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Flooding townhouse back yard

Posted by joshharden222 (My Page) on
Thu, Feb 13, 14 at 18:42

Hello all,

Looking for some advice here. Within the past year I moved into my current home, a center unit townhouse. Our row of townhouses was built poorly, so the ground slopes towards the house with nowhere to go, so it just pools there. Since I'm a center unit I can't divert the water to the sides. I have a constant issue of water pooling in my back yard for the first 24 hours after raining, and the ground remaining soaked for a good 4-5 days depending on the amount of rain. If it rains enough, water actually starts to seep into our 1st floor (ground level). I've searched pretty thoroughly but every drywell/French drain solution I see doesn't quite apply, so I'm looking for some advice anyone might have. Attached is a picture of our home, our fence line, and where the water pools/ground is soaked.

Idea 1 involves digging a hole at a 20 or so degree angle and putting pvc pipe in there with holes towards the bottom. Hopefully this would move the water from where it collects, to underground where the water isn't. This is my favorite idea since the ground near our fence line dries quickly and normally, so it isn't as saturated.

Idea 2 involves large drywells, like a flo-well, to just collect and hold the water. I worry these will fill up quickly with the amount of water our back yard gets. I also worry the ground there is already saturated, which is why the water is collecting there anyway.

Idea 3 involves the same thing as Idea 1, just straight down. The water will be in the same place, just able to get further underground. I again worry that the ground is already saturated there so this might not do much.

Thoughts? Experiences? Is this hopeless, or will one of those ideas work?


Follow-Up Postings:

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RE: Flooding townhouse back yard

Can you not sink or lower a 50 gallon plastic barrel into ground and use it for water collection and then pump it out to storm drain by a flexible pipe otherwise use it for gardening.

Another idea is to grow water loving plants in that area.


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RE: Flooding townhouse back yard

  • Posted by SC77 6B (My Page) on
    Thu, Feb 13, 14 at 22:37

I think we will need an actual photograph. You said the grade slopes toward the house, so how will you route pipes at a 20* angle back away from the house? And where will it drain to. You can't just route it to dirt, you will need a huge underground pool of rocks or something fast draining. This wouldn't be a DIY job and you would have to be able to get some heavy machinery back there. Not sure you could do that, as you would have to drive it through the other end units yards?

Do you have a gutter that currently drains into this area?


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RE: Flooding townhouse back yard

To be of any real help to you we will need a vast amount of data and details on your property. You could start by telling us your town and state.


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RE: Flooding townhouse back yard

To answer all questions in one:

hvp1962; I am unable to pump it much of anywhere since I am a center unit. To compound the issue, my neighbors on both sides have similar water problems, so any solution will involve me building up the soil at the fence line a few inches so their water doesn't become mine. I am very open to the idea of water loving plants, nothing too large, but maybe some tall flowers would be nice?

SC77; Two gutters drain in the backyard. I attached a picture.. the standing water is actually a bit worse on the right side (not pictured). It had very recently stopped raining when this was taken. You can see the standing water, and that area will remain soaked for days.

pls8xx; Jessup, Maryland. The water drains fine elsewhere in the neighborhood, so I don't think i'm sitting on clay or something not very porous.


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RE: Flooding townhouse back yard

Josh,
Do you own this home?
It's a grading issue, which means all of the homes need it along with you.
If you don't grade it correctly, which means the water MUST run away from the home, you will always have problems.
And the problems will get worse.
Water is your homes WORST enemy.
Is this an HOA?
Do you have a deck above the yard in the pic you submitted?
Sorry, I wish it was an easy fix.


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RE: Flooding townhouse back yard

From the photo looks like the volume/qty of water is less than 100 gallons. Your idea 2 looks good to me. Two wells on either side. You can always deepen the well later if required. Cover the well.

Since the soil is not hard clay, water should seep out pretty fast. You can always dig a test well to see how fast it drains.


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RE: Flooding townhouse back yard

As far as I understand them, all of the schemes you propose are some version of a finite capacity french drain. I would give up on any of them being actually able to solve your problem. You might obtain some small degree of temporary satisfaction, but there will always be a bigger rain storm out there that will bring you back to being frustrated over this problem. Water loving plants are not really a practical solution to this problem either.

