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At least 1,081 records · Page 60Linked to original sources
USGS1977

Initial assessment of the ground-water resources in the Monterey Bay region, California

The Association of Monterey Bay Area Governments (AMBAG) has been designated as the areawide waste-treatment-management planning agency for the Monterey Bay region under Sec. 208 of the Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500). Sec. 208 establishes the authority and responsibility of the designated local agency to investigate water-quality problems and plan solutions to them. In developing a waste-management program all aspects of water resources must be evaluated. AMBAG's 208 work plan established an initial problem assessment phase designed to serve as the basis for subsequent 208 program tasks. AMBAG requested that the U.S. Geological Survey make that portion of the initial assessment that was concerned with ground water. This report presents the findings of the assessment.

California↗
USGS2018

State-level freshwater mussel programs: Current status and a research framework to aid in mussel management and conservation

Despite increased focus on their ecology and conservation, freshwater mussels remain one of the most imperiled groups of aquatic organisms. We documented current management actions, resources, and challenges in managing freshwater mussels in the United States through a survey of state natural resource agencies. Approximately 85% of surveyed states ( N = 40) actively managed mussel populations. Common challenges to mussel conservation included limited funding, lack of public awareness, and poor understanding of habitat needs and risks. We present a research framework, currently underway in Missouri, to support a regional mussel conservation assessment whereby habitat needs are identified, risks are assessed, and standardized protocols are developed to monitor and detect trends in mussel assemblages and threats. The research framework conforms to the National Strategy for the Conservation of Native Freshwater Mollusks and is adaptable to other states. With full consideration of resource limitations, we explore how this framework can improve the effectiveness of mussel conservation efforts.

Fisheries↗
USGS1998

A national look at nitrate contamination of ground water

Ground water provides drinking water for more than one-half of the Nation's population (Solley and others, 1993), and is the sole source of drinking water for many rural communities and some large cities. In 1990, ground water accounted for 39 percent of water withdrawn for public supply for cities and towns and 96 percent of water withdrawn by self-supplied systems for domestic use. A variety of chemicals, including nitrate, can pass through the soil and potentially contaminate ground water. Nitrate comes from nitrogen, a plant nutrient supplied by inorganic fertilizer and animal manure. Additionally, airborne nitrogen compounds given off by industry and automobiles are deposited on the land in precipitation and dry particles. Other nonagricultural sources of nitrate include lawn fertilizers, septic systems, and domestic animals in residential areas. Beneath agricultural lands, nitrate is the primary form of nitrogen. It is soluble in water and can easily pass through soil to the ground-water table. Nitrate can persist in ground water for decades and accumulate to high levels as more nitrogen is applied to the land surface every year. Knowing where and what type of risks to ground water exist can alert water-resource managers and private users of the need to protect water supplies. Although nitrate generally is not an adult public-health threat, ingestion in drinking water by infants can cause low oxygen levels in the blood, a potentially fatal condition (Spalding and Exner, 1993). For this reason, the U.S. Environmental Protection Agency (EPA) has established a drinking-water standard of 10 milligrams per liter (mg/L) nitrate as nitrogen (U.S. Environmental Protection Agency, 1995). Nitrate concentrations in natural ground waters are usually less than 2 mg/L (Mueller and others, 1995).

Water Conditioning and Purification↗
USGS2012

Groundwater quality in Coachella Valley, California

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Coachella Valley is one of the study areas being evaluated. The Coachella study area is approximately 820 square miles (2,124 square kilometers) and includes the Coachella Valley groundwater basin (California Department of Water Resources, 2003). Coachella Valley has an arid climate, with average annual rainfall of about 6 inches (15 centimeters). The runoff from the surrounding mountains drains to rivers that flow east and south out of the study area to the Salton Sea. Land use in the study area is approximately 67 percent (%) natural, 21% agricultural, and 12% urban. The primary natural land cover is shrubland. The largest urban areas are the cities of Indio and Palm Springs (2010 populations of 76,000 and 44,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Coachella Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Coachella Valley are completed to depths between 490 and 900 feet (149 to 274 meters), consist of solid casing from the land surface to a depth of 260 to 510 feet (79 to 155 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation. The primary sources of discharge are pumping wells, evapotranspiration, and underflow to the Salton Sea and Imperial Valley areas.

