Backyard Drainage Woes
March 19, 2015 8:16 AM   Subscribe

We have a lake in our backyard. We'd like to fix it, or get it fixed, cheaply.

It last rained 5 days ago, and there is still water standing in our backyard. As mosquito season approaches, this is a health hazard, and also generally terrible for the vibe of our backyard. We also have 2 large dogs and I live for the days when I am not wiping off muddy paws 8+ days after the last rain. We have lived with this problem for 3 years, so we know that it is a year-round issue.

We have a large, flat backyard other than a low spot where an old concrete pad was torn out. Our neighbors' yards are also essentially flat, and their yards also flood. We are not really sure what the problem is because our entire neighborhood is basically flat as a pancake. I guess maybe that IS the problem? There is just nowhere for the water to go. There us about a 15' x 15' area where water stands for days on end, but when it is raining hard (I'm not talking some 100 year storm... basically any hard rain, happens about once a month and more during the winter) almost our entire yard is under water. Then as the water slowly drains we are left with weeks of soggy ground and sticky mud.

Had a drainage guy come out and give a quote today that was way more than we want to pay. He wants to put in 2 catchment basins and a sump pump to pump water out to the street.

We are unwilling to just backfill the yard and make our neighbors' problems worse. We know there will be some kind of digging involved. We only have a 9 foot gate opening so I don't know if that would limit what kind of machinery can get back there.

How can we determine whether a sump pump or necessary? Would a giant dry well/gravel filled pit accomplish the same thing? We can't do French drains because there is no grade to speak of. Is a sump pump something we could reasonably DIY?

Our ideal budget is $1000 or less. Is this even semi-reasonable?

Note: We are on a raised/crawl-space foundation (not a slab) and don't get water in the house or in the crawl space. The biggest problem area is about 30' from the house.
posted by raspberrE to Home & Garden (21 answers total) 4 users marked this as a favorite
You have a vernal pool -- which is a really important natural habitat. You most likely have soil very rich in clay, which expands when wetted and creates a seal so the water can't move through.

Also, you may live in a natural wetland. You can find your location on the National Wetlands Mapper (click "mapper" under step 3). Humans have routinely destroyed wetlands for their own convenience -- I would strongly encourage you to find a more environmentally friendly solution that would not destroy the vernal pool.
posted by DoubleLune at 8:40 AM on March 19, 2015 [3 favorites]

A french drain is independent of the grade (or lack thereof) of your yard. You create the grade for the drain when you (or your contractor) dig it.
posted by dukes909 at 8:40 AM on March 19, 2015 [8 favorites]

While you're figuring this out, consider using mosquito dunks to keep the bugs under control. It's all fun and games until someone gets West Nile.
posted by workerant at 8:47 AM on March 19, 2015

Do you know where groundwater is at in your backyard?

If groundwater is super-shallow, well, there's your problem. There's no place for the water to drain to because the soil is just full of more water. If this is the case, a drywell (or french drain) will do nothing, because you can't drain faster into soil that's already saturated with water. You have to actually remove the water from the area, which is where a sump pump going to the street/storm sewer comes in.

If you don't have shallow groundwater, you may just have a drainage issue (and/or clay soils, as noted above), in which case a drywell or french drain might be effective.

I'm not touching the question re: ethics of removing wetlands habitat, or the related question of whether your yard would actually be considered wetlands habitat in your jurisdiction (tl;dr: it depends). However, I would note that this can be a regulatory/permitting issue in some areas, depending on where you are. (Backfilling would also be a potential permitting issue.)

Based on how you describe this, I suspect you live in an area with very shallow groundwater -- in fact, that's probably why you don't have a basement. I would check with some additional drainage guys and get some new quotes, but I really doubt this would be possible for under $1K.
posted by pie ninja at 8:51 AM on March 19, 2015 [2 favorites]

What's your ideal end point? Is it that you want to use the backyard or that you want it to be less of an eyesore?

