishes. These population increases have been accompanied by increased withdrawals of ground water during the same period: 40 percent in St. Tammany Parish, 63 percent in Livingston Parish, and 35 percent in Tangipahoa Parish. An increase in population in these parishes is expected from population displacement due to damages from Hurricanes Katrina and Rita crossing the Louisiana coast in August and September of 2005. Additional information about ground-water flow and effects of increased withdrawals on water levels in the Amite aquifer and the “2,800-foot” sand is needed to assess ground-water-development potential and to protect this resource. To meet this need, the U.S. Geological Survey, in cooperation with the Louisiana Department of Transportation and Development, began a study in 2005 to determine water levels, flow direction, and water-level trends for the Amite aquifer and “2,800-foot” sand. This report presents data and a map that describe the generalized potentiometric surface of the Amite aquifer and “2,800-foot” sand in southeastern Louisiana. Graphs of water levels in selected wells and a table of withdrawals from the Amite aquifer and “2,800-foot” sand show historical changes in water levels and water use. The generalized potentiometric-surface map illustrates the water levels and ground-water flow directions for June–August 2006. These data are on file at the USGS office in Baton Rouge, Louisiana.

Louisiana↗
USGS2014

Hydrogeology of Puerto Rico and the outlying islands of Vieques, Culebra, and Mona

The availability of hydrogeologic maps for Puerto Rico and the outlying islands of Vieques, Culebra, and Mona are important to hydrogeologists, groundwater specialists, and water resource managers and planners. These maps, in combination with the report, serve as a source of information to all users by providing basic hydrogeologic and hydrologic knowledge in a concise illustrated format. Puerto Rico and the outlying islands cover a total area of 8,927 square kilometers (km 2 ). Of this total area, about 3,500 km 2 are underlain by hydrogeologic units that are classified as intergranular or fissured. These hydrogeologic units form the principal aquifer systems throughout Puerto Rico and the outlying islands. In Puerto Rico, the most extensive and intensely developed aquifers are the North Coast Limestone aquifer system and the South Coastal Alluvial Plain aquifer system. Withdrawals from these two aquifer systems constitute nearly 70 percent of the total groundwater withdrawn in Puerto Rico. The spatial extent of the North Coast Limestone aquifer system is about 2,000 km 2 . Within this aquifer system, groundwater development is greatest in the 800-km 2 area between the Río Grande de Arecibo and the Río de la Plata. This also is the area for which concern is the highest regarding the future use of groundwater as a primary source of water for domestic and industrial use. With an estimated withdrawal of 280,000 cubic meters per day (m 3 /d), groundwater constituted the principal source of water within this area providing 100 percent of the water for self-supplied industries and about 85 percent for public water supplies in 1985. By 2005, groundwater withdrawals decreased to 150,000 m 3 /d. The spatial extent of the South Coastal Alluvial Plain aquifer system is about 470 km 2 . The estimated consumptive groundwater withdrawal from the aquifer system was 190,000 m 3 /d in 1980 and 170,000 m 3 /d in 2005. About 60 percent and 40 percent of the groundwater withdrawal from the South Coastal Alluvial Plain aquifer system was used for public water supply and irrigation, respectively. In the outlying islands of Vieques, Culebra, and Mona, only Vieques is underlain by aquifers of any local importance. The Resolución and Esperanza aquifers underlie an area covering 16 km 2 on the island of Vieques. Prior to 1978 when an underwater public water-supply pipeline connecting Vieques to the main island of Puerto Rico was completed, groundwater withdrawal from the two aquifers was as much as 2,500 m 3 /d. Groundwater withdrawals in Vieques island in 2005 were estimated at less than 100 m 3 /d. The potential development of relatively untapped groundwater resources in Puerto Rico is limited to the Río Grande de Añasco valley and the Río Culebrinas valley in the western part of the island and to the Río Grande de Arecibo part of the North Coast Limestone aquifer system. In general, the North Coast Limestone and the South Coastal Alluvial Plain aquifer systems, which are the two principal groundwater-flow systems in Puerto Rico, show evidence of aquifer overdraft as indicated by regional increases in concentrations of dissolved solids. Optimization of withdrawals through conjunctive use of both surface-water and groundwater sources and by instituting water conservation measures has the greatest potential to ensure the continued use of groundwater resources. In support of these efforts, programs also could be implemented to improve database information regarding groundwater withdrawals and the contribution of surface-water diversions to surface-water flow, especially within the southern coastal plain of Puerto Rico.