California↗
USGS2016

Developing integrated methods to address complex resource and environmental issues

Introduction This circular provides an overview of selected activities that were conducted within the U.S. Geological Survey (USGS) Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing expertise. The project was supported by the USGS Mineral Resources Program, and its products and acquired capabilities have broad applications to missions throughout the USGS and beyond. In addressing challenges associated with understanding the location, quantity, and quality of mineral resources, and in investigating the potential environmental consequences of resource development, a number of field and laboratory capabilities and interpretative methodologies evolved from the project that have applications to traditional resource studies as well as to studies related to ecosystem health, human health, disaster and hazard assessment, and planetary science. New or improved tools and research findings developed within the project have been applied to other projects and activities. Specifically, geophysical equipment and techniques have been applied to a variety of traditional and nontraditional mineral- and energy-resource studies, military applications, environmental investigations, and applied research activities that involve climate change, mapping techniques, and monitoring capabilities. Diverse applied geochemistry activities provide a process-level understanding of the mobility, chemical speciation, and bioavailability of elements, particularly metals and metalloids, in a variety of environmental settings. Imaging spectroscopy capabilities maintained and developed within the project have been applied to traditional resource studies as well as to studies related to ecosystem health, human health, disaster assessment, and planetary science. Brief descriptions of capabilities and laboratory facilities and summaries of some applications of project products and research findings are included in this circular. The work helped support the USGS mission to “provide reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.” Activities within the project include the following: Spanned scales from microscopic to planetary; Demonstrated broad applications across disciplines; Included life-cycle studies of mineral resources; Incorporated specialized areas of expertise in applied geochemistry including mineralogy, hydrogeology, analytical chemistry, aqueous geochemistry, biogeochemistry, microbiology, aquatic toxicology, and public health; and Incorporated specialized areas of expertise in geophysics including magnetics, gravity, radiometrics, electromagnetics, seismic, ground-penetrating radar, borehole radar, and imaging spectroscopy. This circular consists of eight sections that contain summaries of various activities under the project. The eight sections are listed below: Laboratory Facilities and Capabilities, which includes brief descriptions of the various types of laboratories and capabilities used for the project; Method and Software Development, which includes summaries of remote-sensing, geophysical, and mineralogical methods developed or enhanced by the project; Instrument Development, which includes descriptions of geophysical instruments developed under the project; Minerals, Energy, and Climate, which includes summaries of research that applies to mineral or energy resources, environmental processes and monitoring, and carbon sequestration by earth materials; Element Cycling, Toxicity, and Health, which includes summaries of several process-oriented geochemical and biogeochemical studies and health-related research activities; Hydrogeology and Water Quality, which includes descriptions of innovative geophysical, remote-sensing, and geochemical research pertaining to hydrogeology and water-quality applications; Hazards and Disaster Assessment, which includes summaries of research and method development that were applied to natural hazards, human-caused hazards, and disaster assessments; and Databases and Framework Studies, which includes descriptions of fundamental applications of geophysical studies and of the importance of archived data.

Circular↗
USGS2007

Negotiation techniques to resolve western water disputes

There is a growing literature on the resolution of natural resources conflicts. Much of it is practical, focusing on guidelines for hands-on negotiation. This literature can be a guide in water conflicts. This is especially true for negotiations over new environmental values such as instream flow. The concepts of competitive, cooperative, and integrative styles of conflict resolution are applied to three cases of water resource bargaining. Lessons for the effective use of these ideas include: break a large number of parties into small working groups, approach value differences in small steps, be cautious in the presence of an attentive public, keeps decisions at the local level, and understand the opponent's interests.

Journal of the American Water Resources Associatio↗
USGS2012

Energy map of southwestern Wyoming, Part A - Coal and wind

To further advance the objectives of the Wyoming Landscape Conservation Initiative (WLCI) the U.S. Geological Survey (USGS) and the Wyoming State Geological Survey (WSGS) have compiled Part A of the Energy Map of Southwestern Wyoming. Focusing primarily on electrical power sources, Part A of the energy map is a compilation of both published and previously unpublished coal (including coalbed gas) and wind energy resources data, presented in a Geographic Information System (GIS) data package. Energy maps, data, documentation and spatial data processing capabilities are available in a geodatabase, published map file (pmf), ArcMap document (mxd), Adobe Acrobat PDF map (plate 1) and other digital formats that can be downloaded at the USGS website. Accompanying the map (plate 1) and the geospatial data are four additional plates that describe the geology, energy resources, and related infrastructure. These tabular plates include coal mine (plate 2), coal field (plate 3), coalbed gas assessment unit (plate 4), and wind farm (plate 5) information with hyperlinks to source publications and data on the internet. The plates can be printed and examined in hardcopy, or accessed digitally. The data represent decades of research by the USGS, WSGS, BLM and others, and can facilitate landscape-level science assessments, and resource management decisionmaking.

