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USGS2001

Factors affecting reservoir and stream-water quality in the Cambridge, Massachusetts, drinking-water source area and implications for source-water protection

This report presents the results of a study conducted by the U.S. Geological Survey, in cooperation with the city of Cambridge, Massachusetts, Water Department, to assess reservoir and tributary-stream quality in the Cambridge drinking-water source area, and to use the information gained to help guide the design of a comprehensive water-quality monitoring program for the source area. Assessments of the quality and trophic state of the three primary storage reservoirs, Hobbs Brook Reservoir, Stony Brook Reservoir, and Fresh Pond, were conducted (September 1997-November 1998) to provide baseline information on the state of these resources and to determine the vulnerability of the reservoirs to increased loads of nutrients and other contaminants. The effects of land use, land cover, and other drainage-basin characteristics on sources, transport, and fate of fecal-indicator bacteria, highway deicing chemicals, nutrients, selected metals, and naturally occurring organic compounds in 11 subbasins that contribute water to the reservoirs also was investigated, and the data used to select sampling stations for incorporation into a water-quality monitoring network for the source area. All three reservoirs exhibited thermal and chemical stratification, despite artificial mixing by air hoses in Stony Brook Reservoir and Fresh Pond. The stratification produced anoxic or hypoxic conditions in the deepest parts of the reservoirs and these conditions resulted in the release of ammonia nitrogen orthophosphate phosphorus, and dissolved iron and manganese from the reservoir bed sediments. Concentrations of sodium and chloride in the reservoirs usually were higher than the amounts recommended by the U.S. Environmental Protection agency for drinking-water sources (20 milligrams per liter for sodium and 250 milligrams per liter for chloride). Maximum measured sodium concentrations were highest in Hobbs Brook Reservoir (113 milligrams per liter), intermediate in Stony Brook Reservoir (62 milligrams per liter), and lowest in Fresh Pond (54 milligrams per liter). Bed sediments in Hobbs Brook and Stony Brook Reservoirs were enriched in iron, manganese, and arsenic relative to those in the impounded lower Charles River in Boston, Massachusetts. Trophic state indices, calculated for each reservoir based on nutrient concentrations, water-column transparency, and phytoplankton abundances, indicated that the upper and middle basins of Hobbs Brook Reservoir were moderately to highly productive and likely to produce algal blooms; the lower basin of Hobbs Brook Reservoir and Stony Brook Reservoir were similar and intermediate in productivity, and Fresh Pond was relatively unproductive and unlikely to produce algal blooms. This pattern is likely due to sedimentation of organic and inorganic particles in the three basins of Hobbs Brook Reservoir and in Stony Brook Reservoir. Molar ratios of nitrogen to phosphorus ranged from 55 in Stony Brook Reservoir to 120 in Hobbs Brook Reservoir, indicating that phytoplankton algae in these water bodies may be phosphorus limited and therefore sensitive to small increases in phosphorus loading from the drainage basin. Nitrogen loads were found to be less important than phosphorus to the trophic condition of the reservoirs. Hobbs Brook and Stony Brook, the two principle streams draining the Cambridge drinking-water source area, differed in their relative contributions to many of the estimated constituent loads. The estimated load of fecal coliform bacteria was more than seven times larger for the mainly residential Stony Brook subbasin upstream from Kendal Green, Mass., than it was for the more commercial and industrial Hobbs Brook subbasin, though the drainage areas of the two subbasins differ only by about 20 percent. The State standard for fecal coliform bacteria in streams in the Cambridge drinking-water source area (20 colony forming units per 100 milliliters) was exceeded at all sampling stations. Estimated s