I'm inclined to be in the 'if you can't beat 'em, join 'em' aka 'it's a feature, not a bug' camp and were it me, I'd be inclined to research what kinds of ground cover and trees might embrace those conditions. We have a muddy area in our front yard that has a date with some pachysandra and a river birch or three.

Depends on how much water and where you live, but the best use of the money might be landscaping a bog garden which would be pretty and environmentally friendly.
posted by A Terrible Llama at 9:03 AM on March 19, 2015 [3 favorites]

If it is a true wetlands, you may need local town approval to touch it.
posted by 724A at 9:03 AM on March 19, 2015

I planted a couple of weeping willow trees in wet spots in my backyard. Those trees can suck up some serious water. It's not an immediate solution, obviously, but it is a cheap and easy solution.
posted by COD at 9:10 AM on March 19, 2015 [7 favorites]

I suspect that it is not a vernal pool, since those are seasonal and generally appear independently of rainfall. I have a couple on my property and they dry out by mid summer.

Your whole neighborhood probably sits on a very high water table, in which case you are mostly hosed. Consult your town's records regarding wetlands. Your property may or may not qualify.

Consider planting a rain garden, it will help with the standing water. Add raised walkways. Don't know how to help with the dogs and the mud, though, sorry.
posted by lydhre at 9:11 AM on March 19, 2015 [2 favorites]

Response by poster: A terrible llama -

Ideal endpoint is usable backyard for us, future kids, and dogs... i.e. grass. We don't really care how fancy it looks (doesn't need to be a beautifully manicured golf course) as long as one can reasonably walk through some part of the backyard without muck boots on.

A rain garden would be ok except that the wet area is smack in the middle of the yard and also taking up most of the actual ground.
posted by raspberrE at 9:15 AM on March 19, 2015

Response by poster: Pie ninja -

How do we find out where the ground water table is? We don't have a basement because we live in an area of the country where literally no one has a basement.

According to the wetlands map linked above, we live about 5 miles from the nearest wetland (that surround a small river). I don't think our neighborhood is a wetland, given the giant concrete drainage ditches that criss cross the neighborhood. Unfortunately, the nearest ditch is about 5 blocks from our street.
posted by raspberrE at 9:18 AM on March 19, 2015

Maybe a berm? Eventual playscape/sandbox/dog house on top?

You would need to consult with some sort of engineer to get a sense of whether that's going to simply mitigate your problems or cause new ones for the neighbors....
posted by A Terrible Llama at 9:22 AM on March 19, 2015

Are your downspouts emptying into your yard when it rains? If so, you could gain some immediate improvement by connecting a drain tile to each downspout, burying it in a trench, and channeling that water elsewhere. You would be surprised by just how much water comes off your roof when it rains. I've seen drain tiles routed from the downspout to the curb before so that the water goes into the street.

Our house sits on a slab of rock, so the water percolates up from the ground. Bringing more dirt in wouldn't solve the problem because there's nowhere for the water to go. We're getting a french drain installed this spring, in addition to a dry creekbed to channel the water away from the main part of our yard.

Dry creekbeds are pretty big DIY projects, but definitely doable if you don't mind a lot of heavy labor.
posted by Ostara at 9:30 AM on March 19, 2015 [1 favorite]

Civil Engineer here, do you have any photos you can post? sometimes a picture helps (also, if you are comfortable, pm me your address or at least a crossroads in your neighborhood so I can look at the situation on Google earth).

There are several possibilities, some easy to fix, some are just what you got and nothing can be done.

-Clay/poorly drained soils (covered above just fine)-not much you do except try to get the water out to the public drainage system in your street.

-High water table-contact your local public works department and see if they can tell you the water table in your area, or see if their is any well drilling logs available in public records. If your water comes from a municipal well your water utility can probably tell you also.-this is also a not much you can do problem except pipe out the water.

