Ann Arbor officials have the next year to consider two options for fixing Argo Dam
Ann Arbor officials have the next year to consider two options for fixing Argo Dam: either repair the toe drains or reconstruct the dam's earthen embankment.
The Ann Arbor City Council approved a consent agreement Monday night spelling out those terms, officially resolving a dispute with the state of Michigan over a dam safety order.
The agreement puts to rest a costly legal standoff between the city and the Michigan Department of Natural Resources and Environment.
This aerial shot of Argo Dam shows the earthen embankment and headrace that extend to the east. It's the safety of the embankment that has been in question.
The DNRE issued a safety order last August that required the city to dewater the dam's headrace and take other actions to address safety issues. The city disagreed with the state's determinations and disputed the order.
The city negotiated with the DNRE to install a "stop log" in November to stop water flow into the headrace from Argo Pond at the end of the canoe season. Meanwhile, the city installed piezometers to measure water seepage and further study the condition of the dam's earthen embankment.
A report released by the city in December found no imminent threat of failure of the dam's earthen embankment, though it was clear that the toe drains needed to be maintained.
Although the city and the DNRE have disagreed on the extent of the dam's deficiencies, both sides have reached agreement now that supersedes last summer's safety order and resolves the contested case.
The agreement contains provisions for vegetation management, emergency response actions, monitoring and reporting, and a timeline for selecting an option to repair the toe drain system or reconstruct the embankment. It'll be the city's choice.
Sue McCormick, the city's public services area administrator, said the city will be able to lift the stop log and resume operations at the Argo Canoe Livery upon execution of the consent agreement. But the agreement dictates that the stop log be put back in place from Oct. 15, 2010, to May 1, 2011.
City Administrator Roger Fraser said most of the details of the new consent agreement were worked out Monday in the hours leading up to the council meeting. Council members said they were happy to see the agreement come forward, calling it good news.
"I'm really happy to see this has come to us," said Sabra Briere, D-1st Ward. "It is the type of amendment to our agenda that's worth doing at the last minute, and I'm delighted to see this on our agenda tonight."
Section 10 of the agreement states the city must select and execute one of two options — or a combination of both — to either repair the toe drain system or reconstruct the embankment according to the following terms and schedule:Â
- The city must issue a request for proposals no later than Oct. 1, 2010, for the repair of the toe drains and/or for the reconstruction of the embankment.
- The city must apply for the necessary permits for the selected option no later than Feb. 1, 2011.
- Construction of the selected option must commence on or before June 1, 2011, contingent upon receipt of the required DNRE permits by May 15, 2011.
- Construction of the selected option shall be completed by Nov. 15, 2011.
Byron Lane, chief of the DNRE's Dam Safety Program in Lansing, said the concern is that the toe drains — a system of clay pipes underneath the embankment — are not draining properly and that may be causing instability of the embankment.
He said there should be about 60 toe drains — each about 25 feet apart — along the entire 1,500-foot embankment, but only five are visible. Most are buried, he said, and the ones that are showing are cracked and crushed.
"There are issues there — we don't know how bad they are, but they're certainly cause for concern," Lane said.
Lane said a nonfunctional toe drain system can lead to several stability problems. If the toe drain system is blocked, and seepage is not allowed to exit the embankment, that can lead to a rise in water levels within the embankment.
"Seepage may then exit the embankment at a higher location, which could lead to internal erosion of the embankment or erosion of the downstream slope of the embankment," he said. "A second problem that can develop is due to the increased effective weight of the soil in the downstream embankment. This added weight increases stress, causing instability of the embankment. The relatively steep downstream slopes and tree growth on the embankment are also factors that play into the overall stability of the embankment."
Lane said the DNRE is not pushing for removal of the dam. In fact, he said that option has not come up in negotiations with the city, which suggests it's not an option that's on the city's radar at the moment. He said the city proposed the two options in the consent agreement.
McCormick said she expects a broad discussion with the community about the best options for the city going forward.
Ryan J. Stanton covers government for AnnArbor.com. Reach him at ryanstanton@annarbor.com or 734-623-2529.
Comments
Rork Kuick
Thu, May 6, 2010 : 6:58 a.m.
"the real rebuttal was to the claim (originated by HRWC) that the dam was dangerous and must be removed" That's not remotely accurate, and "the city council(s) have merely followed the will of the majority" lacks evidence too, though I must give the rowers credit for their activism. I don't favor repair or fighting DNRE about repair, I advocate removal, thereby avoiding the costs of dam and impoundment maintenance (until it's finally removed at some later date).
Nick
Wed, May 5, 2010 : 5:16 p.m.
And how much is either option going to cost? This is an absurd expenditure in a time when money is short for everyone, including A2.
