Publications

The terrestrial-aquatic interface beneath a riparian corridor was investigated as a region of hydrological and biological control of nutrient flux. Dissolved oxygen (DO) concentration in the hyporheic zone ranged from

No abstract available.

Ecological study of the hyporheic zone is leading to recognition of a need for additional hydrologic understanding. Some of this understanding can be obtained by viewing the hyporheic zone as a succession of isolated boxes adjacent to the stream. Further understanding, particularly relevant to catchment-scale ecology, may come from studies focussed on the fluid mechanics of the flow-path

Federally funded remedial action projects are presently underway in New Jersey and Colorado at sites containing 226Ra and other radionuclides from radium-uranium ore extraction plants that operated during the early twentieth century. They are but the latest chapter in the story of an American industry that emerged and perished in the span of three decades. Major extraction plants were...

No abstract available.

Nitrate-nitrogen (NO3-N) concentrations at public water supply intakes on the Des Moines and Raccoon Rivers in Iowa exceeded the maximum contaminant level (MCL) of 10 mg L-1 for public water supplies established by the USEPA for extended periods of time from March through early August 1990. The excessive NO3-N levels followed 2 yr of less-than normal precipitation in 1988 and 1989. The...

Coastal ocean waters tend to have very different patterns of phytoplankton biomass variability from the open ocean, and the connections between physical variability and phytoplankton bloom dynamics are less well established for these shallow systems. Predictions of biological responses to physical variability in these environments is inherently difficult because the recurrent seasonal...

The National Water-Quality Assessment pilot project for the Central Oklahoma aquifer examined the chemical and isotopic composition of ground water, the abundances and textures of minerals in core samples, and water levels and hydraulic properties in the flow system to identify geochemical reactions occurring in the aquifer and rates and directions of ground-water flow. The aquifer...

No abstract available.

No abstract available.

The subsurface riparian zone was examined as an ecotone with two interfaces. Inland is a terrestrial boundary, where transport of water and dissolved solutes is toward the channel and controlled by watershed hydrology. Streamside is an aquatic boundary, where exchange of surface water and dissolved solutes is bi-directional and flux is strongly influenced by channel hydraulics...

A new mass-conservative method for solution of the one-dimensional advection-dispersion equation is derived and discussed. Test results demonstrate that the finite-volume Eulerian-Lagrangian localized adjoint method (FVELLAM) outperforms standard finite-difference methods, in terms of accuracy and efficiency, for solute transport problems that are dominated by advection. For dispersion...