Ann Arbor reaches partial agreement with state over Argo Dam concerns
Ann Arbor officials announced today they've reached an agreement with the state to immediately begin removing dead and overhanging trees and woody brush from the headrace embankment at Argo Dam.
This aerial photo shows the earthen embankment that extends to the east from the concrete portion of Argo Dam.
City officials met earlier this week with the Michigan Department of Natural Resources and Environment to discuss vegetation concerns that were first raised by the MDNRE in a safety order last August. The city has been disputing the state's claims and recently hired a consultant to conduct a study that concluded there was no threat of failure, contrary to what was suggested by the MDNRE.
City officials said the brush being removed consists primarily of non-native invasive species.
"These deep-rooted woody plants obscure the toe drains and embankment, making routine inspections difficult," the city stated in a press release. "The root systems of the plants also cause a shift in the groundwater flow in and through the embankment, potentially compromising the stability of the embankment. Because of this, the MDNRE asserts that earthen embankments must be free of woody vegetation."
The city also must develop a vegetation management plan that will include both short- and long-term strategies for managing all of the woody vegetation on the embankment.
The city plans to submit a draft plan to the MDNRE in the next two weeks for review and approval. Negotiations on the remaining items in the dam safety order issued last August will continue once the city demonstrates substantial progress in removing the dead and overhanging trees and woody brush.
The city plans to have crews begin working on the embankment on Thursday, and needs to demonstrate substantial progress to the MDNRE within the next 30 to 45 days.Â
Currently, the headrace remains closed, city officials said.
Ryan J. Stanton covers government for AnnArbor.com. Reach him at ryanstanton@annarbor.com or 734-623-2529.
Comments
a2grateful
Thu, Mar 25, 2010 : 2:30 p.m.
Thanks for that link to Chelone Obliqua, aka Purple Turtlehead. Legally protected? Why? "A perennial forb of southern floodplain forests"... Is MI now considered to be in the south? It's not supposed to grow here, right? Global rank? Secure. What is wrong with this system? How did this get classified as native MI species?
aanative
Thu, Mar 25, 2010 : 9:53 a.m.
Sounds like a job for the rowing clubs that have been so adament about retaining the dam!
KJMClark
Thu, Mar 25, 2010 : 6:53 a.m.
81, I read the invasive species bit the other way. There will be people who will be upset that the city is removing all of the "beautiful trees", even though the trees are about half invasive and half trees like boxelder and cottonwood, that are native but weedy. It will look a lot different. It will go from a barely passable jungle look on the trail over the embankment to looking like the Barton Dam embankment, just grass and maybe some shrubs. And it won't necessarily be easy to remove the trees. The easiest thing to do is clearcut, but that will leave a lot of ugly stumps, many of which will resprout (unless they use herbicides close to the river), and may cause a good deal of erosion until the grass grows. It would be tough to mow as well. OTOH, if they remove the stumps, the erosion problems will quadruple. Notice that the press release doesn't say they're removing all of the trees, so they're starting with the invasives and dead trees.
81wolverine
Wed, Mar 24, 2010 : 8:08 p.m.
Removing the trees should have been done years ago. This is an extremely minor issue compared to fixing the toe drains. This announcement by the City is a facade designed to make it look like they're taking action. The truth is just what Karen said. This was directed back in 2001 by the state and has been delayed repeatedly by the City. So, this is NO news item at all. I like the sentence: "City officials said the brush being removed consists primarily of non-native invasive species". Geez. Who cares? This is a non-natural berm created when the dam was built years ago. Furthermore, the species of plants should make no difference in deciding to do something related to public safety.
Karen Sidney
Wed, Mar 24, 2010 : 5:16 p.m.
I'm glad the city finally getting around to doing what the DEQ (now MDNRE) asked them to do back in 2001. It would be interesting to compare the cost of doing what the DEQ requested with the legal fees and staff time of fighting the state safety order.