Massachusetts↗

USGS2004

Hydrogeology of Webb County, Texas

Introduction Webb County, in semiarid South Texas on the U.S.-Mexico border, is a region confronted by increasing stresses on natural resources. Laredo (fig. 1), the largest city in Webb County (population 193,000 in 2000), was one of the 10 fastest-growing metropolitan areas in the country during 1990-2000 (Perry and Mackun, 2001). Commercial and industrial activities have expanded throughout the region to support the maquiladora industry (manufacturing plants in Mexico) along the border and other growth as a result of the passage of the North American Free Trade Agreement. The Rio Grande currently (2002) is the primary source of public water supply for Laredo and other cities along the border in Webb County (fig. 1). Other cities, such as Bruni and Mirando City in the southeastern part of the county, rely on ground-water supplies to meet municipal demands. Increased water demand associated with development and population growth in the region has increased the need for the City of Laredo and Webb County to evaluate alternative water sources to meet future demand. Possible options include (1) supplementing the surface-water supply with ground water, and (2) applying artificial storage and recovery (ASR) technology to recharge local aquifers. These options raise issues regarding the hydraulic capability of the aquifers to store economically substantial quantities of water, current or potential uses of the resource, and possible effects on the quality of water resulting from mixing ground water with alternative source waters. To address some of these issues, the U.S. Geological Survey (USGS), in cooperation with the City of Laredo, began a study in 1996 to assess the ground-water resources of Webb County. A hydrogeologic study was conducted to review and analyze available information on the hydrogeologic units (aquifers and confining units) in Webb County, to locate available wells in the region with water-level and water-quality information from the aquifers, and to analyze the hydraulic properties of the aquifers. The purpose of this report is to document the findings of the study. The information is organized by hydrogeologic unit and presented on this and six other sheets.

Texas↗

USGS2014

Water quality at a biosolids-application area near Deer Trail, Colorado, 1993-1999

The Metro Wastewater Reclamation District (Metro District) in Denver, Colo., applied biosolids resulting from municipal sewage treatment to farmland in eastern Colorado beginning in December 1993. In mid-1993, the U.S. Geological Survey in cooperation with the Metro District began monitoring water quality at the biosolids-application area about 10 miles east of Deer Trail, Colo., to evaluate baseline water quality and the combined effects of natural processes, land uses, and biosolids applications on water quality of the biosolids application area. Water quality was characterized by baseline and post-biosolids-application sampling for selected inorganic and bacteriological constituents during 1993 through 1998, with some additional specialized sampling in 1999. The study included limited sampling of surface water and the unsaturated zone, but primarily focused on groundwater. See report for complete abstract.

Colorado↗

USGS2007

Water-level and land-subsidence studies in the Mojave River and Morongo groundwater basins

Since 1992, the U.S. Geological Survey (USGS), in cooperation with the Mojave Water Agency (MWA), has constructed a series of regional water-table maps for intermittent years in a continuing effort to monitor groundwater conditions in the Mojave River and Morongo groundwater basins. The previously published data, which were used to construct these maps, can be accessed on the interactive map. The associated reports describing the groundwater conditions for the Mojave River groundwater basin for 1992 (Stamos and Predmore, 1995), the Morongo groundwater basin for 1994 (Trayler and Koczot, 1995), and for both groundwater basins for 1996 (Mendez and Christensen, 1997); for 1998 (Smith and Pimentel, 2000), for 2000 (Smith, 2002), for 2002 (Smith and others, 2004), for 2004 (Stamos and others, 2004), and for 2006 (Stamos and others, 2007) can be accessed using this web site. Spatially detailed maps of interferometric synthetic aperture radar (InSAR) methods were used to characterize land subsidence associated with groundwater-level declines during various intervals of time between 1992 and 1999 in the Mojave River and Morongo groundwater basins (Sneed and others, 2003). Concerns related to the potential for new or renewed land subsidence in the basins resulted in a cooperative study between the MWA and the USGS in 2006. InSAR data were developed to determine the location, extent, and magnitude of vertical land-surface changes in the Mojave River and Morongo groundwater basins for time intervals ranging from about 35 days to 14 months between 1999 and 2000 and between 2003 and 2004. (interactive Google map) The results from many future land-subsidence studies, which are scheduled about every 10 years, will be available on this website. Mapping of water-level contours, water-level change and numerous InSAR images were combined in an interactive map. This interactive map may be customized to your needs and viewed at a scale that is appropriate for the data.

California↗

USGS2009

Methodology for Estimation of Flood Magnitude and Frequency for New Jersey Streams

