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At least 649 records · Page 36Linked to original sources

USGS1996

Estimation of flood-frequency characteristics of small urban streams in North Carolina

A statewide study was conducted to develop methods for estimating the magnitude and frequency of floods of small urban streams in North Carolina. This type of information is critical in the design of bridges, culverts and water-control structures, establishment of flood-insurance rates and flood-plain regulation, and for other uses by urban planners and engineers. Concurrent records of rainfall and runoff data collected in small urban basins were used to calibrate rainfall-runoff models. Historic rain- fall records were used with the calibrated models to synthesize a long- term record of annual peak discharges. The synthesized record of annual peak discharges were used in a statistical analysis to determine flood- frequency distributions. These frequency distributions were used with distributions from previous investigations to develop a database for 32 small urban basins in the Blue Ridge-Piedmont, Sand Hills, and Coastal Plain hydrologic areas. The study basins ranged in size from 0.04 to 41.0 square miles. Data describing the size and shape of the basin, level of urban development, and climate and rural flood charac- teristics also were included in the database. Estimation equations were developed by relating flood-frequency char- acteristics to basin characteristics in a generalized least-squares regression analysis. The most significant basin characteristics are drainage area, impervious area, and rural flood discharge. The model error and prediction errors for the estimating equations were less than those for the national flood-frequency equations previously reported. Resulting equations, which have prediction errors generally less than 40 percent, can be used to estimate flood-peak discharges for 2-, 5-, 10-, 25-, 50-, and 100-year recurrence intervals for small urban basins across the State assuming negligible, sustainable, in- channel detention or basin storage.

North Carolina↗

USGS2003

The United Nations Framework Classification for World Petroleum Resources

The United Nations has developed an international framework classification for solid fuels and minerals (UNFC). This is now being extended to petroleum by building on the joint classification of the Society of Petroleum Engineers (SPE), the World Petroleum Congresses (WPC) and the American Association of Petroleum Geologists (AAPG). The UNFC is a 3-dimansional classification. This: Is necessary in order to migrate accounts of resource quantities that are developed on one or two of the axes to the common basis; Provides for more precise reporting and analysis. This is particularly useful in analyses of contingent resources. The characteristics of the SPE/WPC/AAPG classification has been preserved and enhanced to facilitate improved international and national petroleum resource management, corporate business process management and financial reporting. A UN intergovernmental committee responsible for extending the UNFC to extractive energy resources (coal, petroleum and uranium) will meet in Geneva on October 30th and 31st to review experiences gained and comments received during 2003. A recommended classification will then be delivered for consideration to the United Nations through the Committee on Sustainable Energy of the Economic Commission for Europe (UN ECE).

Conference Paper↗

USGS2012

Application of Wind Fetch and Wave Models for Habitat Rehabilitation and Enhancement Projects

Models based upon coastal engineering equations have been developed to quantify wind fetch length and several physical wave characteristics including significant height, length, peak period, maximum orbital velocity, and shear stress. These models were used to quantify differences in proposed island construction designs for three Habitat Rehabilitation and Enhancement Projects (HREPs) in the U.S. Army Corps of Engineers St. Paul District (Capoli Slough and Harpers Slough) and St. Louis District (Swan Lake). Weighted wind fetch was calculated using land cover data supplied by the Long Term Resource Monitoring Program (LTRMP) for each island design scenario for all three HREPs. Figures and graphs were created to depict the results of this analysis. The difference in weighted wind fetch from existing conditions to each potential future island design was calculated for Capoli and Harpers Slough HREPs. A simplistic method for calculating sediment suspension probability was also applied to the HREPs in the St. Paul District. This analysis involved determining the percentage of days that maximum orbital wave velocity calculated over the growing seasons of 2002–2007 exceeded a threshold value taken from the literature where fine unconsolidated sediments may become suspended. This analysis also evaluated the difference in sediment suspension probability from existing conditions to the potential island designs. Bathymetric data used in the analysis were collected from the LTRMP and wind direction and magnitude data were collected from the National Oceanic and Atmospheric Administration, National Climatic Data Center. These models are scheduled to be updated to operate using the most current Environmental Systems Research Institute ArcGIS Geographic Information System platform, and have several improvements implemented to wave calculations, data processing, and functions of the toolbox.

