Geology Reports⌕ Search

SEARCH · Geology Reports

Results for “Resource Publication”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
USGS2019

Quantifying ecological integrity of terrestrial systems to inform management of multiple-use public lands in the United States

The concept of ecological integrity has been applied widely to management of aquatic systems, but still is considered by many to be too vague and difficult to quantify to be useful for managing terrestrial systems, particularly across broad areas. Extensive public lands in the western United States are managed for diverse uses such as timber harvest, livestock grazing, energy development, and wildlife conservation, some of which may degrade ecological integrity. We propose a method for assessing ecological integrity on multiple-use lands that identifies the components of integrity and levels in the ecological hierarchy where the assessment will focus, and considers existing policies and management objectives. Both natural reference and societally desired environmental conditions are relevant comparison points. We applied the method to evaluate the ecological integrity of shrublands in Nevada, yielding an assessment based on six indicators of ecosystem structure, function, and composition, including resource- and stressor-based indicators measured at multiple scales. Results varied spatially and among indicators. Invasive plant cover and surface development were highest in shrublands in northwest and southeast Nevada. Departure from reference conditions of shrubland area, composition, patch size, and connectivity was highest in central and northern Nevada. Results may inform efforts to control invasive species and restore shrublands on federal lands in Nevada. We suggest that ecological integrity assessments for multiple-use lands be grounded in existing policies and monitoring programs, incorporate resource- and stressor-based metrics, rely on publicly available data collected at multiple spatial scales, and quantify both natural reference and societally desired resource conditions.

Nevada↗
USGS2002

Lake Pontchartrain Basin: Bottom sediments and related environmental resources

Lake Pontchartrain is the largest estuary southern Louisiana. It is an important recreational, commercial, and environmental resource for New Orleans and southwestern Louisiana. This publication is part of a 5-year cooperative program led by the USGS on the geological framework and sedimentary processes of the Lake Pontchartrain Basin. This presentation is divided into two main parts: - Scientific Research and Assessments - Multimedia Tools and Regional Resources The scientific sections include historical information on the area; shipboard, field, and remote sensing studies; and a comprehensive sediment database with geological and chemical discussions of the region. The multimedia and resources sections include Geographic Information System (GIS) tools and data, a video demonstrating vibracore sampling techniques in Lake Pontchartrain, and abstracts from four Basics of the Basin symposia.

Louisiana↗
USGS1984

Aeromagnetic, Bouguer gravity, and interpretation maps of the Sheep Hole-Cadiz Wilderness Study Area (CDCA-305), San Bernardino County, California

The Federal Land Policy and Management Act (Public Law 94-579, October 21, 1976) requires the U.S. Geological Survey and the U.S. Bureau of Mines to conduct mineral surveys on certain areas to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. These maps presents the results of a mineral survey of the Sheep Hole-Cadiz Wilderness Study Area (CDCA-305), California Desert Conservation Area, San Bernardino County, California. The U.S. Bureau of Mines conducted a mineral survey of the Sheep Hole-Cadiz Wilderness Study Area, which encompasses approximately 200,000 acres including enclosed private lands, in south-central San Bernardino County, California. The U.S. Bureau of Mines studied the mineral resources of mines, prospects, and mineralized areas; geologic, geochemical, and geophysical investigations were conducted by the U.S. Geological Survey. The study area is located in the Mojave Desert 13 miles east of Amboy, California, 20 miles east of Twentynine Palms, California, and 90 miles east of San Bernardino, and encompasses parts of the Dale Lake, Bristol Lake, Cadiz Valley and Cadiz Lake 15-minute quadrangles. Its borders are defined by the Amboy Road and a gas pipeline service road on the northwest, the unimproved Cadiz Valley access road on the east, State Route 62 along the south, and the Iron Age mine road and an unimproved powerline service road on the west. Major access from the east and west is provided by State Route 62 and access from the north is provided by the Amboy Road. Companion reports to this one describe the mineral resource potential (March and others, 1982), the geology (Howard and John, 1984), and hydrothermal alteration studies (Raines, 1983).

