Johns Hopkins Whiting School of Engineering 1996 Annual Report [text version]

Whiting School of Engineering 1996 Annual Report

Geography and Environmental Engineering
Flushing River Channels
Location, Location, Location
Waging War on Chemical Contaminants
Department Facts

Flushing River Channels
Large reservoirs have much going for them, providing water supply, flood control, and clean power generation. At the same time, they can degrade the river habitat downstream, threatening fish and wildlife populations.

“River channels adjust to the mix of water and sediment supplied to them. The problem comes when storage in the reservoir upsets this balance,” says Associate Professor Peter Wilcock. “The result can be either erosion or deposition, depending on the size of the reservoir, its operating rules, and the nature of the channel downstream. To understand this impact and develop appropriate management strategies, we must discern how both water and sediment move through the river.” Wilcock continues, “In one case we addressed, so much water was diverted at the dam that the river lost almost its entire capacity to transport sediment.” The result was that sediment from tributaries gradually filled in the gravel river bed, eliminating habitat for salmon spawning and rearing.”

After observing water and sediment movement during trial reservoir releases, we were able to recommend a range of release options that could flush the bed,” he comments. “The final solution will require a balance of hydraulic, ecological, safety, and financial considerations, although it is clear that, in order to restore the fishery, much more water must be released into the river.”

One irony in all this is a change in the perception of sediment. Previously, the established view was that sediment is a pollutant not to be returned to the stream. In some states, dam operators can face stiff fines for passing sediment through a reservoir. Wilcock points out that “sediment, particularly the coarser gravel and cobble sizes, is a natural part of a healthy river environment. Structures to bypass sediment around dams are now being considered as part of reservoir design. The key is to find the right mix of water and sediment that will maintain the river channel while permitting useful reservoir operation.”

Location, Location, Location

The concept of “location” is important not only to those who buy and sell real estate, but also to legislators, medical administrators, school boards, and corporations, just to name a few. Deciding where to place community, business, and government structures to maximize use and minimize cost has developed into a field in its own right. Unlike many other areas of scientific endeavor, location science, or location analysis, is young—just over 30 years old. Professor Charles ReVelle has been a major figure in the field’s evolution.

“The birth of location science was due to a concern for the organization of space, the development of the mathematics of optimization, and the availability of the modern computer,” ReVelle says. Mirroring the interdisciplinary nature of location science, ReVelle’s research has encompassed a variety of projects. He has designed location systems for fire stations, ambulance deployment, hospital siting, and power plants. He has also developed models used in water resource management and transportation and communication networks.

Recently, ReVelle has guided several graduate students in their use of location analysis as a new tool in natural area planning and quantitative forestry. In the first area, ReVelle used optimization techniques to design compact and minimal cost reserves for species protection under a constraint on minimal size of the reserve and a constraint on the number of species protected. In quantitative forestry, ReVelle and his students developed a method that divided an area designated for possible harvesting into square grid cells and used computer algorithms to determine the most profitable cells to cut with restrictions on the maximum number of adjacent cells that could be harvested.

What are the new problems location science will be challenged to solve? “In manufacturing companies with multiple sites, there is a growing need to determine the best plant location in which to place specialized machines,” ReVelle comments. “This is also the critical question of siting aeromedical depots and trauma centers so that they interact with one another effectively in their mission to save lives.”

Waging War on Chemical Contaminants

Assistant Professor Lynn Roberts has two simple objectives in mind when it comes to her research: 1) predict the fate of contaminants in the environment and 2) find ways to clean up past problems. Specifically, Roberts investigates the reactions of contaminants in aquatic systems and develops improved technologies for reducing risks associated with contaminated groundwater through promoting the chemical transformation or adsorption of pollutants.

For example, one graduate student working in Roberts’ research group is investigating the fate of agrochemicals discharged to environments such as the Chesapeake Bay. Under appropriate conditions, these react with reduced sulfur species formed in bottom waters of estuaries. Unless a proper accounting is made of the rates of such reactions (including the impacts of toxic products that may result), it is impossible to form rational policies governing agrochemical useage in watersheds.

Ultimately, a proper understanding of the mechanisms through which contaminants are transformed may lead to development of “greener” products. With approximately 60,000 chemicals currently in use, and more synthesized each year, much of Roberts’ work emphasizes development of quantitative models that will predict the fate of chemicals before they have an opportunity to become environmental hazards.

New models and appropriate testing may limit future contamination, but the magnitude of past problems is staggering, with estimated annual cleanup costs in the billions of dollars. One innovative and cost-effective approach to groundwater contamination is to force polluted water through a trench containing iron filings, which serves as an immobilized “reagent” capable of destroying many pollutants. Roberts and her graduate students, together with collaborators at the U.S. Air Force, are searching to discover the mechanisms through which such reactions occur. So far, their research has uncovered a novel pathway through which chlorinated solvents react under environmental conditions. This pathway is noteworthy, since it bypasses the formation of many of the undesirable byproducts which might otherwise result.

In 1994, Roberts won a National Science Foundation Young Investigator Award for her research, one of only two environmental engineering researchers selected that year.

Established 1968
The department took many forms before its present state, beginning in 1919 with civil engineering, then sanitary engineering, and finally environmental engineering science.

Phone 410-516-7093

Email dogee@jhu.edu

WWW http://www.jhu.edu/~dogee/

Students
1995-96 Academic Year
Graduate: 86
Undergraduate: 7 (geography majors)

Faculty and Researchers
J. Hugh Ellis, Chair
William P. Ball
John J. Boland
Edward J. Bouwer
Grace S. Brush
Jack C. Fisher
Steven H. Hanke
David W. Harvey
Benjamin F. Hobbs
Charles R. O'Melia
Marc B. Parlange
Charles S. ReVelle
Lynn A. Roberts
Haydee Salmun
Erica J. Schoenberger
Eugene D. Shchukin
Alan T. Stone
Peter R. Wilcock
M. Gordon Wolman

Research Areas
Environmental Engineering and Chemistry
Geomorphology, Hydrology, and Ecology
Human Geography
Systems Analysis and Economics

Geography and Environmental Engineering Flushing River Channels Location, Location, Location Waging War on Chemical Contaminants Department Facts

Geography and Environmental Engineering
Flushing River Channels
Location, Location, Location
Waging War on Chemical Contaminants
Department Facts