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334 records · Page 19Linked to original sources
USGS2015

Field-based description of rhyolite lava flows of the Calico Hills Formation, Nevada National Security Site, Nevada

Contaminants introduced into the subsurface of Pahute Mesa, Nevada National Security Site, by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas at Pahute Mesa and into the accessible environment is greatest by groundwater transport through fractured volcanic rocks. The 12.9 Ma (mega-annums, million years) Calico Hills Formation, which consists of a mixture of rhyolite lava flows and intercalated nonwelded and bedded tuff and pyroclastic flow deposits, occurs in two areas of the Nevada National Security Site. One area is north of the Rainier Mesa caldera, buried beneath Pahute Mesa, and serves as a heterogeneous volcanic-rock aquifer but is only available to study through drilling and is not described in this report. A second accumulation of the formation is south of the Rainier Mesa caldera and is exposed in outcrop along the western boundary of the Nevada National Security Site at the Calico Hills near Yucca Mountain. These outcrops expose in three dimensions an interlayered sequence of tuff and lava flows similar to those intercepted in the subsurface beneath Pahute Mesa. Field description and geologic mapping of these exposures described lithostratigraphic variations within lava flows and assisted in, or at least corroborated, conceptualization of the rhyolite lava-bearing parts of the formation. In the area south of the Rainier Mesa caldera, surface exposures and nearby subsurface equivalents were studied through compilation of geologic maps, new field mapping, subsurface information from boreholes, and data extracted from three-dimensional geologic framework models. Rhyolite lava flows within the Calico Hills Formation are described in terms of lithostratigraphic variations established for rhyolite lava flows in other volcanic fields. In general, the flows consist of a core of crystallized, flow-banded rhyolite lava, surrounded by a carapace of obsidian, commonly mantled by blocky, pumiceous rhyolite lava and flow breccia. Rhyolite lava flows were correlated and mapped on the basis of distinctive appearance in outcrop, stratigraphic sequence, and the presence of stratigraphic markers. Pyroclastic deposits that are spatially, temporally, and genetically related to the rhyolite lava flows consist of a series of intercalated pyroclastic flows, bedded ash-fall, and reworked tuff that have varying amounts of pumice and volcanic rock clasts. In the area south of the Rainier Mesa caldera, surface and subsurface geologic data are combined to interpret the overall thickness of the Calico Hills Formation and the proportion of lava flow lithology across the study area. The formation is at least 500 meters (m) thick and contains the greatest proportion of rhyolite lava flow to the northeast of Yucca Mountain in the lower part of Fortymile Canyon. The formation thins to the south and southwest where it is between 50 and 200 m thick beneath Yucca Mountain and contains no rhyolite lavas. Geologic mapping and field-based correlation of individual lava flows allow for the interpretation of the thickness and extent of specific flows and the location of their source areas. The most extensive flows have widths from 2 to 3 kilometers (km) and lengths of at least 5–6 km. Lava flow thickness varies from 150 to 250 m above interpreted source vents to between 30 and 80 m in more distal locations. Rhyolite lavas have length-to-height ratios of 10:1 or greater and, in one instance, a length-to-width ratio of 2:1 or greater, implying a tongue-shaped geometry instead of circular domes or tabular bodies. Although geologic mapping did not identify any physical feature that could be positively identified as a vent, lava flow thickness and the size of clasts in subjacent pyroclastic deposits suggest that primary vent areas for at least some of the flows in the study area are on the east side of Fortymile Canyon, to the northeast of Yucca Mountain.

Nevada↗
USGS2012

Characterization of major-ion chemistry and nutrients in headwater streams along the Appalachian National Scenic Trail and within adjacent watersheds, Maine to Georgia

An inventory of water-quality data on field parameters, major ions, and nutrients provided a summary of water quality in headwater (first- and second-order) streams within watersheds along the Appalachian National Scenic Trail (Appalachian Trail). Data from 1,817 sampling sites in 831 catchments were used for the water-quality summary. Catchment delineations from NHDPlus were used as the fundamental geographic units for this project. Criteria used to evaluate sampling sites for inclusion were based on selected physical attributes of the catchments adjacent to the Appalachian Trail, including stream elevation, percentage of developed land cover, and percentage of agricultural land cover. The headwater streams of the Appalachian Trail are generally dilute waters, with low pH, low acid neutralizing capacity (ANC), and low concentrations of nutrients. The median pH value was slightly acidic at 6.7; the median specific conductance value was 23.6 microsiemens per centimeter, and the median ANC value was 98.7 milliequivalents per liter (μeq/L). Median concentrations of cations (calcium, magnesium, sodium, and potassium) were each less than 1.5 milligrams per liter (mg/L), and median concentrations of anions (bicarbonate, chloride, fluoride, sulfate, and nitrate) were less than 10 mg/L. Differences in water-quality constituent levels along the Appalachian Trail may be related to elevation, atmospheric deposition, geology, and land cover. Spatial variations were summarized by ecological sections (ecosections) developed by the U.S. Forest Service. Specific conductance, pH, ANC, and concentrations of major ions (calcium, chloride, magnesium, sodium, and sulfate) were all negatively correlated with elevation. The highest elevation ecosections (White Mountains, Blue Ridge Mountains, and Allegheny Mountains) had the lowest pH, ANC, and concentrations of major ions. The lowest elevation ecosections (Lower New England and Hudson Valley) generally had the highest pH, ANC, and concentrations of major ions. The geology in discrete portions of these two ecosections was classified as containing carbonate minerals which has likely influenced the chemical character of the streamwater. Specific conductance, pH, ANC, and concentrations of major ions (calcium, chloride, magnesium, sodium, and sulfate) were all positively correlated with percentages of developed and agricultural land uses at the lower elevations of the central region of the Appalachian Trail (including the Green-Taconic-Berkshire Mountains, Lower New England, Hudson Valley, and Northern Ridge and Valley ecosections). The distinctly different chemical character of the streams in the central sections of the Appalachian Trail is likely related to the lower elevations, the presence of carbonate minerals in the geology, higher percentages of developed and agricultural land uses, and possibly the higher inputs of sulfate and nitrate from atmospheric deposition. Acid deposition of sulfate and nitrate are important influences on the acid-base chemistry of the surface waters of the Appalachian Trail. Atmospheric deposition estimates are consistently high (more than 18 kilograms per hectare (kg/ha) for sulfate, and more than 16 kg/ha for nitrate) at both the highest and lowest elevations. However, the lowest elevation (Green-Taconic-Berkshire Mountains, Lower New England, Hudson Valley, Northern Glaciated Allegheny Plateau, and Northern Ridge and Valley ecosections) included the largest spatial area of sustained high estimates of atmospheric deposition. Calcium-bicarbonate was the most frequently calculated water type in the Lower New England and Hudson Valley ecosections. In the northern and southern sections of the Appalachian Trail mix-cation water types were most prevalent and sulfate was the predominate anion. The predominance of the sulfate anion in the surface waters of the northern and southern ecosections likely reflects the influence of sulfate deposition. Although the central portion of the Appalachian Trail has the largest spatial area of high atmospheric acid deposition, the lower ionic strength waters in the northern and southern ecosections of the Appalachian Trail may have been more adversely affected by acid deposition. The low ionic strength of the streams in the White Mountains, Blue Ridge Mountains, and Allegheny Mountains ecosections makes parts of these regions susceptible to seasonal or event-driven episodic acidification, which can be detrimental to health of aquatic and terrestrial ecosystems. Median catchment ANC values were classified into three groups - acidic, sensitive, and insensitive. The White Mountains, Blue Ridge Mountains, and Allegheny Mountains ecosections included the highest frequency of catchments classified as acidic or sensitive. More than 56 percent of the catchments from the White Mountains ecosection were classified as sensitive to acidic inputs. In the Blue Ridge ecosection, 1.6 percent of the catchments were classified as acidic, and 38.2 percent of the catchments were classified as sensitive to acidic inputs. In the Allegheny Mountains ecosection, 17.6 percent of the catchments were classified as acidic, and 29.4 percent of the catchments were classified as sensitive to acidic inputs. Median concentrations of nitrogen species were less than 0.4 mg/L, and median concentrations of total phosphorus were less than 0.02 mg/L along the Appalachian Trail. A comparison of median catchment concentrations of nutrients to estimated national background concentrations demonstrated that concentrations along the Appalachian Trail are generally lower. A comparison of median concentrations of total nitrogen and total phosphorus to the U.S. Environmental Protection Agency's (USEPA) nutrient criteria for the Eastern U.S. ecoregions showed that the concentrations of total nitrogen in the northern section of the Appalachian Trail were generally higher than the USEPA criterion. Similarly, median concentrations of total phosphorus in the southern regions of the Appalachian Trail were approximately twice as high as USEPA criteria. Sections of the Appalachian Trail are adjacent to modest amounts of agricultural and developed land areas. These nonforested land areas may be contributing to the percentage of catchments in which concentrations of total nitrogen and total phosphorus are higher than USEPA nutrient ecoregion criteria.