-compacted soils-some soils can compact really well during subdivision construction so that you get a hardpan that develops a few feet below the ground surface. This effectively makes for an impermeable layer that water can't drain through. This is very common in area that used to be farmland but is now a residential subdivision. Years of plowing than driving construction equipment over it can really, really compact a soil and produce this result. This is kinda a best case scenario because you can dig through the compacted layer and then a drywell/raingarden is going to work great.

-blocked drainage channel. Unfortunately a lot of subdivision end up being 'mass graded' and this totally blocks and fills the natural low spots and drainage paths. Mass grading means the developer came in, and just move all the dirt around, knocking down the high spots and filling in the low spots to make a big flat table. They do this because it is easy and cheap to build on. If this is what you are dealing with there is, once again, not much you can do except pipe it out to the public system.

A caveat about piping it to the public system-there may not be one that is adequate or even one that exists depending on the scruples and oversight of the developer. I suspect this may be the case since you mention that the whole neighborhood is this way (once again without context I can't really give much more guidance on this). I would contact your local public works folks (hopefully you are in an incorporated area and there will be some kind of municipal public works department to talk to) and see if they can help you.
posted by bartonlong at 9:39 AM on March 19, 2015 [5 favorites]

A 9 foot gate opening is more than enough to get a Bobcat (properly generically a "skid steer loader") into the backyard. Ought to be big enough for a small dump truck, too.

The Bobcat, if you are good with machinery, you can probably rent and use yourself. They'll run you a few hundred bucks for a day and a rental place should drop it off and pick it up. You'll probably need to have someone deliver other materials, principally crushed stone, if you want to do a drain system yourself.

The first step is to call the "Dig Safe" hotline for your area and have someone come out to mark any underground utilities on your property so you can be sure that you can dig in the yard without any issues. This is super important, do not pass go, do not skip it. Generally if you call them and they fail to mark something and you hit it, problem is on the utility company; if you don't call them and you hit something, joke's on you for the cost of the repair. It's free, just get it done. NB that they won't mark septic systems which you have to be careful driving over, if that is something you have (going to guess/hope with your drainage issues that you don't!).

Anyway, once you are sure you can dig, you could rent a Bobcat for a few days and dig trenches to put in French drains (the process involves digging trenches, putting in crushed stone, putting in drain tile, then more stone; it'll be a few days of hard work at the very least) and have them all lead to a drywell. It seems very doubtful that a drywell on its own will dispose of the water; if that was the case you probably wouldn't have a pool on your lawn. So an outdoor sump with a pump that takes the water via a waste line (needs to be below the frost line!) to a storm sewer might work ... but you will probably need to check and see if that's kosher in your area; some places don't like you dumping sump water into storm sewers, some may require a stormwater/runoff permit, others may not mind. Oh, and a building permit may be generally necessary for any of this stuff.

In terms of lower-cost / lower-effort solutions ... the only thing that comes immediately to mind is maybe you could build up a raised-bed garden (but with an open bottom) in the wet part of the lawn, and put some water-loving plants in there? Maybe till down into the yard soil a bit, mix lots of good gardening soil into it, then build it up 8" or so to form a raised bed, and you'd get a nice garden that probably wouldn't require much watering and you wouldn't have mosquito problems since the water wouldn't be exposed. Not sure what you'd be able to grow in occasionally-soggy soil like that, though. Might not be vegetables.
posted by Kadin2048 at 10:07 AM on March 19, 2015 [2 favorites]

We had this exact problem, and our solution has evolved over the ten+ years we've lived here.
- we started out by planting water-loving plants to suck up excess water
- then we dug a lower area in the yard and backfilled with mulch (and put playground equipment there for the kids)
- then we put in a dry riverbed and naturalized sandbox/beach area. (This is the point at which the problem was effectively solved.)
- but then my spouse built an actual lined pool and converted the dry riverbed to a water feature. We are still working out the kinks on this one.

