Argo

When Sue McCormick, director of public services for the city of Ann Arbor, briefed the city council on the Argo dam at its Sept. 8 work session, she raised the possibility of drilling test bores in the earthen berm for installation of piezometers.

Based on her presentation and my recollection, the work would cost around $20,000, and would be undertaken only after consultation with the MDEQ to confirm that the MDEQ would accept findings from the bores as possible evidence on the question of the earthen berm’s structural status.

The MEDQ has given the city of Ann Arbor and order to close the headrace. [Chronicle coverage here.] The city sees the issue of berm’s toe drain repair as less urgent than the MDEQ, and the test bores are hoped to demonstrate that the earthen berm is not saturated, which might lead the MDEQ to relax its stance somewhat — at least on the timeframe for the closing and dewatering of the headrace.

So if the work is actually proceeding, I’d conclude that the MDEQ had at least agreed to accept the findings of the test bores as relevant to its order.

The foot trail along the Argo millrace berm is open again today. Three “observation test wells” have been installed alongside it, inside blue metal housings (I peeked inside).

There’s also signs of other activity downslope, with neon flagging and a couple of white PVC pipes sticking up.

One of the observation wells is installed near the midpoint of the path, at a location where water is quite visibly seeping out of the base of the berm. I didn’t scramble down to see if this came from one of the notorious “toe drains.”

Incidentally the city staff report presented on the 8th, seemed to me to be an excellent and evenhanded summary. If the current MDEQ order stands, all the timelines for resolving the situation become rather tight (especially for a dam-out solution).