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USGS2015

Effects of Hydrocarbon Extraction on Landscapes of the Appalachian Basin

An important and sometimes overlooked aspect of contemporary natural gas exploration, development, and delivery activities is the geographic profile and spatial footprint that these activities have on the land surface. The function of many ecosystems and the goods and services they provide, in large part, are the result of their natural spatial arrangement on the landscape. Shale-gas development can create alterations to the pattern of land use and land cover, and represents a specific form of land use and land cover change that can substantially impact critical aspects of the spatial pattern, form, and function of landscape interactions, including many biological responses. The need for energy resources has created numerous economic opportunities for hydrocarbon extraction in the Appalachian basin. The development of alternative energy natural gas resources from deep-shale drilling techniques, along with conventional natural gas extraction methods, has created a flurry of wells, roads, pipelines, and related infrastructure across many parts of the region. An unintended and sometimes overlooked consequence of these activities is their effect on the structure and function of the landscape and ecosystems. The collective effect of over 100,000 hydrocarbon extraction permits for oil, coal bed methane, Marcellus and Utica Shale natural gas wells, and other types of hydrocarbon gases and their associated infrastructure has saturated much of the landscape and disturbed the natural environment in the Appalachian basin. The disturbance created by the sheer magnitude of the development of these collective wells and infrastructure directly affects how the landscape and ecosystems function and how they provide ecological goods and services.

New York, Ohio, Pennsylvania, Virginia, West Virgi↗

USGS2002

Occurrence of invertebrates at 38 stream sites in the Mississippi Embayment study unit, 1996-99

A total of 88 invertebrate species and 178 genera representing 59 families, 8 orders, 6 classes, and 3 phyla was identified at 38 stream sites in the Mississippi Embayment Study Unit from 1996 through 1999 as part of the National Water-Quality Assessment Program. Sites were selected based on land use within the drainage basins and the availability of long-term streamflow data. Invertebrates were sampled as part of an overall sampling design to provide information related to the status and trends in water quality in the Mississippi Embayment Study Unit, which includes parts of Arkansas, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee. Invertebrate sampling and processing was conducted using nationally standardized techniques developed for the National Water-Quality Assessment Program. These techniques included both a semi-quantitative method, which targeted habitats where invertebrate diversity is expected to be highest, and a qualitative multihabitat method, which samples all available habitat types possible within a sampling reach. All invertebrate samples were shipped to the USGS National Water-Quality Laboratory (NWQL) where they were processed. Of the 365 taxa identified, 156 were identified with the semi-quantitative method that involved sampling a known quantity of what was expected to be the richest habitat, woody debris. The qualitative method, which involved sampling all available habitats, identified 345 taxa The number of organisms identified in the semi-quantitative samples ranged from 74 to 3,295, whereas the number of taxa identified ranged from 9 to 54. The number of organisms identified in the qualitative samples ranged from 42 to 29,634, whereas the number of taxa ranged from 18 to 81. From all the organisms identified, chironomid taxa were the most frequently identified, and plecopteran taxa were among the least frequently identified.

Open-File Report↗

USGS2017

Mapping land cover through time with the Rapid Land Cover Mapper—Documentation and user manual

The Rapid Land Cover Mapper is an Esri ArcGIS® Desktop add-in, which was created as an alternative to automated or semiautomated mapping methods. Based on a manual photo interpretation technique, the tool facilitates mapping over large areas and through time, and produces time-series raster maps and associated statistics that characterize the changing landscapes. The Rapid Land Cover Mapper add-in can be used with any imagery source to map various themes (for instance, land cover, soils, or forest) at any chosen mapping resolution. The user manual contains all essential information for the user to make full use of the Rapid Land Cover Mapper add-in. This manual includes a description of the add-in functions and capabilities, and step-by-step procedures for using the add-in. The Rapid Land Cover Mapper add-in was successfully used by the U.S. Geological Survey West Africa Land Use Dynamics team to accurately map land use and land cover in 17 West African countries through time (1975, 2000, and 2013).