Connecticut, Georgia, Maine, Massachusetts, Maryla↗
USGS2017

Niobium and tantalum

Niobium and tantalum are transition metals that are almost always found together in nature because they have very similar physical and chemical properties. Their properties of hardness, conductivity, and resistance to corrosion largely determine their primary uses today. The leading use of niobium (about 75 percent) is in the production of high-strength steel alloys used in pipelines, transportation infrastructure, and structural applications. Electronic capacitors are the leading use of tantalum for high-end applications, including cell phones, computer hard drives, and such implantable medical devices as pacemakers. Niobium and tantalum are considered critical and strategic metals based on the potential risks to their supply (because current production is restricted to only a few countries) and the significant effects that a restriction in supply would have on the defense, energy, high-tech industrial, and medical sectors. The average abundance of niobium and tantalum in bulk continental crust is relatively low—8.0 parts per million (ppm) niobium and 0.7 ppm tantalum. Their chemical characteristics, such as small ionic size and high electronic field strength, significantly reduce the potential for these elements to substitute for more common elements in rock-forming minerals and make niobium and tantalum essentially immobile in most aqueous solutions. Niobium and tantalum do not occur naturally as pure metals but are concentrated in a variety of relatively rare oxide and hydroxide minerals, as well as in a few rare silicate minerals. Niobium is primarily derived from the complex oxide minerals of the pyrochlore group ((Na,Ca,Ce) 2 (Nb,Ti,Ta) 2 (O,OH,F) 7 ), which are found in some alkaline granite-syenite complexes (that is, igneous rocks containing sodium- or potassium-rich minerals and little or no quartz) and carbonatites (that is, igneous rocks that are more than 50 percent composed of primary carbonate minerals, by volume). Tantalum is derived mostly from the mineral tantalite ((Fe,Mn)(Ta,Nb) 2 O 6 ), which is found as an accessory mineral in rare-metal granites and pegmatites that are also enriched in lithium and cesium (termed lithium-cesium-tantalum (LCT)-type pegmatites). Brazil and Canada are the leading nations that produce niobium mineral concentrates, but Brazil is by far the leading producer, accounting for about 90 percent of production, which comes mostly from weathered material derived from carbonatites. Brazil and Canada also have the largest identified niobium resources; additional resources, although they are less well reported, occur in Angola, Australia, China, Greenland, Malawi, Russia, and South Africa. Australia and Brazil have been the leading producers of tantalum mineral concentrates, although recently Ethiopia and Mozambique have also been significant suppliers of tantalum. Artisanal mining of columbite-tantalite (also called coltan) is practiced in many countries, particularly Burundi, the Democratic Republic of the Congo (Congo [Kinshasa]), Nigeria, Rwanda, and Uganda. Brazil has about 40 percent of the identified tantalum resources; other countries and regions with identified tantalum resources include, in decreasing order of resources, Australia, Asia, Russia and the Middle East, Africa, North America, and Europe. Identified niobium and tantalum resources in the United States are small, low grade, and difficult to recover and process, and are thus not commercially recoverable at current prices. Consequently, the United States meets its current and expected future needs for niobium and tantalum through imports of primary mineral concentrates and alloys and through recovery from foreign and domestic alloy scrap that contain the metals. Environmentally, the main issues related to niobium and tantalum mining are land disruptions, the volume of waste materials and their disposal, and the radioactivity of some tailings and waste materials that contain thorium and uranium. Because of the relative biological inertness of niobium and tantalum, human and ecological health concerns are generally minimal under most natural conditions. Demand for both niobium and tantalum is expected to increase as the world economy continues to recover from the downturn that began in 2008. Increased demand for niobium is linked to increased consumption of microalloyed steel, which is used in the manufacture of cars, buildings, ships, and refinery equipment. Demand for these steels will likely increase with continued economic development in such countries as Brazil, China, and India. In addition, increased global demand for cars, cell phones, computers, superconducting magnets, and other high-tech devices will likely spur increased demand for both niobium and tantalum. The estimated global reserves and resources of niobium and tantalum are large and appear more than sufficient to meet global demand for the foreseeable future, possibly the next 500 years. The sale of “conflict coltan” attributed to rebel forces waging a civil war in Congo (Kinshasa) has been of recent concern and has highlighted the need for a transparent and traceable global supply chain that can exclude illegal columbite-tantalite from the conventional market while discerning legitimate artisanal mine production in central Africa.