Conference Paper↗

USGS1997

Dynamic deformations and the M6.7, Northridge, California earthquake

A method of estimating the complete time-varying dynamic formation field from commonly available three-component single station seismic data has been developed and applied to study the relationship between dynamic deformation and ground failures and structural damage using observations from the 1994 Northridge, California earthquake. Estimates from throughout the epicentral region indicate that the horizontal strains exceed the vertical ones by more than a factor of two. The largest strains (exceeding ∼100 pstrain) correlate with regions of greatest ground failure. There is a poor correlation between structural damage and peak strain amplitudes. The smallest strains,∼35 pstrain, are estimated in regions of no damage or ground failure. Estimates in the two regions with most severe and well mapped permanent deformation, Potrero Canyon and the Granada-Mission Hills regions, exhibit the largest strains; peak horizontal strains estimates in these regions equal ∼1351 and ∼229 μstrain respectively. Of note, the dynamic principal strain axes have strikers consistent with the permanent failure features suggesting that, while gravity, sub-surface materials, and hydrologic conditions undoubtedly played fundamental roles in determining where and what types of failures occurred, the dynamic deformation field may have been favorably sized and oriented to initiate failure processes. These results support other studies that conclude that the permanent deformation resulted from ground shaking, rather than from static strains associated with primary or secondary faulting. They also suggest that such an analysis, either using data or theoretical calculations, may enable observations of paleo-ground failure to be used as quantitative constraints on the size and geometry of previous earthquakes.

California↗

USGS2004

Microforms in gravel bed rivers: Formation, disintegration, and effects on bedload transport

This research aims to advance current knowledge on cluster formation and evolution by tackling some of the aspects associated with cluster microtopography and the effects of clusters on bedload transport. The specific objectives of the study are (1) to identify the bed shear stress range in which clusters form and disintegrate, (2) to quantitatively describe the spacing characteristics and orientation of clusters with respect to flow characteristics, (3) to quantify the effects clusters have on the mean bedload rate, and (4) to assess the effects of clusters on the pulsating nature of bedload. In order to meet the objectives of this study, two main experimental scenarios, namely, Test Series A and B (20 experiments overall) are considered in a laboratory flume under well-controlled conditions. Series A tests are performed to address objectives (1) and (2) while Series B is designed to meet objectives (3) and (4). Results show that cluster microforms develop in uniform sediment at 1.25 to 2 times the Shields parameter of an individual particle and start disintegrating at about 2.25 times the Shields parameter. It is found that during an unsteady flow event, effects of clusters on bedload transport rate can be classified in three different phases: a sink phase where clusters absorb incoming sediment, a neutral phase where clusters do not affect bedload, and a source phase where clusters release particles. Clusters also increase the magnitude of the fluctuations in bedload transport rate, showing that clusters amplify the unsteady nature of bedload transport. A fourth-order autoregressive, autoregressive integrated moving average model is employed to describe the time series of bedload and provide a predictive formula for predicting bedload at different periods. Finally, a change-point analysis enhanced with a binary segmentation procedure is performed to identify the abrupt changes in the bedload statistic characteristics due to the effects of clusters and detect the different phases in bedload time series using probability theory. The analysis verifies the experimental findings that three phases are detected in the bedload rate time series structure, namely, sink, neutral, and source. ?? ASCE / JUNE 2004.

Journal of Hydraulic Engineering↗

USGS2009

Large area scene selection interface (LASSI): Methodology of selecting landsat imagery for The Global Land Survey 2005

The Global Land Survey (GLS) 2005 is a cloud-free, orthorec-tified collection of Landsat imagery acquired during the 2004 to 2007 epoch intended to support global land-cover and ecological monitoring. Due to the numerous complexities in selecting imagery for the GLS2005, NASA and the U.S. Geological Survey (USGS) sponsored the development of an automated scene selection tool, the Large Area Scene Selection Interface (LASSI), to aid in the selection of imagery for this data set. This innovative approach to scene selection applied a user-defined weighting system to various scene parameters: image cloud cover, image vegetation greenness, choice of sensor, and the ability of the Landsat-7 Scan Line Corrector (SLC)-off pair to completely fill image gaps, among others. The parameters considered in scene selection were weighted according to their relative importance to the data set, along with the algorithm’s sensitivity to that weight. This paper describes the methodology and analysis that established the parameter weighting strategy, as well as the post-screening processes used in selecting the optimal data set for GLS2005.

