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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 631 records · Page 35Linked to original sources
USGS1995

USGS global change research

The Earth's global environment--its interrelated climate, land, oceans, fresh water, atmospheric and ecological systems-has changed continually throughout Earth history. Human activities are having ever-increasing effects on these systems. Sustaining our environment as population and demands for resources increase requires a sound understanding of the causes and cycles of natural change and the effects of human activities on the Earth's environmental systems. The U.S. Global Change Research Program was authorized by Congress in 1989 to provide the scientific understanding necessary to develop national and international policies concerning global environmental issues, particularly global climate change. The program addresses questions such as: what factors determine global climate; have humans already begun to change the global climate; will the climate of the future be very different; what will be the effects of climate change; and how much confidence do we have in our predictions? Through understanding, we can improve our capability to predict change, reduce the adverse effects of human activities, and plan strategies for adapting to natural and human-induced environmental change.

Fact Sheet↗
USGS1907

Pollution of Illinois and Mississippi Rivers by Chicago sewage, a digest of the testimony taken in the case of the State of Missouri v. the State of Illinois and the Sanitary District of Chicago

The testimony taken in the suit of the State of Missouri against the State of Illinois and the sanitary district of Chicago comprises the best symposium on river pollution, its biological and chemical aspects, and its general and special sanitary significance that has ever been assembled. The contentions of both parties to the suit' are supported by the most eminently qualified men in the United States. The evidence presented and the discussions recorded are therefore of unique importance. The final record of testimony occupies 8,000 printed pages, much of which is irrelevant. This digest of testimony is the result of an attempt to recover the valuable material and present it in concise form. A consistent endeavor has been made by the reviewer to eliminate all personal opinions with reference to the issue and to make an impartial presentation of so much of the testimony as in his opinion appears to be relevant and of scientific importance. It will be well to remember in this connection that any digest of so large a volume of testimony must be the result of a final exercise of personal opinion by the reviewer as to those parts which may best be excluded. Naturally opinions will differ on this point; therefore it will be strange if many of those familiar with the case do not find that certain portions of testimony which they consider most important are passed over in this digest without reference. Controversies between counsel, objections to the admission of testimony, legal technicalities and quibbles, badgering cross-examination, and in general all the testimony introduced for purposes of mere corroboration have been disregarded. The object has been to present a faithful statement of the scientific phases of the testimony to the exclusion, if need be, of the legal aspect of the case.

Illinois, Missouri↗
USGS2006

Quantification of the contribution of nitrogen from septic tanks to ground water in Spanish Springs Valley, Nevada

Analysis of total dissolved nitrogen concentrations from soil water samples collected within the soil zone under septic tank leach fields in Spanish Springs Valley, Nevada, shows a median concentration of approximately 44 milligrams per liter (mg/L) from more than 300 measurements taken from four septic tank systems. Using two simple mass balance calculations, the concentration of total dissolved nitrogen potentially reaching the ground-water table ranges from 25 to 29 mg/L. This indicates that approximately 29 to 32 metric tons of nitrogen enters the aquifer every year from natural recharge and from the 2,070 houses that use septic tanks in the densely populated portion of Spanish Springs Valley. Natural recharge contributes only 0.25 metric tons because the total dissolved nitrogen concentration of natural recharge was estimated to be low (0.8 mg/L). Although there are many uncertainties in this estimate, the sensitivity of these uncertainties to the calculated load is relatively small, indicating that these values likely are accurate to within an order of magnitude. The nitrogen load calculation will be used as an input function for a ground-water flow and transport model that will be used to test management options for controlling nitrogen contamination in the basin.