We have definitely spent more than $1k over the years, but you could probably DIY something that would work for that if you were willing to put in a lot of work and just pay for materials.
posted by instamatic at 10:10 AM on March 19, 2015

I got some good advice when I asked a similar/related question.
posted by headnsouth at 11:33 AM on March 19, 2015

You may be able to find groundwater levels -- here's the most relevant USGS page that has some links to State data.

You say you're 5 miles from a delineated wetland. If your entire area is relatively flat, and at a similar elevation to the wetland, that's a big clue that your groundwater table is close to the surface. You can find your topo map & compare.

I suspect that it is not a vernal pool, since those are seasonal and generally appear independently of rainfall.
Vernal pools are caused by high groundwater, and groundwater levels increase due to precipitation or an influx of water say from snowmelt. They are generally seasonal, but aren't limited to those that only appear in the spring. While their pool may or may not be a vernal pool, it seems most likely due to high groundwater.
posted by DoubleLune at 12:16 PM on March 19, 2015 [1 favorite]

After getting some more detailed location information-You are in a 'bottomland' area, flanked by a very large river and a minor tributary in a flood plain. I am not sure there is much you can do that will really fix the problem. The neighborhood is older and not likely to have a good stormdrain system capable of taking any additional water. It is likely your groundwater elevation IS the ground elevation during any wet season (or at least it is the Vadose zone). I like Instamatic's approach a lot for a cost effective way to at least mitigate the issue.

Digging out a trench and then filling in that trench with open graded river rock and turning that into a feature will give the surface water somewhere to go and make your backyard livable and your dogs maybe not so muddy.
posted by bartonlong at 1:10 PM on March 19, 2015 [2 favorites]

What is in the street? If you have storm sewer grates, you are connected to a storm sewer system. If not, you undoubtedly have swales along the side of the road to catch water coming off the road.

For a temporary drainage problem, a portable submersible pump and a length of garden hose will allow you to conduct water to one of the two.
posted by yclipse at 4:02 PM on March 19, 2015

Response by poster: Yclipse - we have a storm sewer in the street. Our next door neighbor has actually done exactly what you describe, but I think we are looking for a more permanent solution.

So I'm starting to think that Instamatic's dry river bed solution is probably where we are going to start researching next. That seems DIY-able and also surely less expensive than any kind of pump.

If any has tips, feel free!
posted by raspberrE at 8:00 PM on March 19, 2015

Oh, hey, sorry, I just saw this. To build a dry riverbed, we did approximately this:
- locate the low areas of the yard. You might want to mark them with landscaping flags next time it rains.
- dig out a slightly winding "naturalized" shaped trench, following the contours of the low spots in the yard. Ours is probably about two and a half feet wide. I'm not sure how deep my husband dug it out-- maybe a foot? Eight inches? You definitely don't want a straight line, or it won't look natural.
- line the bottom of the trench. I think he used a few layers of black landscape fabric.
- then put down sand and cover that with "river rocks" that I think he just got from Home Depot.
- optionally plant wet-loving plants down the sides

Things to think about:
- even with landscaping fabric, you'll likely have weeds grow up through the rocks. We ended up pulling the rocks out and digging the weeds at least once before turning it into a water feature. Weeds weren't growing through the landscape fabric mostly, they were just growing in the sand and rocks. It might make sense to research rock gardens and plant little creeping plants among your rocks to out compete the weeds
- think about how you will get people and lawn mowers and so on from one side of the river to the other. You might not want it to stretch all the way across your yard, or you might want to put a bridge over it.
- he started the "river" at the side of the yard in a man made berm (where we'd lost a tree in a hurricane), with a dry "waterfall" -- a stack of rocks about 18 inches high. That was my favorite part of the dry river, and it made it look a little more natural, I think, for the river to have a waterfall/spring as a source and a sandbox "pond" as the destination. The sandbox filled with water when it was really rainy, and the kids loved splashing and digging in it.
posted by instamatic at 7:52 AM on March 23, 2015

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