Here’s some pancake ice forming in the tailrace (below the Tileston and Hollingsworth Dam on the Milton/Hyde Park border on December 31, at about 5 degrees Fahrenheit. (A tailrace is a channel that carries water away from a water wheel, turbine, etc.)
Not far downstream the river was completely iced over but here the water was evidently moving too fast for the pancakes to link up and freeze. Just upstream the near side of the dam was draped in ice:
Here you can hear the water rushing underneath:
Someone will have to explain to me why water going over a dam freezes from the outside in, forming a series of ice-covered tubes. Do they shield the water from freezing further? Do they ever clog up?
Here’s a look at the entire dam, showing that all the flow was passing through at least a dozen ice-tubes, and none went over the actual top of the dam, thanks to all the holes in the adjustable gate:
Here’s a shot from February 2015. You can see at the lower right that the ice-tubes form from the top down. Sometimes pieces break off and fall on the apron, as is evident a little further to the left:
Ten years ago there weren’t any holes, and the river flowed over the top of the dam:
This is my favorite spot to photo the dam from, but it’s a little tricky to get to. Here, for instance, is where you might start from, next to the new Dollar Tree store:
As is apparent at the lower left, there is some regular traffic here, which leads to the catwalk, which leads to the picturesque falling-down mill on the Milton side:
But there isn’t a lot of traffic. Indeed, the broken-down dam, the collapsing buildings, and the evil bed of submerged PCB-laden mud just upstream make this perhaps the most abused and neglected site on the entire river. Isn’t it time we did something about it?
Willett Pond Manager