Scientific Investigations Report↗
USGS2009

Geomorphic classification of the Lower Platte River, Nebraska

Geomorphic attributes were collected from natural color aerial orthophotography to develop a multiscale classification for the downstream-most 220 kilometers of the Platte River in eastern Nebraska. The intent of this classification is to define discrete reaches that have geomorphic characteristics favorable to endangered interior least terns ( Sternula antillarum ) and threatened piping plovers ( Charadrius melodus ) who use riverine sandbars for nesting habitat. Annual to daily fluctuations in discharge present a challenge to characterizing emergent sandbar habitat directly from existing aerial orthophotography for the Platte River. Therefore, this classification is based on geomorphic measures that are relatively insensitive to prevailing river discharge but may be physically related to emergent sandbar locations. Such features include valley width, channel width, and sinuosity. The results provide four-cluster and seven-cluster classifications for the Lower Platte River based on naturally occurring, statistically determined clusters of features. The classification was validated using tern and plover nest data for 2006–08. Forty-nine percent of the nest locations fell within the same class type in the four-cluster classification, which represented 18 percent of the study area. This class is found primarily in the Eastern Platte River Gorge, downstream from Salt Creek and upstream from the junction of the Platte River with the Missouri River.

Nebraska↗
USGS2013

Simulation of the shallow groundwater-flow system in the Forest County Potawatomi Community, Forest County, Wisconsin

The shallow groundwater system in the Forest County Potawatomi Comminity, Forest County, Wisconsin, was simulated by expanding and recalibrating a previously calibrated regional model. The existing model was updated using newly collected water-level measurements, inclusion of surface-water features beyond the previous near-field boundary, and refinements to surface-water features. The updated model then was used to calculate the area contributing recharge for seven existing and three proposed pumping locations on lands of the Forest County Potawatomi Community. The existing wells were the subject of a 2004 source-water evaluation in which areas contributing recharge were calculated using the fixed-radius method. The motivation for the present (2012) project was to improve the level of detail of areas contributing recharge for the existing wells and to provide similar analysis for the proposed wells. Delineated 5- and 10-year areas contributing recharge for existing and proposed wells extend from the areas of pumping to delineate the area at the surface contributing recharge to the wells. Steady-state pumping was simulated for two scenarios: a base-pumping scenario using pumping rates that reflect what the Community currently (2012) pumps (or plans to in the case of proposed wells), and a high-pumping scenario in which the rate was set to the maximum expected from wells installed in this area, according to the Forest County Potawatomi Community Natural Resources Department. In general, the 10-year areas contributing recharge did not intersect surface-water bodies. The 5- and 10-year areas contributing recharge simulated at the maximum pumping rate at Bug Lake Road may intersect Bug Lake. At the casino near the Town of Carter, Wisconsin, the 10-year areas contributing recharge intersect infiltration ponds. At the Devils Lake and Lois Crow Drive wells, areas contributing recharge are near cultural features, including residences.

Wisconsin↗
USGS2023

An integrated hydrologic model to support the Central Platte Natural Resources District Groundwater Management Plan, central Nebraska

The groundwater and surface-water supply of the Central Platte Natural Resources District supports a large agricultural economy from the High Plains aquifer and Platte River, respectively. This study provided the Central Platte Natural Resources District with an advanced numerical modeling tool to assist with the update of their Groundwater Management Plan. An integrated hydrologic model, called the Central Platte Integrated Hydrologic Model, was constructed using the MODFLOW-One-Water Hydrologic Model code with the Newton solver. This code integrates climate, landscape, surface water, and groundwater-flow processes in a fully coupled approach. Model framework included 163 rows; 327 columns; 2,640 feet cell sides; and 3 vertical layers. A predevelopment model simulated steady-state hydrologic conditions prior to April 30, 1895, and a development period model discretized into 610 stress periods simulated transient hydrologic conditions from May 1, 1895, to December 31, 2016, using 170 biannual stress periods from 1895 to 1980, and monthly stress periods from May 1, 1980, to December 31, 2016. Calibration of the Central Platte Integrated Hydrologic Model involved two phases: a manual adjustment of parameters, followed by the automated calibration completed using BeoPEST that was facilitated by the employment of the singular value decomposition-assist features of PEST that specified 50 super parameters assembled from the 435 adjustable parameters and Tikhonov regularization. The average absolute groundwater-level residuals for model layers one, two, and three were 6.1, 12.4, and 7.4 feet, respectively. Calibrated horizontal hydraulic conductivity was about 70, 32, and 35 feet per day for layers 1, 2, and 3, respectively. The largest development period inflow to groundwater was recharge from deep percolation past the root zone, averaging 1,122,257 acre-feet per year (2.7 inches per year), and the largest outflow was to irrigation wells, averaging 693,171 acre-feet per year (10.2 inches per year for the Central Platte Natural Resources District). Other substantial groundwater outflows included evapotranspiration and base flow. For the total development period, there was a net change in storage of −122,393 acre-feet per year (−0.3 inch per year). The calibrated Central Platte Integrated Hydrologic Model was used to simulate eight different potential future climate and irrigation pumping conditions from January 1, 2017, to December 31, 2049. Simulated future groundwater levels within the Central Platte Natural Resources District varied significantly between scenarios and locally, from 13.8 feet below to 7.6 feet above baseline 1982 groundwater levels. Most areas exhibited groundwater-level declines for the drought scenarios and rises for the alternate irrigation scenarios. Changes in scenario groundwater levels correlated with the relations between farm net recharge and irrigation pumping. Linear “first order second moment” techniques indicated that the uncertainty in projected groundwater altitudes was reduced by 15.33 feet through model calibration.