Methodologies were developed for estimating flood magnitudes at the 2-, 5-, 10-, 25-, 50-, 100-, and 500-year recurrence intervals for unregulated or slightly regulated streams in New Jersey. Regression equations that incorporate basin characteristics were developed to estimate flood magnitude and frequency for streams throughout the State by use of a generalized least squares regression analysis. Relations between flood-frequency estimates based on streamflow-gaging-station discharge and basin characteristics were determined by multiple regression analysis, and weighted by effective years of record. The State was divided into five hydrologically similar regions to refine the regression equations. The regression analysis indicated that flood discharge, as determined by the streamflow-gaging-station annual peak flows, is related to the drainage area, main channel slope, percentage of lake and wetland areas in the basin, population density, and the flood-frequency region, at the 95-percent confidence level. The standard errors of estimate for the various recurrence-interval floods ranged from 48.1 to 62.7 percent. Annual-maximum peak flows observed at streamflow-gaging stations through water year 2007 and basin characteristics determined using geographic information system techniques for 254 streamflow-gaging stations were used for the regression analysis. Drainage areas of the streamflow-gaging stations range from 0.18 to 779 mi2. Peak-flow data and basin characteristics for 191 streamflow-gaging stations located in New Jersey were used, along with peak-flow data for stations located in adjoining States, including 25 stations in Pennsylvania, 17 stations in New York, 16 stations in Delaware, and 5 stations in Maryland. Streamflow records for selected stations outside of New Jersey were included in the present study because hydrologic, physiographic, and geologic boundaries commonly extend beyond political boundaries. The StreamStats web application was developed cooperatively by the U.S. Geological Survey and the Environmental Systems Research Institute, Inc., and was designed for national implementation. This web application has been recently implemented for use in New Jersey. This program used in conjunction with a geographic information system provides the computation of values for selected basin characteristics, estimates of flood magnitudes and frequencies, and statistics for stream locations in New Jersey chosen by the user, whether the site is gaged or ungaged.

Scientific Investigations Report↗

USGS1988

Estimating average dissolved-solids yield from basins drained by ephemeral and intermittent streams — Green River basin, Wyoming

A method was developed to determine the average dissolved-solids yield contributed by small basins characterized by ephemeral and intermittent streams in the Green River basin in Wyoming. The method is different from that commonly used for perennial streams. Estimates of dissolved-solids discharge at eight water quality sampling stations operated by the U.S. Geological Survey in cooperation with the U.S. Bureau of Land Management range from less than 2 to 95 tons/day. The dissolved-solids yield upstream from the sampling stations ranges from 0.023 to 0.107 tons/day/sq mi. However, estimates of dissolved solids yield contributed by drainage areas between paired stations on Bitter, Salt Wells, Little Muddy, and Muddy creeks, based on dissolved-solids discharge versus drainage area, range only from 0.081 to 0.092 tons/day/sq mi. (USGS)

Wyoming↗

USGS2010

Megascopic lithologic studies of coals in the Powder River basin in Wyoming and in adjacent basins in Wyoming and North Dakota

Between 1999 and 2007, the U.S. Geological Survey (USGS) investigated coalbed methane (CBM) resources in the Wyoming portion of the Powder River Basin. The study also included the CBM resources in the North Dakota portion of the Williston Basin of North Dakota and the Wyoming portion of the Green River Basin of Wyoming. This project involved the cooperation of the State Office, Reservoir Management Group (RMG) of the Bureau of Land Management (BLM) in Casper, Wyo., and 16 independent gas operators in the Powder River, Williston, and Green River Basins. The USGS and BLM entered into agreements with these CBM operators to supply samples for the USGS to analyze and provide the RMG with rapid, timely results of total gas desorbed, coal quality, and high-pressure methane adsorption isotherm data. This program resulted in the collection of 963 cored coal samples from 37 core holes. This report presents megascopic lithologic descriptive data collected from canister samples extracted from the 37 wells cored for this project.

Open-File Report↗

USGS2005

Geological, hydrological, and biological issues related to the proposed development of a park at the confluence of the Los Angeles River and the Arroyo Seco, Los Angeles County, California

A new park is being considered for the confluence of the Los Angeles River and the Arroyo Seco in Los Angeles County, California. Components of the park development may include creation of a temporary lake on the Los Angeles River, removal of channel lining along part of the Arroyo Seco, restoration of native plants, creation of walking paths, and building of facilities such as a boat ramp and a visitor center. This report, prepared in cooperation with the Mountains Recreation and Conservancy Authority, delineates the geological, hydrological, and biological issues that may have an impact on the park development or result from development at the confluence, and identifies a set a tasks to help address these science issues. Geologic issues of concern relate to surface faulting, earthquake ground motions, liquefaction, landsliding, and induced seismicity. Hydrologic issues of concern relate to the hydraulics and water quality of both surface water and ground water. Biological issues of concern include colonization-extinction dynamics, wildlife corridors, wildlife reintroduction, non-native species, ecotoxicology, and restoration of local habitat and ecology. Potential tasks include (1) basic data collection and follow-up monitoring, and (2) statistical and probabilistic analyses and simulation modeling of the seismic, hydraulic, and ecological processes that may have the greatest impact on the park. The science issues and associated tasks delineated for the proposed confluence park will also have transfer value for river restoration in other urban settings.

