Location

UMass Amherst

Start Date

27-6-2011 4:05 PM

End Date

27-6-2011 4:25 PM

Description

We present here our initial endeavor to categorize dam removal efforts based on past experience in order to better predict the outcomes and potential impacts of dam removal projects, as well as start to develop conceptual models for dam removal. The Broad Level Classification System for Dam Removals, developed by MacBroom and Wildman in 2010, divides dam removal projects into twelve categories. The categories were determined based on sediment quantity, sediment characteristics, impoundment width, the existence of a legacy channel, and certain limiting factors such as the presence of contaminants, downstream channel bed degradation, and if a portion of the dam w-as left in place. The upstreamchannel and sediment responses, overall systemresponse, and relative recovery times are then summariesby category. Multiple examples of each category are given, from completed dam removal projects across thenation. The classification system is backed by extensive expertise on over 100 dam removal projects, which lead to the determination that obvious patterns and similarities in response exist between specific “categories” of dam removals. Wide impoundments with fine grained sediments respond very different than steep narrow impoundmentswith coarse grained sediments. Some dams have noimpounded sediment stored behind them at all, whileothers have a century or more of accumulated sedimentwithin the impoundment. The system response to a removal differs greatly if the downstream channel issignificantly degraded or if the sill of a dam is left in place during the removal. The results and complexity of a dam removal project will vary depending on these factors and others. The classification system allows us to learn from cumulative project experience by comparing projects that will likely respond in a similar manner.

Comments

Laura Wildman has worked forover20 years as a professional water resource/fisheries engineer focusing on dam removal and river restoration. She has been involved in over 100 dam removal projects; working on all aspects of the projects from inception through design and construction. Ms. Wildman is considered one of the foremost national experts in dam removal, speaking regularly around the country on this subject and developing and assisting with the instructing of courses at the University of Wisconsin and Yale in dam removal fish passage and river restoration. In 2009 she received a Leadership in Restoration award from NOAA’s Princeton Hydro, Ms. Wildman worked on dam removal and fish passage for American Rivers and initiated and led the Northeast Stream Barrier Task Force. Ms. Wildman is currently on the Governing Board of ASCE’s Environmental and Water Resource Institute and is the Chairwoman for the Task Committee on Sediment Dynamics Post Dam Removal. Ms. Wildman has a strong background in fluvial geomorphology, fisheries habitat/flow analysis, dam modification/repair, open channel hydraulics, grant coordination, public outreach, and advanced hydraulic and sediment transport modeling.

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Jun 27th, 4:05 PM Jun 27th, 4:25 PM

Session C3- A Broad level classification system for dam removals

UMass Amherst

We present here our initial endeavor to categorize dam removal efforts based on past experience in order to better predict the outcomes and potential impacts of dam removal projects, as well as start to develop conceptual models for dam removal. The Broad Level Classification System for Dam Removals, developed by MacBroom and Wildman in 2010, divides dam removal projects into twelve categories. The categories were determined based on sediment quantity, sediment characteristics, impoundment width, the existence of a legacy channel, and certain limiting factors such as the presence of contaminants, downstream channel bed degradation, and if a portion of the dam w-as left in place. The upstreamchannel and sediment responses, overall systemresponse, and relative recovery times are then summariesby category. Multiple examples of each category are given, from completed dam removal projects across thenation. The classification system is backed by extensive expertise on over 100 dam removal projects, which lead to the determination that obvious patterns and similarities in response exist between specific “categories” of dam removals. Wide impoundments with fine grained sediments respond very different than steep narrow impoundmentswith coarse grained sediments. Some dams have noimpounded sediment stored behind them at all, whileothers have a century or more of accumulated sedimentwithin the impoundment. The system response to a removal differs greatly if the downstream channel issignificantly degraded or if the sill of a dam is left in place during the removal. The results and complexity of a dam removal project will vary depending on these factors and others. The classification system allows us to learn from cumulative project experience by comparing projects that will likely respond in a similar manner.