California↗
USGS1973

Hydrologic Data of the Neponset and Weymouth River Basins, Massachusetts

The Neponset, Weymouth Fore, and Weymouth Back River basins occupy an area of 183 square miles in eastern Massachusetts south of Boston and Braintree, Brockton, Canton, Dedham, Dover, Foxborough, Hingham, Holbrook, Medfield, Milton, Norwood, Quincy, Randolph, Rockland, Sharon, Stoughton, Walpole, Westwood, and Weymouth. Hydrologic data presented in this report were collected during an investigation of the water resources in the areas of these basins that are upstream from tide effect or heavy urbanization. This investigation was conducted by the U.S. Geological Survey in cooperation with the Massachusetts Water Resources Commission. The data are released in order to make available to the public basic hydrologic and related information that will facilitate the planning of water-resources development and will complement an interpretive report, "Hydrology and water resources of the Neoponset and Weymouth River basins, Massachusetts" (HA-484). The well and boring data contained herein were selected from a larger group of data in order to minimize redundancy of information for intensely drilled areas. All of the data are on filed and available for inspection at the office of the U.S. Geological Survey, Water Resources Division, Boston, Massachusetts.

Massachusetts↗
USGS2014

Public-supply water use in Kansas, 1990-2012

This fact sheet describes water-use data collection and quantities of surface water and groundwater diverted for public supply in Kansas for the years 1990 through 2012. Data used in this fact sheet are from the Kansas Department of Agriculture’s Division of Water Resources and the Kansas Water Office. Water used for public supply represents about 10 percent of all reported water withdrawals in Kansas. Between 1990 and 2012, annual withdrawals for public supply ranged from a low of 121 billion gallons in 1993 to a high of 159 billion gallons in 2012. Differences in annual withdrawals were associated primarily with climatic fluctuations. Six suppliers distributed about one-half of the total water withdrawn for public supply, and nearly three-quarters of the surface water. Surface water represented between 52 and 61 percent of total annual withdrawals for public supply. The proportion of surface water obtained through contracts from Federal reservoirs increased from less than 5 percent in the 1990s to 8 percent in 2011 and 2012. More than 99 percent of the reported water withdrawn for public supply in Kansas in 2012 was metered, which was an increase from 92 percent in 1990. State population increased steadily from 2.5 million people in 1990 to 2.9 million in 2012. Recent estimates indicate that about 95 percent of the total population was served by public water supply; the remainder obtained water from other sources such as private wells. Average per capita water use as calculated for State conservation planning purposes varied by region of the State. The smallest regional average water use for the years 1990–2012 was 98 gallons per person per day in easternmost Kansas, and the largest regional average water use was 274 gallons per person per day in westernmost Kansas.

Kansas↗
USGS1980

Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates. The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies. Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978 a ). The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity data from the Columbia Laboratory and its field laboratories. It presents definitive acute toxicity data on 271 chemicals tested against a variety of freshwater invertebrates and fishes. The chemicals represent all major groups of pesticides, as well as numerous industrial chemicals. This compilation should serve as a useful database for the many agencies and organizations dealing with research and management programs concerned with the impact of chemicals on aquatic resources. The Columbia Laboratory has played a major role in developing currently used standard methodology for static acute toxicity testing. The use of standardized methodology greatly reduces variation in results. The data presented here have been carefully scrutinized to eliminate tests that failed to follow acceptable procedures. Handling of test organisms and procedures for static toxicity tests followed those described by Lennon and Walker (1964) and Macek and McAllister (1970), and conform well with those recommended by Brauhn and Schoettger (1975) and the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975). The species of fish and invertebrates that were tested are listed in phylogenetic order in Tables 1 and 2. Fish were obtained from Federal and State hatcheries as either eggs or fry. Original stocks of invertebrates were collected and cultured from wild populations with no known source of contamination; these populations were replenished regularly. The invertebrates were cultured in the Laboratory by methods similar to those described by Sanders and Cope (1966). Test chemicals usually consisted of technical or analytical grade samples of known purity. Formulations of the chemicals were also tested when available. When purity of test chemicals was known, all calculated concentrations were based on percent active ingredients. Stock solutions were prepared immediately before each test, with commercial grade acetone as the carrier solvent. Occasionally, ethanol or dimethyl-formamide was substituted. Solvent concentrations did not exceed 0.5 mL/L in final dilution water. Test water (dilution water) was reconstituted from deionized water of at least 10 6 ohms resistivity by the addition of appropriate reagent grade chemicals (Marking 1969). Water was buffered to maintain a pH of 7.2 to 7.5, an alkalinity of 30 to 35 mg/L, and a hardness of 40 to 50 mg/L as CaCO 3 . Test water was mixed thoroughly and aerated before transfer into test chambers. Fish were acclimated to dilution water by gradually changing the water in acclimated tanks from 100% well water to 100% reconstituted water over a 1- to 3-day period at the desired testing temperature. Invertebrates were acclimated from well water to dilution water over a 4- to 6-h period. Toxicity tests were conducted under static conditions without aeration, and the organisms were not fed during acclimation or testing. Temperature of test solutions was maintained within ± 1°C of that required for a given test. Toxicity tests with fish were conducted in 18.9-liter (5-gal) wide-mouthed jars containing 15 liters of test solution. Fingerling fish weighing 0.2 to 1.5 g were tested at each concentration. Caution was taken not to exceed 0.8 g of test organisms per liter of solution. Duplicate test chambers were used to accommodate larger fish. Test chambers varied in size for invertebrates, depending on the species used; volume of test solution ranged from 0.25 to 4 liters. At least 10 organisms were exposed to each concentration for all definitive tests. At least six concentrations were used per toxicity test. The tests began upon initial exposure to the toxicant and continued for 96 h. Immobilization tests with invertebrates were conducted for only 48 h. The number of dead or affected organisms in each test chamber were recorded and the dead organisms were removed every 24 h; general observations on the condition of test organisms were also recorded at these times. Toxicity data were analyzed by a statistical method described by Litchfield and Wilcoxon (1949) to determine LC50 (theoretical estimate of the concentration lethal to 50% of the test animals) and 95% confidence intervals. This method is recommended by the American Public Health Association (1971) and by Sprague (1969) for determining median lethal concentrations. The procedure is easily modified for computing a single LC50 when replicate tests are performed.