Scientific Investigations Report↗

USGS1999

Geologic map of the Middletown quadrangle, Frederick, Shenandoah, and Warren Counties, Virginia

The Middletown 1:24,000-scale quadrangle is one of several quadrangles in Frederick County, Virginia mapped or being mapped by geologists from the U.S. Geological Survey in Reston, VA with funding from the National Cooperative Geologic Mapping Program. This map was originally published as a paper product in 1999. It has been converted to GIS-based digital form. This work is part of a project being lead by the U.S. Geological Survey Water Resources Discipline, Virginia District, to investigate the geologic framework and groundwater resources of Frederick County as well as other areas in the northern Shenandoah Valley of Virginia and West Virginia. For more information about the Project see: http://geology.er.usgs.gov/eespteam/Karst/index.html for Geologic Discipline efforts and http://va.water.usgs.gov/va134/index.htm for Water Resources Discipline efforts.

Virginia↗

USGS2018

Prioritization of oil and gas fields for regional groundwater monitoring based on a preliminary assessment of petroleum resource development and proximity to California’s groundwater resources

The California State Water Resources Control Board initiated a regional monitoring program in July 2015 to determine where and to what degree groundwater quality may be adversely impacted by oil and gas development activities. A key issue in the implementation of the regional groundwater monitoring program is that each year, detailed characterization work can be done in only a few of California’s 487 onshore oil and gas fields. The first step in monitoring groundwater near petroleum development is to prioritize oil and gas fields using consistent statewide analysis of available data that indicate potential risk of groundwater to oil and gas development. The U.S. Geological Survey compiled data for four factors that characterize the intensity of petroleum resource development and proximity to groundwater resources: petroleum-well density, volume of water injected in oil fields, vertical proximity of groundwater resources to oil and gas resource development, and water-well density. An overall priority ranking for each field was determined by computing summary metrics, analyzing statewide distributions of summary metrics for all oil and gas fields, using those distributions to define relative categories of potential risk for each factor, and combining relative risk rankings for different factors into an overall priority ranking. This preliminary assessment does not represent an evaluation of groundwater risk to oil and gas development, which needs to be based on detailed analysis and data related to development activities including well stimulation, well integrity issues, produced water ponds, and underground injection. Based on the prioritization analysis, 22 percent (107 fields) of the total number of oil and gas fields in California were ranked as high priority, 23 percent (114 fields) as moderate priority, and 55 percent (266 fields) as low priority. These results indicate that between 100 and 200 oil fields are principal candidates for the next steps in the regional monitoring program. The land area of fields that ranked high priority accounted for 41 percent of the total field area (3,392 square miles). More than half of the high priority fields were in the southern San Joaquin Valley and the Los Angeles Basin. Some of the larger fields tended to have higher rankings because of greater intensity of petroleum development, sometimes coupled with proximity to groundwater resources. The U.S. Geological Survey, in collaboration with the California State Water Resources Control Board and other agencies, has begun regional groundwater monitoring near oil and gas fields selected for study through the California Oil, Gas, and Groundwater cooperative program. Groundwater monitoring includes compiling, analyzing, and developing three-dimensional visualizations of existing data, including geological frameworks, salinity mapping, identification of surface features that could potentially affect groundwater quality, locations and depths of oil/gas and water wells, cataloging well-construction integrity issues, and evaluating the directions of groundwater flow. These analyses are required to determine where existing wells should be monitored and where new monitoring wells may need to be drilled.

California↗

USGS1984

Evaluation of the ground-water resources of coastal Georgia: preliminary report of the data available as of July 1983

A compilation of ground-water data that have been collected for nearly 100 years in the coastal area of Georgia is presented in this report. The compilation of pertinent data indicates what information is available for use in the evaluation of the ground-water resources of the 13 counties of coastal Georgia. Also included in this report is a fairly complete discussion of previous and ongoing investigations and monitoring networks, and an extensive list of references. Maps at 1:24,000 and 1:1,000,000 scales contain well locations and identifiers for all wells in the Ground Water Site Inventory (GWSI) data base of the National Water Data Storage and retrieval System (WATSTORE). Tabular summaries of selected site information from GWSI, including well identifiers and names, latitude-longitude location, depth of well, altitude of land surface, and use of water are presented. Water-use data from the National Water Use Data System, and water use for irrigation from the University of Georgia, Department of Agriculture survey, also are tabulated. Also included are pertinent information on geophysical surveys and data obtained, and proposed project activities, particularly test-monitor well drilling. The data in this report were collected and compiled as part of the cooperative activities between the U.S. Geological Survey and other agencies.

