Nick Olson, Jeff Marr and Gordon Grant narrate a coffer dam breach for the film crew.

A documentary crew visited St. Anthony Falls Laboratory (SAFL) in June to shoot footage of a model study located in the basement of the lab. This model study represents potential geomorphic responses of the Sandy River to the removal of the Marmot Dam. The Marmot Dam, located on the Sandy River near Portland, OR, is a 58-foot-high structure that impounds approximately 900,000 cubic yards of deltaic sediment upstream. Following removal of the dam in summer 2007, the river will once again be able to distribute sediment, initially redistributing the deltaic sediment downstream. To learn more about the Marmot Dam’s removal, click here.

As part of the dam removal project, SAFL/NCED are working with Stream Restoration Community Partner Gordon Grant (US Department of Agriculture Forest Service) and dam owner Portland General Electric (PGE) to model and monitor the response of the river to dam removal. With data from earlier studies (including one study by Stream Restoration Community Partner Stillwater

	NCED summer interns learn to run the Marmot model with SAFL student worker Nick Olson.

Sciences) and a recent LIDAR (light detection and ranging) survey, a SAFL/NCED team led by NCED Stream Restoration Project Manager Jeff Marr designed and built a 35-foot physical model of the river above and below the dam. During summer 2007, Grant, NCED Principal Investigator (PI) Peter Wilcock from John Hopkins University (JHU), and NCED graduate student Chuck Podolak (JHU) will complete detailed preremoval facies mapping of current sediment storage downstream from the dam. They will be assisted by a team of NCED summer undergraduate interns from around the US. These interns began their summer running experiments in the Marmot Dam model and will finish by completing mapping and sediment characterization of the downstream reach of the river most likely to be first impacted by sediment redistribution. NCED hopes to continue to study the effects of Marmot Dam removal with similar sediment monitoring campaigns in future summers—this project represents a wonderful opportunity for long-term data gathering to learn more about how a river digests sediment following dam removal. Combined with modeling work, to be completed by Podolak, NCED foresees field-site data and modeling data to contribute to an understanding of what happens when a dam comes down.

Sediment Dynamics for Dam Operation and Removal Overview [pdf]