Resource Publication↗
USGS1979

Records of selected wells, springs, and test holes, in the Royal, upper Presumpscot, and upper Saco River basins in Maine

The area discussed in this report includes about 1200 square miles in southwestern Maine. Location of the area is shown on the cover, and a sketch map identifying the topographic quadrangles for the study area is given in figure 1. The northern boundary of the area is the divide between the Androscoggin River drainage basin on the north and the Saco, Presumpscot, and Royal River drainage basins on the south. The western boundary is the Maine-New Hampshire State line, and the southwestern boundary is the Little Ossipee River. The southeastern boundary is the mid-latitude of the Gray and Freeport 15-minute topographic quadrangles. The greatest part of the area is in Cumberland and Oxford Counties, a smaller area is in York County, and a small fraction is in Androscoggin County. Included are parts or all of 15 towns in Cumberland County, 15 towns in Oxford County, 5 towns in York County, and 2 towns in Androscoggin County. The report contains geologic and hydrologic data collected as part of an investigation of the surficial geology and ground-water resources made by the U.S. Geological Survey in cooperation with the Maine Public Utilities Commission. These data are made available for use in planning the development of natural resources. An interpretive report containing maps of surficial geology and ground-water availability and related geologic and hydrologic information will be published in the Survey's Water-Resources Investigations series.

Maine↗
USGS1981

Aeromagnetic map of the El Malpais Instant Study Area and adjacent areas, Valencia County, New Mexico

The Federal Land Policy and Management Act (Public Law 94-579, October 21, 1976), requires the U.S. Geological Survey and the U.S. Bureau of Mines to conduct mineral surveys on certain areas to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a mineral survey of the El Malpais Instant Study Area and adjacent areas, Valencia County, New Mexico.

New Mexico↗
USGS1978

United States Geological Survey Yearbook, fiscal year 1977

Fiscal 1977 marked the 98th year the U.S. Geological Survey has endeavored in the unceasing task of providing information about the Earth and its physical resources, and regulating the activities of lessees engaged in extracting petroleum and other minerals from the public domain. The past year also marked the beginning of a third and challenging mission, drawing upon the Survey's scientific talents, to explore and assess the petroleum potential of a vast 37,000 square miles expanse of Alaska's North Slope known as the National Petroleum Reserve in Alaska. The first two missions require detailed and continuing investigations of the location, character, and extent of the Nation's land, water, mineral, and energy resources; a continuing National Topographic Mapping Program; the classification of Federal lands for mineral and waterpower potential; and a continuing program of technical review, safety inspection and royalty auditing of the operations of private parties engaged in mineral development on Federal lands to assure standards of safety, environmental protection, resource conservation, and a fair market return to the public for the development of their resources.

