Dr. Andrea Dietrich
Natural Resources and Environment Fellowships
Sponsor: United States Department of Agriculture
Four Ph.D. students will be funded as part of an USDA interdisciplinary program to support
research in the areas of Land Use and Water Quality Management and Planning, Natural
Resource Policy Design and Analysis, and/or Ecological Monitoring and Assessment.
Students, who must be US citizen or national residents, will receive a $22,000 stipend,
tuition, and $1,000 travel expenses for each of three years, and the possibility of a
$10,000 grant for international research. Students may enter the Ph.D. fellowship program
with either a B.S. or M.S. degree.
This project is designed to train professionals who can comprehend and solve natural
resource and environmental problems using tools and concepts from sustainable development,
ecological risk assessment, institutional analysis, public policy analysis, cost/benefit
analysis, and water quality management. Active research areas in which students could
participate are watershed management, total daily maximum load allocations, water quality
modeling, integrated pest management, benthic impairment, and political economy. Student
work across disciplines with faculty in Civil and Environmental Engineering, Agricultural
and Applied Economics, Biological Systems Engineering, and Entomology.
Student sampling sediment-laden runoff from plasticulture field draining into creek
Chemical Markers for Evaluating E. coli Growth and Transport in Ecological Systems
with Dr. Daniel Gallagher
Sponsor: Virginia Water Resources Research Center
Understanding the survival and regrowth of coliforms from animal and human feces that enter
waterways is critical to developing accurate models for predicating and controlling this
microbial contaminant. This project aims to determine if biomarker can be used to determine
E. coli regrowth in natural systems. This research is important for a variety of environmental
fields, including Total Maximum Daily Load (TMDL) analysis, source water protection for drinking
water utilities, and drinking water distribution systems.
Escherichia coli
Student performing field sampling
Dr. John C. Little
Hypolimnetic oxygenation of stratified reservoirs
Hypolimnetic water in stratified reservoirs may become depleted of oxygen under certain
circumstances, with potential negative consequences for water quality. One remedial strategy
is to replenish the oxygen using hypolimnetic oxygenators. We are developing comprehensive
process models for the three most common systems: the Speece Cone, the bubble-plume diffuser,
and the full-lift hypolimnetic aerator to enable efficient design and optimal operation of
hypolimnetic oxygenation systems. We are also coupling the hypolimnetic oxygenation models
with a 2-D reservoir model to further optimize performance and to investigate the impact of
the systems on mixing and dissolved oxygen distribution within a reservoir.
Contour plot (oC) showing measured thermal structure
of large bubble plume in a deep lake as well as the model
predicted plume diameter.
Optimizing the Aeration Process in a Biological Aerated Filter
Co-PI with Dr. Nancy Love
The mass-transfer characteristics of a submerged-media biological aerated filter (BAF) are
being determined over a wide range of gas and liquid flow rates, a realistic range of water
temperatures, and for both clean and “dirty” water. By evaluating the rates of oxygen transfer
in the BAF, the rate-limiting operational regimes can be identified, and the knowledge used
to optimize system performance.
Flow-through cell
used to measure dissolved oxygen concentration in water sampled
from a bench-scale biological aerated filter.
The Impact of Salt Fluxes on Meromixis in Lakes
Co-PI with Dr. Wüest
Our research goal is to develop a model that simulates the conditions that induce or eradicate
meromixis in lakes, thereby establishing the prevailing redox conditions in the water column.
Because the salt accumulation cycle is relatively complex we are using salinity data to calculate
salt fluxes that can be incorporated into a 1-D hydrodynamic lake model. This seich-extended,
k-epsilon model has proven to be especially effective at predicting vertical turbulent diffusivity
during stratified periods and is therefore well suited for simulating the conditions surrounding
meromixis. Once this model has been developed and verified, it will be used to quantify the effect
of wind, temperature, primary productivity, and river inflow on meromixis.
Contour plot
showing predicted salt concentration in a hard-water lake in
Switzerland as a function of depth. Dense influent river water
with a high salt concentration prevents the lake from being fully
mixing during the first few months of the year.
|
2004
Comments or suggestions?
Contact the webmaster.