Need advice on flooding backyard

Discussion in 'Garden and Lawncare' started by cirdec, Jan 31, 2010.

  1. Jan 31, 2010 #1

    cirdec

    cirdec

    cirdec

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    I am new to the forum. I tried searching this issue before posting. Most of the issues I saw dealt with backyard flooding that threatens the house. Luckily, my flooding issue does not threaten my house, since it sits on an upward slope. As you can see from the pictures below, my back yard slopes downward from the house, then goes up to a steep hill. Water naturally collects at the bottom of the hill. I was told by my realtor that developers installed a drain a few properties down to help with the water issue. Well, in my back yard, when it rains, I can see water slowly moving (like a river) towards what I hope is a drain. However, there is a lower dip in my yard that creates a small pond. Mosquitoes are merciless in the summer. (I live in Tennessee) The pictures below are taken from above and below the hill. I read somewhere that a sump drain (without a pump) could do the trick, but I wanted to get some more advice.

    I am wanting to deal with this because I want to eventually install a privacy fence around my property. During heavy rain, it gets much worse than this. Help!

    (PS - please excuse the dark pictures. My camera phone is not the best in the world)

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  2. Feb 1, 2010 #2

    Wuzzat?

    Wuzzat?

    Wuzzat?

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    We have the same thing in our yard but not as bad.

    Hopefully you can put in a pitched buried drainpipe that discharges the water somewhere else.

    If this swale is the lowest point for quite a distance you might need a pump that can handle muddy water.

    Figuring the gallons/minute, etc., for the system is kind of tricky; if I find my charts and tables on this I'll post them.

    How often does it flood like this?
    Precipitation Maps for USA
     
  3. Feb 1, 2010 #3

    erndog

    erndog

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    Hi I am in Nashville how about you. My advice is to follow the stream and find what it drains into. Then check the elevation difference between your yard and drain. You will probably need to talk to your neighbors(they probably don't like it anymore than you do) and retrench to get any kind of relief. From the looks of the surrounding area your yard was a gully or stream that the developers were nice enough to fill in. Just my 2 cent from an amateur. Good luck. Brian
     
  4. Feb 1, 2010 #4

    Wuzzat?

    Wuzzat?

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    Pipe drainage Sizing

    1. calculate area A in acres to be drained, by surface type. 1 acre is 43560 sf.
    2. determine rainfall intensity rate I in inches per hour
    3. determine runoff coefficient Cr for the surface type. It's 0.05 to 0.3 for cultivated lawns
    4. determine how much slope you have available for drain pipe
    5. calculate flow in cu.ft/sec = Cr x I x A. For 0.5 acre, 2"/hr rainfall and 0.2 Cr, it's 0.5x2x0.2 = 0.2 cu.ft/sec.
    6. using flow rate and drain slope, determine the pipe size using a Manning's pipe flow Chart
    (from Army Technical Manual TM 5-814-1, Aug. 1966)

    [ame=http://www.google.com/search?client=safari&rls=en&q=%22Manning's+pipe+flow+Chart%22&ie=UTF-8&oe=UTF-8]"Manning's pipe flow Chart" - Google Search[/ame]
    [I couldn't get this document to display correctly on my computer.]

    If you post your values I'll try to use my hard copy of this chart to tell your pipe size.

    "Rainfall rate is generally described as light, moderate or heavy. Light rainfall is considered less than 0.10 inches of rain per hour. Moderate rainfall measures 0.10 to 0.30 inches of rain per hour. Heavy rainfall is more than 0.30 inches of rain per hour."
     
    Last edited: Feb 1, 2010
  5. Feb 1, 2010 #5

    cirdec

    cirdec

    cirdec

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    Thanks for your help guys. My biggest issue against installing a drain pipe is that it would require draining into other people's yards. That's why I was wondering if the sump drain would suffice. Sadly, this was not an intentional creek. It look like it was previously sodded, but erosion took over because of the flooding and such. The drain (if there is one) is located many properties down and would probably require the cooperation of all neighbors involved.
     
  6. Feb 2, 2010 #6

    Wuzzat?