Open-File Report↗

USGS1981

E-field ratio telluric survey near the Big Maria Mountains, Riverside County, California

The U.S. Geological Survey (USGS) under the Wilderness Act (Public Law 88-577) and the Federal Land Policy and Management Act (Public Law 94-579) has the responsibility, along with the U.S. Bureau of Mines, to survey certain areas in order to determine their mineral resource potential. This report presents results of three electric-field ratio telluric traverses conducted as part of the Bureau of Land Management Wilderness Program in the Big Maria Mountains, Riverside County, Calif. The telluric traverses were run on the southwest side of the Big Maria Mountains in an attempt to define the location of major buried faults near the eroded front of the range. E-field ratio tellurics is a descriptive name applied to the electrical exploration technique used in this survey. The telluric method refers to the measurement of the earth's electric field generated by induction from natural electromagnetic waves arriving at the surface. The E-field ratio telluric method uses a receiving array of three electrodes spaced equidistant and inline. This array is, in effect, two colinear dipoles sharing a common electrode. The potential difference across each dipole is then proportional to the component of the telluric field in the direction of the array. This configuration permits the measurement of the ratio of the telluric field at each dipole in the direction of the dipole line, and hence the name. The traverse data is extended by moving the three-electrode array forward one dipole length so that the forward electrode becomes the center electrode for the next ratio measurement. Electric-field data so obtained are proportional to the square root of the apparent resistivity of the earth at the location of the dipoles. However, because the apparent resistivity can be a function of the dipole direction, it is important to know the orientation of the dipoles with respect to major structures. Because the resistivity of fluid-saturated earth materials is largely dependent on the porosity of the rocks, the salinity of the pore fluid, and the presence of clays or similar material where surface conduction is high, alluvial fill, argillite and similar rocks tend to have low resistivities whereas igneous or high-grade metamorphic rocks have high resistivities. Variation in the electrical properties along a traverse may then be used to infer lithologic or structural changes.

California↗

USGS1988

Streamflows in Wyoming

A description of the occurrence and availability of surface waters in Wyoming is presented along with explanations of both streamflow-data collection and methods for estimating streamflow characteristics at gaged and ungaged sites. Mountain ranges separate the major drainage basins and have a significant effect on the quantity of precipitation and the volume of runoff that occurs in Wyoming. Perennial streams that originate in the mountains provide the most dependable source of runoff; streams that originate in the plains and deserts generally are intermittent or ephemeral and have extended periods of no flow. Streamflow data for several hundred gaged sites in the State are available for engineering and management purposes. When gaged data are not available, methods for estimating streamflow characteristics are needed. Methods presented in this report for estimating streamflow characteristics have been improved over previous methods through the use of refined analytical techniques and an updated data base. Peak-flow characteristics and mean annual runoff at ungaged sites can be estimated by using regression equations, with either basin characteristics or channel width being independent variables. Log-linear regression equations are used for estimating streamflow characteristics in the mountains; whereas, curvilinear equations of double-exponential form were determined to be more appropriate than log-linear relations for depicting peak flows in the plains and deserts. (USGS)

Water-Resources Investigations Report↗

USGS1978

Effectiveness of sediment-control techniques used during highway construction in central Pennsylvania

A different method for controlling erosion and sediment transport during highway construction was used in each of four adjacent drainage basins in central Pennsylvania. The basins ranged in size from 240 to 490 acres (97 to 198 hectares), and the area disturbed by highway construction in each basin ranged from 20 to 48 acres (8 to 19 hectares). Sediment discharge was measured from each basin for 3 years before construction began and for 2 years during construction. In one of the basins affected by the construction, three offstream ponds were constructed to intercept runoff from the construction area before it reached the stream. In another basin, a large onstream pond was constructed to trap runoff from the construction area after it reached the stream. In a third area, seeding, mulching, and rock dams were used to limit erosion. In the fourth area, no sediment controls were used. The effectiveness of the various sediment-control measures were determined by comparing the sediment loads transported from the basins with sediment controls to those without controls. For most storms the offstream ponds trapped about 60 percent of the sediment that reached them. The large onstream pond had a trap efficiency of about 80 percent, however, it remained turbid and kept the stream flow turbid for long periods following storm periods. Samples of runoff water from the construction area were collected above and below rock dams to determine the reduction in sediment as the flow passed through the device. Rock dams in streams had a trap efficiency of about 5 percent. Seeding and mulching may reduce sediment discharge by 20 percent during construction, and straw bales placed to trap runoff water may reduce sediment loads downstream by 5 percent.