Professional Paper↗
USGS2007

Recommendations for a barrier island breach management plan for Fire Island National Seashore, including the Otis Pike High Dune Wilderness Area, Long Island, New York

The U.S Army Corps of Engineers, New York District is developing engineering plans, including economic costs and benefits, for storm damage reduction along an 83 mile stretch of the coastal barrier islands and beaches on the south shore of Long Island, NY from Fire Island Inlet east to the Montauk Point headland. The plan, expected to include various alternatives for storm protection and erosion mitigation, is referred to as the Fire Island to Montauk Point Reformulation Plan (FIMP). These plans are expected to follow the Corps of Engineers’ Environmental Operating Principles striving for long term environmental sustainability and balance between environmental protection and protection of human health and property. Fire Island National Seashore (FIIS), a 19,579 acre unit of the National Park System includes a 32 mile long coastal barrier island located within the FIMP project area. A seven-mile section of the park, Otis Pike Fire Island High Dune Wilderness Area, is also a designated Federal Wilderness Area. The FIIS includes not only the barrier island and sand dunes, but also several islands, sand flats and wetlands landward of the barrier, submerged parts of Great South Bay shoreface, extending approximately 4,000 feet into the bay with the inner shelf region extending approximately 1,000 feet seaward of the Fire Island shoreline. The Fire Island barrier islands, a sand-starved system dominated by highly dynamic processes, are struggling to maintain their integrity in the face of sea-level rise and storms. Adding to the dilemma is that development on the barriers and the mainland has increased greatly during the past 50 years. As such, managers and decision makers in federal agencies, state agencies and local governments are challenged to balance tradeoffs between protection of lives and property, public access and long term conservation of natural habitats and processes and the plants and animals that depend on these habitats. National Park Service (NPS) policy stipulates that natural coastal processes be maintained to the greatest extent possible and not be impeded so as to conserve landforms, habitats and natural ecosystem resources that reply on the landforms and processes for long-term sustainability of the national park. Storms and associated processes such as waves, tides, currents and relative sea-level change are critical elements for the formation and evolution of these barrier islands, sand dunes, back-barrier sand flats and lagoons and vegetated wetlands. Processes such as wave run-up, overwash and barrier beaching, which occur during elevated storm surge are all necessary processes in enabling the efficient transfer of sediments, nutrients and marine water from the Atlantic Ocean across barriers and into Great South Bay. A large body of scientific data and information published over the past 50 years shows that such transfers of sediment and water from the ocean to the bays are essential for the long-term maintenance of the barrier island and back-bay systems and their biologically diverse habitats an d ecosystems. Current relative sea-level rise (~12 in/century) is chronic and pervasive in driving Long Island coastal change and with the likelihood of accelerating sea level rise in the near future, coastal hazards such as erosion, inundation, and storm surge flooding will increase, with corresponding increased risk to life and property on both Fire Island and on the mainland. In addition, the cumulative effects over the past century and more, both direct and indirect, of human impacts on the Long Island coast have altered the barrier beach and dunes and sediment transport processes. These impacts have likely increased the potential for breaching and increased risk to life and property on the coast and the mainland. Examples of direct impacts are: the stone jetties at Moriches, Shinnecock, and Fire Island tidal inlets and groin field structures at Westhampton that alter littoral processes, armoring and erosion-control stabilization of the headlandds such as the Montauk Point headlands, and deepening of navigation channels by dredging through the tidal inlets and in the bays. Indirect impacts that have a bearing on decisions to deal with breaching are: high-risk development of the barrier islands and low-lying areas of the mainland vulnerable to flooding, and the dredging of nearshore sand shoals for beach nourishment. The NPS strives to employ a coastal management framework for decision making that is based on assessment of the physical and ecological properties of the shoreline as well as human welfare and property. In order to protect developed areas of Fire Island and the mainland from loss of life, flooding, and other economic and physical damage, the NPS will likely need to consider allowing artificial closure of some breaches within the FIIS under certain circumstances. The decision by the NPS to allow breaches to evolve naturally and possibly close or to allow artificially closing breaches is based on four criteria: 1. Volumes of sediment transported landward and exchange of water and nutrients; 2. Elevated water levels and flooding risk to mainland life and property; 3. Engineering processes of artificial closure; and 4. Economic costs and benefits of artificial closure. This report for breach management presents protocols which specify when breach closures within the FIIS might be desirable and necessary, as well as provides recommendations for structural breach closure engineering operations which are indented to minimize negative impacts to the natural wilderness values and cultural resources within the FIIS, particularly the Otis Pike Wilderness Area. The goal of the plan is to strike a balance between protecting natural resources and allowing natural processes to operate and avoiding loss of life and excessive property damage.