    Wuzzat?

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    I'd use a pump that can handle muddy water, but I don't know local code requirements for where the pump output can go. I'd think the nearest storm drain would be OK.
    How often do you get this condition?
     
  7. Feb 2, 2010 #7

    cirdec

    cirdec

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    This happens pretty much whenever there is a good rain. Of course, the "pool" of water is bigger during heavy rain. I was also thinking about installing a pipe to go to the street so the water will go down the drain. However, the city (or developers), in their infinite wisdom did not install ANY curb storm drains on my side of the neighborhood (I live in a circle). This, of course, brings me back to either bringing in some dirt to fill up the sunken part of the backyard and/or installing some type of pipes that will not affect anybody eles's property (such as some type of sump drain).

    I read somewhere that the sump drains can be installed vertically, about 4 or 5 feet deep, which will allow the water to drain into the soil by osmosis. Is this correct or am I mistaken?
     
  8. Feb 2, 2010 #8

    Wuzzat?

    Wuzzat?

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    1 And you might end up with the whole back yard being soggy rather than one area being submerged.

    2 These "French drains" never worked for me but it depends on the porosity of your soil.
    Try it. Dig a hole, fill it with water, and see how long it takes to empty. There are rules of thumb for evaluating the results.
    Design the drain for the 10 year rainfall for your area, and you only have to deal with this creek every 10 years.

    If this creek is 6' wide, 6" deep and 80' long it contains ~900 gallons. This is a cube of water 4' on a side.
    If it flows 80' per minute this is 900 GPM you'd have to dispose of.

    Another option is to fill the swale with bluestone. The water is still there but at least you can walk on the area.
    Or put a long, narrow deck over this.
     
    Last edited: Feb 2, 2010
  9. Feb 2, 2010 #9

    cirdec

    cirdec

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    Thanks! I'll check it out some more. You have given me some more options to consider. I really appreciate it!
     
  10. Feb 2, 2010 #10

    Wuzzat?

    Wuzzat?

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    Glad to help.

    Here's another thought. Fill the swale with pipes suitable for burial, pour some concrete to stabilize them and cover with fill dirt & topsoil & sod. Now you have an underground stream.
     
  11. Feb 2, 2010 #11

    Wuzzat?

    Wuzzat?

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    Glad to help.

    Here's another thought. Fill the swale with pipes suitable for burial, pour some concrete to stabilize them and cover with fill dirt & topsoil & sod. Now you have an underground stream.

    Or see if these people
    http://www.canadaculvert.com/_common/pdfs/TrenchcoatBrochure.pdf
    or some other company make flat, corrugated, coated sheets
    capable of supporting enough pounds per sq. ft.
    Then cover the swale with several of these sheets and cover with fill dirt & topsoil & sod.
     
  12. Feb 2, 2010 #12

    handyguys

    handyguys

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    I have a similar swale in my back yard. Its grass most of the time. There are berms in the swale which cause it to pond up when there is a lot of water. The berms are used to slow down the flow, prevent erosion and encourage the water to perk into the ground on my property.

    Without cooperation of your neighbors there isn't much you can do. You could do a drywell but it would need to be huge and probably isnt practical.
     
  13. Feb 3, 2010 #13

    erndog

    erndog

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    Hi again
    If you have the same clay soil that I have the dry well would not very well. I'd try at least talking to the neighbors and see if they are interested in doing a ditch project. With that hill and the way rain sheets off our clay a ditch or culvert is still the best option I see.
     
  14. Feb 3, 2010 #14

    Con65

    Con65

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    I've had similar problems where I was unable to get rid of the water by draining onto my neighbor's property and there were no storm sewers I could use for a drain. Actually many locations will not allow hooking a drain into a sewer.

    I was never able to PREVENT a puddle of water from forming, but by installing a dry well (or several) the water went down within a day. I also gardually raised to soil level over two years so that the water didn't form as large a pond.

    A couple of points:
    1. Dry wells work best in sandy soils, but they will work in clay also.
    2. If you have a septic tank, don't place the dry well near the septic drain field.
     

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