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Posted on Tue, Aug 23, 2011 : 3:32 p.m.

What's the deal with those rocks in Ann Arbor's West Park? And why all the flags around the pond?

By Ryan J. Stanton

Following up on a story that appeared on on Sunday regarding the failure of a new stormwater system at West Park, a reader posed a couple of questions via e-mail.

"I frequently walk through the park and still am puzzled by what appears to be a cascaded water feature that runs along the south side of the park from North Seventh to the pond," the reader wrote. "It looks like it is designed to have a obvious flow of water over the rock cascades but this doesn't seem to be what happens. What water does come down seems to be only a trickle that only serves to cause water stains around the discharge tubing at the cement barrier nearer the pond. Is there supposed to be a good flow? If not, if seems like a lot of work was done for little effect. Also, what are all the flags on the wires in the pond for?"


Signs lay on the ground near other debris at an entrance to Ann Arbor's West Park.

Ryan J. Stanton | made an inquiry to the city to get the most precise answer. This is the response that came from Nick Hutchinson, project engineer in the city's public services area:

"To answer your reader's questions, the area where water now flows over the surface of the park was designed specifically to handle the runoff that comes from North Seventh Street after a rain storm. Therefore, it will have water in it after a storm but not all the time in between. The rock cascades are what we call 'check dams,' and their purpose is to slow down the water during times of higher flows so that it does not create erosion problems.

"The flags are to dissuade geese from landing in the pond and eating the young aquatic plants while they are establishing. The installation will be taken down in late fall after they are firmly rooted. Our parks department is having some small signs made up to explain this, as we do get this question periodically."

Previous coverage: Ann Arbor investigates failure of stormwater system at West Park; residents concerned about floods

Ryan J. Stanton covers government and politics for Reach him at or 734-623-2529. You also can follow him on Twitter or subscribe to's e-mail newsletters.



Wed, Aug 24, 2011 : 4:19 p.m.

Although it is good to have that water infiltrate through the soil, keep in mind that West park water table varies from a couple of feet below the surface and more. Also , bear in mind that the bottom of the pipe joints back in the 20's were made to allow ground water into the pipe. So these joints also increased the loading of water the pipe was made to carry. These joints, however cause irregularities in the pipe, which increases the pipe friction which decreases the flow per unit of time. Then, increasing urbanization happened and there was said to be no money to increase the pipe size, despite vastly greater flow volumes. With study in hand, the joints were mortared - "Lets really get this water moving fast through here" you could imagine them saying. "Then we we can trick out our pipes and make it look like we're really taking care of the problem" (NOT) Many will remember the many sinkholes that appeared in West Park, often wherever the mortar broke loose on the shifting pipe joints and the fast moving water swirled up and carried soil away. Real ankle-twisters. Then, the latest round of alterations - well intentioned but sadly not delivering the intended result - were made. This provides many more points of access for the water that seemingly was "taken care of" by introducing it into the soil. In nature, things don't disappear. They just change form. This recharged ground-water supply (admittedly, now cleaned by soil filtration) now enters the pipe through these new access points and adds to an already overloaded, inadequate system. Not overloaded by inordinate 24 hour rains nor inordinate 1 hour intensities, mind you - but overloaded by the kind of 24 hour and 1 hour rains and intensities that we should and should have expected all along .


Thu, Aug 25, 2011 : 2:15 a.m.

I'm a little confused by this comment. I'm not positive, but pretty sure that that the underground storm drain pipes in the park were replaced as part of the renovation, and the new pipes are larger diameter than the old ones they replaced. So while this is pretty interesting, it seems to be assuming a situation that doesn't exist.


