Jeff+Krebs+Dam+Removal

Dam removal: Over the past several generations the US has been busy little beavers and has dammed nearly every flowing waterway at least once. We have dammed rivers for hydropower, flood control, invasive species control, and other reasons. Now many of the dams are out of date, no longer functioning, and even dangerous. A large debate has sprung up on the proper course of action for dealing with these dams. For the most part it would be more expensive to refurbish or replace dams in need of service than to simply remove them. As the dams become old and degraded a risk of a blow out, or dam failure, puts lots of people and their property in danger of massive flooding. In an economic view, a one time cost to remove a dam is more effective than to continually rebuild/refurbish it. In an environmental view, man made dams are unnatural. Sedimentation rates change and affect the river both above and below the dam. These dams prevent favorable species such as trout and salmon from migrating to spawning habitat. After a dam is removed the channel quickly changes and creates a more complex channel beneficial to river species (Hayes, 2009). No action is not an option when it comes to dam management. The economic and environmental benefits from removing dams far outweighs the benefits of keeping dam thus we should remove dams; especially those that are out of service, or have degraded to an unsafe point. Up stream and down stream channel complexity increases while overall depth remains nearly constant.(Hayes, 2009)

Keep the dams: In River systems such as the Au Sable River, large dams have created huge ponds, miles long and upwards of 300 feet deep. Originally the Au Sable is a relatively shallow river system. With dams that have dramatically changed the habitat what will happen to these ecosystems if we remove the dams? In many areas the Au Sable River is hugged by high sloping banks. Removing dams would not only make these banks a few hundred feet taller in some areas, but above the dams would see the river cut deeper into the sediment. This area being largely dominated by sandy soils it will also likely cause the banks to undercut then topple into the river. If the dams are removed, a once vast water way with huge fishing opportunities and large paddle boat tours will become a shallow quick moving river cut deep into a ravine. The opportunities available to stakeholders such as paddle boat rides, some types of fishing, recreational boating such as tubing and wildlife viewing will be gone. Not only will these opportunities no longer exist, but they will be replaced by fishing opportunities of a vastly different kind. With significantly less water volume, there is no way the fish biomass can remain at the same levels. There will be less fish of smaller size and it will be harder to access these fishing sights as the banks will be taller and likely less stable as undercutting occurs. Dam removal can also have a negative impact on a stream’s temperature and oxygen levels. The process known as supersaturation causes increased oxygen levels that can be deadly to many fish and insects (Bednarek, 2001). Au Sable Foote Dam media type="youtube" key="U4mfSflSVGo" height="344" width="425"

Bednarek, Angela. 2001. “Undamming Rivers: A Review of the Ecological Impacts of Dam Removal.” Environmental Management 27(6):803-814.

Hayes, Dan. “ Stream Restoration via Dam Removal.” MSU, East Lansing. 18 Nov. 2009