Publications

The hydrogeologic framework of fractured sedimentary bedrock at the former Naval Air Warfare Center (NAWC), Trenton, New Jersey, a trichloroethylene (TCE)-contaminated site in the Newark Basin, is developed using an understanding of the geologic history of the strata, gamma-ray logs, and rock cores. NAWC is the newest field research site established as part of the U.S. Geological Survey...

Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint...

The Nacatoch Sand and Tokio Formation aquifers in southwestern Arkansas and the Nacatoch Sand in northeastern Arkansas are sources of water for industrial, public supply, domestic, and agricultural uses. Potentiometric-surface maps were constructed from water-level measurements made in 61 wells completed in the Nacatoch Sand and in 50 wells completed in the Tokio Formation during spring...

Groundwater is protected in most areas as it is a primary source of drinking water. In the United States, 50% of the population relies on groundwater supplies (Reilly et al., 2008). Groundwater sampling in the United States became commonplace in the 20th century as contaminated water resources became apparent and a growing public concern emerged to protect water resources. In response to...

An existing variable‐density groundwater flow and solute transport model, developed for the northern part of Broward County, Florida, was used to predict the effect of sealevel rise on future coastal groundwater resources. Using average annual conditions from 2005, simulations were performed for 100 years into the future using four different rates of sea‐level rise: 0, 24, 48, and 88...

Electrical resistivity imaging has been used in coastal settings to characterize fresh submarine groundwater discharge and the position of the freshwater/salt-water interface because of the relation of bulk electrical conductivity to pore-fluid conductivity, which in turn is a function of salinity. Interpretation of tomograms for hydrologic processes is complicated by inversion artifacts

The Pamlico Sound (PS) with its sub-estuaries is the largest lagoonal ecosystem in the United States. It exhibits periodically strong salinity stratification and an average freshwater residence time of 1 year for the sound proper. This relatively long residence time promotes effective use and cycling of nutrients, allowing the system to support high rates of primary and secondary...

Rapid climate change jeopardizes tree populations by shifting current climate zones. To avoid extinction, tree populations must tolerate, adapt, or migrate. Here we investigate geographic patterns of genetic variation in valley oak, Quercus lobata Née, to assess how underlying genetic structure of populations might influence this species’ ability to survive climate change. First, to...

Stream restoration has received much attention in recent years, yet there has been little effort to evaluate its impacts on physical habitat, stability, and biota. A popular but controversial stream restoration approach is natural channel design (NCD), which cannot be adequately evaluated without a long-term, independent assessment of its effects on stream habitat. Six reaches of five...

Gradients in contaminant concentrations and isotopic compositions commonly are used to derive reaction parameters for natural attenuation in aquifers. Differences between field‐scale (apparent) estimated reaction rates and isotopic fractionations and local‐scale (intrinsic) effects are poorly understood for complex natural systems. For a heterogeneous alluvial fan aquifer, numerical...

To effectively manage coastal ecosystems, we need an improvedunderstanding of how tidal marsh ecosystem services will respond to sea-level rise and increased nitrogen (N) loading to coastal areas. Here we review existing literature to better understand how these interacting perturbations s will likely impact N removal by tidal marshes. We propose that the keyy factors controlling long...

Observations of turbulent stresses and mean velocities over an entire spring–neap cycle are used to evaluate the dynamics of tidally averaged flows in a partially stratified estuarine channel. In a depth-averaged sense, the net flow in this channel is up estuary due to interaction of tidal forcing with the geometry of the larger basin. The depth-variable tidally averaged flow has the...