New York↗
USGS1972

Water resources inventory of Connecticut Part 6: Upper Housatonic River basin

The upper Housatonic River basin report area has an abundant supply of water of generally good quality, which is derived from precipitation on the area and streams entering the area. Annual precipitation has averaged about 46 inches over a 30-year period. Of this, approximately 22 inches of water is returned to the atmosphere each year by evaporation and transpiration; the remainder flows overland to streams or percolates downward to the water table and ultimately flows out of the report area in the Housatonic River or in smaller streams tributary to the Hudson River. During the autumn and winter precipitation normally is sufficient to cause a substantial increase in the amount of water stored in surface reservoirs and in aquifers, whereas in the summer, losses through evaporation and transpiration result in sharply reduced streamflow and lowered ground-water levels. Mean monthly storage of water in November is 2.8 inches more than it is in June. The amount of water that flows into, through, and out of the report area represents the total amount potentially available for use ignoring reuse. For the 30-year period 1931 through 1960, the annual runoff from precipitation has averaged 24 inches (294 billion gallons). During the same period, inflows from Massachusetts and New York have averaged 220 and 64 billion gallons per year, respectively. A total average annual runoff of 578 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is rarely feasible to use all of it. On the other hand, with increased development, some water may be reused several times. The water availability may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed differ from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, transmissivity, and areal extent of aquifers, and on the variations in chemical and physical quality of water. Differences in precipitation cause differences in the amount of streamflow whereas differences in the proportion of stratified drift affect its timing. Water can be obtained from wells almost anywhere in the area, but the amount obtainable at any particular point depends on the type and water-bearing properties of the aquifers tapped. Stratified-drift aquifers are the only ones generally capable of yielding more than 100 gpm (gallons per minute) to individual wells. Drilled, screened wells tapping this unit yield from 17 to 1,400 gpm, with a median yield of 200 gpm. Till and bedrock are widespread but generally provide only small supplies of water. Till is tapped in a few places by dug wells, which can yield small supplies of only a few hundred gallons per day throughout all or most of the year. Bedrock is the chief aquifer for privately owned domestic and rural supplies; it is tapped by drilled wells, about 90 percent of which will supply at least 2 gpm. Only 1 of 10 bedrock wells, however, will supply more than 30 gpm. The amount of ground water potentially available in the report area depends upon the thickness and hydraulic properties of aquifers, the amount of salvageable natural discharge of ground water, and the quantity of water available by induced infiltration from streams and lakes. From data on transmissivity, thickness, recharge, well performance, and streamflow, preliminary estimates of ground-water availability can be made for most stratified-drift aquifers in the report area. Long-term yields estimated for eight areas of stratified drift especially favorable for development of large ground-water supplies ranged from 0.6 to 5 mgd (million gallons per day). Detailed site studies are needed to verity these estimates and to determine optimum yields, drawdowns, and spacing of individual wells before major ground-water development is undertaken in these or other areas. The chemical quality of water in the report area is generally good; carbonate-bedrock units exert considerable local influence on water quality. Samples of naturally occurring surface water collected at 24 sites during low flow averaged 90 mg/l (milligrams per liter) dissolved solids and 60 mg/l hardness. Water from wells is generally more highly mineralized than naturally occurring water from streams. About 37 percent of the wells sampled yielded water with more than 200 mg/l dissolved solids and 50 percent yielded water with more than 120 mg/l hardness. These concentrations reflect the high degree of mineralization of ground water in carbonate bedrock and unconsolidated deposits derived from this bedrock. The larger streams, which transport varying amounts of industrial and domestic effluents, averaged about 150 mg/l dissolved solids and 90 mg/l hardness. Iron and manganese concentrations in both ground water and surface water at some places exceed recommended limits for domestic and industrial use. Most wells in the report area yield water with little or no iron or manganese. In certain localities however, the probability is high of encountering water with excessive concentrations of these constituents. Schists, especially the unit in the northwestern corner of the basin, are the likely sources of water with excessive iron and manganese. Iron concentrations in naturally occurring stream water exceed 0.3 mg/l under low-flow conditions at 29 percent of the sites sampled. These excessive concentrations result from discharge of iron-bearing water from aquifers or from swamps where iron is released from decaying vegetation. Water temperature in the larger streams ranges from 0°C (degrees Celsius) to about 28°C. Ground water between 30 feet and 200 feet below the land surface has a relatively constant temperature, usually between 8°C and 11°C. The quantity of suspended sediment transported by streams under natural conditions is negligible. Even in streams affected by man, turbidity is rarely a problem. The total amount of water used in the report area for all purposes during 1967 was about 6,360 million gallons, or 140 gpd per person. Public supplies furnished the domestic needs of nearly half the population of the area. All of the 14 public supplies sampled provided water that meets the drinking water standards of the U.S. Public Health Service.

Connecticut↗
USGS2012

The U.S. Geological Survey Ecosystem Science Strategy, 2012-2022 - Advancing discovery and application through collaboration

Ecosystem science is critical to making informed decisions about natural resources that can sustain our Nation’s economic and environmental well-being. Resource managers and policy-makers are faced with countless decisions each year at local, state, tribal, territorial, and national levels on issues as diverse as renewable and non-renewable energy development, agriculture, forestry, water supply, and resource allocations at the urban-rural interface. The urgency for sound decision-making is increasing dramatically as the world is being transformed at an unprecedented pace and in uncertain directions. Environmental changes are associated with natural hazards, greenhouse gas emissions, and increasing demands for water, land, food, energy, mineral, and living resources. At risk is the Nation’s environmental capital, the goods and services provided by resilient ecosystems that are vital to the health and well-being of human societies. Ecosystem science—the study of systems of organisms interacting with their environment and the consequences of natural and human-induced change on these systems—is necessary to inform decision-makers as they develop policies to adapt to these changes. This Ecosystems Science Strategy is built on a framework that includes basic and applied science. It highlights the critical roles that USGS scientists and partners can play in building scientific understanding and providing timely information to decision-makers. The strategy underscores the connection between scientific discoveries and the application of new knowledge. The strategy integrates ecosystem science and decision-making, producing new scientific outcomes to assist resource managers and providing public benefits. The USGS is uniquely positioned to play an important role in ecosystem science. With its wide range of expertise, the agency can bring holistic, cross-scale, interdisciplinary capabilities to the design and conduct of monitoring, research, and modeling and to new technologies for data collection, management, and visualization. Collectively, these capabilities can be used to reveal ecological patterns and processes, explain how and why ecosystems change, and forecast change over different spatial and temporal scales. USGS science can provide managers with options and decision-support tools to use resources sustainably. The USGS has long-standing, collaborative relationships with the DOI and other partners in the natural sciences, in both conducting science and its application. The USGS engages these partners in cooperative investigations that otherwise would lack the necessary support or be too expensive for a single bureau to conduct. The heart of this strategy is a framework and vision for USGS ecosystems science that focuses on five long-term goals, which are seen as interconnected and reinforcing components: • Improve understanding of ecosystem structure, function, and processes. The focus for this goal is an understanding of how ecosystems work, including the dynamics of species, their populations, interactions, and genetics, and how they change across spatial and temporal scales. • Advance understanding of how drivers influence ecosystem change. The challenges here are explaining the drivers of ecosystem change, their spatio-temporal patterns, their uncertainties and interactions, and their influence on ecosystem processes and dynamics. • Improve understanding of the services that ecosystems provide to society. Here the emphasis is on the measurement of environmental capital and ecosystem services, and the identification of sources and patterns of change in space and time. • Develop tools, technologies, and capacities to inform decision-making about ecosystems. This includes developing new technologies and approaches for conducting applications-oriented ecosystem science. A principal challenge will be how to quantify uncertainty and incorporate it in decision analysis. • Apply science to enhance strategies for management, conservation, and restoration of ecosystems. These challenges include development of novel approaches to monitoring, assessment, and restoration of ecosystems; new methods to address species of concern and communities at risk; and innovations in decision analysis and support to address imminent ecosystem changes or those that are underway. Closely integrated with the five goals are four strategic approaches that provide the path forward for the USGS Ecosystems Mission Area. These approaches cross-cut all of the goals and are seen as essential to the implementation of this strategy: • Assess information needs for ecosystem science through enhanced partnerships. Work with the DOI and other agencies and institutions to identify, design, and implement priority decision-driven ecological research. • Promote the use of interdisciplinary ecosystem science. Design and conduct interdisciplinary process-oriented research in ecosystem science. • Enhance modeling and forecasting. Build models to forecast ecosystem change, assess future management scenarios, and reduce uncertainties through an adaptive learning process. • Support decision-making. Use quantitative approaches to assess the vulnerabilities of ecosystems, habitats, and species, and evaluate strategies for adaptation, restoration, and sustainable management. Following the strategic approaches are a set of proposed actions that represent a sampling of specific activities that align with this strategy and that address the Nation’s most pressing environmental needs. The strategy emphasizes coordination of activities across the USGS mission areas pursuant to these goals. Ecosystem science is inherently interdisciplinary and requires a broad perspective that incorporates the biological and physical sciences, climate science, information technology, and scientific capacity in mission areas across the Bureau. With its emphasis on coordination, this strategy can provide a critical underpinning for integrated science efforts with scientists from multiple mission areas of the USGS working together. Of course, the USGS will continue to conduct both discipline-specific and interdisciplinary investigations, and both will continue to be vital parts of the ecosystem science portfolio. Finally, the strategy stresses the importance of coordination with other Federal agencies and organizations in the natural resources community. The USGS collaborates with resource agencies in the DOI and other organizations throughout the world to meet societal needs for species and ecosystem management. Working with these agencies and organizations, the USGS will play a key role over the next decade in advancing the scientific foundation for sustaining the natural resources that diverse, productive, resilient ecosystems provide.