With this type of problem you must explore not just your yard, but the larger area in search of the nearest lower elevation land, looking for the path to it and how you can get the water to take that path. If you're at the bottom of a mountain valley and every direction leads upward, you're screwed. But if you can walk some near distance away and find lower land, you might have a solution. The best solution is if you can scrape a channel into the surface of the ground, all the way to the lower land, that allows the water to run freely and unobstructed. Of course, after you scraped the channel, you would dress things up by smoothing and blending its "banks" into the surrounding grade so that it looked nice and wasn't a danger.

If doing so would mess up ground in such a way that it will cause problems for others, then you can consider if it's possible to install a pipe that runs from your problem area to that lower land. If so, you can place a catch basin drain in your yard which is connected to an underground pipe. Run that pipe (solid pvc with glued joints) all the way to the lower land (it must run at a uniform downhill slope no less than 1/8" per foot, but more is better) where the water will empty out. After the pipe is installed, then its trench is backfilled and the land put back in the same condition that it was before you started. Of course, any of the work you do must occur on your own property or be with the permission of the landowners. I would think the HOA would have some responsibility if it is their property that is blocking your proper drainage. You might consult with them to see if they can be any help. If they won't, you might consult an attorney to see if they have any culpability. There are usually laws that say one landowner cannot block the drainage of another landowner.


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RE: Flooding townhouse back yard

Your picture is confounding me a bit. What's beyond that back gate? A strip of common ground for utilities and development lawn mowing and maintenance? Another close row of townhouses?

In a townhouse development, you customarily only own (or rent) the house, the development owns the land it's sitting on - and in the original construction it seems that lousy or no real proper grading was done. I'd wager you could dig down a bit just barely under the sod and find all kinds of "hidden" construction debris.

Since you've already experienced water seepage into the house, I'd take some good pictures, talk to the neighbors in your row to get everyone with the same issues together and see what, if anything, the HOA will do to mitigate the problem first; seek legal counsel as a second resort. There's strength in numbers, but the HOAs have lawyers too - and usually good ones.

A rain garden doesn't soak up water - they're comprised of plants that do well in wet or boggy conditions. Water loving plants won't dry out the yard.


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RE: Flooding townhouse back yard

To those wanting a better overall picture, see attached. The yellow dot is my house (we own). The blue is the low area which follows all homes in the row, and the red is the high point. Directly north you can see the fence line of the next row of houses. This is obviously a pretty pour grading decision by the original builders. Unfortunately, I don’t have much confidence in the HOA being useful. I have already dealt with them on a parking situation (one neighbor with 9 cars, really?!) and no results. Typical HOA here.

To Yardvaark’s point, fortunately I think I have given up thinking I can combat every rain storm that comes my way. However, if I lessen the impact from the more frequent smaller ones/snow melt, I will be much happier. I realize that heavy rains will still be bad, but due to the layout of our row there isn’t much I can do.

All things considered, I really want to avoid dealing with the HOA and the neighbors. The neighbors obviously don’t care since they have the same problems and have lived her much longer than I have. I’m still leaning towards my original idea 1 and 2. The soil near the top of the hill/fence line dries much quicker, which is why I like idea 1 since it will help drain water to drier spots. Idea 2 definitely seems easier, though.


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RE: Flooding townhouse back yard

This Old House had an episode showing a large dug out pit lined with landscape fabric filled with gravel and a perforated heavy duty plastic collection tub (looked like a smaller version of a cement 'beehive' cesspool. It had a connection on top that would float up and allow water to 'escape if it filled the 'beehive.

It was fed with Bainbridge (?) perforated pipe, in a gravel bed surrounding it and fabric once again to keep it from plugging up. This wouldn't be cheap, but it seems that it would be an effective way to help with the problem. I think building up the level will get you into trouble with the neighbors and probably with the city at some time....and maybe in court if a permit is not pulled.

Jon


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RE: Flooding townhouse back yard

In general, it appears from your sketch that there IS a swale intended to collect water from the back yards and run it left and then toward the front toward parking lot. Is that correct?Since there is only one unit left of yours it seems most likely that something was done to alter the grade next door and changed its ability to drain. Is this neighbor blocking the escape of water in any way?


