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

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At least 37 records · Page 2Linked to original sources
USGS2014

Arkansas StreamStats: A U.S. Geological Survey web map application for basin characteristics and streamflow statistics

The U.S. Geological Survey (USGS) provides streamflow and other related information needed by water-resource managers responsible for protecting people and property from floods, planning and managing water-resource activities, and protecting water quality. Streamflow statistics provided by the USGS, such as the 1-percent annual exceedance probability (100-year flood) and the 7-day 10-year low flow, are frequently used by engineers, flood forecasters, land managers, biologists, and others to guide their everyday decisions. Additionally, resource managers often need to know basin characteristics, the physical and climatic characteristics of a drainage basin, to help understand the mechanisms that control water availability, water quality, and aquatic habitats at various locations. Users of streamflow information often require streamflow statistics and basin characteristics at various locations along a stream. The USGS periodically calculates and publishes streamflow statistics and basin characteristics for streamflowgaging stations and partial-record stations, but these data commonly are scattered among many reports that may or may not be readily available to the public. The USGS also provides and periodically updates regional analyses of streamflow statistics that include regression equations and other prediction methods for estimating statistics for ungaged and unregulated streams across the State. Use of these regional predictions for a stream can be complex and often requires the user to determine a number of basin characteristics that may require interpretation. Basin characteristics may include drainage area, classifiers for physical properties, climatic characteristics, and other inputs. Obtaining these input values for gaged and ungaged locations traditionally has been time consuming, subjective, and can lead to inconsistent results.

Arkansas↗
USGS2018

Using high-resolution aeromagnetic surveys to map subsurface hydrogeology in sediment-filled basins: A case study over the Rio Grande Rift, Central New Mexico, USA

High-resolution aeromagnetic surveys were acquired for the Albuquerque basin in the central Rio Grande rift, a basin filled with poorly consolidated sediments. The surveys proved successful in efficiently and economically mapping previously unknown hydrogeologic features of the shallow subsurface. This success suggests that aeromagnetic methods may be useful in hydrogeologic studies of other sediment-filled basins. The aeromagnetic surveys were used primarily to delineate buried igneous rocks and to locate faults within the basin fill, both important for understanding the subsurface hydrogeology. Buried igneous rocks were recognized from their high-frequency, high-amplitude magnetic responses and characteristic map patterns. The horizontal-gradient and local wavenumber methods were used to obtain estimates of their source depths. The aeromagnetic surveys were also successfully used to locate faults within the basin fill. Magnetic signatures associated with faults are produced by the juxtaposition of sediments having differing magnetic properties rather than the products of secondary processes. Expression of faults is abundant throughout the basin, revealing patterns that cannot be mapped at the surface due to widespread cover. A fault signature recognized in the high-resolution data that has multiple inflection points is best explained by a fault with a thin magnetic layer on the upthrown block and thick magnetic layer on the downthrown block, called the thin-thick layers model. Geologically, this signature indicates erosion of the upthrown block or a growth-faulting scenario: fault-controlled sedimentation for faults that offset sediments, and successive accumulation of basalt on the downthrown block for faults that offset volcanic rocks.

New Mexico↗
USGS1999

Application of aerial gamma-ray spectrometric and magnetic surveys in geologic mapping: a case study in southern Virginia and northern North Carolina

Aerial gamma-ray spectrometric and magnetic survey maps are valuable aids for geologic mapping where rocks are poorly exposed in south-central Virginia and northernmost North Carolina. Broad low areas on the potassium and thorium gamma-ray survey maps distinguish the Carolina, Spring Hope, and Roanoke Rapids terranes from more highly radiogenic areas of the Raleigh and Triplet terranes, reflecting differences in the compositions of residual soils. Granitic rocks are delineated most clearly by potassium highs and less clearly by thorium highs. Nearly all the thorium highs other than those related to granites are associated with amphibolite-facies rocks of the Raleigh and Triplet terranes. Contrasting thorium lows within these terranes help to distinguish the individual rock units. In the Carolina and Roanoke Rapids terranes, high-gradient magnetic patterns delineate stratified metavolcanic and metasedimentary units that are not discernible from the gamma-ray surveys. Circular magnetic highs coincide with gabbro plutons, and numerous magnetic lineaments correspond to Jurassic diabase dikes. Magnetically uniform, low-gradient areas coincide with less mafic plutons. A magnetic lineament (high) coincides with the Nutbush Creek fault zone, and other faults are distinguished as boundaries between zones of contrasting geophysical properties. The gamma-ray spectrometric and magnetic survey maps most effectively indicate geologic features in the region if they are employed collectively, and if they are interpreted in concert with simultaneous geologic field investigations.

