Traverse City Record-Eagle

October 4, 2012

Brown Bridge Dam Pond draining to begin

Work crews hit what appears to be 90-year-old debris


TRAVERSE CITY — The draining of Brown Bridge Dam Pond could start Friday afternoon or Saturday following weeks of literal hard-driving work that took five different sheet pile drivers to complete and left two in pieces.

Molon Excavating, the dam removal project's general contractor, reported Tuesday during a construction meeting that work crews hit piling, rock and other debris while digging out a temporary dewatering structure.

It is believed the current dewatering structure is in the same location as an old diversion channel used 90 years ago when the dam power house was built, according to a Wednesday update report sent to project managers.

Molon workers also found gravel and cobble similar to what is seen in the river's historic channel.

The old sheeting caused a slight delay in the expected mid-week completion of the temporary dewatering structure, but Molon still planned to begin moving water through the 15-foot-wide structure Friday afternoon or Saturday.

It's a busy week for Molon. Workers poured concrete Tuesday in the bottom of the structure and planned to begin installing stop logs and boulders on Wednesday.

The boulders will help dissipate the energy of pond water after it flows into the structure and drops 20 feet before entering the river.

The structure gives engineers control over the volume of pond water released. A state permit requires that only a foot of pond water be released daily. The slow draining helps keep sediment in pond bottom lands, managers said.