Nebraska↗
USGS2014

The Hawaiian Volcano Observatory: A natural laboratory for studying basaltic volcanism

In the beginning of the 20th century, geologist Thomas A. Jaggar, Jr., argued that, to fully understand volcanic and associated hazards, the expeditionary mode of studying eruptions only after they occurred was inadequate. Instead, he fervently advocated the use of permanent observatories to record and measure volcanic phenomena—at and below the surface—before, during, and after eruptions to obtain the basic scientific information needed to protect people and property from volcanic hazards. With the crucial early help of American volcanologist Frank Alvord Perret and the Hawaiian business community, the Hawaiian Volcano Observatory (HVO) was established in 1912, and Jaggar’s vision became reality. From its inception, HVO’s mission has centered on several goals: (1) measuring and documenting the seismic, eruptive, and geodetic processes of active Hawaiian volcanoes (principally Kīlauea and Mauna Loa); (2) geological mapping and dating of deposits to reconstruct volcanic histories, understand island evolution, and determine eruptive frequencies and volcanic hazards; (3) systematically collecting eruptive products, including gases, for laboratory analysis; and (4) widely disseminating observatory-acquired data and analysis, reports, and hazard warnings to the global scientific community, emergency-management authorities, news media, and the public. The long-term focus on these goals by HVO scientists, in collaboration with investigators from many other organizations, continues to fulfill Jaggar’s career-long vision of reducing risks from volcanic and earthquake hazards across the globe. This chapter summarizes HVO’s history and some of the scientific achievements made possible by this permanent observatory over the past century as it grew from a small wooden structure with only a small staff and few instruments to a modern, well-staffed, world-class facility with state-of-the-art monitoring networks that constantly track volcanic and earthquake activity. The many successes of HVO, from improving basic knowledge about basaltic volcanism to providing hands-on experience and training for hundreds of scientists and students and serving as the testing ground for new instruments and technologies, stem directly from the acquisition, integration, and analysis of multiple datasets that span many decades of observations of frequent eruptive activity. HVO’s history of the compilation, interpretation, and communication of long-term volcano monitoring and eruption data (for instance, seismic, geodetic, and petrologic-geochemical data and detailed eruption chronologies) is perhaps unparalleled in the world community of volcano observatories. The discussion and conclusions drawn in this chapter, which emphasize developments since the 75th anniversary of HVO in 1987, are general and retrospective and are intended to provide context for the more detailed, topically focused chapters of this volume.