Culebra;Mona;Vieques↗
USGS2005

Use of a ground-water flow model to delineate contributing areas to the Puchack Well Field, Pennsauken township and vicinity, Camden county, New Jersey

The New Jersey Department of Environmental Protection (NJDEP) Well Head Protection Program, developed in response to the 1986 Federal Safe Drinking Water Act Amendments, requires delineation of Well Head Protection Areas (WHPA's), commonly called contributing areas, for all public and non-community water-supply wells in New Jersey. Typically, WHPA's for public community water-supply wells in New Jersey are delineated using a two-dimensional ground-water flow model incorporating the regional hydraulic gradient; however, NJDEP guidelines allow for the use of a three-dimensional flow model to delineate contributing areas to wells in complex hydrogeologic settings. The Puchack well field in Pennsauken Township, Camden County, N.J., is an area of strong hydraulic connection between the Lower aquifer of the Potomac-Raritan-Magothy aquifer system and the Delaware River. Interactions among and within the public-supply well fields in the area are complex. To delineate the contributing area to the Puchack well field, the U.S. Geological Survey, in cooperation with the NJDEP, developed an 11-layer ground-water flow model of the Potomac-Raritan-Magothy aquifer system in the Pennsauken Township area to simulate flow in the vicinity of the well field. The model incorporates the interaction between the aquifer system and the Delaware River, and includes boundary flows from an existing regional model of the Camden area. Recharge used in the model ranged from 4.5 to 14 inches per year, and horizontal hydraulic conductivity ranged from 50 to 250 feet per day. Values of vertical hydraulic conductivity ranging from 0.001 to 0.5 feet per day were assigned to zones created on the basis of variations in hydrogeologic conditions observed in geophysical logs from wells. A steady-state simulation was used to calibrate the model to synoptic water-level data collected in March 1998. Near the Puchack well field, simulated heads generally were within 1 foot of the measured heads in both the Middle and Lower aquifers. Simulated water-level differences across the confining units at most of the nested wells were within ? 0.5 feet of the differences calculated from measured water levels. The existing flow model was modified to meet NJDEP guidelines for delineating contributing areas in complex hydrogeologic settings. These modifications included rediscretizing the model grid to a finer grid and preparing the water-use data set for use in the rediscretized model. The contributing area to the Puchack well field was delineated by means of particle tracking. An uncertainty analysis was conducted in which 36 model-input parameters were both increased and decreased until the resulting change in simulated heads exceeded the model-calibration criterion of ? 5 feet at any model cell. Porosity most affected the size and shape of the contributing area. The distribution of withdrawals at the Morris/Delair well field and variations in recharge affected both the size and shape of contributing area to the Puchack well field and the source of water to the Puchack wells. The results of the uncertainty analysis were combined to determine the 'aggregate' contributing area to the Puchack well field--a composite of areas on the land surface that contributed flow to the Puchack well field in less than 12 years in any uncertainty simulation. The shape of the aggregate contributing area was most similar to that associated with a reduction in porosity, which indirectly affected the size and shape of the contributing areas by changing travel time.

Scientific Investigations Report↗
USGS2004

Water withdrawals, use, discharge, and trends in Florida, 2000

In 2000, the estimated amount of water withdrawn in Florida was 20,148 million gallons per day (Mgal/d), of which 59 percent was saline and 41 percent was fresh. Ground water accounted for 62 percent of freshwater withdrawals and surface water accounted for the remaining 38 percent. Ninety-two percent of the 15.98 million people in Florida relied on ground water for their drinking water needs in 2000. Almost all of the saline water withdrawals (99.9 percent) were from surface water. Public supply accounted for 43 percent of ground water withdrawn in 2000, followed by agricultural self-supplied (39 percent), commercial-industrial self-supplied (including mining) (8.5 percent), recreational irrigation (4.5 percent), domestic self-supplied (4 percent), and power generation (1 percent). Agricultural self-supplied accounted for 62 percent of fresh surface water withdrawn in 2000, followed by power generation (20 percent), public supply (8 percent), recreational irrigation (6 percent), and commercial-industrial self-supplied (4 percent). Almost all of saline water withdrawn was used for power generation. The largest amount of freshwater was withdrawn in Palm Beach County and the largest amount of saline water was withdrawn in Hillsborough County. Significant withdrawals (more than 200 Mgal/d) of fresh ground water occurred in Miami-Dade, Polk, Orange, Palm Beach, Broward, and Collier Counties. Significant withdrawals (more than 200 Mgal/d) of fresh surface water occurred in Palm Beach, Hendry, and Escambia Counties. The South Florida Water Management District accounted for the largest amount of freshwater withdrawn (49 percent). About 62 percent of the total ground water withdrawn was from the Floridan aquifer system; 17 percent was from the Biscayne aquifer. Most of the surface water used in Florida was from managed and maintained canal systems or large water bodies. Major sources of fresh surface water include the Caloosahatchee River, Deer Point Lake, Hillsborough River, Lake Okeechobee and associated canals, and the canals associated with the headwaters of the Upper St. Johns River. Freshwater withdrawals increased 46 percent and saline water withdrawals increased 25 percent in Florida between 1970 and 2000. Ground-water withdrawals increased 82 percent, and surface-water withdrawals increased 10 percent during this period. Between 1970 and 2000, total freshwater withdrawals increased for public supply by 176 percent and for agricultural self-supplied by 87 percent; withdrawals for commercial-industrial self-supplied decreased by 37 percent, and power generation (thermoelectric) decreased by 57 percent. Recreational irrigation withdrawals increased 127 percent between 1985 and 2000. Between 1995 and 2000, freshwater withdrawals increased 13 percent, and saline withdrawals increased 9 percent. An estimated 52 percent of the freshwater withdrawn in Florida was consumed; the remaining 48 percent was returned for further use. Domestic wastewater discharged in 2000 totaled 1,495 Mgal/d, of which 44 percent was discharged to surface waters, 34 percent to the ground through land application systems, and 22 percent to deep injection wells. Domestic wastewater discharge increased by 33 percent between 1985 and 2000, but decreased by 3 percent between 1995 and 2000. An estimated 11.21 million people were served by domestic wastewater systems in 2000, whereas the remaining 4.77 million people discharged wastewater to more than 1.95 million septic tanks. Discharge from the septic tanks was estimated to be 263 Mgal/d in 2000.

