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Since 1997, repeated, coincident geophysical surveys and extensive hydrologic studies in shallow monitoring wells have been used to study static and dynamic processes associated with surface water-groundwater interaction at a range of spatial scales at the estuarine and ocean boundaries of an undeveloped, permeable barrier island in the Georgia part...

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This chapter describes and discusses laboratory and field techniques for studying microbial transport behavior in aquifer materials and model porous media. Changes in ionic strength (I) during transport studies may occur inadvertently as a result of using halides as conservative tracers and may lead to density-induced sinking of the tracer...

Many studies have examined the differences in bacterial numbers, composition, and activity between groundwater and sediment samples. The majority of the literature has suggested higher percentages of attached bacteria than of unattached bacteria in aquifer systems, including in pristine aquifers and in aquifers contaminated with petroleum, creosote, sewage, and landfill...

No abstract available. ...

This chapter contains sections titled:IntroductionMirror Lake SiteFractures and Geologic MappingHydraulic Properties of Fractured Rock From Meters to KilometersChemical Migration in Fractured RockFracture Controls on Ground‐Water Flow and Chemical Transport at the Mirror Lake SiteSummary...

The interactions between playa hydrology and playa-surface sediments are important factors that control the type and amount of dust emitted from playas as a result of wind erosion. The production of evaporite minerals during evaporative loss of near-surface ground water results in both the creation and maintenance of several centimeters...

Created wetlands are increasingly used to mitigate wetland loss. Thus, identifying wetland creation methods that enhance ecosystem development might increase the likelihood of mitigation success. Noting that the microtopographic variation found in natural wetland settings may not commonly be found in created wetlands, this study explores relationships between induced microtopography,...

Scientific uncertainties often make it difficult for environmental policy makers to determine how to communicate risks to the public. A constructive, holistic, multisectoral dialogue about an issue can improve understanding of uncertainties from different perspectives and clarify options for risk communication. Many environmental issues could benefit from explicit promotion of...

This document discusses results of applying the Integrated Ground-Water Monitoring Strategy (the Strategy) to actual waste sites using existing field characterization and monitoring data. The Strategy is a systematic approach to dealing with complex sites. Application of such a systematic approach will reduce uncertainty associated with site analysis, and therefore...

Current analytical capabilities are allowing scientists to identify possible contaminants in the environment that were previously unmonitored or were present at concentrations too low for detection. New scientific evidence about the exposure pathways and potential impacts of some of these compounds on human or environmental health is regularly being published...

Historical production of metals in the western United States has left a legacy of acidic drainage and toxic metals in many mountain watersheds that are a potential threat to human and ecosystem health. Studies of the effects of historical mining on surface water chemistry and riparian habitat in the Animas...

Arsenic (As) distribution and toxicology in the environment is a serious issue, with millions of individuals worldwide being affected by As toxicosis. Sources of As contamination are both natural and anthropogenic and the scale of contamination ranges from local to regional. There are many areas of research that are...

In situ reductive dechlorination of perchloroethene (PCE) and trichloroethene (TCE) generates characteristic chlorinated (cis-dichloroethene [cis-DCE] and vinyl chloride [VC]) and nonchlorinated (ethene and ethane) products. The accumulation of these daughter products is commonly used as a metric for ongoing biodegradation at field sites. However, this interpretation assumes that reductive dechlorination...

Sorption of sulfamethazine (SMN) and sulfathiazole (STZ) was investigated in three soils, a North Carolina loamy sand, an Iowa sandy loam, and a Missouri loam, under various pH conditions. A significant increase in the sorption coefficient (KD) was observed in all three soils, as the sulfonamides converted from an anionic...

The mid-1970s marked a major turning point in human history, for it was at that moment that the ability of the Earth’s ecosystems to absorb most of the biological impacts of human activities appears to have been exceeded by the magnitude of those impacts. This conclusion is based partly upon...

Hurricanes and tropical storms are critical components of the south Florida hydrologic cycle. These storms cause dramatic and often rapid changes in water level of, salinity of, and discharge into northeastern Florida Bay as well as into adjacent marine estuaries. During 2005, two major hurricanes (Katrina and Wilma) crossed the...

The Interstate 10 Twin Span Bridge over Lake Pontchartrain north of New Orleans, La., was rendered completely unusable by Hurricane Katrina. The cause of the collapse of the bridges generated great interest among hydrologists and structural engineers as well as among the general public. What made this case study even...

We report the concentration, phosphorus (P) and nitrogen (N) content, and size and chemical fractionation of fine suspended particles (0.2‐100 µm) and colloids (3 kilodalton [kDa]‐0.1 µm) in the surface water of Everglades wetlands along regional and P‐enrichment gradients. Total suspended sediment concentrations ranged from 0.7 to 2.7 mg L−1....

The objective of this study was to evaluate the potential sources of pesticides to the Yolo Bypass, including those that could potentially impact critical life stages of resident fish. To assess direct inputs during inundation, pesticide concentrations were analyzed in water and suspended and bed sediment samples collected from source...

We use selected monitoring data to illustrate how localized water diversions from seasonal barriers, gate operations, and export pumps alter water quality across the Sacramento-San Joaquin Delta (California). Dynamics of water-quality variability are complex because the Delta is a mixing zone of water from the Sacramento and San Joaquin Rivers,...

A review of published research on unpaved road effects on surface-water and shallow ground-water hydrology was undertaken to assist the Baca National Wildlife Refuge, Colorado, in understanding factors potentially influencing refuge ecology. Few studies were found that addressed hydrological effects of roads on a comparable area of shallow slope in...

The U.S. Forest Service authorizes the occupancy and use of Forest Service lands by various projects, including water storage facilities, under the Federal Land Policy and Management Act. Federal Land Policy and Management Act permits can be renewed at the end of their term. The U.S. Forest Service analyzes the...

Hydrologic and hydraulic updates for Duck Creek and the lower part of Jordan Creek in Juneau, Alaska, included computation of new estimates of peak streamflow magnitudes and new water-surface profiles for the 10-, 50-, 100-, and 500-year floods. Computations for the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year...