Photogrammetric Engineering and Remote Sensing↗

USGS2007

Re-Evaluation of the 1921 Peak Discharge at Skagit River near Concrete, Washington

The peak discharge record at the U.S. Geological Survey (USGS) gaging station at Skagit River near Concrete, Washington, is a key record that has come under intense scrutiny by the scientific and lay person communities in the last 4 years. A peak discharge of 240,000 cubic feet per second for the flood on December 13, 1921, was determined in 1923 by USGS hydrologist James Stewart by means of a slope-area measurement. USGS then determined the peak discharges of three other large floods on the Skagit River (1897, 1909, and 1917) by extending the stage-discharge rating through the 1921 flood measurement. The 1921 estimate of peak discharge was recalculated by Flynn and Benson of the USGS after a channel roughness verification was completed based on the 1949 flood on the Skagit River. The 1949 recalculation indicated that the peak discharge probably was 6.2 percent lower than Stewart's original estimate but the USGS did not officially change the peak discharge from Stewart's estimate because it was not more than a 10-percent change (which is the USGS guideline for revising peak flows) and the estimate already had error bands of 15 percent. All these flood peaks are now being used by the U.S. Army Corps of Engineers to determine the 100-year flood discharge for the Skagit River Flood Study so any method to confirm or improve the 1921 peak discharge estimate is warranted. During the last 4 years, two floods have occurred on the Skagit River (2003, 2006) that has enabled the USGS to collect additional data, do further analysis, and yet again re-evaluate the 1921 peak discharge estimate. Since 1949, an island/bar in the study reach has reforested itself. This has complicated the flow hydraulics and made the most recent recalculation of the 1921 flood based on channel roughness verification that used 2003 and 2006 flood data less reliable. However, this recent recalculation did indicate that the original peak-discharge calculation by Stewart may be high, and it added to a body of evidence that indicates a revision in the 1921 peak discharge estimate is appropriate. The USGS has determined that a lower peak-discharge estimate (5.0 percent lower) similar to the 1949 estimates is most appropriate based on (1) a recalculation of the 1921 flood using a channel roughness verification from the 1949 flood data, (2) a recalculation of the 1921 flood using a channel roughness verification from 2003 and 2006 flood data, and (3) straight-line extension of the stage-discharge relation at the gage based on current-meter discharge measurements. Given the significance of the 1921 flood peak, revising the estimate is appropriate even though it is less than the 10-percent guideline established by the USGS for revision. Revising the peak is warranted because all work subsequent to 1921 point to the 1921 peak being lower than originally published.

Scientific Investigations Report↗

USGS1964

Geometry of river channels: Discussion by William W. Emmett and Luna B. Leopold

For many years river engineers and geomorphologists have sought a rationale for the general similarity that can be observed among river channels from various environments. Some aspects of this general comparability were noted a century ago by Playfair, and other aspects were examined in a more quantitative way approximately 10 yr ago by R. E. Horton. Such similarities with respect to the channel cross section and the associated hydraulic parameters and their changes downstream were studied by some of the engineers who attained prominence for their work on the self-adjusting irrigation canals of India, especially G. Lacy, 15 C. Inglis, 16 and T. Blench. 17 Among these men, canal characteristics were the principal objects of investigation, although natural river channels assumed an increasing share of the attention of the students of "regime analysis," especially Blench. L. B. Leopold and T. Maddock 18 developed a scheme by which the average relationships among form and hydraulic parameters could be easily described, this description being the one on which the author chose to elaborate.

