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Advice for landscaping in a flood plain, please.

Posted by alphamutt (My Page) on
Tue, Dec 19, 06 at 23:43

We recently moved from a Co-Op townhouse in a large city, to a large house in a small town. We have half an acre here, which is great, but at least a third of the property is a mud pit, which is not so great.
Things to consider:
We have several dogs.
The yard is very wet year round (we have some very healthy and happy weeping willows on the property).
I'm at the point where I'd like to put sand and gravel over the mud soup, but my partner is worried about resale value.

I'd love some advice as to how best to make our backyard useable. The yard is fully fenced, and we want to be able to enjoy it with the dogs. Cost of supplies is not a huge issue, as long as the work can be done by one person (that would be me).

Thanks so much.


Follow-Up Postings:

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RE: Advice for landscaping in a flood plain, please.

I guess the big issue is why is your yard wet? Is it really a flood plain (from a lake or river)? Is it a poor drainage/poor grading issue? Do you have a spring there? Leaking septic tank or water pipes? Have no idea why it's wet?

Depending on why your yard is wet, there are several possible solutions, but to give you my two cents worth, I'd need more info.

How much time, effort and money do you want to devote to solving the problem (lots of solutions can be one person jobs, but are labourious or very pricey) and what effect do you want in the end? Do you want a fancy garden, a few trees, some lawn...

BP


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RE: Advice for landscaping in a flood plain, please.

We are in a true flood plain, but the situation is made more complicated by the fact that the lots for new houses on both sides of ours are built up approximately a foot, and it has made our property into a small, muddy lake. Drainage is lousy, and the septic field (which is being replaced by city sewer hook-up in the spring) is out-dated and inadequate.
The backyard just needs to be drier. I'm not keen on planting anything there, as it is basically a playground for our dogs, and the life expectancy of anything planted there would be short. The front yard will be a garden, but that's another post.
I would like to make the space more dog friendly by putting in the heartiest grass I can find, and by eliminating (or at least lessening) the mud pit factor. Cost of materials is not really a huge issue, although I'd of course like to keep the budget as low as reasonably possible......the dogs don't care about esthetics.

Thanks for any advice you might have to offer.


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RE: Advice for landscaping in a flood plain, please.

Sounds like drainage is your big problem. The neighboring properties being higher than yours are a concern because that's not something you can fix easily. Water will continue to drain onto your property as long as that situation exists.

The best solution (without expensive, professional regrading) is to install some sort of drainage system. If your land has a slope to it, then the drainage channel should be dug in that direction and the water allowed to run out to the low point. If your land doesn't have a slope, or if the low point is the problem area, you can still dig drainage ditches, for the water, but you'll need more of them. You can also look into hooking the drain system into your city sewer - it might not be permitted, but it's worth checking out.

To dig a drainage ditch, you'll need to dig down about 6", and lay some 4" perforated PVC pipe that you can buy in a hardware store. Fill the ditch with gravel, and top it off with some soil. The pipe needs to slope down as it moves away from the wet spot. It doesn't need to slope a lot - an inch for each 10-15 feet is god enough. The water in the saturated part, will enter the perforated pipe and flow away.

One drainage trench is enough if you have a low point to drain it to, but if you don't, you'll probably need to dig several shorter ones. Your standing water is there because the soil under it has become compacted from the constant saturation and it can no longer drain. Once you have dug these trenches the water will enter into them, and flow to a part of the yard that has not been compacted and it will be able to drain away.

The cost for materials isn't that much, but digging the trench/es might be backbreaking work, depending on your soil. Hiring a small backhoe to come dig them might help with your labour. Or you could hire some neighbour's teenagers...

The several willows on your property might be contributing to the problem as well. They have extremely invasive root systems and they may have damaged your septic system and be causing leaks. This is just a guess, since I don't know how your yard is laid out - maybe it's fine.

BP


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RE: Advice for landscaping in a flood plain, please.

That must have been one terrific house for you to have made an offer. DO be very careful about your dogs because if they constantly have wet feet they can develop serious issues with fungi, and other problems.


