Geology topics

Richard B. Moore

Publications and source records attributed to Richard B. Moore.

At least 19 recordsLinked to original sources

USGS2025

User’s guide for the National Hydrography Dataset Plus High Resolution (NHDPlus HR)

The National Hydrography Dataset Plus High Resolution (NHDPlus HR) is a scalable hydrologic geospatial fabric or framework, built from (1) the High Resolution (1:24,000-scale or better) National Hydrography Dataset (NHD), (2) nationally complete Watershed Boundary Dataset (WBD), and (3) 1/3-arc-second 3D Elevation Program (3DEP) digital elevation model (DEM) data (at a 10-meter ground spacing; or 5-meter 3DEP DEM in Alaska only). The NHDPlus HR provides a modeling and assessment framework at a local 1:24,000 scale, while nesting seamlessly into the national context. NHDPlus HR is modeled after the highly successful NHDPlus version 2 (NHDPlusV2). Like NHDPlusV2, the NHDPlus HR includes data for a nationally seamless network of stream reaches, elevation-based catchment areas, flow surfaces, and value-added attributes that enhance stream-network navigation, analysis, and data display. However, NHDPlus HR provides much greater spatial detail than NHDPlusV2, while NHDPlusV2 is, at present, more complete in its attribution of additions, removals, and diversions, as well as stream connectivity. This user’s guide is intended to provide necessary information and guidance in the use of NHDPlus HR data.

Scientific Investigations Report↗

USGS2022

Predicted uranium and radon concentrations in New Hampshire (USA) groundwater—Using Multi Order Hydrologic Position as predictors

Two radioactive elements, uranium (U) and radon (Rn), which are of potential concern in New Hampshire (NH) groundwater, are investigated. Exceedance probability maps are tools to highlight locations where the concentrations of undesirable substances in the groundwater may be elevated. Two forms of statistical analysis are used to create exceedance probability maps for U and Rn in NH groundwater. The first, Boosted Regression Tree (BRT), was selected for estimating U exceedance values. It computes exceedance values directly using the Bernoulli distribution function. The second method of statistical analysis used for Rn to determine exceedance probabilities is ordinary least squares (OLS) regression. In the process of determining exceedance probabilities for U and Rn, the utility of a new dataset is investigated. That new predictor dataset is the Multi-Order Hydrologic Position (MOHP) dataset. MOHP raster datasets have been produced nationally for the conterminous United States at a 30-m resolution. The concept behind MOHP is that, for any given point on the earth's surface, there is the potential for a longer groundwater flow path as one goes deeper beneath the land surface. MOHP predictors were tested in both models. Three MOHP predictors were found useful in the BRT model and two in the OLS model. MOHP data were found useful as predictors along with other site characteristics in predicting U and Rn exceedance probabilities in New Hampshire groundwater.

New Hampshire↗

USGS2019

Multiorder hydrologic position in the conterminous United States: A set of metrics in support of groundwater mapping at regional and national scales

The location of a point on the landscape within a stream network (hydrologic position) can be an important predictive measure in hydrology. Hydrologic position is defined here by two metrics: lateral position and distance from stream to divide, both measured horizontally. Lateral position (dimensionless) is the relative position of a point between the stream and its watershed divide. Distance from stream to divide (units of length) is an indicator of position within a watershed: generally small near a confluence and generally large in headwater areas. Watersheds and watershed divides are defined here by Thiessen polygons rather than topographic divides. Lateral position and distance from stream to divide are also defined in the context of hydrologic order. Hydrologic order “ n ” is defined as the network of streams, and associated divides, of order n and higher. And given that a point can have different positions in different hydrologic orders the term multiorder hydrologic position (MOHP) is used to describe the ensemble of hydrologic positions. MOHP was mapped across the conterminous United States for nine hydrologic orders at a spatial resolution of 30 m (about 8.7 billion pixels). There are 18 metrics for each pixel. Four case studies are presented that use MOHP metrics as explanatory factors in random forest machine learning models. The case studies show that lower order MOHP metrics can serve as indicators of hydrologic process while higher‐order metrics serve as indicators of location. MOHP is shown to have utility as a predictor variable across a large range of scales (50,000 to 8,000,000 km 2 ).