Open-File Report↗
USGS2013

U.S. Geological Survey ecosystems science strategy—Advancing discovery and application through collaboration

Executive Summary Ecosystem science is critical to making informed decisions about natural resources that can sustain our Nation’s economic and environmental well-being. Resource managers and policymakers are faced with countless decisions each year at local, regional, and national levels on issues as diverse as renewable and nonrenewable energy development, agriculture, forestry, water supply, and resource allocations at the urban-rural interface. The urgency for sound decisionmaking is increasing dramatically as the world is being transformed at an unprecedented pace and in uncertain directions. Environmental changes are associated with natural hazards, greenhouse gas emissions, and increasing demands for water, land, food, energy, mineral, and living resources. At risk is the Nation’s environmental capital, the goods and services provided by resilient ecosystems that are vital to the health and wellbeing of human societies. Ecosystem science—the study of systems of organisms interacting with their environment and the consequences of natural and human-induced change on these systems—is necessary to inform decisionmakers as they develop policies to adapt to these changes. This Ecosystems Science Strategy is built on a framework that includes basic and applied science. It highlights the critical roles that U.S. Geological Survey (USGS) scientists and partners can play in building scientific understanding and providing timely information to decisionmakers. The strategy underscores the connection between scientific discoveries and the application of new knowledge, and it integrates ecosystem science and decisionmaking, producing new scientific outcomes to assist resource managers and providing public benefits. We envision the USGS as a leader in integrating scientific information into decisionmaking processes that affect the Nation’s natural resources and human well-being. The USGS is uniquely positioned to play a pivotal role in ecosystem science. With its wide range of expertise, the Bureau can bring holistic, cross-scale, interdisciplinary capabilities to the design and conduct of monitoring, research, and modeling and to new technologies for data collection, management, and visualization. Collectively, these capabilities can be used to reveal ecological patterns and processes, explain how and why ecosystems change, and forecast change over different spatial and temporal scales. USGS science can provide managers with options and decision-support tools to use resources sustainably. The USGS has long-standing, collaborative relationships with the Department of the Interior (DOI) and other partners in the natural sciences, in both conducting science and applying the results. The USGS engages these partners in cooperative investigations that otherwise would lack the necessary support or be too expensive for a single bureau to conduct. The heart of this strategy is a framework for USGS ecosystems science that focuses on five long-term goals, which are seen as interconnected components that reinforce our vision of the USGS providing science that is at the forefront of decisionmaking: Improve understanding of ecosystem structure, function, and processes. The focus for this goal is an understanding of how ecosystems work, including the dynamics of species, their populations, interactions, and genetics, and how they change across spatial and temporal scales. Advance understanding of how drivers influence ecosystem change. The challenges here are explaining the drivers of ecosystem change, their spatio-temporal patterns, their uncertainties and interactions, and their influence on ecosystem processes and dynamics. Improve understanding of the services that ecosystems provide to society. Here the emphasis is on the measurement of environmental capital and ecosystem services, and the identification of sources and patterns of change in space and time. Develop tools, technologies, and capacities to inform decisionmaking about ecosystems. This includes developing new technologies and approaches for conducting applications-oriented ecosystem science. A principal challenge will be how to quantify uncertainty and incorporate it in decision analysis. Apply science to enhance strategies for management, conservation, and restoration of ecosystems. These challenges include development of novel approaches to monitoring, assessment, and restoration of ecosystems; new methods to address species of concern and communities at risk; and innovations in decision analysis and support to address imminent ecosystem changes or those that are underway. Closely integrated with the five goals are four strategic approaches that provide the path forward for the USGS Ecosystems Mission Area. These approaches cross-cut all of the goals and are seen as essential to the implementation of this strategy: Assess information needs for ecosystem science through enhanced partnerships. Work with the DOI and other agencies and institutions to identify, design, and implement priority decision-driven ecological research. Promote the use of interdisciplinary ecosystem science. Design and conduct interdisciplinary process-oriented research in ecosystem science. Enhance modeling and forecasting. Build models to forecast ecosystem change, assess future management scenarios, and reduce uncertainties through an adaptive learning process. Support decisionmaking. Use quantitative approaches to assess the vulnerabilities of ecosystems, habitats, and species, and evaluate strategies for adaptation, restoration, and sustainable management. Following the four strategic approaches are a set of proposed actions that represent a sampling of specific USGS activities that align with this strategy and that address the Nation’s most pressing environmental needs. The strategy emphasizes coordination of activities across the USGS mission areas pursuant to these goals. Ecosystem science is inherently interdisciplinary and requires a broad perspective that incorporates the biological and physical sciences, climate science, information technology, and scientific capacity in mission areas across the Bureau. With its emphasis on coordination, this strategy can provide a critical underpinning for integrated science efforts with scientists from multiple mission areas of the USGS working together. Of course, the USGS will continue to conduct discipline-specific and interdisciplinary investigations, and both will continue to be vital parts of the ecosystem science portfolio. Finally, the strategy stresses the importance of coordination with other Federal agencies and organizations in the natural resources community. The USGS collaborates with resource agencies in the DOI and other organizations throughout the world to meet societal needs for species and ecosystem management. Working with these agencies and organizations, the USGS will play a key role in guiding sound decisionmaking during the next decade by advancing the scientific foundation for sustaining the natural resources that diverse, productive, resilient ecosystems provide.

