U researchers, students use model to study dam removal

Jenna Ross

In the University’s St. Anthony Falls Laboratory lies a 30-foot scale model of Washington’s Elwha River. The mini river, built of wood, sand, concrete and Mississippi River water, flows to its dam as a laser inspects its surface.

Doctoral student Chris Bromley, who traveled from the United Kingdom’s Nottingham University to create this river model, watched the process.

Bromley, with the help of University researchers and students, uses the model to research dam removal and its effects at the laboratory, part of the University’s civil engineering, geology and geophysics departments.

Bromley came to the University last year as part of the St. Anthony Falls Laboratory’s visitors program and said the laboratory has unique facilities he needs for his research.

“In the last few years, dam removal has become a huge issue in the United States,” said Bromley, who received a $35,000 grant for his dam-removal research. “Taking down a dam is an intricate process, and with this model, we hope to find out the best way to perform this process.”

The 200-foot-high Elwha Dam will be removed in 2007. American Indians and environmentalists call for its removal, hoping to re-establish the river’s salmon population.

After researching the river at the University of Oregon, Bromley decided to do a dam removal model to mimic the proposed removal processes.

“Those people involved with the Elwha Dam removal are interested in my research, have been in touch and in some cases have come to the laboratory to see the model,” Bromley said. “The results of my experiments will help them decide how to remove this dam.”

A scaled model replicates the processes seen in nature better than any computer simulation, Bromley said.

“And unlike most rectangular dam models, this is based on the river’s topography,” Bromley said. “I’m not aware of any other model like it.”

After building the model, Bromley began removing the dam at different rates, watching the sediment and water flow change at each speed. A slow process is costly, while the high water flow from a quick process releases sediment built up by the dam.

“If you go too fast, the sediment released can overwhelm the system,” Bromley said. “Oftentimes there is pollution attached to the sediment. When you release that sediment, you can also release that pollution.”

Chris Paola, director for the laboratory, compared removing a dam to removing a tooth.

“If you do it too quickly, it’s like tying the tooth to the string on the door handle and then slamming the door,” Paola said. “It’s painful. With the dam, we’re trying to make the process as painless as possible.”

University graduate Dianna Smith, who worked with Bromley to build the model, said she appreciated the project’s realization.

“It’s rewarding to be involved in taking an idea from concept to reality,” she said.