Surface water drainage system questions?

I had a pad built for my garage building that's going up at the end of the month, as well as a driveway connecting the existing driveway to the building. A nice rain the day it got put in highlighted the need to address runoff. Thankfully I have a nice slope from the front of the property running all the way back to a slight rise leading up to an existing pond.

I've been looking around at the various inlet options and pipe options. I've got a good general idea of how I'll be going about dealing with the water I have.

I'll be putting in around a 10 catch basins in a few key areas including locations to catch water from the gutters and diverting it back to the pond approx 200' behind the house. I am leaning towards using 4" corrugated pipe and plastic catch basins for cost effectiveness and installation ease/flexibility.

I'm finding differing advice on a few installation items.

Depth of pipe installation? Some say 6" below surface and declining to give proper slope. Others say 10-12" minimum. What say the beeb?

Since I'm not running a perforated pipe for subsurface water, do I need to line the trench with gravel/sand?

My rough eye ball level, says my outlet at the pond should be approximately 3-4" above the typical water level in the pond, should I worry about putting something down where the water will discharge?

Are there back flow valves made to use with corrugated pipe specifically or should I just adapt a typical sewage pipe back flow valve? How would I go about that?

Thanks!

 

Get someone to do the elevations for you, Don't trust your eyes.

 

Absolutely, i'm just in the planning stages. I will do slope measurements

 

The black drain pipe is the kind that we use on golf courses and works well. If you use the non-perforated pipe you do not need to place rock around it in the ditch. You do need to lay the drain to that it is level with the inlets and outlets where it attaches to the collection boxes. I think it's about 12". Use some rubberized tape around the connections to the boxes so that grass roots will not get into the pipe.

You can run the drain into the pond a couple of feet since the water in the drain will always go down to the water level that's in the pond in any case. That way you do not have to worry about erosion occurring where the water flows into the pond from the end of the drain pipe if you leave it short of the pond level.

As someone else suggested, get someone with a contractors level to shoot the elevation changes for you since it needs to be laid precisely. Hell, you can rent a level at most rent places and they are easy to use.

Have fun.

 

If there is ANY way for dirt or debris to get into the pipe, I wouldn't use the corigated stuff...I'd use smooth. It will be easier to clean out and if properly sloped the dirt may just empty out the end.....

 

Use 3034 hard pipe not the corrugated flex pipe. The black stuff tends to get crushed after a few years and also if you get a blockage you can't snake it like you can the 3034.

 

Rent a ditch witch, transit, tripod and a shot stick and have at it. The elevation of your lowest inlet and the water height of the pond will determine your trench depth, which sounds like it will vary. The ditch witch will have on the fly adjustable depth with an indicator. Is there an overflow for the pond itself? I'd shoot that against my drain outlet elevation and make sure I was coming in higher. I'd hate to do all of the work only to have the pond overflow become my yard. 3-4" isn't that much. But if it's what you have, then it's what you have. Nowhere else to daylight your drain outlet? And I wouldn't use corrugated. Sch 35 at the least. You can get 20' lengths with bells on the end.

 

I don't particularly like corrugated piping myself... Normal plumbers rule of thumb is a 1" drop per 15 feet IIRC.

 

Minimal dirt/debris entry risk using catch basins at grade.

The smooth pipe does have advantages in that its stronger and doesn't need as much slope to flow well, but it is more expensive($0.59/pft vs $0.96/pft and more difficult to install.

 

The plumbing in your home is smooth internally for a reason...it will wash itself away and is easier to clean should it become blocked...anytime leaves can be introduced into the planned system?

 

Definitely trenching with a ditch witch. Way too long a run to do by hand.

The pond is what it is, at the moment. I plan to expand it substantially sometime in after I recover from the large expense of the shop building. (see pic below)



Yellow new shop building
Lt. Blue Existing Pond
Dk. Blue Future Pond expansion

The future pond expansion is driven partly by some existing springs that keep the areas under the dark blue constantly wet. Typically 3-5" of water on the grade in three large areas.

 

Majority of trees in the area are pine. That being said, I don't find many pine needles in the areas to where catch basins would be installed.



The red arrows indicate (roughly) the runoff flow. I get pooling approximately 50' behind the house at the new driveway to the shop.

 

You've got a LOT of square footage draining there!

Buy much larger catch-basins / drain boxes, & put twice as many as you might think you will need. Those things plug up with leaves & other plant materials WAY faster than you can imagine, especially in a hard rain in the spring or fall. Then you'll get to see how good your worst-case erosion control is. No fun re-digging & adding to your drainage piping. I'm re-doing mine for the 2nd time soon...

Biggest issue with corrugated pipe is maintaining consistent slope, without dips & high spots as things settle.

 

For those advocating/experienced with the solid pipe how does that work?

Do the pipes fit together in the bell end requiring glue?

Will that kind of pipe work with NDS type catch basins like this one?
http://www.lowes.com/pd_21564-676-1...n&pl=1&currentURL=?Ntt=catch+basin&facetInfo=

 

http://www.lowes.com/pd_24140-1814-...entURL=?Ntt=storm+water+drain+pipe&facetInfo=

No need to glue this pipe. I am careful to compact the dirt under my pipe to reduce settling issues. I used 1/4" per foot slope as a minimum, but tried to get 3/8" to 1/2" per foot when I could.

I use gravel all around my drain boxes, & just slip the pipes in the knock-out holes provided. I also drill some small wholes in the boxes as I don't want them to hold water, freeze & break the boxes. I also switch to 6" pipe for the last part of my run, after all of my water converges.

I'm changing out & adding some of these to reduce the surface water I am getting when debris plugs up my grates:

http://www.homedepot.com/p/Tuf-Tite-16-in-2-Hole-Drain-Sump-with-Grate-and-Seals-2HDS-4/203463511

http://www.amazon.com/Storm-Drain-R...=1399904108&sr=8-1&keywords=water+catch+basin

 

Slip joint pipe. Just push it together. Mark how deep the pipe should slide in upon make up and then when your mark is at the face of the bell you know you are home.

 

Thought about going to a larger pipe on the bottom half, providing I can find a y that takes two 4" to a 6".

 

Good info thanks.

So I'm thinking around the northern side of my house I'll have some curves to do to avoid having to cut pipe and buy a few differnt angled joints for the solid pipe. The best route may be to start corrugated uphill and then swap to solid once I get to where straight pipe runs will work.

 

If you can lay the pipe out in the sun and it's hot enough it can be bent to make a gentle sweeping curve. Easier than fittings!

 

Easy to join & change pipe sizes at a drain box. Angles are easy to deal with then, & easy to clean pipe if you ever need to. Long term, better to keep straight runs between boxes, too.