Wyoming↗
USGS1989

Bibliography of Water-Resources Investigations reports published by the U.S. Geological Survey from 1971 through 1982

This report contains a cross-referenced listing of 971 Water-Resources Investigations reports (WRIR's) published by the U.S. Geological Survey from 1971 through 1982. The reports are listed by WRIR number. Most requests for WRIR 's generally are by WRIR number; however, the Survey 's annual catalog, ' Publications of the U.S. Geological Survey (year), ' indexes WRIR 's under the National Technical Information Service number, with the WRIR appearing only at the end of the citation within the index. Additionally, a few WRIR 's have been listed in the index without any reference to their WRIR number; and some WRIR 's appeared only in the discontinued Water Resources Investigations folder series. This report lists WRIR 's in sequential order to assist the readership in locating a particular publication. (USGS)

Open-File Report↗
USGS2012

Groundwater quality in the Antelope Valley, California

Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Antelope Valley is one of the study areas being evaluated. The Antelope study area is approximately 1,600 square miles (4,144 square kilometers) and includes the Antelope Valley groundwater basin (California Department of Water Resources, 2003). Antelope Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lakebeds in the lower parts of the valley. Land use in the study area is approximately 68 percent (%) natural (mostly shrubland and grassland), 24% agricultural, and 8% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Palmdale and Lancaster (2010 populations of 152,000 and 156,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Antelope Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Antelope Valley are completed to depths between 360 and 700 feet (110 to 213 meters), consist of solid casing from the land surface to a depth of 180 to 350 feet (55 to 107 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation and sewer and septic systems. The primary sources of discharge are pumping wells and evapotranspiration near the dry lakebeds.

California↗
USGS2023

Water, water everywhere, but every drop unique: Emerging challenges in the science to understand the role of contaminants in management of drinking water supplies

The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.

GeoHealth↗
USGS2015

Onshore industrial wind turbine locations for the United States up to March 2014

Wind energy is a rapidly growing form of renewable energy in the United States. While summary information on the total amounts of installed capacity are available by state, a free, centralized, national, turbine-level, geospatial dataset useful for scientific research, land and resource management, and other uses did not exist. Available in multiple formats and in a web application, these public domain data provide industrial-scale onshore wind turbine locations in the United States up to March 2014, corresponding facility information, and turbine technical specifications. Wind turbine records have been collected and compiled from various public sources, digitized or position verified from aerial imagery, and quality assured and quality controlled. Technical specifications for turbines were assigned based on the wind turbine make and model as described in public literature. In some cases, turbines were not seen in imagery or turbine information did not exist or was difficult to obtain. Uncertainty associated with these is recorded in a confidence rating.

Scientific Data↗
USGS2025

Derivation and characterization of environmental hazard concentrations for chemical prioritization: A case study in the Great Lakes tributaries

Ongoing anthropogenic activities and analytical advancements yield continuously expanding lists of environmental contaminants. This represents a challenge to environmental managers, who must prioritize chemicals for management actions (e.g., restriction, regulation, remediation) but are often hindered by resource limitations. To help facilitate prioritization efforts, this study presents several strategies for deriving environmental hazard concentrations using publicly accessible data and open-source computational tools. Using a Great Lakes tributaries aquatic monitoring dataset as a case study, environmental hazard concentrations were obtained or derived for 334 organic chemicals. These concentrations were based on (1) current water quality guidelines; (2) apical screening values; (3) apical and (4) nonapical effect concentrations from the ECOTOXicology Knowledgebase; (5) in vitro effect concentrations from the ToxCast database; (6) cytotoxic burst concentrations collated from the Comptox Dashboard; (7) “estimated screening values” derived from modeled or estimated data and available from various regulatory and nonregulatory agencies; (8) pharmaceutical potency estimates from the MaPPFAST database; and (9) quantitative structure-activity relationship (QSAR)–derived acute toxicity estimates. Environmental fate data included aquatic half-lives and bioconcentration factors collated from the Comptox Dashboard or estimated using QSARs. To identify patterns that could be used for characterization, availability of ecotoxicological concentrations and environmental fate data were evaluated. Furthermore, exceedances of hazard concentrations were evaluated and compared across diverse ecotoxicological data types. Altogether, by providing detailed methodology and practical examples generated with real monitoring data, this study demonstrated that these hazard concentration derivation strategies can be efficiently and effectively used with large, complex datasets and identified critical considerations for future prioritization efforts.

