Testing New Field Methods and Modeling Techniques
- Jud Harvey, USGS, Reston, VA
- Chris Fuller, USGS, Menlo Park, CA
- John Duff, USGS, Menlo Park, CA
- Brian Wagner, USGS, Menlo Park, CA
USGS Minidrivepoint sampler allows porewater to be pumped simultaneously from six depths (2.5 - 15 cm) below the streambed.
- Developing auto-recording options for ion-specific electrodes for stream and subsurface measurements of solute concentrations.
- Develop an improved model of water flow in shallow channels where interactions with near-stream groundwater are important to contaminant transport or biogeochemical reactions:
- Simple (1-D) but flexible model of surface flow applicable for many combinations of flow resistance, channel slope, and gradually-varied waves.
- options for diffusive or kinematic approximations of St. Venant equations.
- Algorithms for time-varying flows and water levels in channel with complex stream and bank topography
- Algorithms for time-varying water exchange between channel and near-stream groundwater (hyporheic/riparian zones and alluvial groundwater)
- Algorithm to adjust rate law coefficient for stage-dependent hydraulic resistance.
- Simple model structure (few parameters) allowing for inverse estimation (UCODE)
- Model structured as driver for solute transport code (OTIS)
- Apply model to analysis at Pinal Creek basin, AZ and Shark Slough, Everglades National Park
- Development and application of the USGS minidrivepoint sampler that provides close-interval sampling of solute concentrations from porewater beneath streambeds (Duff et al., 1998; Harvey and Fuller, 1998).
- Experimental design protocols developed for using solute tracers to quantify surface-subsurface water interactions in streams. These methods are the basis for better understanding of the biogeochemical reactions in streambeds that control, for example, rates of removal of contaminants such as metals or excess nutrients from stream water (Wagner and Harvey, 1997; Harvey and Wagner, 2000).