Hawaii↗
USGS2019

Bathymetric contour map, surface area and capacity table, and bathymetric change map for Sugar Creek Lake near Moberly, Missouri, 2018

Managers of water-supply lakes need an accurate estimate of the lake capacity to ensure that enough water is available for uses such as: providing consistent recreation pool levels, preserving downstream aquatic habitat, flood abatement, water supply, and power generation. Lake capacity is particularly important for managers of water-supply lakes during periods of drought, unexpected population growth, or exceptionally high water use in the area supplied by the lake. Sedimentation, primarily from runoff into the lake, will cause a loss of storage capacity as a lake ages; as a result, the capacity table for the lake (if one exists) will overestimate the actual capacity. Lake bathymetric changes can be demonstrated through periodic surveying, and rates of sediment accumulation can be calculated so that managers can better regulate the water supply. The U. S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, completed a bathymetric survey of Sugar Creek Lake in December 2003. Sugar Creek Lake, constructed in 1922, is about 4 miles northwest of Moberly, Missouri, in Randolph County and has a surface area of about 330 acres at the spillway elevation of 746.8 feet. The lake primarily is used for recreation and drinking-water supply for the town of Moberly, Missouri. In September 2018, the U. S. Geological Survey, in cooperation with the Missouri Department of Natural Resources and the City of Moberly, Missouri, surveyed the bathymetry of Sugar Creek Lake to prepare an updated bathymetric map and a surface area and capacity table. The 2003 survey was compared with the 2018 survey to document the changes in the bathymetric surface. The comparison found that in the 14.7 years between the two surveys the lake had lost 230 acre-feet of capacity and had an average sediment accumulation of 0.96 feet.

Missouri↗
USGS2011

The source, discharge, and chemical characteristics of water from Agua Caliente Spring, Palm Springs, California

Agua Caliente Spring, in downtown Palm Springs, California, has been used for recreation and medicinal therapy for hundreds of years and currently (2008) is the source of hot water for the Spa Resort owned by the Agua Caliente Band of the Cahuilla Indians. The Agua Caliente Spring is located about 1,500 feet east of the eastern front of the San Jacinto Mountains on the southeast-sloping alluvial plain of the Coachella Valley. The objectives of this study were to (1) define the geologic structure associated with the Agua Caliente Spring; (2) define the source(s), and possibly the age(s), of water discharged by the spring; (3) ascertain the seasonal and longer-term variability of the natural discharge, water temperature, and chemical characteristics of the spring water; (4) evaluate whether water-level declines in the regional aquifer will influence the temperature of the spring discharge; and, (5) estimate the quantity of spring water that leaks out of the water-collector tank at the spring orifice.

California↗
USGS2012

Isotropic, anisotropic, and borehole washout analyses in Gulf of Mexico Gas Hydrate Joint Industry Project Leg II, Alaminos Canyon well 21-A

Through the use of three-dimensional seismic amplitude mapping, several gas hydrate prospects were identified in the Alaminos Canyon area of the Gulf of Mexico. Two of the prospects were drilled as part of the Gulf of Mexico Gas Hydrate Joint Industry Program Leg II in May 2009, and a suite of logging-while-drilling logs was acquired at each well site. Logging-while-drilling logs at the Alaminos Canyon 21–A site indicate that resistivities of approximately 2 ohm-meter and P-wave velocities of approximately 1.9 kilometers per second were measured in a possible gas-hydrate-bearing target sand interval between 540 and 632 feet below the sea floor. These values are slightly elevated relative to those measured in the hydrate-free sediment surrounding the sands. The initial well log analysis is inconclusive in determining the presence of gas hydrate in the logged sand interval, mainly because large washouts in the target interval degraded well log measurements. To assess gas-hydrate saturations, a method of compensating for the effect of washouts on the resistivity and acoustic velocities is required. To meet this need, a method is presented that models the washed-out portion of the borehole as a vertical layer filled with seawater (drilling fluid). Owing to the anisotropic nature of this geometry, the apparent anisotropic resistivities and velocities caused by the vertical layer are used to correct measured log values. By incorporating the conventional marine seismic data into the well log analysis of the washout-corrected well logs, the gas-hydrate saturation at well site AC21–A was estimated to be in the range of 13 percent. Because gas hydrates in the vertical fractures were observed, anisotropic rock physics models were also applied to estimate gas-hydrate saturations.