Wed, Aug 24, 2011 : 3:45 p.m.

we have the allen creek area, much of the area is also at the bottom of a moraine (*sp) naturally water goes to the lower evelation, additionally much of the westside neighborhoods (I know the westside better, so maybe it is true in other areas) were built with improper drainage to begin with, that is why so many basements end up with water backing up (as well as raw sewage) whenever it rains hard. Several years ago, after yet another raw sewage backup (and subsequent billing the city for lost and damaged property etc) the city paid for installation of sump pumps in homeowners basements, when the city dude came out he flat out said, "I shouldn't be saying this but, the city didn't even use the adequite water drainage guidelines of the day (in the 60's) when they built the subdivision. So the city knew from day one. Naturally retrofitting it is the challange and most people don't want a big dig in their neighborhood to do something about it. The city meanwhile would rather acquire land for a greenbelt, have more public art, talk about idling cars than work on the darn* infrastructure. If the mayor had poop come up in his basement too, then have to throw out stuff and spend hours bleaching ever surface maybe he'd have half a clue.


Wed, Aug 24, 2011 : 5:30 p.m.

I could suggest (if money were no object, or if it weren't spent on art but infrastructure instead) the following. New subdivisions are built with retaining ponds. Some of the old neighborhoods have natural retaining ponds in the form of lakes. There is a big "lake/retaining pond" behind Wines school, you can see this when you enter the freeway. This helps drain water from that neighborhood as well as some of the Haisley neighborhood. However there is no retaining pond for the Abbot subdivision. Abbot is located on a parkway. The islands could easily be dug up and larger pipes/ culverts for draining water could be placed under the islands. There is a pump station located at the end of the neighborhood which pumps water out (often not successfully as there is too much water, when it rains the men in the little trucks, hardhots and orange vests come visit it. Following the flow of water you come out to the woods through a culvert, there is a stream there that fills with water when it rains. The stream could easily be widened and dug deeper. Follow it further and you come to another culvert which runs under the expressway, this culvert could also be replaced with a larger one, the stream is always much deeper on that side than it is closer to the subdivision, on the other side of the expressway you could put a retaining pond (asumming this is not private property, at least some of it is owned by the state as part of the expressway). Just having the stream widened and a larger culvert under the expressway would create a natural retaining pond. Traveling down dexter on your right before you get on the bridge that crosses the expressway there was an old farm house that was torn down (it was a drug house) That whole property could be turned into a retaining pond by also tying into the lines from the abbot neighborhood (which the haisley neighborhood would tie into as well).


Wed, Aug 24, 2011 : 12:34 p.m.

The August 5th memo to council implies that City and County costs are going to be recouped. This is highly, highly doubtful. This has gone on for far, far too long if the City and County has "got the goods" on the manufacturer ... besides - read the warranty-its only for the material cost - not for the extremely, extremely expensive installation . The City says - well - we've used the swirl concentrators before. But ask the County and the City - when and where have we successfully used swirl concentrators at the 150 FOOT OF HEAD - low end of a 830 acre watershed? And, to add to that - as others have correctly pointed out - where there is an extremely impressive amount of powerful water funneling through West Park? The answer was and continues to be never. And County and City and their Consultants Beckett Raeder Inc. and Environmental Consulting and Technologies should have come to that same conclusion - before - not after the fact. And while were on the swirl concentrators, the manufacturer has requirements regarding protective bollards to protect the swirl concentrators. Though the bollards are ugly, if the decision was made to use these swirl concentrators, they should have been installed according to the manufacturer's standards. They weren't. Why not? And no weight was supposed to bear on the HDPE risers at the top of the swirl concentrators. That also did not hold true. Why not? The County and City and their Consultants should also not have allowed a main path of swirl-concentrator-crushing vehicular travel so close to the swirl concentrators. And if that's not bad enough, the County, the City and their Consultants shouldn't have allowed the swirl concentrators to be unprotected by the protective bollards. It is not coincidental that the one that in fact collapsed completely was closest to the path of vehicular travel.


Wed, Aug 24, 2011 : 4:19 a.m.

