DEQ Issues Report on Cause of Brown Bridge Dam FailureAgency: Environmental Quality
June 30, 2014
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Bill Creal, 517-242-2766, firstname.lastname@example.org
Brad Wurfel, 517-284-6713, email@example.com
Report finds soil conditions to be root cause of October, 2012 incident
The DEQ has released a new report on the agency's investigation into the root cause of the Oct. 6, 2012, failure of a temporary dewatering structure constructed to facilitate the removal of the Brown Bridge Dam on the Boardman River.
The removal of the Brown Bridge Dam was the first of a series of dam removals and improvements intended to restore the Boardman River to a more natural state. The City of Traverse City, owner of the Brown Bridge Dam, obtained a permit for impoundment drawdown and dam removal from the DEQ. The permit also included construction and use of the TDS adjacent to the dam. On the morning of Oct. 6, 2012, when first put to use, the TDS failed, resulting in significant flooding along the Boardman River.
The DEQ's Water Resources Division has investigated various potential causes of the TDS failure and has determined that the most likely cause of the TDS failure was internal erosion of the foundation material from underneath the water control structure within the TDS. This unsuitable subsurface soil condition likely led to the failure.
The complete Root Cause Analysis conducted by the DEQ is available on the DEQ's Web page at: http://michigan.gov/deq/0,4561,7-135-3313---,00.html.