Scientific Investigations Report↗
USGS2015

Estimated freshwater withdrawals in Washington, 2010

Every 5 years since 1950, the U.S. Geological Survey (USGS) has compiled data on the amount of water used in homes, businesses, industries, and farms throughout the State. This water-use data, combined with other related USGS information, has facilitated a unique understanding of the effects of human activity on the State’s water resources. As water availability continues to emerge as an important issue in the 21st century, the need for consistent, long-term water-use data will increase to support wise use of this essential natural resource. The amount of public- and self-supplied water used for domestic, irrigation, livestock, aquaculture, industrial, mining, and thermoelectric power was estimated for state, county, and eastern and western regions of Washington during calendar year 2010. Withdrawals of freshwater for offstream uses were estimated to be about 4,885 million gallons per day. The total estimated freshwater withdrawals for 2010 was approximately 15 percent less than the 2005 estimate because of decreases in irrigation and thermoelectric power withdrawals.

Washington↗
USGS2013

Hurricane Sandy science plan: coastal impact assessments

Hurricane Sandy devastated some of the most heavily populated eastern coastal areas of the Nation. With a storm surge peaking at more than 19 feet, the powerful landscape-altering destruction of Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. In response to this natural disaster, the U.S. Geological Survey (USGS) received a total of $41.2 million in supplemental appropriations from the Department of the Interior (DOI) to support response, recovery, and rebuilding efforts. These funds support a science plan that will provide critical scientific information necessary to inform management decisions for recovery of coastal communities, and aid in preparation for future natural hazards. This science plan is designed to coordinate continuing USGS activities with stakeholders and other agencies to improve data collection and analysis that will guide recovery and restoration efforts. The science plan is split into five distinct themes: coastal topography and bathymetry, impacts to coastal beaches and barriers, impacts of storm surge, including disturbed estuarine and bay hydrology, impacts on environmental quality and persisting contaminant exposures, impacts to coastal ecosystems, habitats, and fish and wildlife. This fact sheet focuses assessing impacts to coastal beaches and barriers.

East Coast↗
USGS2018

Rio Grande transboundary integrated hydrologic model and water-availability analysis, New Mexico and Texas, United States, and Northern Chihuahua, Mexico