North Carolina;Virginia↗
USGS2012

Bathymetric and underwater video survey of Lower Granite Reservoir and vicinity, Washington and Idaho, 2009-10

The U.S. Geological Survey conducted a bathymetric survey of the Lower Granite Reservoir, Washington, using a multibeam echosounder, and an underwater video mapping survey during autumn 2009 and winter 2010. The surveys were conducted as part of the U.S. Army Corps of Engineer's study on sediment deposition and control in the reservoir. The multibeam echosounder survey was performed in 1-mile increments between river mile (RM) 130 and 142 on the Snake River, and between RM 0 and 2 on the Clearwater River. The result of the survey is a digital elevation dataset in ASCII coordinate positioning data (easting, northing, and elevation) useful in rendering a 3×3-foot point grid showing bed elevation and reservoir geomorphology. The underwater video mapping survey was conducted from RM 107.73 to 141.78 on the Snake River and RM 0 to 1.66 on the Clearwater River, along 61 U.S. Army Corps of Engineers established cross sections, and dredge material deposit transects. More than 900 videos and 90 bank photographs were used to characterize the sediment facies and ground-truth the multibeam echosounder data. Combined, the surveys were used to create a surficial sediment facies map that displays type of substrate, level of embeddedness, and presence of silt.

Washington;Idaho↗
USGS2012

Integrated geophysical surveys for mapping lati-andesite intrusive bodies, Chino Valley, Arizona

Three different geophysical methods (magnetic, transient electromagnetic (TEM) and gravity) were used near Chino Valley, Arizona, USA in order to map a suspected lati-andesite intrusive body (plug) previously located by interpretation of aeromagnetic data. The magnetic and TEM surveys provided the best indication of the location and depth of the plug. The north-south spatial extent of this plug was estimated to be approximately 600 meters. The depth to the top of the plug was found from the TEM survey to be approximately 350 meters near the center of the survey. The location of the plug defined by the ground magnetic data is consistent with that from the TEM data. Gravity data mostly image the basin-basement interface with a small contribution from the plug of about 0.5 mGal. Results from this investigation can be used to help define the irregular subsurface topography caused by several intrusive lati-andesite plugs that could influence groundwater flow in the area.

Arizona↗
USGS2013

Archive of post-Hurricane Isabel coastal oblique aerial photographs collected during U.S. Geological Survey Field Activity 03CCH01 from Ocean City, Maryland, to Fort Caswell, North Carolina and Inland from Waynesboro to Redwood, Virginia, September 21 - 23, 2003

On September 21 - 23, 2003, the United States Geological Survey (USGS) conducted an oblique aerial photographic survey along the Atlantic coast from Ocean City, Md., to Fort Caswell, N.C., and inland oblique aerial photographic survey from Waynesboro to Redwood, Va., aboard a Navajo Piper twin-engine airplane. The coastal survey was conducted at an altitude of 500 feet (ft) and approximately 1,000 ft offshore. For the inland photos, the aircraft tried to stay approximately 500 ft above the terrain. These coastal photos were used to document coastal changes like beach erosion and overwash caused by Hurricane Isabel, while the inland photos looked for potential landslides caused by heavy rains. The photos may also be used as baseline data for future coastal change analysis. The USGS and the National Aeronautics and Space Administration (NASA) surveyed the impact zone of Hurricane Isabel to better understand the changes in vulnerability of the Nation’s coasts to extreme storms (Morgan, 2009). This report serves as an archive of photographs collected during the September 21 - 23, 2003, post-Hurricane Isabel coastal and inland oblique aerial survey along with associated survey maps, KML files, navigation files, digital Field Activity Collection System (FACS) logs, and Federal Geographic Data Committee (FGDC) metadata. Refer to the Acronyms page for expansions of all acronyms and abbreviations used in this report. The USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) assigns a unique identifier to each cruise or field activity. For example, 03CCH01 tells us the data were collected in 2003 for the Coastal Change Hazards (CCH) study and the data were collected during the first field activity for that project in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the ID number. The photographs provided here are Joint Photographic Experts Group (JPEG) scanned images of the analog 35 millimeter (mm) color positive slides. The photograph locations are estimates of the location of the plane (see the Navigation page). The metadata values for photo creation time, GPS latitude, GPS longitude, GPS position (latitude and longitude), keywords, credit, artist, caption, copyright, and contact were added to each photograph's EXIF header using EXIFtool (Subino and others, 2012). Photographs can be opened directly with any JPEG-compatible image viewer by clicking on a thumbnail on the contact sheet, or, when viewing the Google Earth KML file, by clicking on the marker and then clicking on either the thumbnail or the link below the thumbnail. Nathaniel Plant (USGS - St. Petersburg, Fla.), and Ann Marie Ascough (formerly contracted at the USGS - St. Petersburg, Fla.) helped with the creation of KML files. To view the photos and survey maps, proceed to the Photos and Maps page.

