Drainage - The Final Chapter

[HawkinsHollow]

So I have one more drainage task I need to get done before the winter rains arrive in the southeast. I need to backfill around the back door of my addition. This is a special challenge because LOTS of water, comes to this point. Essentially the entire half of our lot to the right of the driveway edge comes through that point.

My plan for this is to pour a curb (yellow line) to direct all that water into the 6" corrugated pipe that will bring the water out through the cinder block wall I will build (purple line). Luckily the slope works all the way out and down the hill to the left along the back of our screen porch. It is hard to see in the picture but the natural slope of the land is gently sloped to the left in the picture. I used 6" because in the worst of a rainstorm a LARGE volume of water moved through here. I think 6" should be enough for 98% of rain events. For the other 2% I will make an overflow gutter that runs along the garage and pour over the wall (green line). Does anyone have issue with this being corrugated? I want it to be cleanable and accessible. The 90's I got are essentially a T with one side closed. I hope to find a solution to add a clean out where that 6" comes out of the wall.
The 4" rigid is coming from the front of the house. One is a freedom drain that runs along the front and side of the house. It is perforated until the corner of the house and then solid until it joins the other pipe. The lay of the land there is such that any extra water that comes that direction will naturally drain out the corner of the house to daylight. The other 4" rigid is a surface drain from the front corner of the house that catches the gutter water from the front of the addition and the little bit of roof that is that little jog in. It is not obvious in this pic but as that 4" comes out from the corner of the cinder wall there will be a Y that will allow me to add a clean out. The upstream end of the pipe is very accessible as well. This 4" will then turn and run along the back of the house, eventually catching another surface drain from the front of the house and the gutters from the entire back of the house.

There are obviously 2 spot I will need to leave a void in that cinder block wall to allow these 2 pipes to come through. I plan on using a metal lintel under these cavities. I plan on gluing the cinder blocks together and then using Quickcrete Quikwall. You basically dry stack the blocks and then smear this stucco like substance on the wall and they hold together.

All of this water will be dumped towards the back corner of my property.

Does anyone see any issues with my plan? Questions, concerns, comments? I think it is solid, but I have learned one thing. If you want to find the chinks in the armor of any plan, post it on TBN and someone will have an issue with it

 

[JJT]

Is all of the pipe smooth wall interior? If so, this looks good to me. If not, swap out the corrugated with smooth wall.

 

[HawkinsHollow]

Unfortunately the 6" is corrugated. I already had it, and I am not sure where to get the smooth walled corrugated locally. Can you tell me the disadvantage of using corrugated?

 

[Rockbadchild]

Why using a T with one side close ? I would be more incline to used 2, 45 degree to make the turn smoother, that will be your bottle neck and you can't snake through a 90 degree.

 

[HawkinsHollow]

Why using a T with one side close ? I would be more incline to used 2, 45 degree to make the turn smoother, that will be your bottle neck and you can't snake through a 90 degree.

Yeah, I see your point. But that is all I could find locally for 6" corrugated. Luckily the upstream intake end will allow easy access to the underground short run. And there will be ample slope to all of it, I am hoping that will keep there from being too many clogging issues.

 

[Eagle1]

How many leaves and debris will come to your drain? Does not take a lot to clog a 6" line.
Heck even 18" clog regular around these part.

 

[HawkinsHollow]

Why using a T with one side close ? I would be more incline to used 2, 45 degree to make the turn smoother, that will be your bottle neck and you can't snake through a 90 degree.

Oh yeah, also I was thinking of using concrete to fill the closed end of the T I am not using. It is hard to see from the pic but the 90 I am using to turn the vertical to horizontal has that closed end of the T pointed down allowing a place for water to pool. I plan on filling that void with concrete so water cannot accumulate there. I supposed I could do that where it turns the corners too.

 

[HawkinsHollow]

How many leaves and debris will come to your drain? Does not take a lot to clog a 6" line.
Heck even 18" clog regular around these part.

Well I will have a strainer on the end. But really not that much will come that way. The water moves in sheets and doesn't bring a lot of material with it. What does come that way will be caught by the stainer. I will walk by that strainer numerous times a day so when it gets leaves in it I will notice immediately, and be able to clean it.

 

[CADplans]

The last pipe I priced,, there was little difference in price of corrugated and plastic sewer pipe.
(That was comparing 4 inch)

I have switched to the smooth interior pipe
WHY??
The corrugations catch and hold leaves, and sticks.

You will get clogs 20X as often with corrugated.

I had a guy re-do culverts on my driveway, 15" and 18"
He REFUSED to install the corrugated pipe,
The pipe we used is corrugated on the outside, but, it is double wall
The second wall inside is smooth,

He said he had too many complaints about clogs, with pipe that is corrugated inside.

 

[Eagle1]

I get a huge volume of leaves and stuff from the hills all around. Nothing but trees as far as you can see....

 

[HawkinsHollow]

The last pipe I priced,, there was little difference in price of corrugated and plastic sewer pipe.
(That was comparing 4 inch)

I have switched to the smooth interior pipe
WHY??
The corrugations catch and hold leaves, and sticks.

You will get clogs 20X as often with corrugated.

I had a guy re-do culverts on my driveway, 15" and 18"
He REFUSED to install the corrugated pipe,
The pipe we used is corrugated on the outside, but, it is double wall
The second wall inside is smooth,

He said he had too many complaints about clogs, with pipe that is corrugated inside.