Scientific Investigations Report↗
USGS2005

Framework for regional synthesis of water-quality data for the glacial aquifer system in the United States

The glacial aquifer system is the largest principal aquifer in aerial extent and ground-water use for public supply in the United States. A principal aquifer is defined as a regionally extensive aquifer or aquifer system that has the potential to be used as a source of potable water (U.S. Geological Survey, 2003). Multiple aquifers often are grouped into large, extensive aquifer systems such as the glacial aquifer system. The glacial aquifer system is considered here to include all unconsolidated aquifers above bedrock north of the line of continental glaciation throughout the country (fig. 1). Total withdrawals from the glacial aquifer system were 3,560 million gallons per day in 2000, which constitutes almost 5 percent of total withdrawals from all aquifers in the United States (Maupin and Barber, 2005). Approximately 41 million people relied on the glacial aquifer for public supply and domestic use in 2000. The U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program began assessing the glacial aquifer system in 1991. The assessment of water-quality data on a regional scale, such as the glacial aquifer system, is coincident with the regional framework established by the Regional Aquifer-System Analysis Program (RASA) (Sun and others, 1997). From 1978 to 1995, the RASA Program systematically evaluated 25 of the Nation's most important groundwater systems including studies in the glacial aquifer system in the northeast, Midwest, and northern Midwest United States. The NAWQA Program is building on the work of the RASA Program to study the water quality of 16 of the most important ground-water systems (Lapham and others, 2005). Over 1,700 water-quality samples have been collected by the NAWQA Program from 1991 to 2004 to assess the glacial aquifer system. This large data set is unique in that the samples have been collected using a consistent sampling protocol, and multiple nested samples. The nested samples address the recently recharged shallow ground water, deeper water from principal aquifers often used for domestic supply, and source water used for public supplies within the glacial aquifer system. Information concerning the NAWQA Program including study unit boundaries is shown in figure 1 (Lapham and others, 2005). A framework for comparison of water quality across the glacial aquifer system has been developed based on two primary characteristics: intrinsic susceptibility and vulnerability. Intrinsic susceptibility, which is a measure of the ease at which water enters and moves through aquifer material, is a characteristic of the aquifer and overlying material and of the hydrologic conditions. Intrinsic susceptibility is independent of the chemical characteristics of the contaminant and its sources. In this way, intrinsic susceptibility assessments do not target specific natural or anthropogenic sources of contamination but instead consider only the physical factors affecting the flow of water to, and through the ground-water resource (Focazio and others, 2002). On a regional scale, intrinsic susceptibility is represented by the spatial distribution of fine- or coarse-grained material at the land surface, and the physical setting of the aquifer system. Vulnerability, which is a function of both intrinsic susceptibility and the proximity and characteristics of contaminant sources, includes consideration of features related to anthropogenic sources of contaminants, such as the character of the upgradient land use (for example, urban, agricultural, undeveloped, and others); as well as features related to natural sources of contaminants, such as the mineralogy of the aquifer material or the geochemical conditions within the aquifer system. The framework helps categorize this large region into areas of similar hydrogeologic characteristics for which water quality can be compared. The purpose of this report is to describe this framework and how it will be used for regional synthesis of water-quality da