Water Supply Paper↗

USGS2009

Improving the design of amphibian surveys using soil data: A case study in two wilderness areas

Amphibian populations are known, or thought to be, declining worldwide. Although protected natural areas may act as reservoirs of biological integrity and serve as benchmarks for comparison with unprotected areas, they are not immune from population declines and extinctions and should be monitored. Unfortunately, identifying survey sites and performing long-term fieldwork within such (often remote) areas involves a special set of problems. We used the USDA Natural Resource Conservation Service Soil Survey Geographic (SSURGO) Database to identify, a priori, potential habitat for aquatic-breeding amphibians on North and South Manitou Islands, Sleeping Bear Dunes National Lakeshore, Michigan, and compared the results to those obtained using National Wetland Inventory (NWI) data. The SSURGO approach identified more target sites for surveys than the NWI approach, and it identified more small and ephemeral wetlands. Field surveys used a combination of daytime call surveys, night-time call surveys, and perimeter surveys. We found that sites that would not have been identified with NWI data often contained amphibians and, in one case, contained wetland-breeding species that would not have been found using NWI data. Our technique allows for easy a priori identification of numerous survey sites that might not be identified using other sources of spatial information. We recognize, however, that the most effective site identification and survey techniques will likely use a combination of methods in addition to those described here.

Natural Areas Journal↗

USGS2019

Streambed flux measurement informed by distributed temperature sensing leads to a significantly different characterization of groundwater discharge

Groundwater discharge though streambeds is often focused toward discrete zones, indicating that preliminary reconnaissance may be useful for capturing the full spectrum of groundwater discharge rates using point-scale quantitative methods. However, many direct-contact reconnaissance techniques can be time consuming, and remote sensing (e.g. thermal infrared) typically does not penetrate the water column to locate submerged seepages. In this study we tested whether dozens of groundwater discharge measurements made at "uninformed" (i.e., selected without knowledge on high-resolution temperature variations at the streambed) point locations along a reach would yield significantly different Darcy-based groundwater discharge rates when compared with “informed” measurements, focused at streambed thermal anomalies that were identified a-priori using fiber-optic distributed temperature sensing (FO-DTS). A non-parametric U-test showed a significant difference between median discharge rates for uninformed (0.05 m·d-1; n = 30) and informed (0.17 m·d-1; n = 20) measurement locations. Mean values followed a similar pattern (0.12 versus 0.27 m·d-1) and frequency distributions for uninformed and informed measurements were also significantly different based on a Kolmogorov-Smirnov test. Results suggest that even using a quick “snapshot-in-time” field analysis of FO-DTS data can be useful in streambeds with groundwater discharge rates <0.2 m·d-1, a lower threshold than proposed in a previous study. Collectively, study results highlight that FO-DTS is a powerful technique for identifying higher-discharge zones in streambeds, but the pros and cons of informed and uninformed sampling depend in part on groundwater/surface water exchange study goals. For example, studies focused on measuring representative groundwater and solute fluxes may be biased if high-discharge locations are preferentially sampled. However, identification of high-discharge locations may complement more randomized sampling plans and lead to improvements in interpolating streambed fluxes and upscaling point measurements to the stream reach scale.

Nebraska↗

USGS2013

Habitat, wildlife and one health: Arcanobacterium pyogenes in Maryland and Upper Eastern Shore white-tailed deer populations

Background : Understanding the distribution of disease in wildlife is key to predicting the impact of emerging zoonotic one health concerns, especially for wildlife species with extensive human and livestock interfaces. The widespread distribution and complex interactions of white - tailed deer ( Odocoileus virginianus ) with humans suggest deer population health and management may have implications beyond stewardship of the animals. The intracranial abscessation suppurative meningitis (IASM) disease complex in deer has been linked to Arcanobacterium pyogenes , an under - diagnosed and often misdiagnosed organism considered commensal in domestic livestock but associated with serious disease in numerous species, including humans. Methods : Our study used standard bacterial culture techniques to assess A. pyogenes prevalence among male deer sampled across six physiogeographic regions in Maryland and male and female deer in the Upper Eastern Shore under Traditional Deer Management (TDM) and Quality Deer Management (QDM), a management protocol that alters population demographics in favor of older male deer. Samples were collected from antler pedicles for males, the top of the head where pedicles would be if present for females, or the whole dorsal frontal area of the head for neonates. We collected nasal samples from all animals by swabbing the nasopharyngeal membranes. A gram stain and catalase test were conducted, and aerobic bacteria were identified to genus and species when possible. We evaluated the effect of region on whether deer carried A. pyogenes using Pearson's chi-square test with Yates’ continuity correction. For the white-tailed deer management study, we tested whether site, age class and sex predisposed animals to carrying A. pyogenes using binary logistic regression. Results : A. pyogenes was detected on deer in three of the six regions studied, and was common in only one region, the Upper Eastern Shore. In the Upper Eastern Shore, 45% and 66% of antler and nasal swabs from deer were positive for A. pyogenes , respectively. On the Upper Eastern Shore, prevalence of A. pyogenes cultured from deer did not differ between management areas, and was abundant among both sexes and across all age classes. No A. pyogenes was cultured from a small sample of neonates. Conclusion : Our study indicates A. pyogenes may be carried widely among white-tailed deer regardless of sex or age class, but we found no evidence the pathogen is acquired in utero. The distribution of A. pyogenes across regions and concentration in a region with low livestock levels suggests the potential for localized endemicity of the organism and the possibility that deer may serve as a maintenance reservoir for an emerging one health concern.