Georgia↗

USGS2012

Modification of selected South Carolina bridge-scour envelope curves

Historic scour was investigated at 231 bridges in the Piedmont and Coastal Plain physiographic provinces of South Carolina by the U.S. Geological Survey in cooperation with the South Carolina Department of Transportation. These investigations led to the development of field-derived envelope curves that provided supplementary tools to assess the potential for scour at bridges in South Carolina for selected scour components that included clear-water abutment, contraction, and pier scour, and live-bed pier and contraction scour. The envelope curves consist of a single curve with one explanatory variable encompassing all of the measured field data for the respective scour components. In the current investigation, the clear-water abutment-scour and live-bed contraction-scour envelope curves were modified to include a family of curves that utilized two explanatory variables, providing a means to further refine the assessment of scour potential for those specific scour components. The modified envelope curves and guidance for their application are presented in this report.

South Carolina↗

USGS2016

Development of novel microsatellite markers for the Northern Goshawk ( Accipiter gentilis ) and their utility in cross-species amplification

The Northern Goshawk ( Accipiter gentilis ) is a large forest raptor with a Holarctic distribution and, in some portions of its range, a species of conservation concern. To augment previously reported genetic markers, 13 novel polymorphic microsatellite markers were developed to establish individual identification and familial relationships, to assess levels of genetic diversity, and to identify diagnostic markers. Of the 22 loci tested, 13 were polymorphic, seven were monomorphic, and two failed to amplify. This suite of microsatellite loci yielded a combined probability of parental exclusion of 98%; a single individual sampled from a North American population can be reliably identified using a combination of seven of the 13 polymorphic loci. Cross-species screening in Cooper's Hawks ( A. cooperii ) and Sharp-shinned Hawks ( A. striatus ) of the 20 loci that successfully amplified in Northern Goshawks identified 13 loci as polymorphic in each species. Six of these loci (Age1303, Age1308, Age1309, Age1312, and Age1314) appeared to be useful in distinguishing between Accipiter species. These markers will be useful to researchers investigating populations of North American accipiters.

Avian Biology Research↗

USGS2014

Analysis of water quality in the Blue River watershed, Colorado, 1984 through 2007

Water quality of streams, reservoirs, and groundwater in the Blue River watershed in the central Rocky Mountains of Colorado has been affected by local geologic conditions, historical hard-rock metal mining, and recent urban development. With these considerations, the U.S. Geological Survey, in cooperation with the Summit Water Quality Committee, conducted a study to compile historical water-quality data and assess water-quality conditions in the watershed. To assess water-quality conditions, stream data were primarily analyzed from October 1995 through December 2006, groundwater data from May 1996 through September 2004, and reservoir data from May 1984 through November 2007. Stream data for the Snake River, upper Blue River, and Tenmile Creek subwatersheds upstream from Dillon Reservoir and the lower Blue River watershed downstream from Dillon Reservoir were analyzed separately. (The complete abstract is provided in the report)

Colorado↗

USGS2016

Processing of multichannel seismic reflection data acquired in 2013 for seismic investigations of gas hydrates in the Gulf of Mexico

As part of a cooperative effort among the U.S. Geological Survey (USGS), the U.S. Department of Energy, and the U.S. Department of the Interior Bureau of Ocean Energy Management, two grids of two-dimensional multichannel seismic reflection data were acquired in the Gulf of Mexico over lease blocks Green Canyon 955 and Walker Ridge 313 between April 18 and May 3, 2013. The purpose of the data acquisition was to fill knowledge gaps in an ongoing study of known gas hydrate accumulations in the area. These data were initially processed onboard the recording ship R/V Pelican for more quality control during the recording. The data were subsequently processed in detail by the U.S. Geological Survey in Denver, Colorado, in two phases. The first phase was to create a “kinematic” dataset that removed extensive noise present in the data but did not preserve relative amplitudes. The second phase was to create a true relative amplitude dataset that included noise removal and “wavelet” deconvolution that preserved the amplitude information. This report describes the processing techniques used to create both datasets.