Rork Kuick
Wed, May 5, 2010 : 2:40 p.m.
"Perhaps if a reputable local environmental organization like the Watershed Council had chosen to abandon its mistaken romance with dam removal and support LOCAL best interest, this waste would not have occurred." Are you saying the Watershed folks caused Ann Arbor to waste money fighting the DNRE? I don't follow. (I might add the Watershed council is concerned with the watershed as a whole. Perhaps you don't want to consider that regional a level, but it makes some sense with respect to water, in order to protect against a tragedy of the commons.)
Rork Kuick
Wed, May 5, 2010 : 2:05 p.m.
"Three times the DNRE has been successfully rebutted and through it all: the Watershed Council has supported the DNRE against ACTUAL evidence". Didn't Ann Arbor just agree to repair the toe drains or reconstruct the embankment, essentially like DNRE wanted? Seems more like useless but expensive rebuttal, no? Maybe I am missing some detail, and if so help me understand.
Epengar
Wed, May 5, 2010 : 11:54 a.m.
^glenn thompson: The problem toe drains are on the downstream slope of the embankment, where they would drain into the river. It sounds like you were looking in the upstream headrace side. If I recall correctly, the dam's spillways and gates are going to need several hundred thousand dollars in maintenance in less than 5 years. It will be interesting to see how the fight goes then. Some months ago, there were rumors that the Veterans Administration medical center was on the lookout for local sources of clean energy and reliable electricity, and might be interested in contributing funds to restore hydroelectric generation at Argo. That might change the economic calculation. I wonder what's going on with that?
Rork Kuick
Wed, May 5, 2010 : 9:28 a.m.
"puts to rest a costly legal standoff". Yeah, how much money has been spent fiddling with this? Is it approaching the cost of having just done what DNRE ask to begin with? Mr. Stanton, in this sentence "In fact, he said that option has not come up in negotiations with the city, which suggests it's not an option that's on the city's radar at the moment." is it you or Lane who is giving the dubious "which suggests" opinion? I still think dam removal is economically and environmentally smart.
Gary Schmidt
Wed, May 5, 2010 : 9 a.m.
Rather than spending hundreds of thousands of dollars from our water fund to fix this thing, we should invest the money where it should be invested: rebuilding our deficient water and wastewater infrastructure.
81wolverine
Wed, May 5, 2010 : 8:48 a.m.
At least this will hopefully stop the wasteful use of public resources on the dam repair issue. The City spent way more time and money debating, fighting, analyzing, and discussing this issue than it would have cost to just fix the dam in the first place when the State originally brought the deficiencies to their attention. This was always just a straight-forward, simple matter of dam maintenance that has gotten dragged out over years, and then made unnecessarily complicated by the Huron Watershed Council's campaign to remove the dam. Hopefully, we can just move on now and enjoy Argo Pond, Huron River and the surrounding trails in their current state like we always have.
amlive
Wed, May 5, 2010 : 8:27 a.m.
Just wait until we get a season of rain like Tennessee had in the last week or two. Nature will take care of it for us - of course the dam will still be intact, but maybe the mill race embankment will make way for the new course of the river, and the debate would be over.
Top Cat
Wed, May 5, 2010 : 7:46 a.m.
I wish the dam would come down but accept the fact that it will be here for a long time.
water
Wed, May 5, 2010 : 7:25 a.m.
Look at #15 on the consent agenda and there is an option to do nothing....or remove the dam.
yohan
Wed, May 5, 2010 : 12:01 a.m.
But we have the people on our side The dam will stay
braggslaw
Tue, May 4, 2010 : 10:07 p.m.
Charley, I have time, the environment, science and money on my side. The dam will come down.
markguy
Tue, May 4, 2010 : 8:15 p.m.
I'd really like to be there when they pull that plate out. Should be pretty cool seeing the water rush in, at least initially.
Charley Sullivan
Tue, May 4, 2010 : 7:11 p.m.
Bragg, you've lost that argument. Give it a rest.
braggslaw
Tue, May 4, 2010 : 7:07 p.m.
The dam should be torn down.
glenn thompson
Tue, May 4, 2010 : 4:11 p.m.
I think we are again inflating this problem. I believe the toe drains are 20 to 25 feet apart, this was from one of the maps of the area. The millrace is about 1500ft long therefore there should be 60 to 75 toe drains, not 90. A friend and I went looking for them last summer. In the section we looked we found almost every one. We only looked along a section of the millrace, but even in that section more than 5 were visible. Most appeared to be clear and flowing a small trickle of water.
Andrew Thomas
Tue, May 4, 2010 : 4:07 p.m.
Good news -- I've really been looking forward to the start of conoe season. Just paddling around Argo wouldn't be the same.