Water Resources Research↗

USGS2019

User's guide for the national hydrography dataset plus (NHDPlus) high resolution

The National Hydrography Dataset Plus High Resolution (NHDPlus HR) is a scalable geospatial hydrography framework built from the High Resolution (1:24,000-scale or better) National Hydrography Dataset (NHD), nationally complete Watershed Boundary Dataset (WBD), and ⅓-arc-second (10-meter ground spacing) 3D Elevation Program (3DEP) digital elevation model (DEM) data. The NHDPlus HR brings modeling and assessment to a local neighborhood level while nesting seamlessly into the national context. NHDPlus HR is modeled after the highly successful NHDPlus version 2 (NHDPlus V2). Like the NHDPlus V2, the NHDPlus HR includes data for a nationally seamless network of stream reaches, elevation-based catchment areas, flow surfaces, and value-added attributes that enhance stream-network navigation, analysis, and data display. Users will find that the NHDPlus HR, however, provides much greater detail. This User’s Guide is intended to provide necessary information and guidance in the use of NHDPlus HR data.

Open-File Report↗

USGS2019

Digital database of the geologic map of the middle east rift geothermal subzone, Kīlauea Volcano, Hawai‘i

This database release contains all the information used to produce Geologic Investigations Series I-2614 ( https://pubs.usgs.gov/imap/2614/ ). The main component of this digital release is a geodatabase prepared using ArcGIS, but Esri shapefiles are included as well. Kīlauea is an active shield volcano in the southeastern part of the Island of Hawai‘i. The middle East Rift Zone (MERZ) map includes about 27 square kilometers of the MERZ and shows the distribution of the products of 34 separate eruptions during late Holocene time. Lava flows erupted during 1983–86 have reached the mapped area. The subaerial part of the MERZ is 3–4 km wide and about 18 km long. It is a constructional ridge, 50–150 m above the adjoining terrain, marked by low spatter ramparts and cones as high as 60 m. Lava typically flowed either northeast or southeast, depending on vent location relative to the topographic crest of the rift zone. The MERZ receives more than 100 inches of rainfall annually and is covered by tropical rain forest. Vegetation begins to grow on lava a few months after its eruption. Relative heights of trees can be a guide to relative ages of underlying lava flows, but proximity to faults, presence of easily weathered cinders, and human activity also affect the rate of growth. The rocks have been grouped into five basic age groups. The framework for the ages assigned is provided by eight radiocarbon ages from nearby mapping by the authors and a single date from within this investigation area. The numerical ages are supplemented by observations of stratigraphic relations, degree of weathering, soil development, and vegetative cover.

Hawaii↗

USGS2017

Brackish groundwater in the United States

For some parts of the Nation, large-scale development of groundwater has caused decreases in the amount of groundwater that is present in aquifer storage and that discharges to surface-water bodies. Water supply in some areas, particularly in arid and semiarid regions, is not adequate to meet demand, and severe drought is affecting large parts of the United States. Future water demand is projected to heighten the current stress on groundwater resources. This combination of factors has led to concerns about the availability of freshwater to meet domestic, agricultural, industrial, mining, and environmental needs. To ensure the water security of the Nation, currently [2016] untapped water sources may need to be developed. Brackish groundwater is an unconventional water source that may offer a partial solution to current and future water demands. In support of the national census of water resources, the U.S. Geological Survey completed the national brackish groundwater assessment to better understand the occurrence and characteristics of brackish groundwater in the United States as a potential water resource. Analyses completed as part of this assessment relied on previously collected data from multiple sources; no new data were collected. Compiled data included readily available information about groundwater chemistry, horizontal and vertical extents and hydrogeologic characteristics of principal aquifers (regionally extensive aquifers or aquifer systems that have the potential to be used as a source of potable water), and groundwater use. Although these data were obtained from a wide variety of sources, the compiled data are biased toward shallow and fresh groundwater resources; data representing groundwater that is at great depths and is saline were not as readily available. One of the most important contributions of this assessment is the creation of a database containing chemical characteristics and aquifer information for the known areas with brackish groundwater in the United States. Previously published digital data relating to brackish groundwater resources were limited to a small number of State- and regional-level studies. Data sources for this assessment ranged from single publications to large datasets and from local studies to national assessments. Geochemical data included concentrations of dissolved solids, major ions, trace elements, nutrients, and radionuclides as well as physical properties of the water (pH, temperature, and specific conductance). Additionally, the database provides selected well information (location, yield, depth, and contributing aquifer) necessary for evaluating the water resource. The assessment was divided into national-, regional-, and aquifer-scale analyses. National-scale analyses included evaluation of the three-dimensional distribution of observed dissolved-solids concentrations in groundwater, the three-dimensional probability of brackish groundwater occurrence, and the geochemical characteristics of saline (greater than or equal to 1,000 mg/L of dissolved solids) groundwater resources. Regional-scale analyses included a summary of the percentage of observed grid cell volume in the region that was occupied by brackish groundwater within the mixture of air, water, and rock for multiple depth intervals. Aquifer-scale analyses focused primarily on four regions that contained the largest amounts of observed brackish groundwater and included a generalized description of hydrogeologic characteristics from previously published work; the distribution of dissolved-solids concentrations; considerations for developing brackish groundwater resources, including a summary of other chemical characteristics that may limit the use of brackish groundwater and the ability of sampled wells producing brackish groundwater to yield useful amounts of water; and the amount of saline groundwater being used in 2010.