Conference Paper↗

USGS2020

InFRM Flood Decision Support Toolbox user guide

Digital geospatial flood inundation mapping can be a powerful tool for flood risk management. Flood preparedness, communication, warning, response and mitigation can be enhanced by flood inundation mapping that shows floodwater extent and depth over the land surface. Flood inundation maps that accurately reflect observed and forecasted hydrodynamic conditions enable officials to make timely operational and public safety decisions before and during flood events. Real-time inundation maps, based on U.S. Geological Survey (USGS) real-time streamgage observations, National Weather Service (NWS) forecasts and US Army Corps of Engineers (USACE) flood operations, can significantly enhance a community’s flood warning and response operations and systems. These maps enable local officials to make more informed flood risk management decisions and enhance the communication of these decisions to the public, thereby reducing loss of life and property. In addition, flood inundation maps and scenario analysis can inform all parties of the potential risk associated with various flood management options, prior to an actual flood event.

Report↗

USGS2006

Ground-Water Levels in Huron County, Michigan, 2004-05

In 1990, the U.S. Geological Survey (USGS) completed a study of the hydrogeology of Huron County, Michigan (Sweat, 1991). In 1993, Huron County and the USGS entered into a continuing agreement to measure water levels at selected wells throughout Huron County. As part of the agreement, USGS has operated four continuous water-level recorders, installed from 1988 to 1991 on wells in Bingham, Fairhaven, Grant, and Lake Townships (fig. 1) and summarized the data collected in an annual or bi-annual report. The agreement was altered in 2003, and beginning January 1, 2004, only the wells in Fairhaven and Lake Townships retained continuous waterlevel recorders, while the wells in Grant and Bingham Townships reverted primarily to periodic or quarterly measurement status. USGS also has provided training for County or Huron Conservation District personnel to measure the water level, on a quarterly basis, in 25 wells. USGS personnel regularly accompany County or Huron Conservation District personnel to provide a quality assurance/quality control check of all measurements being made. Water-level data collected from the 25 periodically or quarterly-measured wells is summarized in an annual or bi-annual report. In 1998, the USGS also completed a temporal and spatial analysis of the monitoring well network in Huron County (Holtschlag and Sweat, 1998). The altitude of Lake Huron and precipitation are good indicators of general climatic conditions and, therefore, provide an environmental context for ground-water levels in Huron County. Figure 2 shows the mean-monthly water-level altitude of Lake Huron, averaged from measurements made by the U.S. Army Corps of Engineers at sites near Essexville or Harbor Beach, or both (National Oceanic and Atmospheric Administration, 2003-05), and monthly precipitation measured in Bad Axe (National Oceanic and Atmospheric Administration, 2003-05). In March 2003, a new low-water level for the period from 1991 through 2005 was measured in Lake Huron. There was almost no net change in the water level of Lake Huron from January 2004 through December 2005. In 2004, annual precipitation measured in Port Hope was about 3.7 inches above normal, but precipitation measured in Bad Axe was about 1.4 inches below normal. About 14.5 inches of precipitation was measured in Bad Axe during the 2004 summer growing season (May through August), which is about the same as was measured in Port Hope