Great Lakes region↗
USGS2011

Development of an assessment methodology for hydrocarbon recovery potential using carbon dioxide and associated carbon sequestration-Workshop findings

The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO 2 ) and requested that the USGS estimate the "potential volumes of oil and gas recoverable by injection and sequestration of industrial carbon dioxide in potential sequestration formations" (121 Stat. 1711). The USGS developed a noneconomic, probability-based methodology to assess the Nation's technically assessable geologic storage resources available for sequestration of CO 2 (Brennan and others, 2010) and is currently using the methodology to assess the Nation's CO2 geologic storage resources. Because the USGS has not developed a methodology to assess the potential volumes of technically recoverable hydrocarbons that could be produced by injection and sequestration of CO 2 , the Geologic Carbon Sequestration project initiated an effort in 2010 to develop a methodology for the assessment of the technically recoverable hydrocarbon potential in the sedimentary basins of the United States using enhanced oil recovery (EOR) techniques with CO 2 (CO 2 -EOR). In collaboration with Stanford University, the USGS hosted a 2-day CO 2 -EOR workshop in May 2011, attended by 28 experts from academia, natural resource agencies and laboratories of the Federal Government, State and international geologic surveys, and representatives from the oil and gas industry. The geologic and the reservoir engineering and operations working groups formed during the workshop discussed various aspects of geology, reservoir engineering, and operations to make recommendations for the methodology.

Fact Sheet↗
USGS2023

Nisqually River Delta—Humans and nature benefiting together

Introduction This is a brochure created in partnership with the U.S. Geological Survey (USGS), the Nisqually Indian Tribe, and the Billy Frank Jr. Nisqually National Wildlife Refuge. Designed for a public audience, the brochure describes the history of the Nisqually Indian Tribe, the ecology of the delta, the resources and recreational opportunities available for Refuge visitors, future challenges posed by climate change, and opportunities to protect wildlife and their habitats in the future.

Washington↗
USGS2007

Vascular Plant and Vertebrate Inventory of Tonto National Monument

This report summarizes the results of the first biological inventory of plants and vertebrates at Tonto National Monument (NM). From 2001 to 2003, we surveyed for vascular plants and vertebrates (amphibians, reptiles, birds, and mammals) at Tonto NM to record species presence. We focused most of our efforts along the Cave Springs riparian area, but surveyed other areas as well. We recorded 149 species in the riparian area, and 369 species overall in the monument, including 65 plant species and four bird species that were previously unrecorded for the monument. We recorded 78 plant species in the riparian area that previous studies had not indicated were present there. Several species of each taxonomic group were found only in the riparian area, suggesting that because of their concentration in this small area these populations are vulnerable to disturbance and may be of management concern. Four of the bird species that we recorded (Bell's vireo, yellow warbler, summer tanager, and Abert's towhee) have been identified as riparian 'obligate' species by other sources. Bird species that are obligated to riparian areas are targets of conservation concern due to widespread degradation of riparian areas in the desert southwest over the last century. The flora and fauna of the riparian area would benefit from continued limited public access. The dependence of the riparian area on the spring and surface flow suggests monitoring of this resource per se would benefit management of the riparian area's flora and fauna as well. The monument would benefit from incorporating monitoring protocols developed by the Sonoran Desert Network Inventory and Monitoring program rather than initiating a separate program for the riparian area. Park managers can encourage the Inventory and Monitoring program to address the unique monitoring challenges presented by small spatial areas such as this riparian area, and can request specific monitoring recommendations. We suggest that repeat inventories for vertebrates, and census (rather than sampling) of perennial vegetation may be the most effective long-term monitoring strategies in the riparian area to verify species persistence through time in this unique and spatially limited environment.

Open-File Report↗
USGS2012

Calculation of hydrocarbon-in-place in gas and gas-condensate reservoirs - Carbon dioxide sequestration

The Energy Independence and Security Act of 2007 (Public Law 110-140) authorized the U.S. Geological Survey (USGS) to conduct a national assessment of geologic storage resources for carbon dioxide (CO 2 ), requiring estimation of hydrocarbon-in-place volumes and formation volume factors for all the oil, gas, and gas-condensate reservoirs within the U.S. sedimentary basins. The procedures to calculate in-place volumes for oil and gas reservoirs have already been presented by Verma and Bird (2005) to help with the USGS assessment of the undiscovered resources in the National Petroleum Reserve, Alaska, but there is no straightforward procedure available for calculating in-place volumes for gas-condensate reservoirs for the carbon sequestration project. The objective of the present study is to propose a simple procedure for calculating the hydrocarbon-in-place volume of a condensate reservoir to help estimate the hydrocarbon pore volume for potential CO 2 sequestration.