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RE: Advice for landscaping in a flood plain, please.

If you are on a true flood plain, there will be legal restrictions on what you can do including restrictions on changing drainage patterns or adding fill. Check with your local planning department before doing anything. If your local watershed is governed by a Conservation Authority (all watersheds in Ontario are governed), then you will need to check with it as well -- the planning department will know about this.

Is your house new as well? The developer should have designed drainage and water control into the development.

A consultation with a qualified landscape architect would be money well spent.


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RE: Advice for landscaping in a flood plain, please.

Ugh! I knew digging ditches was going to figure into this. :o)
The house is worth the hassle of the yard. The problems are not so bad that they can't be fixed, and my dogs love the space. Lucy....we're really careful about the dogs' feet. They get dried every time they come in from the mud pit, no fungus among us!
Thanks, all, for the sound advice. I guess it'll soon be pick and shovel time. Woo hoo.


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RE: Advice for landscaping in a flood plain, please.

How much higher is your yard, that the spring and summer water level of the receded body of water?

Was that a pasture before?

If you dig a scoop of soil out with a shovel, is the soil a few inches down, as mushy as the surface?

If you dig a small hole, does a puddle accumulate in the bottom when there is no rain?

I might have a few ideas for you. I worked at one country club that had a creek flood sections of it each year, and another country club that was below the water level of the Columbia River that runs between Oregon and Washington.

But I need a few extra facts about your propery and soil before suggesting an idea or two.


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RE: Advice for landscaping in a flood plain, please.

I have finished digging the first trench, 6"-8" deep, about 50'long, and I'm just waiting for the rain to stop so that I can get the PCV pipe installed. The soil is mud at 6", and the trench filled with water as fast as I dug it. Holes or dips of any size are filled with water, rain or no.
I don't know whether this used to be pasture land. Quite possibly yes. We are on Agricultural Reserve Land......although I can't imagine any crop other than rice thriving here.


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RE: Advice for landscaping in a flood plain, please.

I would advise not digging too much trench while it's raining. Wet soil is much more subject to compaction than drier soil when worked or walked on, and I think compaction is one of your main problems. The soil you backfill around the trenches needs to allow water to pass.

In any event, stick with just one or two good size trenches for now, and see what it does this year. Drainage from the problem area isn't going to be instant, no matter how many trenches you dig, so see how fast it drains with the one or two trenches, and then decide if it's worth it to go for more. Until the structure of the soil in the wet area improves you will always have standing water there after a rain (trenches will carry it away, but not instantly) - so be patient :-)

Once it has dried out a bit come spring, you can spread some compost around. It will encourage the worms to work the soil, which will improve drainage eventually. If you plan to try growing a lawn there at some point the compost and worm action will be a good thing too.

We are on Agricultural Reserve Land

Your neighbours altered the grade of their lots on this sort of land? Hmmmmm... I believe adding fill or removing soil on reserve land requires a permit (not 100% sure on that, but pretty sure), and in theory requires approval - it doesn't sound like they did it right, if their lots drain onto yours.

Any idea what your land was used for before you bought it?

BP


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RE: Advice for landscaping in a flood plain, please.

The contractors who built the new houses on either side of ours put in drain tiles, and that was supposed to eliminate run-off. It didn't.

Patience.....hmmmm, not my strongest suit, but being advised not to dig any more trenches in the rain works for me! :o)

I'll remember the compost idea in the spring.....although my dogs seem to think compost = yummy new treat.

The house is 40 years old, and I have no clue what the land was used for prior to being zoned Residential, or whatever the zoning is called when it's on ARL, probably Limited Residential, since the house can't take up more than 10% of the area of the property. Ours is one of the oldest houses in the area, so I assume this was just undeveloped land.


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RE: Advice for landscaping in a flood plain, please.

I've been away for a prolonged period having just transferred to a new place. I found that I have a similar problem with water pooling in a spot in my lawn. My immediate neighbor's yard has a drain but the 'trench' leading to the drain is in my yard. Most interesting but not a huge challenge. I intend to put a weeping tile in place, allowing water from neighbors to flow out to the neighbors drain. I also plan to add some rocks and pebbles mixed in with plants that love boggy areas to help soften the landscape.