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USGS1993

1993 Annual Report: San Francisco estuary regional monitoring program for trace substances

This first annual report of the San Francisco Estuary Regional Monitoring Program contains the results of monitoring measurements made in 1993. Measurements of conventional water quality parameters and trace contaminant concentrations were made at 16 stations throughout the Estuary three times during the year: the wet period (March), during declining Delta outflow (May), and during the dry period (September). Water toxicity tests were conducted at 8 of those stations. Measurements of sediment quality and contaminant concentrations were made at the same 16 stations during the wet and dry sampling periods. Sediment toxicity was measured at 8 of those stations. Transplanted, bagged bivalve bioaccumulation and condition was measured at 11 stations during the wet and dry sampling periods. Water Monitoring. Total or near-total (dissolved + particulate, see text) arsenic, cadmium, selenium, and dissolved (0.45 µm filtered) arsenic, cadmium, copper, nickel, silver, and zinc in water were highest in the South Bay. In general, dissolved metals in water were usually lowest in the Central Bay due to ocean influences. Near-total nickel and total mercury in water were highest in the northern estuary (San Pablo and Suisun Bays). Dissolved chromium and lead were highest at the Sacramento and San Joaquin River confluence stations. Six of the ten dissolved trace metals were highest in March during high runoff. Dissolved and total arsenic, selenium, and near-total cadmium were highest in September. Concentrations of trace organic contaminants are reported for the March sampling period. Total PAHs and PCBs were highest in the South Bay, but PCBs were also high in the Napa River. Dissolved PAHs were highest in the Central Bay, and dissolved PCBs were highest in the Napa River. Total and dissolved pesticides were highest in the Sacramento River and in the Extreme South Bay. Concentrations of trace elements in water (except selenium) were usually closely related with other environmental parameters. Total or near-total metals concentrations in water were most often associated with the amount of particulate material (TSS) in the water. Dissolved concentrations were usually associated with salinity or dissolved organic carbon (DOC) content. Dissolved PAHs were well correlated with TSS, but dissolved and total trace organic contaminants were poorly correlated with other water parameters. Based on deviations from conservative mixing of fresh and salt water, three different patterns of possible sources of metals were identified in 1993. For dissolved chromium and lead, rivers and local runoff appeared to be important sources. For dissolved arsenic, cadmium, copper, and nickel year-round inputs from the South Bay appeared to be important sources. Dissolved mercury, selenium, and zinc were associated with local runoff in the South Bay during the wet period. Dissolved silver did not fit any of these patterns. Although most contaminant concentrations were below water quality objectives, several trace contaminants were above the objectives at some stations. Comparisons to water quality objectives are used as a guide for evaluation of contaminant concentrations, but there are some differences in the way the RMP data are measured and that prescribed for regulatory purposes (see text). Concentrations of 5 metals in water were above EPA or Regional Basin Plan water quality objectives at six stations (see Table 30). Most of these elevated levels occurred at the northern estuary stations. Total PCB concentrations were above EPA human health objectives at all RMP stations. The pesticides chlordane, dieldrin, and DDTs were above the EPA objectives at several RMP stations, particularly at the northern-most, and river confluence stations. Although some of the contaminant concentrations were above water quality objectives, water toxicity tests (96 hour algal growth and 48 hour bivalve larval development tests) did not indicate toxicity (sometimes inconclusive) associated with the water samples collected at any of the RMP stations in 1993. Exposure to Bay San Francisco Estuary Regional Monitoring Program Regional Monitoring Program 1993 Report ii water actually enhanced algal growth at most stations. In addition to the Estuary-wide sampling, the Sacramento and San Joaquin Rivers were sampled upstream from their confluence. Stations in each river were sampled six times over a 6 week period of high flows. In the Sacramento River, seven of the ten dissolved metals measured had concentrations lower than those measured at the river confluence stations. Some metals concentrations in the San Joaquin River were higher, and some were lower than concentrations from the river confluence station. Metals concentrations in the Sacramento River were poorly related to river flow because the station at Rio Vista is under considerable tidal influence. In the San Joaquin River, flows were inversely related to 7 of 10 total metals concentrations. Sediment Monitoring. Concentrations of silver, mercury, and lead in sediment were highest in the South Bay. However, concentrations of most trace metals in sediments were highest in the northern estuary at stations with the finest (silt, clay) sediments. The northern estuary stations with the coarsest (sand, shell) sediments generally had the lowest metals concentrations. There were differences in concentrations of cadmium, lead, and selenium in sediments between the sampling periods, but no consistent trend as to which sampling period had higher values. In September, PAHs and PCBs in sediments were highest in the Central Bay, but pesticides in sediments were highest in the northern estuary and Extreme South Bay. NOAA’s Median Effects Ranges (ERM) for sediments were used as a guide for evaluation of sediment contaminant concentrations. Nickel was the only trace contaminant in sediment above the ERM guidelines, and it was high at all RMP stations. These high levels are probably due to natural, geologic sources. Although sediment contaminant concentrations were below ERMs, sediment toxicity tests (10 day amphipod mortality, and 48 hour bivalve larval development in elutriates) indicated toxicity at all stations tested. Sediment factors that could have caused the toxicity were not investigated. Bivalve Bioaccumulation. Mussels, oysters, and freshwater clams were transplanted to the RMP stations to evaluate bioaccumulation of trace substances. Trace metals were bioaccumulated at nearly all RMP stations. However, arsenic, lead, and mercury did not appear to bioaccumulate. There was generally more bioaccumulation during the dry season than during the wet season. In September, PAHs, PCBs, and pesticides accumulated in all samples. Bioaccumulation of PAHs and pesticides was generally highest at the river confluence stations, and the Napa River. PCBs accumulated most at Redwood Creek. There were substantial differences in the degree of bioaccumulation among the species. Oysters appeared to accumulate higher concentrations of trace metals than the other species, especially copper, which may be a natural phenomenon. There are no established tissue contaminant standards for trace metal and organic contaminants. Therefore, comparisons to Median International Standards (MIS) for human consumption, or U.S. Food and Drug Administration (USFDA) action levels for trace organics are used to evaluate the bioaccumulation results. Concentrations of selenium were higher than MIS guidelines at all stations during the wet season. Other trace metal concentrations were higher than MIS guidelines at various stations during one or the other sampling period. However, none of the bivalves contained concentrations above the USFDA or National Academy of Sciences (NAS) guidelines for trace organic contaminants. The transplanted bivalves survived well at all stations except in the Napa River where less than 35% survived during both sampling seasons. Measures of bivalve condition (dry weight, shell volume) indicated that bivalves deployed in the Central Bay grew significantly, but those at most other stations actually lost weight. Whether these differences were due to natural causes such as salinity or food supply, or to contamination, was not determined. Pilot Studies. Two pilot monitoring studies were conducted in 1993. A pilot study of Estuary hydrography and phytoplankton was conducted by scientists from the U.S. Summary Geological Survey in Menlo Park and U.C. Davis. Water column profiles at up to 37 stations were monitored along a transect of the Estuary run monthly between the South Bay and the Delta. The primary objective of this study was to define physical (salinity, temperature, suspended particulate matter, and light penetration), chemical (dissolved oxygen) and biological (chlorophyll a) characteristics of Estuary water that may influence other chemical and biological reactions. A second objective was to investigate planktonic indicators of ecosystem structure and function. The data collected in 1993 showed the extent and duration of the spring phytoplankton bloom in the South Bay, other localized blooms in the northern estuary, the stratification and mixing associated with the entrapment zone in the northern estuary, and mixing in the Estuary resulting from the high rainfall in 1993. Knowledge of the duration and extent of these natural features of the Estuary provide context for interpretation of the RMP contaminant data collected only 3 times per year. Another pilot study of suspended sediment transport processes was conducted by the USGS in Sacramento. This study used continuous recording sensors at Point San Pablo and the Bay Bridge to measure the amount of suspended sediment in the water at mid-depth and near the bottom, as well as tide height. The objectives of this study were to estimate which factors determine suspended solids concentrations in the Central Bay and to collect time series of suspended solids that are appropriate for continuous monitoring of suspended solids and for calibration and validation of numerical models. The investigators determined that spring tides accounted for most of the variation in suspended solids concentrations at the stations monitored, not runoff from the Sacramento or San Joaquin Rivers, or semidiurnal and diurnal tides. Comparisons were also made between measurements made by the continuous recordings and the RMP samples collected during the regular monitoring cruises. The different ways of measuring TSS were generally comparable, however only 3 measurements per year as made by the RMP could not provide the information of TSS variation actually occurring in the Estuary. This information is important because as shown by the RMP data, total contaminant concentrations in Estuary water is largely dependent on the TSS in the water. This implies that the RMP measurements alone cannot determine accurately the range of contaminant concentrations without better characterizing the dynamics of TSS. The RMP Pilot Studies are important to the developing RMP because they will help put RMP measurements into the perspective of Estuary processes and mechanisms at other time scales. The studies can relate those processes to the RMP measurements and will facilitate revision of sampling design and interpretation. Summaries of other monitoring activities pertinent to regional monitoring are also included in the Report: a description of the Regional Board’s Bay Protection Studies, the Sacramento Coordinated Monitoring Program, and a wetlands monitoring plan are included.