Professional Paper↗

USGS2016

Database compilation for the geologic map of the San Francisco volcanic field, north-central Arizona

The main component of this publication is a geologic map database prepared using geographic information system (GIS) applications. The geodatabase of geologic points, lines, and polygons was produced as a compilation from five adjoining map sections originally published as printed maps in 1987 (see references in metadata). Four of the sections (U.S. Geological Survey Miscellaneous Field Studies Maps MF–1957, MF–1958, MF–1959, MF–1960) were created by scanning and geo-referencing stable base map material consisting of mylar positives. The final section (MF–1956) was compiled by hand tracing an enlargement of the available printed paper base map onto mylar using a #00 rapidograph pen, the mylar positive was then digitally scanned and geo-referenced. This method was chosen because the original basemap materials (mylar positives) for the MF–1956 section were unavailable at the time of this publication. Due to the condition of the available MF–1956 map section used as the base (which had previously been folded) the accuracy within the boundary of the MF–1956 section is presumed to be degraded in certain areas. The locations of the degraded areas and the degree of degradation within these areas is unclear. Final compilation of the database was completed using the ArcScan toolset, and the Editor toolset in ESRI ArcMap 10.1. Polygon topology was created from the lines and labels were added to the resultant geological polygons, lines, and points. Joseph A. Bard and David W. Ramsey updated and corrected the geodatabase, created the metadata and web presence, and provided the GIS-expertise to bring the geodatabase and metadata to completion. Included are links to files to view or print the original map sheets and the accompanying pamphlets. The orignial geologic maps were prepared under the Geothermal Research Program of the U.S. Geological Survey as a basis for interpreting the history of magmatic activity in the volcanic field. The San Francisco field, which is largely Pleistocene in age, is in northern Arizona, just north of the broad transition zone between the Colorado Plateau and the Basin and Range province. It is one of several dominantly basaltic volcanic fields of the late Cenozoic age situated near the margin of the Colorado Plateau. The volcanic field contains rocks ranging in composition from basalt to rhyolite—the products of eruption through Precambrian basement rocks and approximately a kilometer of overlying, nearly horizontal, Paleozoic and Mesozoic sedimentary rocks. About 500 km 3 of erupted rocks cover about 5,000 km 2 of predominantly Permian and locally preserved Triassic sedimentary rocks that form the erosionally stripped surface of the Colorado Plateau in Northern Arizona.

Arizona↗

USGS2014

Nutrient load summaries for major lakes and estuaries of the Eastern United States, 2002

Nutrient enrichment of lakes and estuaries across the Nation is widespread. Nutrient enrichment can stimulate excessive plant and algal growth and cause a number of undesirable effects that impair aquatic life and recreational activities and can also result in economic effects. Understanding the amount of nutrients entering lakes and estuaries, the physical characteristics affecting the nutrient processing within these receiving waterbodies, and the natural and manmade sources of nutrients is fundamental to the development of effective nutrient reduction strategies. To improve this understanding, sources and stream transport of nutrients to 255 major lakes and 64 estuaries in the Eastern United States were estimated using Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models.

Eastern United States↗

USGS2013

Simulating stream transport of nutrients in the eastern United States, 2002, using a spatially-referenced regression model and 1:100,000-scale hydrography

Existing Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models for the northeastern and southeastern regions of the United States were recalibrated to achieve a hydrographically consistent model with which to assess nutrient sources and stream transport and investigate specific management questions about the effects of wetlands and atmospheric deposition on nutrient transport. Recalibrated nitrogen models for the northeast and southeast were sufficiently similar to be merged into a single nitrogen model for the eastern United States. The atmospheric deposition source in the nitrogen model has been improved to account for individual components of atmospheric input, derived from emissions from agricultural manure, agricultural livestock, vehicles, power plants, other industry, and background sources. This accounting makes it possible to simulate the effects of altering an individual component of atmospheric deposition, such as nitrate emissions from vehicles or power plants. Regional differences in transport of phosphorus through wetlands and reservoirs were investigated and resulted in two distinct phosphorus models for the northeast and southeast. The recalibrated nitrogen and phosphorus models account explicitly for the influence of wetlands on regional-scale land-phase and aqueous-phase transport of nutrients and therefore allow comparison of the water-quality functions of different wetland systems over large spatial scales. Seven wetland systems were associated with enhanced transport of either nitrogen or phosphorus in streams, probably because of the export of dissolved organic nitrogen and bank erosion. Six wetland systems were associated with mitigating the delivery of either nitrogen or phosphorus to streams, probably because of sedimentation, phosphate sorption, and ground water infiltration.