Scientific Investigations Report↗
USGS2006

Mineral resource assessment of selected areas in Clark and Nye Counties, Nevada

During 2004-2006, the U.S. Geological Survey conducted a mineral resource assessment of selected areas administered by the Bureau of Land Management in Clark and Nye Counties, Nevada. The purpose of this study is to provide the BLM with information for land planning and management and, specifically, to determine mineral resource potential in accordance with regulations in 43 CFR 2310, which governs the withdrawal of public lands. The Clark County Conservation of Public Land and Natural Resources Act of 2002 (Public Law 107-282) temporarily withdraws a group of areas designated as Areas of Critical Environmental Concern (ACECs) from mineral entry, pending final approval of an application for permanent withdrawal by the BLM. This study provides information about mineral resource potential of the ACECs. Existing information was compiled about the ACECs, including geology, geophysics, geochemistry, and mineral-deposit information. Field examinations of selected areas and mineral occurrences were conducted to determine their geologic setting and mineral potential.

Nevada↗
USGS2007

Water Use in Arkansas, 2005

The water-use program in Arkansas is a cooperative effort between the Arkansas Natural Resources Commission and the U.S. Geological Survey to inventory water use. During 2005, the amount of water withdrawn from ground- and surface-water sources in Arkansas was estimated to be 11,455 million gallons per day (Mgal/d). Of this amount, about 7,510 Mgal/d (66 percent) was from ground-water and about 3,946 Mgal/d (34 percent) was from surface-water sources. Approximately 93 percent of the population (2.6 million people) in Arkansas was served by public supply systems during 2005. These systems withdrew approximately 404 Mgal/d. Most of the water, 66 percent, was from surface-water sources. The statewide average for per-capita residential use from public supply systems was 157 gallons per day and increased about 35 percent between 1965 and 2005. The largest use of water was for irrigation (8,265 Mgal/d), which accounted for 92 percent (6,942 Mgal/d) of the ground water withdrawn in Arkansas and 72 percent of the total withdrawals (both ground water and surface water). The next largest use category is thermoelectric generation (1,997 Mgal/d), followed by public supply (404 Mgal/d) and duck (hunting) clubs (269 Mgal/d). The withdrawal categories of domestic, commercial, industrial, mining, livestock, and aquaculture each withdrew less than 260 Mgal/d.

Scientific Investigations Report↗
USGS2008

Estimated use of water in the Upper Duck River watershed, central Tennessee, and water-demand projections through 2030

Future municipal water demand was estimated for the Bedford, Coffee, Marshall, and Maury-southern Williamson water-service areas in the upper Duck River watershed in central Tennessee through 2030. The Duck River, a primary source of municipal water, provided a total of 24.3 million gallons per day (Mgal/d) or 92 percent of the total water use in the study area during 2000. Municipal water use increased 46 percent from 1981 to 2000 (from 18.0 to 26.3 Mgal/d). Water demand for municipal use is expected to continue to increase through 2030 because of the recent intensive and anticipated growth in the residential and commercial sectors. Constant-rate models were used to estimate future municipal water demand. Data on residential and nonresidential billing accounts and estimates of public use and losses were used to calibrate the models. Two watershed scenarios for each water-supply system that depends on the Duck River for supply were simulated. Scenario 1 considered monthly water demand during typical weather conditions as represented by monthly per account use during 2003 and a rate of growth in customer accounts from 1999 to 2003. Results showed that total municipal water use could increase about 104 percent to 51 Mgal/d by 2030, residential water use could increase about 140 percent to 24 Mgal/d, nonresidential water use could increase about 110 percent to 17 Mgal/d, and public use and losses could increase about 83 percent to 11 Mgal/d. Scenario 2 considered monthly water demand during drought conditions as represented by monthly per account use during 2000 and recent growth in customer accounts from 1999 to 2003 or, for selected water-supply systems, an increasing rate of growth. Results showed that total municipal water use could increase about 120 percent to 55 Mgal/d, residential water use could increase about 160 percent to 26 Mgal/d, nonresidential water use could increase about 122 percent to 18 Mgal/d, and public use and losses could double and increase to 12 Mgal/d. For both scenarios the model assumed that the Duck River would supply all future surface-water needs in the study area, that ground-water resources would be sufficient to meet growing demands of the water-supply systems that depend on ground water, and that the amount of surface water sold to water-supply systems primarily dependent on ground water would remain the same through 2030.

