Storm Water Drainage Challenge

by Phyllis Turner
(Lathrop, MO)

For more detailed information in this topic, visit my page on Landscape Grading.

I will try to describe our problem as best I can but I'll attach photos as well. We are located about an hour north of Kansas City, Missouri. When we have bad storms, not calm, gentle rain but a good shower, the gutters become overwhelmed in the corners where the house and barn meet (Photo #1). Our house was built on a concrete slab with a barn built on to the back of the house(Photo #2). These heavy rains have challenged us for the entire 6 years we've lived here and ever year we do something to help ease the problem but it just seems like trying to band aid an amputated limb. The house/barn sit on the side of a hill so rain runs down the hill from another property and the west side of the barn (shown in photo #2) gets flooded with rain water as well. We've installed a French drain on the north side of the barn which has helped solve part of the problem but on the west side, water still comes flowing in. We dug two deep holes at the barn door and put in a length of PVC pipe covered with a drain screen which helps some but they get overwhelmed as well and fill with water and the water eventually ends up coming in the barn (just not as soon as it used to). Our next "fix" is to build a retaining wall with a French drain on the back side of the wall (photo 3) we just started this project this summer before it got too hot and we took a break. Even if we solve the problem that causes water flowing downhill and into the barn, we still have the issue of what to do with the water that spills over the gutters where the barn and house meet up. We had a couple of bad storms recently which has caused us to re-address these issues and finally consult someone that knows more than we do. We don't even really know what type of professional we need to consult with at this point.

ANY suggestions would be appreciated!
Thank you for your time,
Phyllis

ANSWER

Hi Phyllis,

First, my apologies for taking so long to get back to you. I had just left for a two week vacation when you sent in your question.

In addition, I only received one of your photos. You went into a lot of detail and spent much time referencing them. Could you please send me an email via my Contact Form so that I can send you my email address? Then you can re-send the photos to me via email...if you don't mind.

Thanks,
Susan

REPLY AND ANSWER TO DRAINAGE PROBLEMS

Hi Phyllis,
I took a look at the photos you sent, referencing them to your comments
in the email.

Your problem is that the land around your house is either completely
flat, or else it is sloping towards your house. What you have to do is
lead the water away. This can be done in one of two ways, or a
combination of the both.

1. Re-grade the land where it meets your house away for a minimum
(preferably more) of 5 feet out. This should be done at a 2% slope which
equates to 1/4" per foot. So, the land five feet out from your house
must be graded so that it is at least 1.2" lower than the area at your
house. This should be done all along your house, or problem areas. Now,
the water at this five foot point must go somewhere also and not just
sit there. You must create a swale which is like a subtle stream that
you almost can't see going through the lawn. This must also pitch a 1/4"
per foot so that it drains well and it also must empty out somewhere.
Ideally you would have a lower elevations somewhere where this can be
done. If not, you can create a dry well. This is a large pit filled with
gravel where the water can percolate down to the lower ground. It should
be quite large...approximately 5' in diameter and about 7 feet deep.
This is rough.

2. Your second option would be to install french drains all around the
house foundation. These are perforated pipes, allowing the water to
enter the pipes. However, the pipes must also be pitched at 2%, to once
again allowing the water to flow. The perforated pipes must connect to
solid pipes which will be under the ground and lead the water away from
your house.

Your leader drain cannot empty right at your house. It must be led away
too. Lead it to the swale or connect it to the perforated pipe along the
house, depending on which of the two above options you choose. The size
of any pipes you use must be large enough to handle the capacity of your
roof and surface water.

I recently had some major regrading done at my own house as I had a
similar problem to you. I bought my house when there was snow on the
ground and never saw the way the land pitched. I re-laid my patio for
proper pitch away from the house. I then regraded as explained to you
above. I had another area where regrading was not possible, and here I
installed the perforated pipe, connected it to a solid pipe to lead the
water away.

If you would like me to help you with this let me know but I hope this
was helpful anyway.

Regards,
Susan