Scientific Investigations Report↗

USGS2012

Nutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003

The U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) began regional studies in 2003 to synthesize information on nutrient concentrations, trends, stream loads, and sources. In the northeastern United States, a study area that extends from Maine to central Virginia, nutrient data were evaluated for 130 USGS water-quality monitoring stations. Nutrient data were analyzed for trends in flow-adjusted concentrations, modeled instream (non-flow-adjusted) concentrations, and stream loads for 32 stations with 22 to 29 years of water-quality and daily mean streamflow record during 1975-2003 (termed the long-term period), and for 46 stations during 1993-2003 (termed the recent period), by using a coupled statistical model of streamflow and water quality developed by the USGS. Recent trends in flow-adjusted concentrations of one or more nutrients also were analyzed for 90 stations by using Tobit regression. Annual stream nutrient loads were estimated, and annual nutrient yields were calculated, for 47 stations for the long-term and recent periods, and for 37 additional stations that did not have a complete streamflow and water-quality record for 1993-2003. Nutrient yield information was incorporated for 9 drainage basins evaluated in a national NAWQA study, for a total of 93 stations evaluated for nutrient yields. Long-term downward trends in flow-adjusted concentrations of total nitrogen and total phosphorus (18 and 19 of 32 stations, respectively) indicate regional improvements in nutrient-related water-quality conditions. Most of the recent trends detected for total phosphorus were upward (17 of 83 stations), indicating possible reversals to the long-term improvements. Concentrations of nutrients in many streams persist at levels that are likely to affect aquatic habitat adversely and promote freshwater or coastal eutrophication. Recent trends for modeled instream concentrations, and modeled reference concentrations, were evaluated relative to ecoregion-based nutrient criteria proposed by the U.S. Environmental Protection Agency. Instream concentrations of total nitrogen and total phosphorus persist at levels higher than proposed criteria at more than one-third and about one-half, respectively, of the 46 stations analyzed. Long-term trends in nutrient loads were primarily downward, with downward trends in total nitrogen and total phosphorus loads detected at 12 and 17 of 32 stations, respectively. Upward trends were rare, with one upward trend for total nitrogen loads and none for total phosphorus. Trends in loads of nitrite-plus-nitrate nitrogen included 7 upward and 8 downward trends among 32 stations. Downward trends in loads of ammonia nitrogen and total Kjeldahl nitrogen were detected at all six stations evaluated. Long-term downward trends detected in four of the five largest drainage basins evaluated include: total nitrogen loads for the Connecticut, Delaware, and James Rivers; total Kjeldahl nitrogen and ammonia nitrogen loads for the Susquehanna River; ammonia nitrogen and nitrite-plus-nitrate nitrogen loads for the James River; and total phosphorus loads for the Connecticut and Delaware Rivers. No trends in load were detected for the Potomac River. Nutrient yields were evaluated relative to the extent of land development in 93 drainage basins. The undeveloped land-use category included forested drainage basins with undeveloped land ranging from 75 to 100 percent of basin area. Median total nitrogen yields for the 27 undeveloped drainage basins evaluated, including 9 basins evaluated in a national NAWQA study, ranged from 290 to 4,800 pounds per square mile per year (lb/mi 2 /yr). Total nitrogen yields even in the most pristine drainage basins may be elevated relative to natural conditions, because of high rates of atmospheric deposition of nitrogen in parts of the northeastern United States. Median total phosphorus yields ranged from 12 to 330 lb/mi 2 /yr for the 26 undeveloped basins evaluated. The undeveloped category includes some large drainage basins with point-source discharges and small percentages of developed land; in these basins, streamflow from undeveloped headwater areas dilutes streamflow in more urbanized reaches, and dampens but does not eliminate the point-source "signal" of higher nutrient loads. Median total nitrogen yields generally do not exceed 1,700 lb/mi 2 /yr, and median total phosphorus yields generally do not exceed 100 lb/mi 2 /yr, in the drainage basins that are least affected by human land-use and waste-disposal practices. Agricultural and urban land use has increased nutrient yields substantially relative to undeveloped drainage basins. Median total nitrogen yields for 24 agricultural basins ranged from 1,700 to 26,000 lb/mi 2 /yr, and median total phosphorus yields ranged from 94 to 1,000 lb/mi 2 /yr. The maximum estimated total nitrogen and total phosphorus yields, 32,000 and 16,000 lb/mi 2 /yr, respectively, for all stations in the region were in small (less than 50 square miles (mi 2 )) agricultural drainage basins. Median total nitrogen yields ranged from 1,400 to 17,000 lb/mi 2 /yr in 26 urbanized drainage basins, and median total phosphorus yields ranged from 43 to 1,900 lb/mi 2 /yr. Urbanized drainage basins with the highest nutrient yields are generally small (less than 300 mi2) and are drained by streams that receive major point-source discharges. Instream nutrient loads were evaluated relative to loads from point-source discharges in four drainage basins: the Quinebaug River Basin in Connecticut, Massachusetts, and Rhode Island; the Raritan River Basin in New Jersey; the Patuxent River Basin in Maryland; and the James River Basin in Virginia. Long-term downward trends in nutrient loads, coupled with similar trends in flow-adjusted nutrient concentrations, indicate long-term reductions in the delivery of most nutrients to these streams. However, the absence of recent downward trends in load for most nutrients, coupled with instream concentrations that exceed proposed nutrient criteria in several of these waste-receiving streams, indicates that challenges remain in reducing delivery of nutrients to streams from point sources. During dry years, the total nutrient load from point sources in some of the drainage basins approached or equaled the nutrient load transported by the stream.