Infection Ecology and Epidemiology↗

USGS2021

Calcite U-Pb dating unravels the age and hydrothermal history of the giant Shuiyindong Carlin-type gold deposit in the Golden Triangle, south China

The ages of Carlin-type gold deposits in the Golden Triangle of South China have long been questioned due to the general lack of minerals unequivocally linked to gold deposition that can be precisely dated using conventional radiogenic isotope techniques. Recent advances in U-Pb methods show that calcite can be used to constrain the ages of hydrothermal processes, but few studies have been applied to ore deposits. Herein, we show that this approach can be used to constrain the timing of hydrothermal activity that generated and overprinted the giant Shuiyindong Carlin-type gold deposit in the Golden Triangle. Three stages of calcite (Cal-1, Cal-2, and Cal-3) have been recognized in this deposit based on crosscutting relationships, cathodoluminescence colors, and chemical (U, Pb, and rare earth element [REE]) and isotope (C, O, Sr) compositions. Cal-1 is texturally associated with ore-stage jasperoid and disseminated Au-bearing arsenian pyrite in hydrothermally altered carbonate rocks, which suggests it is synmineralization. Cal-2 fills open spaces and has a distinct orange cathodoluminescence, suggesting that it precipitated during a second fluid pulse. Cal-1 and Cal-2 have similar carbonate rock-buffered chemical and isotopic compositions. Cal-3 occurs in veins that often contain realgar and/or orpiment and are chemically (low U, Pb, and REE) and isotopically (higher δ 13 C, lower δ 18 O and Sr i values) distinct from Cal-1 and Cal-2, suggesting that it formed from a third fluid. U-Pb isotope analyses, by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) for U-rich Cal-1 and Cal-2 and by LA-multicollector (MC)-ICP-MS for U-poor Cal-3, yield well-defined age constraints of 204.3 to 202.6, 191.9, and 139.3 to 137.1 Ma for Cal-1, Cal-2, and Cal-3, respectively. These new ages suggest that the Shuiyindong gold deposit formed in the late Triassic and was overprinted by hydrothermal events in the early Jurassic and early Cretaceous. Given the association of Cal-3 with orpiment and realgar, and previous geochronologic studies of several other major gold deposits in the Golden Triangle, we infer that the latest stage of calcite may be associated with an early Cretaceous regional gold metallogenic event. Combined with existing isotopic ages in the region, these new ages lead us to propose that Carlin-type gold deposits in the Golden Triangle formed during two metallogenic episodes in extensional settings, associated with the late Triassic Indochina orogeny and early Cretaceous paleo-Pacific plate subduction. This study shows that the calcite U-Pb method can be used to constrain the timing of Carlin-type gold deposits and successive hydrothermal events.

Golden Triangle, south China↗

USGS2005

Rainfall-runoff in the Albuquerque, New Mexico, area: Measurements, analyses and comparisons

Albuquerque, New Mexico, has experienced significant growth over the last 20 years like many other cities in the Southwestern United States. While the US population grew by 37% between the 1970 and 2000 censuses, the growth for Albuquerque was 83%. More people mean more development and increased problems of managing runoff from urbanizing watersheds. The U.S. Geological Survey (USGS) in cooperation with the Albuquerque Arroyo Metropolitan Flood Control Authority (AMAFCA) and the City of Albuquerque has maintained a rainfall-runoff data collection program since 1976. The data from measured precipitation events can be used to verify hydrologic modeling. In this presentation, data from a representative gaged watershed is analyzed and discussed to set the overall framework for the rainfall-runoff process in the Albuquerque area. Of particular interest are the basic relationships between rainfall and watershed runoff response and an analysis of curve numbers as an indicator of runoff function. In urbanized areas, four land treatment types (natural, irrigated lawns, compacted soil, and impervious) are used to define surface infiltration conditions. Rainfall and runoff gage data are used to compare curve number (CN) and initial abstraction/uniform infiltration (IA/INF) techniques in an Albuquerque watershed. The IA/INF method appears to produce superior results over the CN method for the measured rainfall events.

