Lecture 19 - Extra Info: Dam Removal

Wisconsin Dam Removal Policy

For anyone with interest in Wisconsin's dam removal policy (as discussed in today's lecture), the link below will take you to the report written by the River Alliance of Wisconsin in association with Trout Unlimited.

http://www.wisconsinrivers.org/documents/dams/restoring.pdf?PHPSESSID=bf53be08781f296de95c143e2a0e8fb4

Klamath River Dam Removal
The link provides an overview of the 20 year battle between various stakeholders to remove several dams along the Rogue and Klamath River.

http://www.latimes.com/news/nationworld/nation/la-na-oregon-dam10-2009oct10,0,4938332.story

This is the citation of a great paper that talks about dam removal along with considerations to be made when removing a dam or steps to be taken to restore some natural proccess of a river system without going to the extreme of dam removal. I am providing a summary I did of the article but would encourage anyone interested to read the article as it has some great information.

Citation:
William J. Trush, Scott McBain, and Luna B. Leopold. Attributes of an alluvial river and their relation to water policy and management. Applied Physical Sciences. Vol. 97; no. 22; pages 11858-11863; October 24, 2000.

Summary:
In this paper Trush et al. lays out ten attributes that he deems as concepts and components that “govern how alluvial channels work.” They give a brief description of each of the ten attributes and how the attribute is important to the river channel. The paper and attributes are designed to be a guideline to consider in two different scenarios: when restoring alluvial processes below an existing dam without going as far as removing the dam and to preserve alluvial river integrity below proposed dams.
Trush continues to lay out and explain all ten of the attributes and their importance to river systems.
Attributes:
1. The primary geomorphic and ecological unit of an alluvial river is the alternate bar sequence.
2. Each annual hydrograph component accomplishes specific geomorphic and ecological functions.
3. The channelbed surface is frequently mobilized.
4. Alternate bars must be periodically scoured deeper than their coarse surface layers.
5. Fine and coarse sediment budgets are balanced.
6. Alluvial channels are free to migrate.
7. Flood plains are frequently inundated.
8. Large floods create and sustain a complex mainstem and flood plain morphology.
9. Diverse riparian plant communities are sustained by the natural occurrence of annual hydrograph components.
10. Groundwater in the valley bottomlands is hydraulically connected to the mainstem channel.

After laying out the ten attributes the authors used the Trinity River at Lewiston to explain an example in which their attributes will be used in new management applications. In 1963 90% of the natural streamflow of the Trinity River was diverted to feed the Sacramento River for power generation as well as agricultural and municipal water supply. Historic daily flow of the Trinity ranged from 2.8 m^3/s baseflows to near 2,300 m^3/s floods in wet years. After the diversion the flow was held constant at 4.2 m^3/s. This drastic change in flow brought about drastic changes to the channel morphology as well as the biotic community. The authors discuss how changes in their ten attributes brought about predictable changes throughout the river system.

Managers were attempting to use the attributes as a blueprint in order to rebuild and maintain a self-sustaining alternate bar morphology and riparian community.

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