Yeah, I totally get it. I can get rigid 6". But that stuff is EXPENSIVE as are the T's. I think they are $70 just for a T. But that might be a better way to do this. And I don't need a ton of it.

I feel like with the strainer and the short underground run clogs won't be as much of an issue. But I could see how a regular culvert exposed to all the leaves and sticks it can eat would have much greater issues more frequently.

 

[Rockbadchild]

Oh yeah, also I was thinking of using concrete to fill the closed end of the T I am not using. It is hard to see from the pic but the 90 I am using to turn the vertical to horizontal has that closed end of the T pointed down allowing a place for water to pool. I plan on filling that void with concrete so water cannot accumulate there. I supposed I could do that where it turns the corners too.

Is in front of the screen house won't be backfilled like behind the wall from where you are standing from the picture ? .. if it will be backfilled I would be tempted to use the end of the second T (by the wall) as a clean out, so you have a straight thought access to it, if it not going to be backfill and you can access right up to the T by the wall by hands then its a other story but I think you will have trouble getting through the first 90 with a snake in order to make it to the underground part... going through a 90 from vertical to horizontal is pretty much impossible with a snake.. better to be safe then sorry.

Also put a screen at the offtake end so critter doesn't nest in it during the dry seasons.

 

[HawkinsHollow]

Is in front of the screen house won't be backfilled like behind the wall from where you are standing from the picture ? .. if it will be backfilled I would be tempted to use the end of the second T (by the wall) as a clean out, so you have a straight thought access to it, if it not going to be backfill and you can access right up to the T by the wall by hands then its a other story but I think you will have trouble getting through the first 90 with a snake in order to make it to the underground part... going through a 90 from vertical to horizontal is pretty much impossible with a snake.. better to be safe then sorry.

Also put a screen at the offtake end so critter doesn't nest in it during the dry seasons.

Yessir! The T that is to the right of the cinderblock will be accessible, that is where I plan on putting a clean out. As far as the vertical to the horizontal I will easily be able to reach my arm down there to make that turn. I am not super worried about that underground section clogging at all, it's short, very accessible and it will have a decent slope to it. Oh and yes most of that pipe running along the back of the house will be partially/mostly exposed.

 

[Rockbadchild]

Yessir! The T that is to the right of the cinderblock will be accessible, that is where I plan on putting a clean out. As far as the vertical to the horizontal I will easily be able to reach my arm down there to make that turn. I am not super worried about that underground section clogging at all, it's short, very accessible and it will have a decent slope to it. Oh and yes most of that pipe running along the back of the house will be partially/mostly exposed.

if that's the case there is no problem

 

[texas42]

Unfortunately the 6" is corrugated. I already had it, and I am not sure where to get the smooth walled corrugated locally. Can you tell me the disadvantage of using corrugated?

Corrugated is the least efficent pipe type

 

[Snobdds]

So one thing I learned while putting in my heated driveway...you need a large surface area to act as a catch to dump water into a drain. If you just try and catch all the water in a drain, a lot will just overspill in a heavy rain and run off in a direction you don't want. Where your yellow line is, put in a gutter drain (channel drain) that is about 6 feet long, and then dumps into your pipe. This will catch a lot more water than just that pipe.

I would also put a French drain below the cinder block wall to catch run-off in that small area. That is a lot of hydrostatic pressure on the wall if there is no way to get the water from above, out past the wall. Then just tie it into the main drain.

I wish I had a better picture, but you can see where the snow is on my driveway, is where the gutter drains are. I have zero issues with water when the snow melts. It's all captured by the drains and put into the forrest where it drains to the creek.

 

[BleedingOrange]

Snobdds, I love the look of your mansion. Did you have it built, or did you buy it from a previous owner ?

 

[HawkinsHollow]

Excellent info @Snobdds!
I guess that is why there is such thing as a catch basin huh? A place for water to accumulate as it is moved out. A gutter drain is a great idea but there is one snafu. I will eventually resurface my driveway, and when I do the level of it will raise by 4-6 inches in that spot. It will be hard (but not impossible) to raise the level of that gutter drain. I was just planning on creating a deeper basin around the 6” vertical drain when that happened. Definitely food for thought though.

I appreciate you bringing up a French drain against cinder block wall. But 2 things are in my favor there. The ground slopes naturally towards the wall opening in the corner. And I will have ample gravel there to allow water movement. And I plan on sloping pad so water runs off the back so I don’t think it will catch a lot of water. But I have the perf. 4” so I might throw it in there for good measure anyways.

 

[JJT]

Unfortunately the 6" is corrugated. I already had it, and I am not sure where to get the smooth walled corrugated locally. Can you tell me the disadvantage of using corrugated?

Corrugated interior is a bunch of riffles just waiting to get filled up with silt, sand, leaves, water, etc. Smooth wall interior is better at keeping everything moving and has a higher crush rating. I'd run a pair of four inch smooth wall lines before using a single corrugated 6". The price of pipe is small considering your labor.

Will this ever freeze? If so, there's another reason not to use corrugated.

 

[Snobdds]

Snobdds, I love the look of your mansion. Did you have it built, or did you buy it from a previous owner ?

That is my house in Steamboat. We use it mainly in the winter, as I like to Snowboard.

We built it about 10 years ago now. I wanted a non maintenance house. I don't want to rely upon unreliable contractors to remove the snow in the winter. I had too many times when I arrived on a Friday night and then proceed to be out there until midnight removing snow. I solved that problem.