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City of Ann Arbor SSWWEP - Citizens Advisory Committee Coordination — City of Ann Arbor

2.102 -O- Can grading help reduce peak footing water in target areas?

Posted by Lori Byron on 28 Jan, 2014
Category: Category 2 - about potential recommendations

Frank Burdick’s Log Number: N/A
Submitted by: Email, from resident
Category (1,2,3): 2
Status: Open
Estimated date to address: N/A

Q. There are a number of possible  fixes to reduce peak footing drain water particularly in a target area like Lansdowne, with external grading, if it can be shown that preventing surface water from entering the backfill is effective. (The two lakes adjacent to my house must have had a major dilution effect...) A possible "on-the-table" candidate?

A. This idea, as well as many others will be considered during the alternatives evaluation portion of the project.

Comments

Jim Osborn on 28 Jan, 2014:

This statement, posted as a question, is interesting. I'd like a lot more detail, though. If, as I suspect, it is mentioning a method to reduce the ground water saturation near a home's footing and therefore the water that enters the san. sewer from the footings, I'd love to have data that can prove how much. Also, this must be for a neighborhood, since doing this to one home might only increase the flow from a neighbor's footing drains. So, the overall storm drain system is very important.

Frank Burdick on 29 Jan, 2014:

This makes sense considering the "bath tub" effect that has been created at each basement excavation and the impervious nature of the hard packed clay in this Lansdowne area.

Peter Houk on 1 Feb, 2014:

More info on this topic should be a high priority.  Can we significantly impact flow into the footing drains by grading and other changes around the foundation?

Jim Osborn on 1 Feb, 2014:

I have wondered about this topic for a long time, and feel that it needs further information. It might be an effective solution. I wish I could have attended that meeting last Wednesday. Are there minutes or notes from that public meeting?

Joe Conen on 1 Feb, 2014:

Jim, I do not think you have to take a neighborhood approach to gain benefit from this option. Grading a yard to divert flow away from the foundations (or reducing soil permeability near the foundation) does not have to result in the flow impinging on another home's foundation; the flow should divert around a foundation toward the drain system.  In addition, it may be most beneficial to start at homes at "the bottom of the hill" where the uphill flow may already pool.
In some areas, though, some of the flow may result from the relative height of the water table at the home, so that grading near a home may not reduce the underground flows.

Jim Osborn on 1 Feb, 2014:

Joe, all true, but if the drain system is at capacity, then this fails for those homes at the bottom of the hill. I suspect that increasing the storm water drain system may be needed in those areas where the water collects, forming pools from the top of the curbs or more.

yard grading definitely benefits those homes closer to the top of a hill.

Peter Houk on 1 Feb, 2014:

I wonder if a carefully considered house-to-house campaign of grading could ever be a permanent solution.  A future homeowner who didn't understand the importance of proper grading could undo the work to make way for landscaping.  Or could settling and shifting of soil eventually reduce the effectiveness grading improvements?  

Jim Osborn on 1 Feb, 2014:

If done right, it cannot settle enough. Most home owners do not regrade a yard, and if they do, most will improve it rather than harm it. Still, some future homeowners could undo it, but a very small percentage.

Joe Conen on 3 Feb, 2014:

We had to do some minor regrading many years ago. We were getting damp walls in our basement, and we noted that in several locations near our house the ground had settled. The regrading was minor (included some reroute of eves drains further away from walls), but it encourages water to drain away from the wall. We still have low spots in our yard where water will pool away from the house; we did not try to regrade the whole yard.
Peter,
As far as I know, all solutions will require some level of care and maintenance t be permanent. To date. we have not had to do further grading work - about 20 years now.
Jim,
The pooling at the bottom of the hill you describe requires its own solution. Keeping water away from the walls of an uphill house should be every homeowner's goal.