Saturday, September 22, 2012

Of riffles and muck


September 21, 2012 - With the diversion channel finally in place, RC&D began removing sediment from the impoundment this week.  Sediment was trapped by the dam over hundreds of years.  It is stratified into two layers: a surficial layer of silt (muck) and a layer of sand.  Beneath the sand is the historic floodplain of the Mill River.  Crews are removing the silt layer and placing it in an upland reuse area nearby.

Also this week, crews began building a riffle where the Mill River enters the (former) impoundment.  Above is a picture of the excavator as it builds the riffle.  Below is a short video clip.
video

Finally, crews graded the channel for the Mill River at the downstream end of the project area.  Eventually, the crews will construct a riffle here and build river banks.  I took this picture standing at the upstream end of where the spillway of the dam used to be.




Monday, September 10, 2012

Dewatering and Diversion Continue

Work on diverting the Mill River through a new temporary channel is continuing today. This lined channel will carry the river while a new channel is constructed through the impoundment. This is when the exciting work of river restoration begins - creating meander bends, channel banks and woody habitat.

Remnants of the old mill were still visible last week. The crew was unable to break apart these larger sections of the old mill walls which have stood the test of time and machinery. A report on the industrial archaeology of the mill will be completed at the end of the project, and we will use the information to create interpretive signage at the site.