Interpretive sign in the parking lot.  ESA performed the geomorphology design portions of this project.

From downstream to upstream.  Peirce Mill dam was necessary to force water into the historic mill race, which allowed the hydrology to drive the grist mill.

Upstream intake.

Look inside on the left and you can see a glass observation window.  If you open a man-hole cover on the left you can climb down and into an underground concrete vault and look out the window.  I took the photo during a drought, where no water was even flowing over the dam.  During normal spring migration of anadromous fisheries, the window would be underwater, so that you could actually observe fish using the ladder.

The denil ladder are a series of stairs (baffles).  As the fish work upstream (center of the weirs) they can rest in the slack water of the wings on the sides of the ladder.  The ladder creates highly oxygenated water, which is the necessary 'attraction' water migrating fish key-in on as they work upstream.  The dam has been a long term fisheries (shad, herring, alewife and perch) impediment.