Tennessee↗
USGS2008

Estimated Flood-Inundation Mapping for the Upper Blue River, Indian Creek, and Dyke Branch in Kansas City, Missouri, 2006-08

In the interest of improved public safety during flooding, the U.S. Geological Survey, in cooperation with the city of Kansas City, Missouri, completed a flood-inundation study of the Blue River in Kansas City, Missouri, from the U.S. Geological Survey streamflow gage at Kenneth Road to 63rd Street, of Indian Creek from the Kansas-Missouri border to its mouth, and of Dyke Branch from the Kansas-Missouri border to its mouth, to determine the estimated extent of flood inundation at selected flood stages on the Blue River, Indian Creek, and Dyke Branch. The results of this study spatially interpolate information provided by U.S. Geological Survey gages, Kansas City Automated Local Evaluation in Real Time gages, and the National Weather Service flood-peak prediction service that comprise the Blue River flood-alert system and are a valuable tool for public officials and residents to minimize flood deaths and damage in Kansas City. To provide public access to the information presented in this report, a World Wide Web site (http://mo.water.usgs.gov/indep/kelly/blueriver) was created that displays the results of two-dimensional modeling between Hickman Mills Drive and 63rd Street, estimated flood-inundation maps for 13 flood stages, the latest gage heights, and National Weather Service stage forecasts for each forecast location within the study area. The results of a previous study of flood inundation on the Blue River from 63rd Street to the mouth also are available. In addition the full text of this report, all tables and maps are available for download (http://pubs.usgs.gov/sir/2008/5068). Thirteen flood-inundation maps were produced at 2-foot intervals for water-surface elevations from 763.8 to 787.8 feet referenced to the Blue River at the 63rd Street Automated Local Evaluation in Real Time stream gage operated by the city of Kansas City, Missouri. Each map is associated with gages at Kenneth Road, Blue Ridge Boulevard, Kansas City (at Bannister Road), U.S. Highway 71, and 63rd Street on the Blue River, and at 103rd Street on Indian Creek. The National Weather Service issues peak stage forecasts for Blue Ridge Boulevard, Kansas City (at Bannister Road), U.S. Highway 71, and 63rd Street during floods. A two-dimensional depth-averaged flow model simulated flooding within a hydraulically complex, 5.6-mile study reach of the Blue River between Hickman Mills Drive and 63rd Street. Hydraulic simulation of the study reach provided information for the estimated flood-inundation maps and water-velocity magnitude and direction maps. Flood profiles of the upper Blue River between the U.S. Geological Survey streamflow gage at Kenneth Road and Hickman Mills Drive were developed from water-surface elevations calculated using Federal Emergency Management Agency flood-frequency discharges and 2006 stage-discharge ratings at U.S. Geological Survey streamflow gages. Flood profiles between Hickman Mills Drive and 63rd Street were developed from two-dimensional hydraulic modeling conducted for this study. Flood profiles of Indian Creek between the Kansas-Missouri border and the mouth were developed from water-surface elevations calculated using current stage-discharge ratings at the U.S. Geological Survey streamflow gage at 103rd Street, and water-surface slopes derived from Federal Emergency Management Agency flood-frequency stage-discharge relations. Mapped flood water-surface elevations at the mouth of Dyke Branch were set equal to the flood water-surface elevations of Indian Creek at the Dyke Branch mouth for all Indian Creek water-surface elevations; water-surface elevation slopes were derived from Federal Emergency Management Agency flood-frequency stage-discharge relations.

Scientific Investigations Report↗
USGS2010

Estimated water withdrawals and return flows in Vermont in 2005 and 2020

In 2005, about 12 percent of total water withdrawals (440 million gallons per day (Mgal/d)) in Vermont were from groundwater sources (51 Mgal/d), and about 88 percent were from surface-water sources (389 Mgal/d). Of total water withdrawals, about 78 percent were used for cooling at a power plant, 9 percent were withdrawn by public suppliers, about 5 percent were withdrawn for domestic use, about 3 percent were withdrawn for use at fish hatcheries, and the remaining 5 percent were divided among commercial/industrial, irrigation, livestock, and snowmaking uses. About 49 percent of the population of Vermont was supplied with drinking water by a public supplier, and 51 percent was self supplied. Some of the Minor Civil Divisions (MCDs) that had large self-supplied populations were located near the major cities of St. Albans, Burlington, Montpelier, Barre, and Rutland, where the cities themselves were served largely by public supply, but the surrounding areas were not. Most MCDs where withdrawals by community water systems totaled more than 1 Mgal/d used predominantly surface water, and those where withdrawals by community water systems totaled 1 Mgal/d or less used predominantly groundwater. Withdrawals of groundwater greater than 1 Mgal/d were made in Middlebury, Bethel, Hartford, Springfield, and Bennington, and withdrawals of surface water greater than 2 Mgal/d were made in Grand Isle, Burlington, South Burlington, Mendon, Brattleboro, and Vernon. Increases in groundwater withdrawals greater than 0.1 Mgal/d are projected for 2020 for Fairfax, Hardwick, Middlebury, Sharon, Proctor, Springfield, and Manchester. The largest projected increases in surface-water withdrawals from 2005 to 2020 are located along the center axis of the Green Mountains in the ski-area towns of Stowe, Warren, Mendon, Killington, and Wilmington. In 2005, withdrawals were at least 1 Mgal/d greater than return flows in South Burlington, Waterford, Orange, Mendon, Woodford, and Vernon. Many of these MCDs had small populations themselves but provided water to community water systems in neighboring towns or cities. Wilmington probably will be added to this list by 2020 because of proposed new withdrawals for snowmaking in Dover. About 15 percent of MCDs had greater return flows than withdrawals; possible reasons are water importation, larger service areas for municipal sewer than for municipal water resulting in underestimation of withdrawals, leakage into sewer pipes, faulty assumptions in assigning coefficients, or other limitations of the study methods. To store and facilitate retrieval of water-use estimates and data for 2005 and projections for 2020, a water-use database for Vermont was designed and populated. Data include withdrawals and return flows from and to groundwater and surface water for all individual facilities and entities that are in Vermont drinking water, discharge permit, or other State water-use databases, along with estimates for many other facilities. Also included are estimates for aggregated domestic and livestock withdrawals and return flows by census block. Retrievals from the database and summaries presented in this report can be used to help identify areas where projected growth in Vermont from 2005 to 2020 might affect groundwater availability.