Open-File Report↗

USGS2022

Bathymetric and velocimetric surveys at highway bridges crossing the Missouri River near Kansas City, Missouri, August 2019, August 2020, and October 2020

Bathymetric and velocimetric data were collected by the U.S. Geological Survey, in cooperation with the Missouri Department of Transportation, near 9 bridges at 8 highway crossings of the Missouri River near Kansas City, Missouri, on August 13–14, 2019. A multibeam echosounder mapping system was used to obtain channel-bed elevations for river reaches about 1,550 to 1,660 feet longitudinally and generally extending laterally across the active channel from bank to bank during moderate flood-flow conditions. These surveys indicated the channel conditions at the time of the surveys and provided characteristics of scour holes that may be useful in developing predictive guidelines or equations for scour holes. These data also may be useful to the Missouri Department of Transportation as a low to moderate flood-flow assessment of the bridges for stability and integrity issues with respect to bridge scour during floods. Bathymetric data were collected around every pier that was in water, except around the nose of one pier that was surrounded by a persistent debris raft. Scour holes were present at most piers for which bathymetry could be obtained, except those on banks or surrounded by riprap. The observed scour holes at the surveyed bridges generally were examined with respect to shape and depth. Comparisons between bathymetric surfaces from previous surveys and this study do not indicate any consistent correlation in channel-bed elevations with streamflow conditions at the times of the surveys. The predominant overall scour observed between the various surveys implies the channel bed in the 2019 surveys might have been rebounding from more substantial scour caused by the high streamflow earlier in March and June 2019, which was the highest streamflow since 1993. Pier size and nose shape had a substantial effect on the size of the scour hole observed at a given pier. Many of the piers at the Kansas City area bridges have wide or blunt noses caused by exposed footings, seal courses, or caissons, which resulted in large, deep scour holes at most piers. Several of the structures had piers that were skewed to primary approach flow; and, at most of the structures, the scour hole was deeper and longer on the side of the pier with impinging flow than the leeward side, with some amount of deposition on the leeward side, as typically has been observed at piers skewed to approach flow. Limited additional bathymetric data were collected by the U.S. Geological Survey, in cooperation with Clarkson Construction, near the main channel piers of the U.S. Highway 169 (Broadway) and the Interstate 435 (Randolph) bridges on August 17 and October 23, 2020, to determine the channel-bed conditions before and after installation of scour countermeasures near those piers. Survey results from before and after installation of these countermeasures show these features had a substantial effect on mitigating the observed scour at these piers, particularly when compared to piers at other sites without such features.

Missouri↗

USGS2010

Hydrologic Data for Deep Creek Lake and Selected Tributaries, Garrett County, Maryland, 2007-08

Introduction Recent and ongoing efforts to develop the land in the area around Deep Creek Lake, Garrett County, Maryland, are expected to change the volume of sediment moving toward and into the lake, as well as impact the water quality of the lake and its many tributaries. With increased development, there is an associated increased demand for groundwater and surface-water withdrawals, as well as boat access. Proposed dredging of the lake bottom to improve boat access has raised concerns about the adverse environmental effects such activities would have on the lake. The Maryland Department of Natural Resources (MDDNR) and the U.S. Geological Survey (USGS) entered into a cooperative study during 2007 and 2008 to address these issues. This study was designed to address several objectives to support MDDNR?s management strategy for Deep Creek Lake. The objectives of this study were to: Determine the current physical shape of the lake through bathymetric surveys; Initiate flow and sediment monitoring of selected tributaries to characterize the stream discharge and sediment load of lake inflows; Determine sedimentation rates using isotope analysis of sediment cores; Characterize the degree of hydraulic connection between the lake and adjacent aquifer systems; and Develop an estimate of water use around Deep Creek Lake. Summary of Activities Data were collected in Deep Creek Lake and in selected tributaries from September 2007 through September 2008. The methods of investigation are presented here and all data have been archived according to USGS policy for future use. The material presented in this report is intended to provide resource managers and policy makers with a broad understanding of the bathymetry, surface water, sedimentation rates, groundwater, and water use in the study area. The report is structured so that the reader can access each topic separately using any hypertext markup (HTML) language reader. In order to establish a base-line water-depth map of Deep Creek Lake, a bathymetric survey of the lake bottom was conducted in 2007. The data collected were used to generate a bathymetric map depicting depth to the lake bottom from a full pool elevation of 2,462 feet (National Geodetic Vertical Datum of 1929). Data were collected along about 90 linear miles across the lake using a fathometer and a differentially corrected global positioning system. As part of a long-term monitoring plan for all surface-water inputs to the lake, streamflow data were collected continuously at two stations constructed on Poland Run and Cherry Creek. The sites were selected to represent areas of the watershed under active development and areas that are relatively stable with respect to development. Twelve months of discharge data are provided for both streams. In addition, five water-quality parameters were collected continuously at the Poland Run station including pH, specific conductance, temperature, dissolved oxygen, and turbidity. Water samples collected at Poland Run were analyzed for sediment concentration, and the results of this analysis were used to estimate the annual sediment load into Deep Creek Lake from Poland Run. To determine sedimentation rates, cores of lake-bottom sediments were collected at 23 locations. Five of the cores were analyzed using a radiometric-dating method, allowing average rates of sedimentation to be estimated for the time periods 1925 to 2008, 1925 to 1963, and 1963 to 2008. Particle-size data from seven cores collected at locations throughout the study area were analyzed to provide information on the amount of fine material in lake-bed sediments. Groundwater levels were monitored continuously in four wells and weekly in nine additional wells during October, November, and December of 2008. Water levels were compared to recorded lake levels and precipitation during the same period to determine the effect of lake-level drawdown and recovery on the adjacent aquifer systems. Water use in the Deep Creek Lake wa