during the same period. Provisional precipitation totals for 2005 were 30.7 inches for January through November in Port Hope, and about 31.7 inches for the year in Bad Axe. About 10.6 inches of precipitation was measured in Bad Axe during the 2005 summer growing season, which is about 0.2 inches more than was recorded at Port Hope during the same period. Two wells equipped with continuous-data recorders are completed in the Saginaw and Marshall aquifers in Fairhaven and Lake Townships, respectively. From January 2004 through December 2005, the net rise in the water level in the Fairhaven Township well was 0.71 ft, and the net rise in the Lake Township well was 0.98 ft. The Fairhaven Township well is drilled adjacent to Saginaw Bay (Lake Huron), and, as previously noted, there was almost no net change in the water level in Saginaw Bay over the same period. Hydrographs showing water levels are presented for the two wells equipped with continuous-data recorders. Continuous-data recorders were discontinued in the Grant and Bingham Township wells at the end of 2003 due to budget constraints. The decision of which two wells to discontinue was based on an analysis of the intrinsic value to Huron County of data from each well. The Grant Township well was selected for periodic or quarterly measurement at that time because it is completed in the glacial aquifer, which is little used for drinking water purposes or absent in much of Huron County. The Bingham Township well, which is completed in the Marshall aquifer, was selected for periodic or quarterly measurement because water levels in the well are often perturbed as a result of pumpage from nearby production wells and do not reflect baseline conditions within the aquifer. Twenty five wells were measured on a periodic or quarterly basis in 2004-05. These wells are completed in the glacial, Saginaw, and Marshall aquifers, and the Coldwater confining unit. Although each quarterly measurement only provides a “snapshot” water level (measured in feet below land surface), the data adequately define the generalized water-level trend in the aquifer near the well. Water levels in 15 quarterlymeasured wells had a net rise ranging from 0.20 to 1.31 ft for the period from January 2004 to December 2005, while water levels in 10 of the wells had a net decline ranging from 0.07 to 0.99 ft over the same period (fig. 3; table 1). Period-of-record (the time period when water levels have been measured by U.S. Geological Survey or their cooperators) minimum depths to water (high-water levels) were measured in March 2004 in two quarterly-measured wells completed in the Marshall aquifer in Lake and Hume Townships. Period-of-record maximum depths to water were measured in September 2005 in three wells completed in the Marshall aquifer near Bad Axe. Water levels in those three wells recovered about 3 to 5 ft between September and December 2005. No period-of-record minimum or maximum depths to water were measured for the period from January 2004 through December 2005 in wells completed in either the glacial and Saginaw aquifers, or the Coldwater confining unit. Hydrographs showing water levels measured in each well are presented for the 25 wells measured on a quarterly basis. Water-level trends measured for the period from January 2004 through December 2005 in other wells in Lower Michigan have similarities to those measured in Huron County wells. Several external factors influence water-level trends including proximity to nearby production wells, amount and timing of precipitation events, evapotranspiration and type of prevalent ground cover, proximity of aquifer to the surface, and hydraulic characteristics of overlying geologic materials.