Scientific Investigations Report↗
USGS2011

Water resources of Rockland County, New York, 2005-07, with emphasis on the Newark Basin Bedrock Aquifer

Concerns over the state of water resources in Rockland County, NY, prompted an assessment of current (2005-07) conditions. The investigation included a review of all water resources but centered on the Newark basin aquifer, a fractured-bedrock aquifer over which nearly 300,000 people reside. Most concern has been focused on this aquifer because of (1) high summer pumping rates, with occasional entrained-air problems and an unexplained water-level decline at a monitoring well, (2) annual withdrawals that have approached or even exceeded previous estimates of aquifer recharge, and (3) numerous contamination problems that have caused temporary or long-term shutdown of production wells. Public water supply in Rockland County uses three sources of water in roughly equal parts: (1) the Newark basin sedimentary bedrock aquifer, (2) alluvial aquifers along the Ramapo and Mahwah Rivers, and (3) surface waters from Lake DeForest Reservoir and a smaller, new reservoir supply in the Highlands part of the county. Water withdrawals from the alluvial aquifer in the Ramapo River valley and the Lake DeForest Reservoir are subject to water-supply application permits that stipulate minimum flows that must be maintained downstream into New Jersey. There is a need, therefore, at a minimum, to prevent any loss of the bedrock-aquifer resource--to maintain it in terms of both sustainable use and water-quality protection. The framework of the Newark basin bedrock aquifer included characterization of (1) the structure and fracture occurrence associated with the Newark basin strata, (2) the texture and thickness of overlying glacial and alluvial deposits, (3) the presence of the Palisades sill and associated basaltic units on or within the Newark basin strata, and (4) the streams that drain the aquifer system. The greatest concern regarding sustainability of groundwater resources is the aquifer response to the seasonal increase in pumping rates from May through October (an average increase of 25 percent in 2005). In most cases, pump rates would have to be reduced as aquifer yield declines. This analysis underlines the fragility of the aquifer given the fact that recent years (2003-06) have been relatively wet. Impervious surfaces increase the amount of stormflow and decrease the amount of base flow in streams. Analysis of stormflows in watersheds with 11.9 and 17 percent impervious surface area increased the percentage of rainfall that becomes stormflow in streams by 7 to 8 percent and by 12.5 to 16.5 percent, respectively. Recharge was estimated from streamflow data and from groundwater-level data. Estimates from across the county in 1961 ranged from 24.8 inches in the northwest (New York Highlands area) to 14.7 inches in the southeast. Water budgets were generated for three basins with streamflow data. During 1959-94 and in 2006, groundwater pumpage for public supply accounted for 12 to 24 percent of recharge within the Mahwah River near Suffern, NY, watershed. Public-supply pumpage as a percentage of recharge in 2006 at the two other currently gaged watersheds (Pascack Brook and Saddle River) was 18 and 21 percent, respectively. About 12.9 billion gallons of water was used in Rockland County in 2005. The majority (63 percent) was for base-line domestic supply (non-growing season rates of use); of this amount, about 6 percent was from domestic wells and 94 percent was from production wells and reservoirs. Commercial, industrial, and institutional users made up 10 percent of total water use, and growing-season increases accounted for 18 percent. Sanitary sewers serve much of Rockland County and the majority of treated wastewater is discharged to the Hudson River, which is an estuary with brackish water adjacent to Rockland County. Inflow of stormwater and infiltration of groundwater constitute a significant additional contribution of water to the sanitary sewer system.