Errata **September 28, 2018: The purpose of a USGS Open-file report (OFR) is dissemination of information that must be released immediately to fill a public need or information that is not sufficiently refined to warrant publication in one of the other USGS series. As part of that refinement process, an error was discovered in one of the input data sets of the Rio Grande Transboundary Integrated Hydrologic Model (RGTIHM) that this OFR was based upon. The error involved the assignment of storage properties to “phantom cells.” Phantom cells are required for most variants of MODFLOW that use a structured finite-difference grid when individual stratigraphic layers are represented as separate layers. Using phantom cells is a common practice that allows separate model layers to be maintained without having to combine stratigraphic layers into equivalent model layers or to use an unstructured grid. Typically, phantom cell horizontal hydraulic conductivities and storage properties are set to a small number and vertical hydraulic conductivities are set to a number large enough to allow vertical flow between the vertically adjacent layers. In the RGTIHM, the specific storage properties of the phantom cells for the upper (RGTIHM layers 3 and 4), middle (RGTIHM layers 5 and 6), and lower (RGTIHM layers 7 and 8) members of the Santa Fe Group were inadvertently assigned a value of 1 feet -1 . The revision of these specific storage values to a small number (1.0 x 10 -09 feet -1 ) required additional trial-and-error model calibration and a new sensitivity analysis. After calibration, the overall model fit remained similar to the fit described in the OFR, but the fit for many individual features such as project water available for diversions at the American Canal and Acequia Madre improved due to the reduction in flow coming from lower layers. Overall, there is still an average net depletion of groundwater flow, and the conclusions of the report are not changed. The revised average annual groundwater flow depletion simulated for the period 1953-2014 is -1,480 acre-feet/year for the entire model region, and -3,660 acre-feet/year for the portion of the model in the United States. The final version of the model will be the basis of the USGS Scientific Investigations Report that will supersede this OFR. An updated Model Archive of RGTIHM is available upon request to the USGS California Water Science Center. The corrected version of the model WAS the basis for the USGS Scientific Investigations Report that SUPERSEDED this Open-File Report.** Abstract Changes in population, agricultural development and practices (including shifts to more water-intensive crops), and climate variability are increasing demands on available water resources, particularly groundwater, in one of the most productive agricultural regions in the Southwest—the Rincon and Mesilla Valley parts of Rio Grande Valley, Doña Ana and Sierra Counties, New Mexico, and El Paso County, Texas. The goal of this study was to produce an integrated hydrological simulation model to help evaluate water-management strategies, including conjunctive use of surface water and groundwater for historical conditions, and to support long-term planning for the Rio Grande Project. This report describes model construction and applications by the U.S. Geological Survey, working in cooperation and collaboration with the Bureau of Reclamation. This model, the Rio Grande Transboundary Integrated Hydrologic Model, simulates the most important natural and human components of the hydrologic system, including selected components related to variations in climate, thereby providing a reliable assessment of surface-water and groundwater conditions and processes that can inform water users and help improve planning for future conditions and sustained operations of the Rio Grande Project (RGP) by the Bureau of Reclamation. Model development included a revision of the conceptual model of the flow system, construction of a Transboundary Rio Grande Watershed Model (TRGWM) water-balance model using the Basin Characterization Model (BCM), and construction of an integrated hydrologic flow model with MODFLOW-One-Water Hydrologic Flow Model (referred to as One Water). The hydrologic models were developed for and calibrated to historical conditions of water and land use, and parameters were adjusted so that simulated values closely matched available measurements (calibration). The calibrated model was then used to assess the use and movement of water in the Rincon Valley, Mesilla Basin, and northern part of the Conejos-Médanos Basin, with the entire region referred to as the “Transboundary Rio Grande” or TRG. These tools provide a means to understand hydrologic system response to the evolution of water use in the region, its availability, and potential operational constraints of the RGP. The conceptual model identified surface-water and groundwater inflows and outflows that included the movement and use of water both in natural and in anthropogenic systems. The groundwater-flow system is characterized by a layered geologic sedimentary sequence combined with the effects of groundwater pumping, operation of the RGP, natural runoff and recharge, and the application of irrigation water at the land surface that is captured and reused in an extensive network of canals and drains as part of the conjunctive use of water in the region. Historical groundwater-level fluctuations followed a cyclic pattern that were aligned with climate cycles, which collectively resulted in alternating periods of wet or dry years. Periods of drought that persisted for one or more years are associated with low surface-water availability that resulted in higher rates of groundwater-level decline. Rates of groundwater-level decline also increased during periods of agricultural intensification, which necessitated increasing use of groundwater as a source of irrigation water. Agriculture in the area was initially dominated by alfalfa and cotton, but since 1970 more water-intensive pecan orchards and vegetable production have become more common. Groundwater levels substantially declined in subregions where drier climate combined with increased demand, resulting in periods of reduced streamflows. Most of the groundwater was recharged in the Rio Grande Valley floor, and most of the pumpage and aquifer storage depletion was in Mesilla Basin agricultural subregions. A cyclic imbalance between inflows and outflows resulted in the modeled cyclic depletion (groundwater withdrawals in excess of natural recharge) of the groundwater basin during the 75-year simulation period of 1940–2014. Changes in groundwater storage can vary considerably from year to year, depending on land use, pumpage, and climate conditions. Climatic drivers of wet and dry years can greatly affect all inflows, outflows, and water use. Although streamflow and, to a minor extent, precipitation during inter-decadal wet-year periods replenished the groundwater historically, contemporary water use and storage depletion could have reduced the effects of these major recharge events. The average net groundwater flow-rate deficit for 1953–2014 was estimated to be about 8,990 acre-feet per year.