More background on the flows through West Park: The idea is to let some stormwater flow relatively slowly over open ground, so that it has time to soak down through the soil into the ground water. There it gets filtered and cooled as it gradually works its way to the Huron. This gradual input is healthier for the river, cooler water holds more oxygen. Also, phosphorus, a nutrient that is in excess levels in the Huron, gets removed as it flows through the ground. Stormwater runoff that just hits streets and goes straight through pipes to the river arrives in a big blast immediately after a rain, is warmer, and carries a load of sediment, pollutants, and excess nutrients that's hard on the river and promotes algae growth. Trapping rainwater and letting it soak in is how things work in natural systems here. It's the same principle as a rain garden, just larger. The stormwater features in West Park aren't going to solve all our water pollution problems, but they help.

Mike D.

Wed, Aug 24, 2011 : 12:03 p.m.

Epenger, you clearly have no business posting on Informed opinions from people with subject area expertise are frowned upon. Only whiny dilettantes who see something they don't understand and then complain about the mayor are welcome here.


Wed, Aug 24, 2011 : 2:37 a.m.

More Hieftjeism! UGH!!

David Briegel

Wed, Aug 24, 2011 : 1:32 a.m.

Bunny, What really would have been helpful is if our civil servants hadn't destroyed our very own Central Park West in such a shoddy and haphazard fashion. Thousands of Ann Arborites have enjoyed the pleasure of West Park only to have these "improvements" destroy the quality of their future enjoyment. And not one single tax dollar should be spent to fix this gross miscalculation! A "professional" engineer had to have signed off on this and he or his liability insurer should make it right! Come on Mr. Mayor, if your staff can't spell at least show some professionalism and fix this debacle!


Wed, Aug 24, 2011 : 4:05 a.m.

"Destroyed"? Hogwash. The Project Grow garden is great, there is theater *and* concerts and the bandshell, and the waterplants around the new pond are blooming nicely. There has been some stumbling, but on the whole I think the renovation has been a big improvement.


Wed, Aug 24, 2011 : 1:17 a.m.

speaking more to the first story regarding hiring a second consultant to figure out what is wrong with the stormwater system, I cant help but wonder why this is not covered under the warranty or insurance of the first project. Why should the tax payers have to pay to figure out what went wrong with the project?


Tue, Aug 23, 2011 : 11:58 p.m.

it would have helped for there to be photos attached to the article to see what it is people are talking about

Vivienne Armentrout

Tue, Aug 23, 2011 : 9:56 p.m.

I am especially chagrined with this mess since I live near West Park. This was supposed to be a major improvement but the city is leaving the impression that hype and performance do not mesh. It is ugly and the approach from Seventh is virtually nil.


Tue, Aug 23, 2011 : 9:41 p.m.

2 sum it up. it is a mess and not right!

5c0++ H4d13y

Wed, Aug 24, 2011 : 12:06 a.m.

It's shovel ready now.


Tue, Aug 23, 2011 : 8:54 p.m.

I ride my bike through the park daily and have noticed another problem. At the south end of the baseball diamond, water draining off the diamond washed about 4 inches of the warning track gravel across the main path and it ultimately ended up in the little stream south of tis area. A few more good gullywasher rains and all the loose gravel on the warning track will have washed into the little water feature. Plus having 4 inches of loose gravel on the path makes it almost impossible to walk/ride through safely. That being said, I think the renovation was a good one and really enjoy my rides through the park.

Charlie Brown's Ghost

Wed, Aug 24, 2011 : 7:56 a.m.

It's probably by design. Ann Arbor has the worst ball fields in the county, if not the state. This will bring this newly-redone field down to the level of the others in town.


Wed, Aug 24, 2011 : 4:02 a.m.

I sent a message about this to the city. The gravel on the path was cleaned up several days ago and the warning track smoothed out.

David Cahill

Tue, Aug 23, 2011 : 8:28 p.m.

I hope the parks department does better on the new signs than on the one in the picture. "Trespassing" is misspelled.


Wed, Aug 24, 2011 : 4:01 a.m.

I think that was a construction company sign, not produced by the city.

Ryan J. Stanton

Tue, Aug 23, 2011 : 8:54 p.m.

Good eye, David.