Maryland, North Carolina, Virginia↗
USGS2025

Spatiotemporal variability of algal biomass and nitrate in Owasco and Seneca Lakes in the Finger Lakes Region, New York, in 2019

Cyanobacterial harmful algal blooms (CyanoHABs) have become increasingly common, threatening the security of water resources globally. The U.S. Geological Survey conducted high-resolution nearshore mapping surveys using boat-mounted multiparameter sondes and nitrate sensors during the summer and fall of 2019 on Owasco Lake and Seneca Lake, two lakes with documented CyanoHABs in the Finger Lakes region of New York State. Discrete sensor measurements and water-quality samples were collected at fixed points along survey routes and continuous data were generated at open-water monitoring platforms. This investigation examined whether water-quality information from nearshore surveys was representative of open-water conditions and if nearshore surveys could be used to identify areas with localized nearshore CyanoHABs and potential sources of nutrients not captured by tributary sampling. In addition to comparisons across methods, nearshore concentrations of nitrate and chlorophyll were evaluated relative to tributary outlets, cyanobacterial abundance and biovolume at discrete locations, and the locations of near-surface CyanoHABs that were designated as “confirmed with high toxins” by the New York State Department of Environmental Conservation. Nitrate and chlorophyll concentrations were comparable across methods for each lake, although concentration ranges were typically higher for nearshore mapping datasets than for nearshore discrete datasets. Nearshore surveys indicated areas of nitrate enrichment that varied temporally in both lakes. Orthophosphate was not routinely detected. Across methods, median chlorophyll concentrations were higher for the summer survey than for the fall survey in Owasco Lake. Nearshore chlorophyll concentrations varied more temporally in Owasco Lake than in Seneca Lake. Phytoplankton and cyanobacterial abundance and biovolume were about five times higher in Owasco Lake than in Seneca Lake. Cyanobacteria dominated the phytoplankton community in most samples, and Microcystis comprised the bulk of the cyanobacterial biovolume. The most abundant potential cyanotoxin-producing (specifically microcystins) genera were Microcystis , Synechococcus , Aphanocapsa , and Pseudanabaena . The cyanobacterial community composition was comparable between open-water monitoring platforms and nearshore samples. Microcystins were detected in seven survey samples from Owasco Lake, in one survey sample from Seneca Lake, and in one sample each from the open-water monitoring platforms on Owasco and Seneca Lakes that were collected about 7 days before the fall surveys. Microcystin detections were not consistently associated with high cyanobacterial cell counts or cyanotoxin-producing genera. Results from nearshore surveys were comparable to open-water monitoring platforms and discrete nearshore observations in the absence of nearshore or open-water CyanoHABs in these systems during the study. Patterns of nearshore concentrations of nitrate and chlorophyll from nearshore surveys may aid in the identification of areas with localized nitrate loading and shifts in phytoplankton abundance and community composition.

New York↗
USGS1977

Water table in the surficial aquifer and potentiometric surface of the Floridan Aquifer in selected well fields, west-central Florida, May 1976

The water table in the surficial aquifer (sand) and the potentiometric surface of the Floridan aquifer (limestone) in a 1,200-square-mile area in west-central Florida are mapped semiannually by the U.S. Geological Survey. Maps are prepared each May and September to coincide with seasonal low and high ground-water levels. The mapped area contains nine producing well fields which supplied 92.8 million gallons on May 12, 1976 to municipalities along the Gulf Coast. This pumpage came from the Floridan aquifer, the major aquifer in the State of Florida. The effect of well-field withdrawals is shown on the maps as cones of depression in both the potentiometric and water-table surfaces. The May 1976 maps indicate that water levels have declined below sea level in some areas. The decline results from reduced recharge during the dry spring combined with an increase in pumpage for lawn irrigation.

Open-File Report↗
USGS1978

Water table in the surficial aquifer and potentiometric surface of the Floridan Aquifer in selected well fields, west-central Florida, September 1977

The water table in the surficial aquifer and the potentiometric surface of the Floridan aquifer in a 1,200 square-mile area in west-central Florida are mapped semiannually by the U.S. Geological Survey. Maps are prepared on the basis of water levels measured in wells each May to coincide with seasonal low levels; and in September, when levels are high. The mapped area for this report contains nine producing wells fields which supplied 76.2 million gallons on September 21, 1977, to municipalities in the Tampa Bay area. The effect of localized withdrawal of groundwater from the Floridan aquifer is shown on the maps as cones of depression in both the potentiometric surface and water table. In September, water levels in observation wells in the Floridan aquifer were above those measured in May. These increases ranged from about 1 foot at the Eldridge-Wilde well field to about 25 feet at the Sun City well field. (Woodard-USGS)

Open-File Report↗
USGS1979

Water table in the surficial aquifer and potentiometric surface of the Floridan Aquifer in selected well fields, west-central Florida, May 1979

The water table is the surficial aquifer and the potentiometric surface of the Floridan aquifer in a 1,200-square-mile area in west-central Florida are mapped semiannually by the U.S. Geological Survey. Maps are prepared showing water levels measured in wells each May to coincide with seasonal low levels, and each September to coincide with seasonal high levels. The mapped area shows 16 well fields which supplied 128 million gallons to municipalities on May 15, 1979. The water is withdrawn from the Floridan aquifer, the major aquifer in Florida. Water levels were significantly higher in May 1979 than in May 1978. Heavy rains on May 7 and 8th deluged the well-field areas with 2 to 18 inches of rain. The maximum increase in water levels from May 1978 to May 1979 was more than 8 feet at the Eldridge-Wilde well field. (USGS)

Open-File Report↗