Connecticut;Delaware;Maine;Maryl;Massachusetts;New↗

USGS2011

Source and delivery of nutrients to receiving waters in the Northeastern and Mid-Atlantic regions of the United States

This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake.

Journal of the American Water Resources Associatio↗

USGS2009

Evaluation of catchment delineation methods for the medium-resolution National Hydrography Dataset

Different methods for determining catchments (incremental drainage areas) for stream segments of the medium-resolution (1:100,000-scale) National Hydrography Dataset (NHD) were evaluated by the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA). The NHD is a comprehensive set of digital spatial data that contains information about surface-water features (such as lakes, ponds, streams, and rivers) of the United States. The need for NHD catchments was driven primarily by the goal to estimate NHD streamflow and velocity to support water-quality modeling. The application of catchments for this purpose also demonstrates the broader value of NHD catchments for supporting landscape characterization and analysis. Five catchment delineation methods were evaluated. Four of the methods use topographic information for the delineation of the NHD catchments. These methods include the Raster Seeding Method; two variants of a method first used in a USGS New England study-one used the Watershed Boundary Dataset (WBD) and the other did not-termed the 'New England Methods'; and the Outlet Matching Method. For these topographically based methods, the elevation data source was the 30-meter (m) resolution National Elevation Dataset (NED), as this was the highest resolution available for the conterminous United States and Hawaii. The fifth method evaluated, the Thiessen Polygon Method, uses distance to the nearest NHD stream segments to determine catchment boundaries. Catchments were generated using each method for NHD stream segments within six hydrologically and geographically distinct Subbasins to evaluate the applicability of the method across the United States. The five methods were evaluated by comparing the resulting catchments with the boundaries and the computed area measurements available from several verification datasets that were developed independently using manual methods. The results of the evaluation indicated that the two New England Methods provided the most accurate catchment boundaries. The New England Method with the WBD provided the most accurate results. The time and cost to implement and apply these automated methods were also considered in ultimately selecting the methods used to produce NHD catchments for the conterminous United States and Hawaii. This study was conducted by a joint USGS-USEPA team during the 2-year period that ended in September 2004. During the following 2-year period ending in the fall of 2006, the New England Methods were used to produce NHD catchments as part of a multiagency effort to generate the NHD streamflow and velocity estimates for a suite of integrated geospatial products known as 'NHDPlus.'

New England↗

USGS2008

Methods for and estimates of 2003 and projected water use in the Seacoast Region, Southeastern New Hampshire