Scientific Investigations Report↗
USGS2011

Water withdrawals, wastewater discharge, and water consumption in the Apalachicola-Chattahoochee-Flint River Basin, 2005, and water-use trends, 1970-2005

The Apalachicola-Chattahoochee-Flint (ACF) River Basin covers about 20,500 square miles that drains parts of Alabama, Florida, and Georgia. The basin extends from its headwaters northern Georgia to the Gulf of Mexico. Population in the basin was estimated to be 3.7 million in 2005, an increase of about 41 percent from the 1990 population of 2.6 million. In 2005, slightly more than 721,000 acres of crops were irrigated within the basin. In 2005, the total amount of water withdrawn in the ACF River Basin was about 1,990 million gallons per day (Mgal/d). Of this, surface water accounted for 1,591 Mgal/d (80 percent) and groundwater accounted for 399 Mgal/d (20 percent). Surface water was the primary water source of withdrawals in the northern and central parts of the basin, and groundwater was the primary source in the southern part. The largest surface-water withdrawals was from Cobb County, Georgia (410 Mgal/d, mostly from the Chattahoochee River and Lake Alatoona), and the largest groundwater withdrawals was from Dougherty County, Georgia (38 Mgal/d, mostly from the Upper Floridan aquifer system). Thermoelectric power generation accounted for the largest water withdrawals in 2005 at 788 Mgal/d (40 percent). Most of these withdrawals were used for once-through cooling, and nearly all water used for this purpose was returned to its source. Public supply accounted for 609 Mgal/d (30 percent) of total withdrawals in 2005, followed by agricultural self-supplied (including crop, golf course irrigation, and livestock) at 365 Mgal/d (18 percent), commercial-industrial self-supplied (including mining) at 191 Mgal/d (10 percent), and domestic self-supplied at 37 Mgal/d (2 percent). Public-supply withdrawals were lowest during January, February, and March (about 500 Mgal/d), and highest during September (about 700 Mgal/d). As the population of the ACF River Basin increased by 1.7 million (83 percent) in the 35 years between 1970 and 2005, total withdrawals in the basin increased by more than 515 Mgal/d (35 percent). Of this increase, surface-water accounted for 206 Mgal/d (15 percent) and groundwater accounted for 309 Mgal/d (350 percent). Since 1980, total water withdrawals have generally declined, except in 2000 when they peaked because of below-average rainfall. In 2000, an estimated 49 percent of the water withdrawn for public supply in the basin was consumed, and the remaining 51 percent was returned to the hydrologic system through wastewater treatment systems. In 2005, an estimated 38 percent was consumed and 62 percent was returned to the hydrologic system. This contrast between water withdrawals and wastewater discharges for these years was caused primarily by below-average rainfall during 2000 (a dry year) and above-average rainfall during 2005 (a wet year).

Scientific Investigations Report↗
USGS2012

Description of 2005-10 domestic water use for selected U.S. cities and guidance for estimating domestic water use

Domestic water-use and related socioeconomic and climatic data for 2005-10 were used in an analysis of 21 selected U.S. cities to describe recent domestic per capita water use, investigate variables that potentially affect domestic water use, and provide guidance for estimating domestic water use. Domestic water use may be affected by a combination of several factors. Domestic per capita water use for the selected cities ranged from a median annual average of 43 to 177 gallons per capita per day (gpcd). In terms of year-to-year variability in domestic per capita water use for the selected cities, the difference from the median ranged from ± 7 to ± 26 percent with an overall median variability of ± 14 percent. As a percentage of total annual water use, median annual domestic water use for the selected cities ranged from 33 to 71 percent with an overall median of 57 percent. Monthly production and water sales data were used to calculate daily per capita water use rates for the lowest 3 consecutive months (low-3) and the highest 3 consecutive months (high-3) of usage. Median low-3 domestic per capita water use for 16 selected cities ranged from 40 to 100 gpcd. Median high-3 domestic per capita water use for 16 selected cities ranged from 53 to 316 gpcd. In general, the median domestic water use as a percentage of the median total water use for 16 selected cities was similar for the low-3 and high-3 periods. Statistical analyses of combined data for the selected cities indicated that none of the socioeconomic variables, including cost of water, were potentially useful as determinants of domestic water use at the national level. However, specific socioeconomic variables may be useful for the estimation of domestic water use at the State or local level. Different socioeconomic variables may be useful in different States. Statistical analyses indicated that specific climatic variables may be useful for the estimation of domestic water use for some, but not all, of the selected cities. National average public supply per capita water use declined from 185 gpcd in 1990 to 171 gpcd in 2005. National average domestic delivery per capita water use declined from 105 gpcd in 1990 to 99 gpcd in 2005. Average State domestic delivery per capita water use ranged from 51 to 189 gpcd in 2005. The average annual total per capita water use in 19 selected cities that provided data for each year declined from 167 gpcd in 2006 to 145 gpcd in 2010. During this time period, average per capita water use measured during the low-3 period each year declined from 115 to 102 gpcd, and average per capita use measured during the high-3 period declined from 250 to 211 gpcd. Continued collection of data on water deliveries to domestic populations, as well as updated estimates of the population served by these deliveries, is recommended for determination of regional and temporal trends in domestic per capita water use. Declines in various measures of per capita water use have been observed in recent years for several States with municipal water use data-collection programs. Domestic self-supplied water use historically has not been metered. Estimates of self-supplied domestic water use are made using estimates of the population that is not served by public water suppliers and per capita coefficients. For 2005, the average State domestic self-supplied per capita use in the United States ranged from 50 to 206 gpcd. The median domestic self-supplied per capita use was 76 gpcd for States in which standard coefficients were used, and 98 gpcd for States in which coefficients were based on domestic deliveries from public supply. In specific areas with scarce resources or increasing numbers of households with private wells, an assessment of domestic water use may require metering of households or development of more specific per capita coefficients to estimate water demand.