Conference Paper↗

USGS2008

Joint inversion of fundamental and higher mode Rayleigh waves

In this paper, we analyze the characteristics of the phase velocity of fundamental and higher mode Rayleigh waves in a six-layer earth model. The results show that fundamental mode is more sensitive to the shear velocities of shallow layers (< 7 m) and concentrated in a very narrow band (around 18 Hz) while higher modes are more sensitive to the parameters of relatively deeper layers and distributed over a wider frequency band. These properties provide a foundation of using a multi-mode joint inversion to define S-wave velocity. Inversion results of both synthetic data and a real-world example demonstrate that joint inversion with the damped least squares method and the SVD (Singular Value Decomposition) technique to invert Rayleigh waves of fundamental and higher modes can effectively reduce the ambiguity and improve the accuracy of inverted S-wave velocities.

Chinese Journal of Geophysics (Acta Geophysica Sin↗

USGS1978

Tectonomagnetic effects

Measurements of the actual stress within the Earth and its changes with time are very difficult. It is much easier to monitor the direct effects of this stress, such as ground strain, or the indirect effects, such as changes in resistivity, strain, changes in seismic velocity or changes in magnetic field, and so forth. The latter technique is one of the more promising methods for monitoring substantial volumes of the Earth's crust near active faults with only a few instruments. It derives from the piezomagnetic properties of rocks (that is, the change in rock magnetization and, therefore, local magnetic field due to a change in applied stress). AS stress and strain fields along active faults vary, these variations should be reflected in changing local magnetic fields. In particular, rapidly changing fields might be expected to occur just before a large earthquake. We know that earthquakes result from the sudden release of elastic strain, the end product, most likely, of a long period of gradual stress accumulation in the crust. At the U.S Geological Survey, our magnetic fields studies have two main directions. First, a determination of the magnetic behavior accompanying shallow earthquakes (seismomagnetic effects). Second, a long-term monitoring of the magnetic field in the vicinity of an active fault to detect magnetic changes due to general tectonic activity, particularly that which ultimately leads to earthquakes. These magnetic changes are generally termed "tectonomagnetic effects."

Earthquake Information Bulletin (USGS)↗

USGS2016

Efficacy of spray –Dried Pseudomonas fluorescens, strain CL145A (Zequanox®), for controlling Zebra Mussels ( Dreissena polymorpha ) within Lake Minnetonka, MN enclosures

The efficacy of whole water column and subsurface applications of the biopesticide Zequanox®, a commercially prepared spray-dried powder formulation of Pseudomonas fluorescens (strain CL145A), were evaluated for controlling zebra mussels (Dreissena polymorpha) within 27-m2 enclosures in Lake Minnetonka (Deephaven, Minnesota). Five treatments consisting of (1) two whole water column Zequanox applications, (2) two subsurface Zequanox applications, and (3) an untreated control were completed on each of three independent treatment days during September 2014. The two types of samplers used in the study were (1) type 1 samplers, which were custom built multi-plate samplers (wood, perforated aluminum, and tile substrates) that were placed into Robinson’s Bay in June of 2013 to allow for natural colonization by zebra mussels, and (2) type 2 samplers, which consisted of zebra mussels adhering to perforated aluminum trays that were placed into mesh containment bags. One day prior to treatment, three individual samplers of each type were distributed to test enclosures and exposed to a randomly assigned treatment. Sampling to determine the zebra mussel biomass adhering to type 1 samplers and the survival assessments for zebra mussels contained in type 2 samplers were completed ~40 days after exposure. The zebra mussel biomass adhering to type 1 samplers and the survival of zebra mussels contained in type 2 samplers were significantly less in groups treated with the highest Zequanox concentrations and in groups that received whole water column applications than comparable groups treated with lower Zequanox concentrations and subsurface applications. However, standardization of biomass and survival results to the amount of Zequanox applied showed that the lower concentrations and subsurface applications were more cost efficient, with respect to product used, at reducing zebra mussel biomass and for inducing zebra mussel mortality. Although the subsurface application methods and lower treatment concentrations were more cost efficient, biological significance and management goals should be evaluated prior to selecting the application method. Development and refinement of additional application techniques may improve the utility of the subsurface Zequanox applications.