Yearbook↗
USGS1983

Geochemical map of the Arnold Mesa Roadless Area, Yavapai County, Arizona

The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a geochemical survey of the Arnold Mesa Roadless Area (U.S. Forest Service number 03092) in the Prescott and Tonto National Forests, Yavapai County, Arizona. The Arnold Mesa Roadless Area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979. During 1980 the U.S. Geological Survey and the U.S. Bureau of Mines (USBM) conducted field investigations to evaluate the mineral resource potential of the Arnold Mesa Roadless Area, Yavapai County, Arizona. Field studies included geologic mapping (Wolrfe, 1983), aeromagnetic mapping (Davis and Wolfe, 1983), geochemical sampling (this report), and a survey of known mines and prospects (McColly and Korzeb, 1981). The Arnold Mesa Roadless Area comprises about 28,000 acres (11,300 hectares) in and along the flanks of the Black Hills south of Camp Verde, Arizona. The Black Hills form a northwest-trending drainage divide, between the Agua Fria drainage on the west and Verde River on the east, that extends through the roadless area. The crest and southwest flank of the divide within the study area are moderately dissected, gently rolling uplands. The northeast flank is steep terrain that forms the western wall of the Verde Valley. The northeast flank has a total relief within the study area of almost 4,000 ft (more than 1,200 m) and is deeply incised by the canyons of Gap and Chasm Creeks. Unpaved roads provide access to much of the perimeter of the Arnold Mesa Roadless Area, but the interior is accessible only by foot, horse, or helicopter.

Arizona↗
USGS1995

Ground-water recharge in Escambia and Santa Rosa Counties, Florida

Ground water is a major component of Florida's water resources, accounting for 90 percent of all public-supply and self-supplied domestic water withdrawals, and 58 percent of self-supplied commercial-industrial and agricultural withdrawals of freshwater (Marella, 1992). Ground-water is also an important source of water for streams, lakes, and wetlands in Florida. Because of their importance, a good understanding of these resources is essential for their sound development, use, and protection. One area in which our understanding is lacking is in characterizing the rate at which ground water in aquifers is recharged, and how recharge rates vary geographically. Ground-water recharge (recharge) is the replenishment of ground water by downward infiltration of water from rainfall, streams, and other sources (American Society of Civil Engineers, 1987, p. 222). The recharge rates in many areas of Florida are unknown, of insufficient accuracy, or mapped at scales that are too coarse to be useful. Improved maps of recharge rates will result in improved capabilities for managing Florida's ground-water resources. In 1989, the U.S. Geological Survey, in cooperation with the Florida Department of Environmental Regulation, began a study to delineate high-rate recharge areas in several regions of Florida (Vecchioli and others, 1990). This study resulted in recharge maps that delineated areas of high (greater than 10 inches per year) and low (0 to 10 inches per year) recharge in three counties--Okaloosa, Pasco, and Volusia Counties--at a scale of 1:100,000. This report describes the results of a similar recharge mapping study for Escambia and Santa Rosa Counties (fig. 1), in which areas of high- and low-rates of recharge to the sand-and-gravel aquifer and Upper Floridan aquifer are delineated. The study was conducted in 1992 and 1993 by the U.S. Geological Survey in cooperation with the Florida Department of Environmental Protection.

Florida↗
USGS1986

Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Pyramid Roadless Area, El Dorado County, California

The Wilderness Act (Public Law 88-577, September 3, 1964) and related acts require the U.S. Geological Survey and the U.S. Bureau of Mines to survey certain areas on Federal lands to determine their mineral resource potential. Results must be made available to the public and be submitted to the President and the Congress. This report presents the results of a geochemical survey of the Pyramid Roadless Area (5203) in the Eldorado National Forest and Lake Tahoe Basin Management Unit, El Dorado County, California. This roadless area was classified as a further planning area during the Second Roadless Area Review and Evaluation (RARE II) by the U.S. Forest Service, January 1979. The Pyramid Roadless Area lies near the crest of the Sierra Nevada about 75 miles east of Sacramento, California. the area, which is adjacent to and almost encircles the Desolation Wilderness, encompasses approximately 31,400 acres in Eldorado National Forest and the Lake Tahoe Basin Management Unit in El Dorado County, California. The area is dominated by deep rugged canyons that run eastward from the Sierra Nevada crest to Lake Tahoe basin and westward toward the Sacramento Valley. Elevations range from about 5,500 feet along Big Silver Creek on the west side of the study area to 8,895 feet at Echo Peak along the southeastern side of the roadless area. Geochemical sampling was conducted during 1982. This report summarizes the results of that investigation and provides details of the geochemical evaluation used in producing the final mineral resource assessment of the study area (Armstrong and others, 1983).