New methods were developed to estimate water use in 2003 and future water demand in 2017 and 2025 in the Seacoast region in southeastern New Hampshire, which has experienced a 37-percent population increase during 1980 to 2000. Water-use activities for which estimates were developed include water withdrawal, delivery, demand, consumptive use, release, return flow, and transfer by registered and aggregated unregistered (less than 20,000 gallons per day (gal/d)) users at the census-block and town scales. Estimates of water use rely on understanding what influences water demand and its associated consumptive use, because changes in demand and consumptive use affect withdrawal and return flow. Domestic water demand was estimated using a per capita water demand model that related metered deliveries to domestic users with census block and block-group data. The model was used to predict annual, summer, and winter per capita water-demand coefficients for each census block. Significant predictors of domestic water demand include population per housing unit, median value of owner-occupied single family homes, median year of housing construction (with 1900 as the base value), population density, housing unit density, and proportion of housing units that are in urban areas. Mean annual domestic per capita water-demand coefficient in the Seacoast region was 75 gal/d; the coefficient increased to 91 gal/d during the summer and decreased to 65 gal/d during the winter. Domestic consumptive use was estimated as the difference between annual and winter domestic water demand. Estimates of commercial and industrial water demand were based on coefficients derived from reported use and metered deliveries. Projections of water demand in 2017 and 2025 were determined by using the housing and employee projections for those years developed through a Transportation Demand Model and applying current domestic and non-domestic coefficients. Water demand in 2003 was estimated as 25.8 million gallons per day (Mgal/d), 35 percent of which was during the summer months of June, July, and August. Domestic water demand was 18.6 Mgal/d (72 percent), commercial water demand was 3.7 Mgal/d (14 percent), industrial water demand was 2.9 Mgal/d (11 percent), irrigation water demand was 0.3 Mgal/d (1 percent), and mining and aquaculture water demand was 0.2 Mgal/d (1 percent). Domestic consumptive use for the Seacoast region was 16 percent of domestic water demand, which translates to a loss of 3 Mgal/d over the entire Seacoast region. In 2003, water withdrawal was 771.2 Mgal/d, of which 742.2 Mgal/d was instream use for hydroelectric power generation and thermoelectric power cooling. The remaining 29.0 Mgal/d was withdrawn by community water systems (22.6 Mgal/d; 72 percent), domestic users (6.4 Mgal/d; 21 percent), commercial users (1.0 Mgal/d; 3 percent), industrial users (1.0 Mgal/d; 3 percent), irrigation (0.2 Mgal/d; 1 percent) and other users (less than 0.1 Mgal/d). Return flow for 2003 was 772.2 Mgal/d, of which 742.0 Mgal/d was returned following use for hydroelectric power generation and thermoelectric plant cooling. The remaining 30.2 Mgal/d was returned by community wastewater systems (20.2 Mgal/d; 68 percent), domestic users (7.8 Mgal/d; 26 percent), commercial users (1.2 Mgal/d; 3 percent), industrial users (0.8 Mgal/d; 3 percent), and other users (0.1 Mgal/d). Domestic water demand is projected to increase by 54 percent to 28.7 Mgal/d from 2003 to 2025 based on projection of future population growth. Non-domestic (commercial, industrial, irrigation, and mining) water demand is projected to increase by 66 percent to 11.8 Mgal/d from 2003 to 2025.

Scientific Investigations Report↗

USGS2006

Geologic map of the middle east rift geothermal subzone, Kīlauea Volcano, Hawaiʻi

Kīlauea is an active shield volcano in the southeastern part of the Island of Hawai'i. The middle east rift zone (MERZ) map includes about 27 square kilometers of the MERZ and shows the distribution of the products of 37 separate eruptions during late Holocene time. Lava flows erupted during 1983-96 have reached the mapped area. The subaerial part of the MERZ is 3-4 km wide and about 18 km long. It is a constructional ridge, 50-150 m above the adjoining terrain, marked by low spatter ramparts and cones as high as 60 m. Lava typically flowed either northeast or southeast, depending on vent location relative to the topographic crest of the rift zone. The MERZ receives more than 100 in. of rainfall annually and is covered by tropical rain forest. Vegetation begins to grow on lava a few months after its eruption. Relative heights of trees can be a guide to relative ages of underlying lava flows, but proximity to faults, presence of easily weathered cinders, and human activity also affect the rate of growth. The rocks have been grouped into five basic age groups. The framework for the ages assigned is provided by eight radiocarbon ages from previous mapping by the authors and a single date from the current mapping effort. The numerical ages are supplemented by observations of stratigraphic relations, degree of weathering, soil development, and vegetative cover.

Hawaii↗

USGS2006

Preliminary Geologic Map of Mount Pagan Volcano, Pagan Island, Commonwealth of the Northern Mariana Islands

