Corrugated vs smoothwall drain pipe\ French drain vs catch basin

[strutaeng]

I know there are frequently questions regarding drainage problems on this forum, and a lot of folks recommend the "French drains". Not many seem to to care for the catch basins, for some reason.

Catch basins are nice because they allow you to collect and clean any debris that will fall into it, before entering the pipe. You can see what is in it. Yes, they do require periodic cleaning! On the other hand, it is hard to inspect French drains short of a drain camera. Also, fine silt/sediment will mitigate the water inflow as these eventually clog the sock most people install, especially with clay soils and other soil conditions with fines.

I've stated a few times in different threads that I recommend smoothwall drain pipe (solid PVC, SDR, triplewall HDPE) over corrugated. Reason being that it flows better and it is much easier to maintain a positive slope downward, being that it is rigid. Easy to get "bellies" with corrugated because it is flexible. Yes, corrugated is easier to install. I'm no expert on the subject, but I have read 2-3 ft/sec is a good velocity to obtain a "scouring effect." Basically, there is enough velocity such that pipe cleans itself as water flows. This can be accomplished with minimal recommended slope.

Here are some nice calculators:
https://www.ndspro.com/tools-and-calculators/drainage-calculator
https://www.ndspro.com/tools-and-calculators/drainage-pipe-calculator/
https://www.prinsco.com/resources/drainage-calculator-by-pipe-size/


I installed a drain system about 3 years ago. I have (2) 9" catch basins that drain into a larger 12" catch basin and that drains into 6" SDR 35 and runs about 130' or so and discharges into daylight at the back of my house. Yesterday I cut into it to tie a gutter downspout and noticed that it had no debris and was dry! We had a big storm a few days ago.

The system has works very well. I had a low area in my driveway that ponded about 4" of water in heavy storms. Eventually it would get absorbed into the soil and didn't flood the house, but was a big nuisance. We regularly get storms of 2-3 in/hr throughout the year and driveway is dry now. In this area standing water is a magnet for mosquitoes in the Summer time.

So I decided to check on the catch basins, and they had a good 1-2" of dirt. Combined, about 1/2 cubic foot of dirt. A few small roots also. First time cleaning them since installation.

Anyways, just thought it worthwhile to state that catchbasins and smoothwall drain pipe are a good alternative for yard drains and to collect storm water runoff. At one point I considered installing a French drain, but glad I went this route.

 

[scottydosnntkno]

Rigid vs flex/corrugated doesn’t really matter unless your getting a lot of leaves, small sticks, stones etc coming in.

With corrugated (solid or perforated) any silt that comes in eventually fills in the bottom corregations and the water still flows through a smooth round pipe from what it sees

It’s when you start getting leaves and sticks that get stuck in those corregations and create clogs when you start seeing issues. Solid smooth wall the leaves just wash out.

Solid pipe is the ‘best’ but it also depends on how it’s installed. If the ground moves at all it can crack, let in dirt and roots and get clogged. Flex pipe would just flex with the movement and create small dips. Realistically the water flow isn’t affected. Because when’s the last time you’ve seen a gravity drain pipe 100% filled with flowing water? Never. If you lost an inch of height with a small settling spot from the flex it’s not going to affect the performance

 

[fourjeepin]

I like rigid pipe and usually use the pvc sewer pipe. With a catch basin, no French drain. The corrugated is easier to install but doesn’t flow as well and is more likely to get clogged.

 

[SGKent]

I stopped using corrugated because it fills up with dirt faster and also collapses easier. A corrugated pipe lasted 5 years. I replaced it with smooth wall. That is now 20 years old and still working well.

 

[mcbane]

Corrugated vs smooth doesn’t matter if you account for the hydraulic inefficiency of corrugated pipe in your design. Lots more friction so some times you need to go up a size.


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[SGKent]

Corrugated vs smooth doesn’t matter if you account for the hydraulic inefficiency of corrugated pipe in your design. Lots more friction so some times you need to go up a size.


Sent from my iPhone using The Garage Journal mobile app

and dig a wider and deeper trench... .

 

[3onthetree]

Rigid vs flex/corrugated doesn’t really matter unless your getting a lot of leaves, small sticks, stones etc coming in.

It does matter for anything flowing through, there is a distinct difference between using the two.

With corrugated (solid or perforated) any silt that comes in eventually fills in the bottom corregations and the water still flows through a smooth round pipe from what it sees

Water does still flow, however the vertical "dips" that occur in any corrugated installation can start to collect more silt. Think of a sandbar in a river.

Solid pipe is the ‘best’ but . . . If the ground moves at all it can crack, let in dirt and roots and get clogged.

Nope, smooth wall won't, otherwise there'd be a lot of leaking sewer pipes everywhere. Besides, even if a perforated smooth-wall pipe somehow gets punctured, it just becomes more perforated. Dirt should be kept at bay by the burrito (or inferior socks) wrap and roots are attracted to sitting water, which is what corrugations hold and smooth-wall pipe doesn't.

 

[theoldwizard1]

Anyways, just thought it worthwhile to state that catchbasins and smoothwall drain pipe are a good alternative for yard drains and to collect storm water runoff. At one point I considered installing a French drain, but glad I went this route.

"Preaching to the choir" here !

I have one installation where I have to move water from around a garage foundation (grade too high, can not be fixed). My French Drain and Dry Well Project

The second case, is an area near a crawl space vent. Normally not an issue, but if it rains hard, water will get above the bottom edge of the vent. Trenching, for better run off was not practical.

I dug a 3' hole tapering down to about 2' at the center. Dug a trench for the smooth wall drain pipe which goes "to daylight" about 30' away. Lined the hole with landscape cloth, set the catch basin (drilled extra 1/2" holes around it about 6" from the top) and back filled with decorative stone making sure the the grate was a couple of inches lower than the the surrounding area.

My one failure in about 10 years was not making sure the grate on the exit was clear ! I really only need to do this about twice a year.