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USGS1968

Water resources inventory of Connecticut Part 3: lower Thames and southeastern coastal river basins

The lower Thames and southeastern coastal river basins have a relatively abundant supply of water of generally good quality which is derived from streams entering the area and precipitation that has fallen on the area. Annual precipitation has ranged from about 32 inches to 65 inches and has averaged about 48 inches over a 30-year period. Approximately 22 inches of water are returned to the atmosphere each year by evaporation and transpiration; the remainder of the annual precipitation either flows overland to streams or percolates downward to the water table and ultimately flows out of the report area through estuaries and coastal streams or as underflow through the deposits beneath. During the autumn and winter months precipitation normally is sufficient to cause a substantial increase in the amount of water stored underground and in surface reservoirs within the report area, whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced stream-flow and lowered ground-water levels. The mean monthly storage of water on an average is about 3.8 inches higher in November than it is in June. The amount of water that flows through and out of the report area represents the total amount of water potentially available for use by man. For the 30-year period 1931 through 1960, the annual runoff from the report area has averaged nearly 26 inches (200 billion gallons), from the entire Thames River basin above Norwich about 24 inches (530 billion gallons), and from the Pawcatuck River basin about 26 inches (130 billion gallons). A total average annual runoff of 860 billion gallons is therefore available. Although runoff indicates the total amount of water potentially available, it is usually not economically feasible for man to use all of it. On the other hand, with increased development, it is possible that some water will be reused several times. The water available may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed vary from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, permeability, and areal extent of aquifers, and on the variations in chemical and physical quality of the water. Differences in streamflow from point to point are due primarily to differences in the proportion of stratified drift in the drainage basin above each point, which affect the timing of streamflow, and to differences in precipitation, which affect the amount of streamflow. Ground water can be obtained from wells almost anywhere in the area, but the amount obtainable at any particular point depends upon the type and water-bearing properties of the aquifers. For practical purposes, the earth materials in the report area comprise three aquifers--stratified drift, bedrock, and till. Stratified drift is the only aquifer generally capable of yielding more than 100 gpm (gallons per minute) to individual wells. It covers about 20 percent of the area and occurs chiefly in lowlands where it overlies till and bedrock. The coefficient of permeability of the coarse-grained unit of stratified drift averages about 1,500 gbd (gallons per day) per sq ft. Drilled, screened wells tapping this unit are known to yield from 4 to 88o gpm and average 146 gpm. Dug wells in coarse-grained stratified drift supply about 2 gpm per foot of drawdown over a period of a few hours. Fine-grained stratified drift has an average coefficient of permeability of about 300 gpd per sq ft and can usually yield supplies sufficient for household use to dug wells. Bedrock and till are widespread in extent but generally provide only small water supplies. Bedrock is tapped chiefly by drilled wells, about 90 percent of which will supply at least 3 gpm. Very few, however, will supply more than 50 gpm. Till is tapped in a few places by dug wells which can yield small supplies of only a few hundred gpd throughout all or most of the year. The coefficient of permeability of till ranges from about 0.2 gpd per sq ft to 120 gpd per sq ft. The amount of ground water potentially available in the report area depends upon the amount of ground-water outflow, the amount of ground water in storage, and the quantity of water available by induced infiltration from streams and lakes. From data on permeability, saturated thickness, recharge, yield from aquifer storage, well performance, and streamflow, preliminary estimates of ground-water availability can be made for any point in the report area. Long-term yields estimated for 18 areas of stratified drift especially favorable for development of large ground-water supplies ranged from 1.3 to 66 mgd. Detailed site studies to determine optimum yields, drawdowns, and spacing of individual wells are needed before major ground-water development is undertaken in these or other areas. The chemical quality of water in the report area is generally good to excellent. Samples of naturally occurring surface water collected at 24 sites contained less than 151 ppm (parts per million) of dissolved solids and less than 63 ppm of hardness. Water from wells is more highly mineralized than naturally occurring water from streams. Even so only 12 percent of the wells sampled yielded water with more than 200 ppm of dissolved solids and only 8 percent yielded water with more than 120 ppm of hardness. Even in major streams, which are used to transport industrial waste, hardness rarely exceeds 60 ppm and the dissolved mineral content is generally less than 200 ppm. At a few places in the town of Montville however, waters may contain dissolved mineral concentrations of 2,000 to 4,000 ppm. Iron and manganese in both ground water and surface water are the only constituents whose concentrations commonly exceed recommended limits for domestic and industrial use. Most wells in the report area yield clear water with little or no iron or manganese, but distributed among them are wells yielding ground water that contains enough of these dissolved constituents to be troublesome for most uses. Iron concentrations in naturally occurring stream water exceed 0.3 ppm under low-flow conditions at 33 percent of the sites sampled. Large concentrations of iron in stream water result from discharge of iron-bearing water from aquifers or from swamps where it is released largely from decaying vegetation. Ground water more than 30 feet below the land surface has a relatively constant temperature, usually between 48°F and 52°F. Water temperature in very shallow wells may fluctuate from about 38°F in February or March to about 55°F in late summer. Water temperature in the larger streams fluctuates much more widely, ranging from 32°F at least for brief periods in winter, to about 85°F occasionally during summer. The quality of suspended sediment transported by streams in the area is negligible. Turbidity in streams is generally not a problem although amounts large enough to be troublesome may occur locally at times. The total amount of water used in the report area for all purposes during 1964 was about 118,260 million gallons, of which 105,600 million gallons was estuarine water used for cooling by industry. The average per capita water use, excluding estuarine, temporary summer residence, and institutional water was equivalent to 186 gpd. Public water systems supplied the domestic needs of nearly tw0-thirds the population of the report area. All of the 19 systems, which were sampled, provided water of better quality than the U.S. Public Health Service suggests for drinking water standards.