Open-File Report↗

USGS1998

Walden Pond, Massachusetts: Environmental setting and current investigations

Introduction Walden Pond, in Concord, Massachusetts, is famous among lakes because of its unique social history. Walden was the setting for American naturalist Henry David Thoreau's well-known essay 'Walden; or, Life in the Woods,' first published in 1854. Thoreau lived and wrote at Walden Pond from July 1845 to September 1847. In 'Walden,' Thoreau combined highly admired writing on Transcendental philosophy with pioneering observations of aquatic ecology and physical aspects of limnology, the study of lakes. Because Thoreau also defended so effectively the value of living close to nature in the Walden woods, the pond is considered by many to be the birthplace of the American conservation movement. Visitors come from all over the world to the pond, which has been designated a National Historic Landmark, and its fame has resulted in a major fund drive to preserve the surrounding woods. Walden Pond has no surfacewater inflow or outflow, and much of its ground-water contributing area likely is preserved within the Walden Pond Reservation area (fig. 1). Only 15 miles from Boston, the pond is unusually clear and pristine for an urban-area lake. However, point sources of nutrients near the pond, and a large annual visitor attendance, concentrated during the summer when the swimming beach (fig. 2) is open, may contribute a nutrient load sufficient to change the pond environment. The occurrence of nuisance algal species, a recent beach closing, and an awareness of water-quality problems suffered by other ponds in the region raise concerns about the risk of ecological change at Walden Pond. Despite the role of Walden Pond as a cultural and environmental icon, little is known about the pond's ecological features, such as its internal nutrient cycling or the structure of its food web, nor have consistent measurements been made to determine whether these features are changing or are stable. Production rates of aquatic plants in lakes and ponds naturally undergo a slow increase as plant nutrients, organic matter, and soil are leached and eroded from the surrounding watershed. This process is known as eutrophication. The term 'cultural eutrophication' refers to an accelerated form of the natural process in which extra soil and nutrients are derived from people's use of fertilizer, rerouting of surface drainage, and disposal of domestic and industrial waste. Cultural eutrophication can lead to excessive growth of aquatic plants, pond filling by decayed plants and eroded soils, reduced water clarity, and depletion of dissolved oxygen in deep water with subsequent loss of cold-water fish habitat. In order to document the longterm ecological health of Walden Pond, the U.S. Geological Survey (USGS), working in cooperation with the Massachusetts Department of Environmental Management (MDEM), is investigating factors that could contribute to cultural eutrophication of Walden. Through measurements of mass balance of nutrients and oxygen in the pond's deep water, the investigation will establish a baseline data set on Walden's trophic state, which is a measure of the pond's ability to support plant growth. The baseline data will be used to detect trends and give early warning of trophic changes or trophic response to pond remediation projects. This Fact Sheet provides background information on the environmental setting, limnological features, and cultural eutrophication of Walden Pond, and describes the joint USGS/MDEM study.

Massachusetts↗