Michigan↗

USGS2006

Ground-water levels in Huron County, Michigan, 2004-05

Michigan↗

USGS2013

National assessment of shoreline change: historical shoreline change along the Pacific Northwest coast

Beach erosion is a chronic problem along most open ocean shores of the United States. As coastal populations continue to increase and infrastructure is threatened by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There is also a need for a comprehensive analysis of shoreline movement that is consistent from one coastal region to another. To meet these national needs, the U.S. Geological Survey (USGS) is conducting an analysis of historical shoreline changes along the open-ocean sandy shores of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline movement so that periodic, systematic, and internally consistent updates regarding coastal erosion and land loss can be made nationally. In the case of the analysis of shoreline change in the Pacific Northwest (PNW), the shoreline is the interpreted boundary between the ocean water surface and the sandy beach. This report on the PNW coasts of Oregon and Washington is the seventh in a series of regionally focused reports on historical shoreline change. Previous investigations include analyses and descriptive reports of the U.S. Gulf of Mexico (Morton and others, 2004), the southeastern Atlantic (Morton and Miller, 2005), the sandy shorelines (Hapke and others, 2006) and coastal cliffs (Hapke and Reid, 2007) of California, the New England and mid-Atlantic coasts (Hapke and others, 2011), and parts of the Hawaii coast (Fletcher and others, 2012). Like the earlier reports in this series, this report summarizes the methods of analysis, interprets the results of the analysis, provides explanations regarding long- and short-term trends and rates of shoreline change, and describes how different coastal communities are responding to coastal erosion. This report differs from the early USGS reports in the series in that those shoreline change analyses incorporated only four total shorelines to represent specific time periods. This assessment of the PNW incorporates all available shorelines that meet minimum quality standards for resolution and positional accuracy. Shoreline change evaluations are based on a comparison of historical shoreline positions digitized from maps or aerial photographic data sources with recent shorelines, at least one of which is derived from lidar surveys. The historical shorelines cover a variety of time periods ranging from the 1800s through the 1980s, whereas the lidar shoreline is from 2002. Long-term rates of change are calculated using all available shoreline data and short-term rates of change are calculated using the lidar shoreline and the historical shoreline that will produce an assessment for a 15- to 35-year period. The rates of change presented in this report represent conditions up to the date of only the most recent shoreline data and therefore are not intended for predicting future shoreline positions or rates of change. The PNW coast was subdivided into eight analysis regions for the purpose of graphically reporting regional trends in shoreline change rates. The average rate of long-term shoreline change for the entire PNW coast was 0.9 meter per year (m/yr) of progradation with an uncertainty of 0.07 m/yr. This rate is based on 8,823 individual transects, of which 36 percent was determined to be eroding. Long-term shoreline change was generally more progradational in Washington than in Oregon. This is primarily due to the influence of the Columbia River and human perturbations to the natural system, particularly the construction of jetties at both the mouth of the Columbia River and at Grays Harbor, Washington. The majority of the beaches in southwestern Washington have responded to these large-scale engineered structures by experiencing dramatic beach progradation during the past century. Although these beaches are still responding to the human effects, in several locations beaches that had been rapidly prograding are now either prograding at a slower rate or eroding. The average rate of short-term shoreline change in the PNW was also progradational at a rate of 0.9 m/yr with an uncertainty of 0.03 m/yr. This rate is based on 9,087 individual transects, of which 44 percent was determined to be eroding. Similar to the results of the long-term shoreline change analysis, the shorelines in Washington were typically more progradational than those in Oregon in the short term. However, many stretches of coast in Oregon are either less accretional, changed from accretional to erosional, or more erosional when comparing the long- and short-term rate calculations. In the long and short term, there are significantly different historical shoreline change trends for beaches deriving their modern sediments from the Columbia River in southwestern Washington and northwestern Oregon, and beaches elsewhere in the PNW. The majority of shorelines in Oregon and in Washington’s Olympic Peninsula are not influenced by the human effects to the Columbia River littoral cell and typically have not experienced the human-induced century-scale trends apparent in southwestern Washington and northwestern Oregon. An increase in erosion hazards in much of Oregon may be related to the effects of sea-level rise and increasing storm wave heights. Of importance, particularly in the short term, is the alongshore variability in land uplift rates due to tectonics, which results in an alongshore varying rate of relative sea level rise that appears to at least partially control the regional variability in short-term shoreline change rates. Other climate related processes, such as the occurrence of major El Niño events, also significantly affect the shoreline changes in the region. Major El Niño events elevate monthly mean sea levels by tens of centimeters throughout the winter and produce a shift in the storm tracks, resulting in alongshore redistributions in sand volumes on the beaches, leading to hotspot beach erosion and property losses north of headlands and tidal inlets to bays and estuaries. There are limited modern-day sources of sand to Oregon’s beaches, with much of the sand being relict in having arrived thousands of years ago at a time of lowered sea levels when headlands did not prevent the alongshore movement of the beach sediments, the result being that many beaches today are deficient in sand volumes and therefore do not provide sufficient buffer protection to backshore properties during winter storms.

Oregon;Washington↗

USGS2000

Methodology, data collection, and data analysis for determination of water-mixing patterns induced by aerators and mixers