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RE: Flooding townhouse back yard

  • Posted by SC77 6b (My Page) on
    Sat, Feb 22, 14 at 21:54

I was thinking of an episode of This Old House as well.. I couldn't find the exact episode, but they do have a pretty good DIY guide on building a dry well. Based on the picture above, the slope doesn't look too bad, so I think you could handle this yourself. Lots of digging and hope you don't hit any massive rocks. If you do hit massive rocks, you will need to get them out yourself. I'd recommend a hammer drill and wedge and shims. I have been very successful using this method on huge granite rocks. Or... you can use a Dexpan instead of wedge and shims (sometimes called wedge and feathers)... to get the job done.

Maybe before you do this, you could install rain barrels to catch the water coming off of the gutters and then re-evaluate how much of the problem is coming from your own downspouts and how much is the grading. I'd recommend getting the cheap 55 gallon food grade barrels off craigslist and just building them on the cheap. You could even re-use them for the dry well after evaluating the problem.

If it seems to be majority grading, you will need a drain at the low spot like This One. The drain can be used in combination with a "rain garden". The plants won't do anything to soak up the water. The idea of a rain garden is to incorporate river rock, which you would fill deep down to improve the drainage. You could build it at the back of the fence or on the sides, depending on where you are finding the most water is coming in from (I assume the back slope?).

Here is an example of that: River Rock drainage solution


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RE: Flooding townhouse back yard

In general, these drainage and flooding questions can easily involve, not just what is happening on one's own lot, but what is happening on the land outside of and surrounding it. If those pieces of the puzzle are not provided, it might not -- probably won't -- be possible to provide good advice about how to SOLVE the problem. Instead, you might get band-aids and cough syrup for what turns out to be a viral ailment. These things don't cure, they treat symptoms.

I will re-ask the questions again, this time referencing the picture:

From point A to point B, is there a uniform slope? Does it fall or rise?; about how much? For point B to point C, same questions.

it is usually is easy to determine, in a rough, but reasonably accurate way how much higher the distant elevation is. Stand at what seems to be the low end, measure from your eyes to ground and note that measurement. Keep your eyes aimed level (use a carpenter's level as a guide, if necessary) while sighting to the opposite end. Sight on a distant reference point which is level with your eyes, make note of it for later reference and measure from it to the ground. Compare the measurements from point C to point B, and from point B to point A, to determine the differential between the pairs of locations. The differential represents an approximate elevation change between each pair of points. Measure, by pacing off in 3' strides, the linear distance from point A to point B, and from point B to point C. (Post all measurements here.) This will allow the approximate slope to be calculated, which should be at least 2% for there to be a reasonable expectation of achieving drainage.

Observe if other homeowners have built structure in the drainage swale that would stop or impede the flow of water. Observe in particular, if any structures have been built at the end unit left of yours. What is the object I've marked between the two yellow arrows, which appears wall-like? Is there anything built at that end unit that might impede the flow of water coming from your unit?

It would be helpful if you added pictures taken from where I show light blue arrows.


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RE: Flooding townhouse back yard

If you seal the fence perimeter by constructing a berm all-around the fence, you can at least prevent neighbors water coming into your property. Than if you change the slope of the ground towards north away from your house (bit of hard work) than you can shift the water-logging issue toward your back door side.

For that you need to construct another berm towards your house also. Basically changing the slope direction to the other side so that the water flows toward the back door.For this to work the three sides of the fence should be somewhat watertight and there will be difference in elevation along the fence on both sides.

Just a thought.


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RE: Flooding townhouse back yard

Very crude sketch attached


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RE: Flooding townhouse back yard

If this property is laid out with the swale as I have speculated (though this remains still unconfirmed) it would be a huge mistake to start berming up around it, ignoring the effects it has on the neighbor immediately upstream ... as where will their property drain? They would have the legal right to force the berming person to undo their work.

I am also speculating that this is what may have already happened at the end unit at left. If it's the case, the proper solution would be for that owner to undo their work, or for a suitable work-around to be found. We can't know what it really is until the OP answers some question and confirms information.


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