Open-File Report↗
USGS2007

Potentiometric Surfaces and Water-Level Trends in the Cockfield and Wilcox Aquifers of Southern and Northeastern Arkansas, 2006

The Cockfield Formation of Claiborne Group and the Wilcox Group contain aquifers that provide sources of ground water in southern and northeastern Arkansas. In 2000, about 9.9 million gallons per day was withdrawn from the Cockfield Formation of Claiborne Group and about 22.2 million gallons per day was withdrawn from the Wilcox Group. Major withdrawals from the aquifers were for industrial and public water supplies. A study was conducted by the U.S. Geological Survey in cooperation with the Arkansas Natural Resources Commission and the Arkansas Geological Survey to determine the water level associated with the aquifers in the Cockfield Formation of Claiborne Group and the Wilcox Group in southern and northeastern Arkansas. During February and March 2006, 56 water-level measurements were made in wells completed in the Cockfield aquifer and 59 water-level measurements were made in wells completed in the Wilcox aquifer, 16 in southwestern and 43 in northeastern Arkansas. This report presents the results as potentiometric-surface maps and as long-term water-level hydrographs. The regional direction of ground-water flow in the Cockfield Formation of Claiborne Group generally is towards the east and southeast, away from the outcrop, except in areas of intense ground-water withdrawals, such as western Drew County, southeastern Lincoln County, southwestern Calhoun County, and near Crossett in Ashley County. There are three cones of depression indicated by relatively low water-level altitudes in southeastern Lincoln County, southwestern Calhoun County, and near Crossett in Ashley County. The lowest water-level altitude measured was 44 feet above the National Geodetic Vertical Datum of 1929 in Lincoln County; the highest water-level altitude measured was 346 feet above the National Geodetic Vertical Datum of 1929 in Columbia County at the outcrop area. Hydrographs from 40 wells with historical water levels from 1986 to 2006 were evaluated using linear regression to calculate the annual rise or decline. Calhoun and Cleveland Counties have mean annual rises from 0.01 to 0.07 feet per year. Arkansas, Ashley, Bradley, Chicot, Columbia, Drew, Lincoln, and Union Counties have mean annual declines from 0.4 to 0.55 feet per year. Desha County has a mean annual decline of about 1.35 feet per year. The direction of ground-water flow in the southwestern study area of the Wilcox Group generally is south and east. The lowest water-level altitude measured in southwestern Arkansas was 147 feet above the National Geodetic Vertical Datum of 1929 near the Ouachita River in Clark County; the highest water-level altitude measured was 397 feet above the National Geodetic Vertical Datum of 1929 in the outcrop area of Hempstead County. The direction of ground-water flow in the northeastern study area of the Wilcox Group generally is south and east. The lowest water-level altitude measured in northeastern Arkansas was 120 feet above the National Geodetic Vertical Datum of 1929 near West Memphis in Crittenden County; the highest water-level altitude measured was 368 feet above the National Geodetic Vertical Datum of 1929 on Crowleys Ridge in Clay County. Hydrographs from 28 wells with historical water levels from 1986 to 2006 were evaluated using linear regression to calculate the annual rise or decline. All 28 wells showed an annual decline from 1986 to 2006. Craighead, Greene, Mississippi, and Poinsett Counties have mean annual declines from 0.27 to 1.00 feet per year. Crittenden, Lee, and St. Francis Counties have mean annual declines from 1.39 to 1.64 feet per year.

Scientific Investigations Report↗
USGS1977

Availability of ground water in the lower Connecticut River basin, southwestern New Hampshire

This map scale 1:125,000 presents a preliminary assessment of the availability of ground water in the lower Connecticut River basin in southwestern New Hampshire. It is a generalization of several hydrogeologic factors and provides a guideline for ground-water exploration useful in water- and land-use planning. It does not describe the absolute quantity or quality of ground water available. The best aquifers in the basin are deposits of stratified sand or sand and gravel of Pleistocene age. Large aquifers of this type occur in places in the Connecticut River valley and in valleys of tributaries to the Connecticut River. Ground water is generally of good chemical quality. Iron and manganese in concentrations greater than the recommended limits for drinking water suggested by the U.S. Public Health Service are not uncommon. (USGS).

New Hampshire↗