By the way, compost is always a great addition to lawns & garden but since they are organic, they tend to float in water so... unless you want organic floatsome in your yard, do mix it in with soil.

Ianna


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RE: Advice for landscaping in a flood plain, please.

I think the best advice is to try and dry things out where you can, so you have a decent area to enjoy, but in other spots work with the above average moisture conditions by planting moisture loving plants. Sounds like you are already doing this with willows.

Someone sort of gave me similar advice for my compact clay soil. I try to modify it, but keep in mind plants that tolerate such conditions when choosing stuff.

Glen


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RE: Advice for landscaping in a flood plain, please.

I've been surfing the internet and came across many solutions to this problem. What we need to look into is a rain garden which really allows the water to pool and slowly drain off. We can even add some plants that help to soak up the water. This is a link to one of them.

http://www.uri.edu/ce/healthylandscapes/NKTownhall2.html

Ianna


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RE: Advice for landscaping in a flood plain, please.

I have the same grounds problem as alphamutt, although we have a much smaller lot size on our established property that was built some 60+ yrs. ago. Our yard as well as all our neighbors on our block have the same "standing water" issue. Funny that the neighbors directly behind our yard, don't flood.
Not only does our dog enjoy running in the backyard, but it serves a purpose to our children and it seems there are only a few days out of the year that the yard could actually be used. We will try the digging and placing the PVC drainage, in addition, we're looking to landscape ourselves. Any suggestions on hearty plants or perennials that could with stand the high moisture, plus full sun June- August. ??


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RE: Advice for landscaping in a flood plain, please.

well dawn, we opted to use a weeping tile(PVC) to drain out the yard and it worked very well. We dug a trench, placed a layer of gravel, and then the perforated PVC pipe which had a sleeve, then filled the hole with river stones. It looks like a dry river bed. On the side closer to the fence, I mounded the earth a bit, preventing the neighbors' water from creeping down into our area. Besides the drain is located in another neighbor's yard and they should do something to channel their water towards that area.

As for planting, you could use echinacea, siberian iris, liatris, spiderwort, joe pye weed, rudbeckia goldsturm, butterfly weed, dogwood and so many more..


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RE: Advice for landscaping in a flood plain, please.

Hi all,

I have a drainage issue at our backyard and unfortunately, there's not much we can do. We live in a townhouse and it's at the center of 8 houses. I've spoke to our neigbhours and all of them has the same issue. Water/Rain seems to stay at the left top corner of our yard. Unfortunately, they's not coming into our house.

Last year, we have hired a contactor, hoping he can fixed the problem (and so he said). He digged up 4 holes and filled them with gravel and builded a flower bed on top of it. He stated that it'll fixed our problem and he also planted a few plants (cedar...etc) at the flower bed.

Of coz, we found out few weeks later that the problem still exist and all of the plants die the following year.

Any advice or suggestion? Thank you in advance!


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RE: Advice for landscaping in a flood plain, please.

Helena,

I would have called the local municipality first to complain about the standing water. Perhaps it's a question of regrading everyone's property to water flows out to the nearest drain.

One thing everyone there should have checked is to find the drain. There must be one located in someone's yard. If it was blocked (like they did something to block water from draining into it) then it should be regraded. This is the job of the inspector and for him to issue the order to unblock the drain. And if there is no such drain, he probably could still provide you with advise on your next steps.

re the contractor -- I'm very surprised that he attempted to do a dry well which is what it seems to be based on your description. However a proper dry well involves a concrete casement perforated and filled with rocks. The idea is that it will be a place for water to collect and to drain out slowing in the surrounding soil. However in a small yard as yours (from the sounds of it)it would be ineffective. Ive seen this used in large landscapes so water can be redistributed in antoher part of the yard and far away from the house. Pretty useless if it's being dispersed in the very area you wish to drain off. anyway here's a link to a dry well system.. Check it out for yourself

Here is a link that might be useful: dry well system.


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