Brownbridge Dam deconstruction
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After removal |
The Conservation Resource Alliance, acting as contracted Project Manager, has led the Boardman Dams Implementation Team (IT) through the complex process of removing Brown Bridge Dam on the Boardman River. Brown Bridge Dam was the first of three historic hydro-electric dams on this Blue Ribbon designated trout stream slated for removal. This massive community driven project was set in motion nearly a decade ago.
It took a total of 21,270 man hours, equal to 14 people everyday for 5 months, to complete the construction phase of this initiative.
The phase of the project wrapped up on schedule and within budget as compared to anticipated outcomes.
Much of the work performed during June, July, and early August of 2012 related to prepping the site for removal of the powerhouse and spillway as well as construction of access roads to the east end (delta area) of the project.
For the balance of the summer and through the fall, work at the site focused on:
- Removal of the powerhouse superstructure and spillway
- Grading and shaping of floodplain
- Removal of sand and fine sediment from channel (260,000 cubic yards were removed)
- Activities related to the October 6th incident
- Placement of large wood along toe of banks as well as in-channel for fish cover
The following is complete as of August 2013:
- Re-established 2.5 miles of river channel & 12.2 acres of floodplain through handling and grading of 260,000 cubic yards of sediment that had accumulated in the former impoundment over the last 89 years. This amount of sediment is equivalent to a football field 10 stories or 122’ high. In many areas of the newly formed river channel, naturally occurring gravel beds are resurfacing. An additional .5 mile of river immediately upstream of the former impoundment extending to Grasshopper Creek is no longer slow and full of sand due to the dam removal.
- Placement of 985 lineal feet of woody debris for bank protection & habitat. By placing woody debris along newly formed streambanks, the river current is deflected away from sensitive areas prone to erosion.
- Placement of 5,100 lineal feet of woody debris for instream habitat. Since the newly established riparian corridor through the former Brown Bridge impoundment is not forested, natural recruitment of woody debris and overhanging vegetation will be limited for some time as the river now flows through. Thus, active incorporation of woody debris is imperative towards providing instream habitat.
- Turtle rescue, including an estimated 37 painted turtles and 1 snapper turtle.
- Multiple fish rescue efforts during dewatering.
- Complete removal of Brown Bridge Dam, powerhouse, and dewatering structure. A breach of the dam occurred on October 6, 2012 as the dewatering structure was put online. However, the Implementation Team, AMEC and Molon Excavating have been working collaboratively to remedy resulting impacts to landowners and the river downstream with success. Questions and answers regarding the October 6th incident can be viewed on the project website (click here).
In addition to the construction and restoration work performed, a contract was negotiated with the Au Sable Institute to perform macroinvertebrate assessments pre- Brown Bridge dam removal in the project area. The fieldwork was subsequently carried out, and a report has been drafted and circulated to the IT and others for review.
Concurrent with the dam removal project is a long-term planning initiative for the Boardman River Watershed. The Boardman Watershed Prosperity Plan has been focused on developing a new approach to natural resource planning - one that leverages the economic and community development potential of a unique asset (the 291 square mile Boardman River watershed) with protection of that watershed. The plan is intended to reflect one of the prime tenets of Michigan’s long-term vision: creating a sense of place and emphasizing the importance of natural resources to regional prosperity.
The project Communications Plan has continued to be implemented resulting in press releases related to the project. Updates and documents have been posted on the dedicated project website: www.theboardman.org. Please follow the progress of this project by visiting this site.
In addition to focusing on the next two dam removals at Boardman and Sabin, the IT has worked at the development and convening of a working team consisting of groups/agencies most likely to assist in funding as well as designing the Cass Road bridge replacement at Boardman dam. This team includes the Grand Traverse County Road Commission, CRA, the Grand Traverse Conservation District, URS, the US Army Corps of Engineers, and the Michigan Department of Transportation.
Click here for a list of current funders.