Event Title

Concurrent Sessions A: Dam Removal I - Cost-Effective Sediment Management For Small Dam Removal Projects

Location

Construction & Engineering Hall, Oregon State University

Start Date

25-6-2013 10:40 AM

End Date

25-6-2013 11:00 AM

Description

One of the most challenging aspects of small dam removal projects is determining how to manage the sediment trapped by the dam. In New England, small dam removal projects involve anywhere from 200 to 80,000 cubic yards of potentially mobile sediment. Depending on the geomorphic context, impoundment sediment may be dominated by gravel, cobbles and boulders, or it may be fine-grained silts and clays. The least expensive way to manage sediment is to allow it to erode downstream. This approach may not be possible, however, due to sediment contamination or the presence of downstream infrastructure such as culverts, flood walls, and private property. On the other hand, excavating and removing even small volumes of sediment can be prohibitively expensive for dam owners and agencies that fund restoration projects. This presentation 1) summarizes common sediment management methods used in New England dam removal projects and the associated per unit costs; 2) highlights projects where creative approaches to sediment management have reduced the construction cost; and 3) offers a decision-making framework for simple, cost-effective sediment management.

Comments

Beth Lambert manages the River Restoration Program for the Massachusetts Division of Ecological Restoration. The River Restoration Program has removed over 20 dams in the last five years and has more than 30 projects in the planning stages. Beth is a fluvial geomorphologist with river restoration experience in Oregon, New Hampshire, and Massachusetts.

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Jun 25th, 10:40 AM Jun 25th, 11:00 AM

Concurrent Sessions A: Dam Removal I - Cost-Effective Sediment Management For Small Dam Removal Projects

Construction & Engineering Hall, Oregon State University

One of the most challenging aspects of small dam removal projects is determining how to manage the sediment trapped by the dam. In New England, small dam removal projects involve anywhere from 200 to 80,000 cubic yards of potentially mobile sediment. Depending on the geomorphic context, impoundment sediment may be dominated by gravel, cobbles and boulders, or it may be fine-grained silts and clays. The least expensive way to manage sediment is to allow it to erode downstream. This approach may not be possible, however, due to sediment contamination or the presence of downstream infrastructure such as culverts, flood walls, and private property. On the other hand, excavating and removing even small volumes of sediment can be prohibitively expensive for dam owners and agencies that fund restoration projects. This presentation 1) summarizes common sediment management methods used in New England dam removal projects and the associated per unit costs; 2) highlights projects where creative approaches to sediment management have reduced the construction cost; and 3) offers a decision-making framework for simple, cost-effective sediment management.