Report↗

USGS1981

Strains of infectious hematopoietic necrosis (IHN) virus may be identified by structural protein differences

The development of an effective vaccine to infectious hematopoietic necrosis virus (IHNV) in fish requires a knowledge of the virus serotypes in nature. At least two serotypes were found among three IHNV strains (12). Attempts in our laboratory to extend this study with additional virus strains by classical immunological techniques were unsatisfactory. Thus, we sought another method for comparing IHNV strains. We report here that different strains of IHNV can be distinguished by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the viron polypeptides. Major strain differences were noted in the molecular weights of the envelope glycoprotein, G, and the nucleocapsid protein, N. The strains of IHNV were established from samples taken at several locations in California, Oregon, Washington, and Alaska. These strains were also characterized by growth rate at 15° and 18°C and average plaque size. Distinct differences in growth rate at the two temperatures were found for the California strains. The California strains were distinguished from the other strains by the production of minute plaques.

Developments in Biological Standardization↗

USGS2022

UAS-based tools for mapping and monitoring hydrothermal systems: An example from Mammoth Lakes, California

Unoccupied Aerial Systems (UAS) can accommodate a variety of tools for mapping and monitoring hydrothermal systems (e.g., magnetic, gas, photogrammetry, and thermal infrared [TIR]). These platforms offer increased speed, coverage area, and uniformity compared to ground-based measurements, as well as lower flight height – and therefore higher resolution – than occupied aircraft. We adapted a suite of tools for use with UAS and implemented these methods in a study focused on the area around Shady Rest Park, Mammoth Lakes, California, within the Long Valley Caldera. This location, which contains tree kills, gas vents, soil gas emissions, heated ground, and hydrothermal alteration, is the site of ongoing efforts to monitor changes in the surface expression of the local hydrothermal system. The methods applied in this study include: (1) airborne visible imagery for surficial mapping and the creation of high-resolution digital elevation models; (2) airborne magnetic measurements; (3) airborne TIR imagery; (4) airborne gas emission measurements; and (5) ground-based gravity measurements. We conducted these surveys in May and October of 2021, in part to establish baseline TIR and gas data against which future changes to the hydrothermal system may be assessed. UAS-based magnetic and ground-based gravity data were collected to map subsurface geology and to characterize potential subsurface controls on thermal anomalies and gas emissions. Results of these efforts at mapping and monitoring the hydrothermal system at Mammoth Lakes demonstrate how an integrated UAS- and ground-based approach may be applied more broadly to study other known or potential hydrothermal and volcanic systems. We consider the benefits and limitations of each method, particularly the TIR and gas sensors, which have less well-developed processing techniques in place for UAS applications. By integrating results from several of these different methods, however, the limitations facing each individual approach may be mitigated, and a better understanding of the hydrothermal system may be reached.

California↗

USGS2004

Geophysical techniques in detection to river embankments - A case study: To locate sites of potential leaks using surface-wave and electrical methods

Geophysical technologies are very effective in environmental, engineering and groundwater applications. Parameters of delineating nature of near-surface materials such as compressional-wave velocity, shear-wave velocity can be obtained using shallow seismic methods. Electric methods are primary approaches for investigating groundwater and detecting leakage. Both of methods are applied to detect embankment in hope of obtaining evidences of the strength and moisture inside the body. A technological experiment has done for detecting and discovering the hidden troubles in the embankment of Yangtze River, Songzi, Hubei, China in 2003. Surface-wave and DC multi-channel array resistivity sounding techniques were used to detect hidden trouble inside and under dike like pipe-seeps. This paper discusses the exploration strategy and the effect of geological characteristics. A practical approach of combining seismic and electric resistivity measurements was applied to locate potential pipe-seeps in embankment in the experiment. The method presents a potential leak factor based on the shear-wave velocity and the resistivity of the medium to evaluate anomalies. An anomaly found in a segment of embankment detected was verified, where occurred a pipe-seep during the 98' flooding.

Conference Paper↗

USGS1977

Technique for estimating depth of 100-year floods in Tennessee

Preface: A method is presented for estimating the depth of the loo-year flood in four hydrologic areas in Tennessee. Depths at 151 gaging stations on streams that were not significantly affected by man made changes were related to basin characteristics by multiple regression techniques. Equations derived from the analysis can be used to estimate the depth of the loo-year flood if the size of the drainage basin is known.

Open-File Report↗