Pagan Island is the subaerial portion of two adjoining Quaternary stratovolcanoes near the middle of the active Mariana Arc, [FAT1]north of Saipan. Pagan and the other volcanic islands that constitute part of the Arc form the northern half of the East Mariana Ridge[FAT2], which extends about 2-4 km above the ocean floor. The > 6-km-deep Mariana Trench adjoins the East Mariana Ridge on the east, and the Mariana Trough, partly filled with young lava flows and volcaniclastic sediment, lies on the west of the Northern Mariana Islands (East Mariana Ridge. The submarine West Mariana Ridge, Tertiary in age, bounds the western side of the Mariana Trough. The Mariana Trench and Northern Mariana Islands (East Mariana Ridge) overlie an active subduction zone where the Pacific Plate, moving northwest at about 10.3 cm/year, is passing beneath the Philippine Plate, moving west-northwest at 6.8 cm/year. Beneath the Northern Mariana Islands, earthquake hypocenters at depths of 50-250 km identify the location of the west-dipping subduction zone, which farther west becomes nearly vertical and extends to 700 km depth. During the past century, more than 40 earthquakes of magnitude 6.5-8.1 have shaken the Mariana Trench. The Mariana Islands form two sub-parallel, concentric, concave-west arcs. The southern islands comprise the outer arc and extend north from Guam to Farallon de Medinilla. They consist of Eocene to Miocene volcanic rocks and uplifted Tertiary and Quaternary limestone. The nine northern islands extend from Anatahan to Farallon de Pajaros and form part of the inner arc. The active inner arc extends south from Anatahan, where volcanoes, some of which are active, form seamounts west of the older outer arc. Other volcanic seamounts of the active arc surmount the East Mariana Ridge in the vicinity of Anatahan and Sarigan and north and south of Farallon de Pajaros. Six volcanoes (Farallon de Pajaros, Asuncion, Agrigan, Mount Pagan, Guguan, and Anatahan) in the northern islands have erupted during the past century, and Ruby Seamount erupted in 1996.

Open-File Report↗

USGS2006

Assessment of total nitrogen in the upper Connecticut River basin in New Hampshire, Vermont, and Massachusetts, December 2002–September 2005

A study of total nitrogen concentrations and loads was conducted from December 2002 to September 2005 at 13 river sites in the upper Connecticut River Basin. Ten sites were selected to represent contributions of nitrogen from forested, agricultural, and urban land. Three sites were distributed spatially on the main stem of the Connecticut River to assess the cumulative total nitrogen loads. To further improve the understanding of the sources and concentrations and loads of total nitrogen in the upper Connecticut River Basin, ambient surface water-quality sampling was supplemented with sampling of effluent from 19 municipal and paper mill wastewater-treatment facilities. Mean concentrations of total nitrogen ranged from 0.19 to 2.8 milligrams per liter (mg/L) at river sampling sites. Instantaneous mean loads of total nitrogen ranged from 162 to 58,300 pounds per day (lb/d). Estimated mean annual loads of total nitrogen ranged from 49,100 to 21.6 million pounds per year (lb/yr) with about 30 to 55 percent of the loads being transported during the spring. The estimated mean annual yields of total nitrogen ranged from 1,190 to 7,300 pounds per square mile per year (lb/mi 2 )/yr. Mean concentrations of total nitrogen ranged from 4.4 to 30 mg/L at wastewater-treatment sampling sites. Instantaneous mean loads of total nitrogen from municipal wastewater-treatment facilities ranged from 36 to 1,780 lb/d. Instantaneous mean loads of total nitrogen from paper mill wastewater-treatment facilities ranged from 96 to 160 lb/d. The median concentration of total nitrogen was 0.24 mg/L at forested sites, 0.48 mg/L at agricultural sites, 0.54 mg/L at urban sites, 0.48 mg/L at main-stem sites, and 14 mg/L at wastewater-treatment sites. Concentrations of total nitrogen at forested sites were significantly less than at all other site types (p<0.05). Concentrations of total nitrogen at agricultural, urban, and main stem sites were not significantly different among each other (p>0.05) but were significantly greater (p<0.05) than at forested sites and significantly less than concentrations at wastewater-treatment sites (p<0.05). Total nitrogen concentrations at wastewater-treatment sites were significantly different from all other site types (p<0.05). Annual yields of total nitrogen ranged from 732 to 1,920 (lb/mi 2 )/yr at forested sites; 1,550 to 2,980 (lb/mi 2 )/yr at agricultural sites; 1,280 to 1,860 (lb/mi 2 )/yr at urban sites that were not directly affected by wastewater effluent; 7,090 to 7,770 (lb/mi 2 )/yr at an urban site directly affected by wastewater effluent; and 1,300 to 2,390 (lb/mi 2 )/yr at main-stem sites. In this study, the mean annual load and yield of total nitrogen at the Connecticut River at Wells River, VT, was estimated at 4.47 million lb/yr and 1,690 (lb/mi 2 )/yr, respectively. The mean annual load and yield of total nitrogen at the Connecticut River at North Walpole, NH, was estimated at 9.60 million lb/yr and 1,750 (lb/mi 2 )/yr, respectively. The mean annual load and yield of total nitrogen leaving the upper Connecticut River Basin, as estimated at the Connecticut River at Thompsonville, CT, was 21.6 million lb/yr and 2,230 (lb/mi 2 )/yr, respectively.