California↗
USGS2011

Rainfall intensity-duration thresholds for postfire debris-flow emergency-response planning

Following wildfires, emergency-response and public-safety agencies can be faced with evacuation and resource-deployment decisions well in advance of coming winter storms and during storms themselves. Information critical to these decisions is provided for recently burned areas in the San Gabriel Mountains of southern California. A compilation of information on the hydrologic response to winter storms from recently burned areas in southern California steeplands is used to develop a system for classifying magnitudes of hydrologic response. The four-class system describes combinations of reported volumes of individual debris flows, consequences of debris flows and floods in an urban setting, and spatial extents of the hydrologic response. The range of rainfall conditions associated with different magnitude classes is defined by integrating local rainfall data with the response magnitude information. Magnitude I events can be expected when within-storm rainfall accumulations (A) of given durations (D) fall above the threshold A = 0.4D0.5 and below A = 0.5D0.6 for durations greater than 1 h. Magnitude II events will be generated in response to rainfall accumulations and durations between A = 0.4D0.5 and A = 0.9D0.5 for durations less than 1 h, and between A = 0.5D0.6 and A = 0.9D0.5 or durations greater than 1 h. Magnitude III events can be expected in response to rainfall conditions above the threshold A = 0.9D0.5. Rainfall threshold-magnitude relations are linked with potential emergency-response actions as an emergency-response decision chart, which leads a user through steps to determine potential event magnitudes and identify possible evacuation and resource-deployment levels. Use of this information in planning and response decision-making process could result in increased safety for both the public and emergency responders. ?? 2011 US Government.

Natural Hazards↗
USGS1981

Map showing mineral resource potential of the Sierra Ancha Wilderness and Salome Study Area, Gila County, Arizona

The Wilderness Act (Public Law 88-577, Sept. 3, 1964) and certain related Acts require the Geological Survey and the Bureau of Mines to survey certain areas on Federal lands to determine their mineral-resource potential. Results must be made available to the public and be submitted to the Administration and the Congress. These maps and reports present the results of a geologic and mineral survey of the Sierra Ancha Wilderness and Salome Study Area, Gila County, Arizona.

Arizona↗
USGS1990

A proposal to conserve black-footed ferrets and the prairie dog ecosystem

Prairie dogs ( Cynomys spp.) have been poisoned throughout this century because of grazing competition with livestock. Recent evidence showed these early claims were exaggerated, but animal control was already entrenched in government policy. As a result, ongoing government subsidized poisoning has reduced prairie dogs to about 2% of their former distribution. The reduction of prairie dogs diminished species diversity in the arid grasslands of North America, including the potential extinction of the black-footed ferret ( Mustela nigripes ). Cost-benefit analysis revealed that poisoning costs more than any grazing benefits accrued. This analysis did not consider the long-term costs of reversing ecosystem degradation, the intangible value of biological diversity as a public benefit, or the depletion of biotic resources as a loss of actual or potential wealth. The government presently finances the poisoning policy and the preservation of endangered species like the black-footed ferret, two apparently conflicting programs. We, therefore, propose an integrated management plan that considers both interests. We propose that federal monies allocated to the poisoning program be converted into a rebate for ranchers who manage livestock while preserving the prairie dog community. This would redirect funds and personnel already allocated to prairie dog eradication to an incentive for ranchers who manage for livestock and wildlife. Livestock interests and grassland biotic diversity would both benefit.

Environmental Management↗
USGS2022

Quantifying aspects of rangeland health at watershed scales in Colorado using remotely sensed data products

During grazing permit renewals, the Bureau of Land Management assesses land health using indicators typically measured using field-based data collected from individual sites within grazing allotments. However, agency guidance suggests assessments be completed at larger spatial scales. We explored how the current generation of remotely sensed data products could be used to quantify aspects of land health at watershed scales in Colorado to provide broad spatial and temporal context for the land health assessment process. We found multiple indicators could be quantified using these data products and were relevant to land health standards. Within focal watersheds, bare ground cover decreased over the past 30 years, while annual herbaceous cover has increased over the last 10 years. Vegetation productivity was variable over time, but interannual fluctuations were consistent across watersheds. Remotely sensed data products can help resource managers understand how current conditions relate to broad spatial and temporal trends in the region and could provide another line of evidence for the land health assessment process. They may also identify target areas where management strategies, such as eradication of invasive annual grasses, should be focused, and could help resource managers communicate complex issues to the public.