Connecticut↗
USGS1967

Water resources inventory of Connecticut Part 2: Shetucket River Basin

The Shetucket River basin has a relatively abundant supply of water of generally good quality which is derived from precipitation that has fallen on the basin. Annual precipitation has ranged from about 30 inches to 75 inches and has averaged about 45 inches over a 35-year period. Approximately 20 inches of water are returned to the atmosphere each year by evaporation and transpiration; the remainder of the annual precipitation either flows overland to streams or percolates downward to the water table and ultimately flows out of the basin in the Shetucket River or as underflow through the deposits beneath. During the autumn and winter months precipitation normally is sufficient to cause a substantial increase in the amount of water stored underground and in surface reservoirs within the basins whereas in the summer most of the precipitation is lost through evaporation and transpiration, resulting in sharply reduced streamflow and lowered groundwater levels. The mean monthly storage of water in the basin on an average is 3.5 inches higher in November than it is in June. The amount of water that flows out of the basin in the Shetucket River represents the total amount of water potentlally available for use by man. Annual runoff from the entire basin above the Quinebaug River has ranged from about 13 to 42 inches since 1929, and has averaged about 23 inches (300 billion gallons). Although runoff indicates the total amount of water potentially available, it is usually not economically or legally feasible for man to use all of it. On the other hand, with increased development, It is possible that some water will be reused several times. The water available may be tapped as it flows through the area or is temporarily stored in streams, lakes, and aquifers. The amounts that can be developed vary from place to place and time to time, depending on the amount of precipitation, on the size of drainage area, on the thickness, permeability and areal extent of aquifers, and on the variations in chemical and physical quality of the water. Differences in streamflow from point to point are due primarily to differences in the proportion of stratified drift in the drainage basin above each point, which affect the timing of streamflow, and to differences in precipitation, which affect the amount of streamflow. Information on streamflow from gaging stations may be extended to ungaged sites by accounting for both of these factors ,in calculations. Future floods on the upper Willimantic River or the Shetucket River are unlikely to cause major damage so long as buildings are not constructed below the highest flood elevations to be expected with the present system of reservoirs for flood control. Ground water can be obtained from wells almost anywhere in the Shetucket River basin, but the amount obtainable from individual wells at any particular point depends upon the type and water-bearing properties of the aquifers present. For practical purposes, the earth materials in the basin comprise three aquifers--stratified drift, till, and bedrock, Stratified drift is the only aquifer generally capable of yielding more than 100 gpm to individual wells. This aquifer covers about 18 percent of the basin and occurs chiefly In lowlands where it overlies till or bedrock. Coefficient of permeability of the coarse-grained unit of stratified drift averages about 1,900 gpd per sq ft. Drilled, screened wells tapping this unit, are known to yield from 200 to 675 gpm. Dug wells in coarse-grained stratified drift should supply at least 2 gpm per foot of drawdown over an 8-hour period. Fine-grained stratified drift has an average coefficient of permeability of about 400 gpd per sq ft and can usually yield to dug wells supplies sufficient for household use. Till and bedrock are widespread in extent but can provide only small to moderate water supplies. Till is tapped chiefly by dug wells; permanent supplies of more than 200 gpd can be obtained from dug wells at a majority of sites in areas of till, but there are many sites where the till is too impermeable or too thin to provide this much water throughout the year. The coefficient of permeability of till ranges from about 0.2 gpd per sq ft to 55 gpd per sq it. Bedrock Is tapped chiefly by drilled wells, about 90 percent of which will supply at least 3 gpm. Very few, however, will supply more than 50 gpm. The amount of ground water potentially available In an area depends upon the amount of groundwater outflow, the amount of ground water in storage, and the quantity of water available by Induced infiltration from streams and lakes. From data on permeability, saturated thickness, recharge, yield from aquifer storage, well performance, and streamflow, preliminary estimates of ground-water availability can be made for any point in the basin. Long-term yields estimated for 15 areas especially favorable for development of large ground-water supplies ranged from 1.3 to 61.8 mgd. Detailed site studies to determine optimum yields, drawdowns, and spacing of individual wells are needed before major ground-water development is undertaken In these or other areas. The chemical quality of water in the Shetucket basin Is generally good to excellent. Samples of naturally occurring surface water collected from 32 sites contained less than 61 ppm of dissolved solids and less than 32 ppm of hardness. Water from wells is more highly mineralized than naturally occurring water from streams. Even so only 7 percent of wells sampled yielded water with more than 200 ppm of dissolved sol-ids and only 9 percent yielded water with more than 120 ppm of hardness. Even in the major rivers, which are used to transport industrial waste, the dissolved mineral content is less than 100 ppm and hardness rarely exceeds 40 ppm. One notable exception occurs in the lower reaches of Little River where an exceptional amount of industrial waste is discharged into the river near Versailles. This waste is particularly noticeable during low streamflow. Iron and manganese In both ground water and surface water are the only constituents whose concentrations commonly exceed recommended limits for domestic and industrial use. Most wells in the basin yield clear water with little or no iron or manganese, but distributed among them are wells with ground water that contains enough of these dissolved constituents to be troublesome for most uses. iron concentrations in naturally occurring stream water exceeded 0.3 ppm under tow-flow conditions at 20 percent of the sites sampled. Large concentrations of iron in stream water result from discharge of iron-bearing ground water or from the discharge of water from swamps. In swamps the iron is released largely from decaying vegetation. Ground water more than 30 feet below the land surface has a relatively constant temperature, usually between 48°F and 50°F. Water temperature in very shallow wells may fluctuate from about 38°F in February or March to about 55°F in late summer. Water temperature in the larger streams fluctuates much more widely, ranging from 32°F at least for brief periods in winter, to about 85°F occasionally during The quantity of suspended sediment transported by streams in the basin is negligible, though amounts large enough to be troublesome may occur locally at times. The total amount of water used In the Shetucket Rlver basin for all purposes during 1961 was about 5,810 million gallons~ which is equivalent to 208 gpd per person, Public water systems supplied the domestic needs of nearly half the population of the basin; 10 systems were sampled, all of which provided water of better quality than the U.S. Public Health Service suggests for drinking water standards.

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