New Mexico, Northern Chihuahua, Texas↗
USGS2010

Forecasting the effects of land-use and climate change on wildlife communities and habitats in the lower Mississippi Valley

Landscape patterns and processes reflect both natural ecosystem attributes and the policy and management decisions of individual Federal, State, county, and private organizations. Land-use regulation, water management, and habitat conservation and restoration efforts increasingly rely on landscape-level approaches that incorporate scientific information into the decision-making process. Since management actions are implemented to affect future conditions, decision-support models are necessary to forecast potential future conditions resulting from these decisions. Spatially explicit modeling approaches enable testing of different scenarios and help evaluate potential outcomes of management actions in conjunction with natural processes such as climate change. The ability to forecast the effects of changing land use and climate is critically important to land and resource managers since their work is inherently site specific, yet conservation strategies and practices are expressed at higher spatial and temporal scales that must be considered in the decisionmaking process.

Fact Sheet↗
USGS2018

Delineation of selected lithologic units using airborne electromagnetic data near Cedar Rapids, Iowa

The U.S. Geological Survey, in cooperation with the City of Cedar Rapids, began a study in 2013 to better understand the effects of drought stress on the Cedar River alluvial aquifer. After an evaluation of the existing groundwater-flow models for the alluvial aquifer, a plan was begun to construct an updated groundwater-flow model capable of evaluating the effect of prolonged drought and increased demand. As part of the effort to update the existing groundwater-flow model, data were collected during an airborne electromagnetic (AEM) survey in May 2017. The study area for the AEM survey encompasses about 53 square kilometers of the Cedar River Basin, west of Cedar Rapids, Iowa, and includes a 19-kilometer reach of the Cedar River. The AEM survey of the Cedar River alluvial aquifer and adjacent areas was completed to characterize the subsurface geology of the area to refine a lithologic framework. The collected AEM data were postprocessed by numerical inversion using the program EM1DFM to produce subsurface apparent resistivity cross sections. Changes observed in resistivity profile values with depth were used to infer lithologic changes and delineate three of the four lithologic units designated in the lithologic framework for this area: alluvial deposits, glacial till, and bedrock; hereafter referred to as the “lithologic framework.” The fourth unit, composed of surficial eolian sediments, was not delineated in these profiles because these units are thin and discontinuous and are not reliably distinguishable from flood plain alluvial deposits. For the purposes of delineating lithologic units using the AEM data, bedrock was assumed to be the lowest unit in a profile, glacial till was deposited on a bedrock surface, and alluvium was deposited on erosional till or bedrock surfaces. A three-dimensional fence diagram was created as part of the lithologic framework to further define the extent and thickness of the lithologic units near the Cedar River alluvial aquifer. The fence diagram shows a three-dimensional perspective of unit thickness, extent, and orientation of the delineated lithologic framework. A lithologic framework, by design, is intended to represent a simplification of a more complex natural system through data interpolation between known points, which usually are lithologic logs. The resistivity profiles produced from the AEM survey allow for continuous mapping and accurate interpolation of lithology between lithologic logs; however, the apparent resistivity value may reflect several characteristics of subsurface materials including variations in lithology, porosity, water quality, grain sorting, and degree of saturation. In this study, the only variables considered were those related to changes in the subsurface material.

Iowa↗
USGS2020

Development of regional skew coefficients for selected flood durations in the Columbia River Basin, northwestern United States and British Columbia, Canada