The U.S. Geological Survey collected and analyzed data to describe mixing patterns induced by aerators and mixers to aid in the calibration and verification of a three-dimensional hydrodynamic model. During September 1995, three-dimensional water-velocity profiles were collected during the operation of fine-bubble and coarse-bubble aerators in a test tank at the U.S. Army Corps of Engineers Waterways Experiment Station. Three-dimensional water velocity, water-temperature, pH, dissolved oxygen concentration, and specific conductivity profiles were collected during operation of a coarse-bubble aerator in a reservoir in Schaumburg, Illinois, during summer 1996 and summer 1997, during strongly stratified and weakly stratified conditions. The effects of a submersible mixer alone and in combination with coarse-bubble aerators and a surface mixer alone also were investigated during summer 1997. The mixing patterns induced by the operation of aerators, submersible mixers, and surface mixers were described and compared with mixing patterns predicted by model simulations. Bubble-plume characteristics during tests in strongly stratified and weakly stratified conditions in the reservoir were documented and compared with characteristics simulated by different models. Lemckert and Imberger?s model simulates an entrainment rate similar to the rate measured during a test in the reservoir under strongly stratified conditions, whereas Schladow?s one-dimensional model appears to underestimate the total entrainment rate by about 50 percent. Schladow?s model was accurate during weak stratification but underestimated the radius of the plume during strong stratification. For 5 days during daylight hours, water temperature profiles were collected continuously during the operation of four aerators. Water temperatures in the reservoir were significantly affected by the operation of the aeration system. These changes were compared to simulations from a one-dimensional Dynamic Lake Model (DLM) simulation. DLM accurately simulated changes as a result of aeration, including daily changes. On the basis of temporal and spatial dissolved oxygen measurements, the volumetric quantity of oxygen in the reservoir was quantified before and after operation of a submersible mixer. A net loss of oxygen was calculated. This net loss may have resulted from a net warming of water throughout the reservoir or submerged supersaturated water releasing oxygen when the water came in contact with the atmosphere.

Water-Resources Investigations Report↗

USGS2014

11.12 - Volatile hydrocarbons and fuel oxygenates

Petroleum hydrocarbons and fuel oxygenates are among the most commonly occurring and widely distributed contaminants in the environment. This chapter presents a summary of the sources, transport, fate, and remediation of volatile fuel hydrocarbons and fuel additives in the environment. Much research has focused on the transport and transformation processes of petroleum hydrocarbons and fuel oxygenates, such as benzene, toluene, ethylbenzene, and xylenes and methyl tert‐butyl ether, in groundwater following release from underground storage tanks. Natural attenuation from biodegradation limits the movement of these contaminants and has received considerable attention as an environmental restoration option. This chapter summarizes approaches to environmental restoration, including those that rely on natural attenuation, and also engineered or enhanced remediation. Researchers are increasingly combining several microbial and molecular-based methods to give a complete picture of biodegradation potential and occurrence at contaminated field sites. New insights into the fate of petroleum hydrocarbons and fuel additives have been gained by recent advances in analytical tools and approaches, including stable isotope fractionation, analysis of metabolic intermediates, and direct microbial evidence. However, development of long-term detailed monitoring programs is required to further develop conceptual models of natural attenuation and increase our understanding of the behavior of contaminant mixtures in the subsurface.

Book chapter↗

USGS2024

Joint Agency Commercial Imagery Evaluation (JACIE)

The Joint Agency Commercial Imagery Evaluation (JACIE) was formed to leverage resources from several Federal agencies for the characterization of remote sensing data and to share those results across the remote sensing community (U.S. Geological Survey, 2024). Remote sensing data and the quality of that data are vital to (1) understanding the physical world and (2) supporting the science and engineering applications that strive to advance that understanding. The growing number of remotely sensed data sources offers users more choices. Understanding the characteristics and capabilities of current and new data sources, along with the quality of data they provide, is an important function of the multi-agency JACIE team. By performing data-quality analysis of civil and commercial remote sensing data and information products, the JACIE team provides the remote sensing community with awareness and independent verification of image data quality.

Fact Sheet↗

USGS2023

Potentiometric surface map of the Southern High Plains aquifer in the Cannon Air Force Base area, Curry County, New Mexico, 2020

