Drainage Systems For Yards - How To Solve With a Swale

by Sherry

I need information on drainage systems for yards and how to solve with a swale.

I have a real challenge for you and I hope you can help me. I live on a very steep hill with the hill coming down towards my house. When it rains, it goes under my front porch that has no foundation. Whoever built the porch just laid the boards, etc.

Now when it rains hard, the rain hits the tires of cars, comes up over the curb and down the hill under my porch. I have hardwood floors that I need to replace due to the rain and a dog (hmmm) and plan to do that hopefully next year AFTER I get the landscaping on front yard done. Anyway, I have had a few guys come by and look at the yard, say they will get back to me on ideas and prices for a drainage system, and I never hear from them again. Another guy said it would be between 5,000-6,000 dollars which I can't afford. I'm a single mom of 2 little girls I adopted a couple years ago and work 3rd shift, so end up paying about 17 hours a day for daycare so needless to say, there isn't a LOT of money left over but have saved up some.

If you could give me some ideas on what to do with it I would appreciate it. It also slopes from one end to the other and one guy said I would need like a flat start on west end to about either a 3 or 4 foot tall retaining wall on the east end. My spot I need fixed is about 30 feet across (roughly) and then I think I have to leave a leeway from the work done to the road so roughly about 7-10 feet out from house area wise.

Sherry

ANSWER

Hi Sherry,

From what you have told me, I am picturing your property sloping towards your home with a cross slope to the side. I would generally suggest the following:

From the porch, your grade must be sloped away from the house. It should be graded away to a lower elevation for a distance of at least five feet at 1/4 inch per foot. This means that the elevation five feet out should
be 1 1/4 inches lower than the grade at your porch.

This is standard grading procedure that any qualified landscaper should be aware of. You can grade to a lower point further out, but no closer. You can grade to
a lower elevation than above, but no higher. The slope coming down from the street meets these points that are five feet out and a gentle "swale", or channel, is created leading the water away. The area beneath your porch, hopefully will now not be a problem since not much water is leading towards your home. You can look under your porch to see how steep it is.

This will make the area from the street to the newly created swale steeper. Depending on the steepness of the slope, this may not be the greatest solution; a retaining wall would be another way to go, running
parallel to your house, as this can allow for a gentler slope. I am suggesting the first solution due to cost differences and your situation.

Everything begins from the porch/house area. The cross slope will just follow. At some point you will get to a low point of the swale. Legally, you are not allowed to lead water off your property onto a neighbor's property, so this water must be addressed. If you have woods, great. If not,you might have to install a drainage pit to collect the water. This is similar to a large drum with holes on the sides so that water will
enter it and then slowly percolate out.

This is all general information and it would depend on your particular grades, which I don't have. You might consider calling an engineering company, explaining your situation and asking them to recommend a qualified landscape contractor.

If I can be of any further help, please let me know. I understand your frustration and that drainage systems for yards can be difficult to understand. However, I also think it's a matter of just finding the right contractor.

Susan