Edward Vielmetti | AnnArbor.com

At the end of December, I noted on a walk along the Argo mill race embankment that the mill race was still draining. Two and a half months later, the water levels in this long, narrow pond are still going down. I wonder how low they will go, and what you'll see at the bottom as it's exposed.

The check dam at Argo Dam keeps the flow of water in the mill race down to a very slow trickle.

Edward Vielmetti | AnnArbor.com

The lower water levels are more striking at the upstream end, because the pond is shallower there and thus exposes more in the way of mud flats, with the occasional broken bottle, abandoned tire or small plastic margarine tub on the bottom. I'm betting that the tubs once held bait for fishing.

This portion of the 1913 original drawings for the Argo Power Plant shows the original depth of the bottom of the head race.

Gardner S. Williams for Eastern Michigan Edison Co., 1913

How deep is the mill race? These drawings, pulled from the 2009 study by Soil and Materials Engineers Inc. of Plymouth, show the original bottom of the mill race was at or near the level of the bottom of the river. I don't have a current set of survey data, but even if there has been silt buildup it's likely that there's a relatively deep channel in at least part of that pond still.

How low will the water levels go? Some of the original discussion had anticipated that the head race would drop 3 feet. I don't have a ready way to measure how much it actually has gone down, but it's easily twice that right now. With only a trickle of water coming in from the now stopped spillway at Argo Pond, it's quite plausible that a combination of evaporation and slow drainage through the earthen levee will let waters go down quite a bit more.