Declining water levels and the potential impact on water resources on and around Cannon Air Force Base (AFB), New Mexico, has necessitated an up-to-date review of the potentiometric surface to evaluate the availability of water resources for future use. Analysis of groundwater-flow directions and hydraulic gradients can provide an understanding of depletion by heavy groundwater pumping and recharge through playa lakes, as well as the relationship between the groundwater levels and underlying geology. The objectives of this study, conducted by the U.S. Geological Survey in cooperation with the U.S. Air Force Civil Engineer Center, are to assist Cannon AFB in understanding and interpreting current and local hydrologic conditions and to evaluate groundwater-level change from 2015 to 2020 using new and historical data. A groundwater potentiometric surface contour map was constructed to better understand the Southern High Plains aquifer around Cannon AFB and to show the altitude of the water-table surface and groundwater-flow patterns. Four hydrographs were created from periodic measurements of groundwater levels in wells on and around Cannon AFB to provide information about historical groundwater-level changes and visualize trends from the water-level records. The long-term trend present in all four hydrographs is a steady decline in groundwater levels, with some areas declining faster than others. The groundwater-level change map presented in this study provides a visual representation of the change in groundwater level from the winter 2015 to winter 2020 measuring events. Results show that among corresponding wells measured in 2015 and 2020, 50.7 percent indicated a decline in water levels, 29.9 percent indicated neutral water levels, and 19.4 percent indicated a rise in water levels. The region to the north of the groundwater trough on Cannon AFB contained most of the groundwater-level rises, whereas the regions located near the trough and just west of Clovis, N. Mex., contained most of the declines. These results suggest that continued monitoring of declining groundwater levels in the area would provide valuable decision-support information for assessing the sustainability of this water resource.

New Mexico↗

USGS2005

Southern California — Wildfires and debris flows

Wildland fires are inevitable in the western United States. Expansion of man-made developments into fire-prone wildlands has created situations where wildfires can destroy lives and property, as can the flooding and debris flows that are common in the aftermath of the fires. Fast-moving, highly destructive debris flows triggered by intense rainfall are one of the most dangerous post-fire hazards. Such debris flows are particularly dangerous because they tend to occur with little warning. Their mass and speed make them particularly destructive: debris flows can strip vegetation, block drainages, damage structures, and endanger human life. The U.S. Geological Survey’s Landslide Hazards Program is participating in a multi-agency cooperative effort to investigate debris flows in burned areas of southern California and other parts of the western United States. Participating agencies are the USDA Forest Service, the Natural Resources Conservation Service, and the California, Colorado, and Montana Geological Surveys. The objective of this project is to develop methods needed to estimate the locations, probability of occurrence, and size of potentially destructive debris flows. Public officials can use this information to plan and execute emergency response and post-fire rehabilitation. Analysis of data collected from studies of debris flows following wildfires can answer many of the questions fundamental to post-fire hazard assessments— what and why, where, when, how big, and how often?

California↗

USGS2008

A Study of the Connection Among Basin-Fill Aquifers, Carbonate-Rock Aquifers, and Surface-Water Resources in Southern Snake Valley, Nevada

The Secretary of the Interior through the Southern Nevada Public Lands Management Act approved funding for research to improve understanding of hydrologic systems that sustain numerous water-dependent ecosystems on Federal lands in Snake Valley, Nevada. Some of the streams and spring-discharge areas in and adjacent to Great Basin National Park have been identified as susceptible to ground-water withdrawals (Elliott and others, 2006) and research has shown a high potential for ground-water flow from southern Spring Valley into southern Snake Valley through carbonate rocks that outcrop along a low topographic divide known as the Limestone Hills (Welch and others, 2007). Comprehensive geologic, hydrologic, and chemical information will be collected and analyzed to assess the hydraulic connection between basin-fill aquifers and surface-water resources, water-dependent ecological features, and the regional carbonate-rock aquifer, the known source of many high-discharge springs. Understanding these connections is important because proposed projects to pump and export ground water from Spring and Snake Valleys in Nevada may result in unintended capture of water currently supplying springs, streams, wetlands, limestone caves, and other biologically sensitive areas (fig. 1). The methods that will be used in this study may be transferable to other areas in the Great Basin. The National Park Service, Bureau of Land Management, U.S. Fish and Wildlife Service, and U.S. Forest Service submitted the proposal for funding this research to facilitate science-based land management. Scientists from the U.S. Geological Survey (USGS) Water Resources and Geologic Disciplines, and the University of Nevada, Reno, will accomplish four research elements through comprehensive data collection and analysis that are concentrated in two distinct areas on the eastern and southern flanks of the Snake Range (fig. 2). The projected time line for this research is from July 2008 through September 2011.

Fact Sheet↗