Flood-frequency (hereinafter frequency) estimates provide information used to design, operate, and maintain hydraulic structures such as bridges and dams. Failures of these structures could cause catastrophic loss of property, life, or both. In addition to frequency estimates that use annual peak streamflow, frequency estimates of flood durations are required to safely and effectively operate the numerous dams in the Columbia River Basin of the northwestern United States, and British Columbia, Canada. Frequency studies rely on U.S. Geological Survey Guidelines for Determining Flood Flow Frequency (Bulletin 17C, published in 2018). A major consideration in estimating frequencies is the use of skew coefficients, which measure the asymmetry of flood flow distributions. Large uncertainties are associated with estimating the at-site skew coefficients directly from streamflow records, which are limited in length. Skew also is sensitive to extreme events for limited record lengths. Bulletin 17C recommends using regional skew coefficients to weight with the at-site skew estimate for more reliable frequency estimates. In this study, streamflow records from 313 unregulated U.S. Geological Survey streamgage sites and 97 regulated sites with naturalized streamflow records provided by the U.S. Army Corps of Engineers were used to develop regional skew models for the Columbia River Basin. The naturalized streamflow records were synthesized by removing regulatory components such as withdrawals and reservoir storage. Skew models were developed for 1-, 3-, 7-, 10-, 15-, 30-, and 60-day flood durations and used to estimate regional skew coefficients for the Columbia River Basin. This report used Bayesian statistical regression methods to develop and analyze regional skew models based on hydrologically important basin characteristics. After examining a suite of available basin characteristics, mean annual precipitation had the strongest correlation to skew across the flood durations. Regional skew regression models were fit using mean annual precipitation for selected subbasins in the Columbia River Basin.

Columbia River Basin↗
USGS2011

Science supporting Gulf of Mexico oil-spill response, mitigation, and restoration activities-Assessment, monitoring, mapping, and coordination

The St. Petersburg Coastal and Marine Science Center of the U.S. Geological Survey (USGS) investigates physical processes related to coastal and marine environments and societal implications related to natural hazards, resource sustainability, and environmental change. Immediately after the Deepwater Horizon event, the USGS began responding to data requests, directing response personnel, and providing coastal and shelf geophysical data to coastal-resource managers. The USGS provided oil-spill responders with up-to-date coastal bathymetry, geologic data, and maps characterizing vulnerability and levels of risk from potential spill impacts in Louisiana, Mississippi, and Alabama. Baseline conditions prior to any spill impacts were documented through programs that included shoreline sampling and sediment coring from east Texas to the east coast of Florida and aerial photography of many environmentally sensitive Gulf coastal areas. The USGS responded to numerous verbal and written data requests from Federal, State, and local partners and academic institutions with USGS scientific staff participating in the Coast Guard Unified Commands (UC) and Operational Science Advisory Teams (OSAT). The USGS conducted technical review of reports and plans for many response activities. Oil-spill responders, managers, and personnel on the ground, including partners such as the National Park Service, Gulf Islands National Seashore, Chandeleur Islands Refuge, and State agencies, continue to rely on USGS products.

General Information Product↗
USGS2006

Applicability of terrestrial LIDAR scanning for scientific studies in Grand Canyon National Park, Arizona

In November 2004, an experimental high flow release of water from Glen Canyon Dam into the Colorado River through Grand Canyon National Park in Arizona was conducted. The goal of the experiment was to evaluate the use of high flow events as a management tool for the preservation and restoration of natural resources in the Colorado River below Glen Canyon Dam. The U.S. Geological Survey (USGS), Grand Canyon Monitoring and Research Center (GCMRC) located in Flagstaff, Arizona performed oversight of all aspects of scientific data collection including suspended sediment transport studies, biological population variations, effects on archaeological resources, and morphological studies of river sand bars. As part of the experimental high flow studies, the USGS Coastal and Marine Geology (CMG) team was invited to participate to test the effectiveness of utilizing terrestrial LIDAR technology for gathering morphological data on sand bars, biological habitats, and archaeological sites. The CMG is equipped with a terrestrial LIDAR unit and has used the technique in a variety of terrains to gather high-resolution morphological data. A three-member team from CMG participated in the experiment, joining a GCMRC team on a river trip from November 18 to November 21, 2004. This report begins with a brief description of the LIDAR technique and then outlines the data collected, processing required, and results for three study areas located within the Grand Canyon. Specifically, studies were performed at the Mile 30 Sand Bar, at Vaseys Paradise (Mile 32), and at the Mile 66 Palisades Archaeological Site. Conclusions and recommendations for utilizing terrestrial LIDAR for future studies at each of these sites are also included.

Arizona↗