Colorado↗
USGS2003

The National Map: from geography to mapping and back again

When the means of production for national base mapping were capital intensive, required large production facilities, and had ill-defined markets, Federal Government mapping agencies were the primary providers of the spatial data needed for economic development, environmental management, and national defense. With desktop geographic information systems now ubiquitous, source data available as a commodity from private industry, and the realization that many complex problems faced by society need far more and different kinds of spatial data for their solutions, national mapping organizations must realign their business strategies to meet growing demand and anticipate the needs of a rapidly changing geographic information environment. The National Map of the United States builds on a sound historic foundation of describing and monitoring the land surface and adds a focused effort to produce improved understanding, modeling, and prediction of land-surface change. These added dimensions bring to bear a broader spectrum of geographic science to address extant and emerging issues. Within the overarching construct of The National Map, the U.S. Geological Survey (USGS) is making a transition from data collector to guarantor of national data completeness; from producing paper maps to supporting an online, seamless, integrated database; and from simply describing the Nation’s landscape to linking these descriptions with increased scientific understanding. Implementing the full spectrum of geographic science addresses a myriad of public policy issues, including land and natural resource management, recreation, urban growth, human health, and emergency planning, response, and recovery. Neither these issues nor the science and technologies needed to deal with them are static. A robust research agenda is needed to understand these changes and realize The National Map vision. Initial successes have been achieved. These accomplishments demonstrate the utility of The National Map to the Nation and give confidence in evolving its future applications.

Photogrammetric Engineering and Remote Sensing↗
USGS1956

Water resources of the New Orleans area, Louisiana

Industry, commerce, and public utilities in 1954 withdrew about 1,500 mgd from surface- and groundwater sources in the New Orleans area. Most of the withdrawal was made from the Mississippi River. However, some withdrawal of surface water was made from Lake Pontchartrain. A large part of the withdrawal from both ground- and surface-water sources is available for reuse. Ground-water withdrawal amounts to about 100 mgd and is primarily for industrial and commercial uses. The average flow of the Mississippi River for the 23-year period, 1931--54, amounted to 309,000 mgd, and the approximate average flow of all the tributaries to Lake Pontchartrain is about 4,000 mgd. The flow of the Pearl River, which adjoins the tributary drainage area of Lake Pontchartrain, averages about 8,000 mgd. Total withdrawal of ground and surface waters amounts to less than 3 percent of the recorded minimum flow of the Mississippi River or less than 1 percent of the average flow. Although large quantities of water are always available in the Mississippi River the quality of the Water is not suitable for all uses. Streams from the north that drain into Lakes Maurepas and Pontchartrain, and the aquifers in that area, offer one of the best sources of fresh water in the State. Industry, if located on the northern shores of Lake Maurepas or Lake Pontchartrain near the mouths of these tributaries, would be assured of an ample supply of either ground or surface water of excellent quality. All the tributaries north of Lake Pontchartrain have dry-weather flows which are dependable. The Pearl River above Bogalusa also is a good source of fresh water of excellent quality. At present it serves to dilute the tidal flow of salt water into Lake Pontchartrain through the Rigolets, the principal outlet of the lake. In the area north of Lake Pontchartrain, wells 60 to 2,000 feet deep yield fresh water. There are no known wells tapping sands below 2,000 feet. However, electrical logs of. oil-test wells show that fresh water is available to a maximum depth of 3,000 feet. In the area south of Lake Pontchartrain, there is no withdrawal of ground water for public water supplies because of the saline content of the water. Three principal water-bearing sands, the '200-foot, ' '400-foot, ' and '700-foot'sands, are tapped in the New Orleans area south of Lake Pontchartrain for industrial and commercial use. In this area all deeper sands yield salt water. In some areas the '200-foot' sand contains saline water of the sodium chloride type. Consequently, this sand is not developed extensively. Water from the 200-foot' sand is relatively fresh north of the Mississippi River and becomes increasingly saline to the south and west. The 400-foot' sand is the second most highly developed aquifer in the New Orleans industrial district. The aquifer appears to be very prolific, but its full capabilities have not yet been determined. This aquifer yields a highly mineralized sodium chloride water in some areas; however, elsewhere it is a source of large quantities of fresh water. The '700-foot' sand is the most continuous freshwater bearing sand in the area and is the principal source of fresh ground water in the New Orleans industrial district. Most of the wells tapping this aquifer yield soft water of the bicarbonate type. In the southern and western parts of the industrial district the water in the '700-foot' sand is too mineralized to be suitable for human consumption.

Circular↗