Massachusetts, New Hampshire, Vermont↗

USGS2005

Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska

High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11 geographically distributed lavas with ages ranging from 47+/-14 to 127+/-2 k.y. date construction of the Westdahl volcanic center. Lava flows cut by an apparent caldera-rim structure yielded ages of 81+/-5 and 121+/-8 k.y., placing a maximum date of 81 ka on caldera formation. Late Pleistocene and Holocene lavas fill the caldera, but most of them are obscured by the large summit icecap.

Alaska↗

USGS1999

Relation of arsenic, iron, and manganese in ground water to aquifer type, bedrock lithogeochemistry, and land use in the New England coastal basins

In a study of arsenic concentrations in public-supply wells in the New England Coastal Basins, concentrations at or above 0.005 mg/L (milligrams per liter) were detected in more samples of water from wells completed in bedrock (25 percent of all samples) than in water from wells completed in stratified drift (7.5 percent of all samples). Iron and manganese were detected (at concentrations of 0.05 and 0.03 mg/L, respectively) at approximately the same frequency in water from wells in both types of aquifers. Concentrations of arsenic in public-supply wells drilled in bedrock (in the National Water-Quality Assessment Program New England Coastal Basins study unit) vary with the bedrock lithology. Broad groups of lithogeochemical units generalized from bedrock lithologic units shown on state geologic maps were used in the statistical analyses. Concentrations of arsenic in water from public-supply wells in metasedimentary bedrock units that contain slightly to moderately calcareous and calcsilicate rocks (lithogeochemical group M c ) were significantly higher than the concentrations in five other groups of bedrock units in the study unit. Arsenic was detected, at or above 0.005 mg/L, in water from 44 percent of the wells in the lithogeochemical group M c and in water from less than 28 percent of wells in the five other groups. Additionally, arsenic concentrations in ground water were the lowest in the metasedimentary rocks that are characterized as variably sulfidic (group M s ). Generally, concentrations of arsenic were low in water from bedrock wells in the felsic igneous rocks (group I f ) though locally some bedrock wells in granitic rocks are known to have ground water with high arsenic concentrations, especially in New Hampshire. The concentrations of arsenic in ground water also correlate with land-use data; significantly higher concentrations are found in areas identified as agricultural land use than in undeveloped areas. There is, however, more agricultural land in areas overlying the metasedimentary rocks of lithogeochemical groups M c and the minimally-deformed clastic sediments of group M md than in areas overlying other lithogeochemical groups. This correlation complicates the interpretation of sources of arsenic to ground water in bedrock. A test of this association revealed that relations between arsenic concentrations and the metasedimentary rocks of group M c are not weakened when data associated with agricultural land use is removed; the reverse is true, however, if the data associated with the group M c are removed from the analysis. The occurrence and variability of arsenic in water from bedrock supply wells could be related to several factors. These include (1) the distribution and chemical form of arsenic in soils and rocks that are part of the ground-water-flow system, (2) the characteristics that influence the solubility and transport of arsenic in ground water, (3) the differing degrees of vulnerability of ground-water supplies to surface contamination, and (4) the spatial associations between land use, geology, and ground-water-flow patterns. Strong relations between agricultural land use and the metasedimentary rocks of group M c complicate the interpretation of arsenic source to water in these bedrock aquifers. This is due in part to the past use of arsenical pesticides; additionally, few whole-rock geochemical data are available for the rock types in the lithogeochemical groups of aquifers that contain ground water with elevated concentrations of arsenic. Without such data, identifying specific bedrock types as arsenic sources is not possible. In southern Maine and south-central New Hampshire, and in northern Massachusetts, the few available whole-rock analyses suggest, at least for these local areas, a connection between known bedrock chemistry and ground-water arsenic levels. Although the lithogeochemical group and land-use category variables individually describe much of the variance in the concentrations of arsenic in ground water, the lithogeochemical relation is statistically stronger than the land-use relation. Low concentrations of arsenic in water from bedrock public-supply wells are associated with the metasedimentary rocks of group M s (characterized as variably sulfidic). This association could reflect a variety of factors and suggests that simple dissolution of arsenic-bearing iron phases, such as sulfides, may not explain concentrations of arsenic in water in this bedrock aquifer group. Whole-rock geochemical data and more complete water-chemistry data, as well as studies of historical variation of arsenic concentrations (time-line studies), and site-specific studies, will be critical in addressing the arsenic source issue.

New England coastal basins↗