California;Kansas;Mississippi;Montana;Texas;Wiscon↗
USGS2012

Groundwater quality in West Virginia, 1993-2008

Approximately 42 percent of all West Virginians rely on groundwater for their domestic water supply. However, prior to 2008, the quality of the West Virginia’s groundwater resource was largely unknown. The need for a statewide assessment of groundwater quality prompted the U.S. Geological Survey (USGS), in cooperation with West Virginia Department of Environmental Protection (WVDEP), Division of Water and Waste Management, to develop an ambient groundwater-quality monitoring program. The USGS West Virginia Water Science Center sampled 300 wells, of which 80 percent were public-supply wells, over a 10-year period, 1999–2008. Sites for this statewide ambient groundwater-quality monitoring program were selected to provide wide areal coverage and to represent a variety of environmental settings. The resulting 300 samples were supplemented with data from a related monitoring network of 24 wells and springs. All samples were analyzed for field measurements (water temperature, pH, specific conductance, and dissolved oxygen), major ions, trace elements, nutrients, volatile organic compounds, fecal indicator bacteria, and radon-222. Sub-sets of samples were analyzed for pesticides or semi-volatile organic compounds; site selection was based on local land use. Samples were grouped for comparison by geologic age of the aquifer, Groups included Cambrian, Ordovician, Silurian, Devonian, Pennsylvanian, Permian, and Quaternary aquifers. A comparison of samples indicated that geologic age of the aquifer was the largest contributor to variability in groundwater quality. This study did not attempt to characterize drinking water provided through public water systems. All samples were of raw, untreated groundwater. Drinking-water criteria apply to water that is served to the public, not to raw water. However, drinking water criteria, including U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL), non-enforceable secondary maximum contaminant level (SMCL), non-enforceable proposed MCL, or non-enforceable advisory health-based screening level (HBSL), were used as benchmarks against which to compare analytical results. Constituent concentrations were less than the MCLs in most samples. However, some samples exceeded non-enforceable SMCLs, proposed MCLs, or advisory HBSLs. Radon-222 concentrations exceeded the proposed MCL of 300 pCi/L in 45 percent of samples, and iron concentrations exceeded the SMCL of 300 µg/L in 57 percent of samples. Manganese concentrations were greater than the SMCL (50 µg/L) in 62 percent of samples and greater than the HBSL (300 µg/L) in 25 percent of the samples. Other sampled constituents, including organic compounds and trace elements, exceeded drinking-water criteria at much lower frequencies. The radon-222 median concentrations in samples from Cambrian, Ordovician, Silurian, Permian, and Quaternary aquifers exceeded the proposed 300 pCi/L MCL. Although median radon concentrations for wells in Devonian, Mississippian, and Pennsylvanian aquifers were less than the proposed MCL, radon concentrations greater than the proposed MCL were measured in samples from aquifers of all geologic ages. The median iron concentrations for samples from Devonian and Pennsylvanian aquifers were greater than the 300 µg/L SMCL. Iron concentrations exceeded the SMCL in aquifers of all geologic ages, except Cambrian. Median concentrations of manganese exceeded the SMCL in samples from Devonian, Pennsylvanian, and Quaternary aquifers. As with iron, manganese concentrations were found to exceed the SMCL in at least one sample from aquifers of all geologic ages, except Cambrian. Pesticides were detected most frequently and in higher concentrations in limestone-dominated areas. Most of West Virginia’s agriculture is concentrated in those areas. This study, the most comprehensive assessment of West Virginia groundwater quality to date, indicates the water quality of West Virginia’s groundwater is generally good; in the majority of cases raw-water samples met primary drinking water-criteria. However, some constituents, notably iron and manganese, exceeded the secondary drinking criteria in more than half the samples.

West Virginia↗