View Full Version : Drainage/Rain garden
I am in the process of writing up an estimate for a commercial customer of mine. At one of his properties, the building has a berm built up making an area for drainage to collect. I have attached a picture, hopefully it opens correctly. My question and his question, is do I need to contact the city in order to be able to make this into a rain garden. I wouldnt be doing any grading or removing of the soil, but rather would be adding stone and boulders, and moisture bearing plants to the area. With that being said, any recommendations on what types of plants I could look into, as well as any ideas to keep the unsightly wet/muddy center area unseen or cleaned up?
05-11-2009, 09:15 AM
From the looks of it you shouldn't have to contact the city to do anything you describe. As far as the water filled ditch line it with river rock like the beds against the building. Are you going to do anything with the downspouts ? just doing something with those ugly things would be a big improvement.
This was obviously an intended thing. Rain/gardens, grass lined swales, bioretention areas, and such are the current thing in "Planner Land". More than likely, this was a required feature in permitting the building. You should contact the Planning Board, or "Growth Management", Zoning Board of Appeals, or whatever board approves commercial site plans in your city. It is probably in an Order of Conditions.
They are a great and worthy concept, but more often than not the result is something that looks like this.
Keep in mind that adding rocks won't make the soil take in that water any faster. For it to work better, you would need to increase the surface area of the soil which might not be very easy because of utilities. A stone lined trench would do that (surface area of the sidewalls absorbs water, too).
PS. Watch out for dragons.
Dreams To Designs
05-12-2009, 10:32 AM
Andrew, are you challenging the myth of "magic rock"? You mean piling rock in a wet area doesn't magically make it go away? I see it all the time at the bottoms of downspouts, drain outlets and in swales...
This was likely exactly as AGLA has stated, an intended area for drainage permeation, but neglect has created a marshy grass mess.. Checking with the appropriate authority and determine what restriction or assistance they can offer, is the first move. It's proximity to the building and utilities, (electric & phone) would make me question it's intention, but things change onsite. The solution is rather interesting and an excellent educational tool on what not to do with downspouts, but hopefully it was a temporary fix, until a solution could be implemented.
This would be an ideal location and use for a rain garden, but the maintenance will be nearly as important as the design and installation. That maintenance is more costly than just having the turf mowed, but will insure a properly operating drainage system. Are stone and boulders local to your area? If so, use that type of material for your accents. Be prepared to find the permeable layer of soil and create a planting bed and filtering layer of soil to remove all the water it collects, in a reasonable amount of time. Getting rid of that standing water has got to be the goal, filtering it and make a beautiful garden are the true benefits.
I would like to think I could handle this job, bring in some washed stone, and larger boulders, but I know there is more to it.
Dreams to Designs could you explain, "Be prepared to find the permeable layer of soil and create a planting bed and filtering layer of soil to remove all the water it collects, in a reasonable amount of time."
How would you go about this project? I was thinking add some washed stone, along with a good deal of larger (accent)boulders,rocks to help hide the standing water, and plant some water bearing plants on the outer walls to hide whats in the middle.
Dreams To Designs
05-13-2009, 07:30 AM
this will give you an idea of the type of soil you are dealing with and it's permeability. It does not take into account what a builder may have removed or added. The site is a bit cumbersome to deal with, but the information is worth the aggravation.
Hiding the runoff is not a viable solution, if you are going to do this properly. All soil has a degree of permeability, sand allows water to run through more quickly than clay, due to it's structure. If you are able to find a reasonably permeable layer near the surface, you need to take advantage of that and get the runoff to that layer so that it will infiltrate back into the soil, to recharge the the existing groundwater. By lining your drainage ditch with the right type of soils and plants, you can filter that water returning to the ground and keep the contaminants from polluting your drinking water.
The types of plants, construction methods and additional information can be found at many sources on the internet.
05-17-2009, 11:15 PM
It is obvious from the picture that this is a fairly new building. The Soil Survey would be helpful if this was an isolated building in the midst of farmland or undisturbed area. In any urban development such as this the existing soil will be nothing like that described in the Soil Survey if it even has a description. During construction the various soil layers get removed and / or mixed with other layers.
The biggest problem is loss of soil structure and compaction. Soil particles naturally 'clump together' to form structures that allow water and air to move through the soil. When machinery is driven all over the soil, especially when it is wet, the soil structure is destroyed. Much of the pore space is eliminated which inhibits root growth and water movement. In order for a rain garden to work on disturbed soil you need to remove or bypass the compacted layer. It is common practice to remove the compacted soil layer and replace it with an appropriate soil blend that will drain. The Bruce Company sells a DNR approved soil mix for rain gardens. Contact Amy Sausen at The Bruce Company for information.
I would say that maybe a bigger problem is that planning people are getting too aggressive about where and when to require rain gardens. It is the "in thing" and the planners are being told that they need to go anywhere and everywhere and the planet will be a better place.
Sometimes, they force stupid solutions.
05-18-2009, 08:43 AM
fill in the ditch and create a large (8") (maybe 2) subsurface drains that catch surface water and water from the roof.
I would say adding a surface drains wouldn't be a bad idea, unfortunately the bermed up drainage area was made for a reason. Thank you for the reply's I will do some more research and see what I come up with.
PSU tur: Thanks for the local advice!
This is clearly a requirement by a regulatory board and you can't just decide to change it into something practical and reasonable without finding that out.
05-19-2009, 08:32 AM
This is a totally different direction than everyone else but here it goes. Have you checked the pitch to see where the water is supposed to go? I am looking at the picture thinking that this was intended as a swale to get the water to another place and the person who did the grading didn't do their job. If you were to raise the bottom of the ditch six inches (just a thought) and have the grade pitch both directions gradually and properly, where could the water go?
It just seems like a low spot in a ditch that was intended to get the water away.
My 2 cents
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