How to cover drainage swale

I have a stormwater drainage swale that runs from one side of my backyard to another. It works fine, but I would like to level up that area. Could I use a french drain in that area, cover it , and level up the area? If so, how do I size the diameter of the pipe to be used?

 

Does your backyard serve as a drainage pathway for storm water from your neighbor(s) property ?

That surface elevation may have been defined in the Sub-Division Permit issued when your lots were originally developed.

I'd check with the Zoning Administrator in your jurisdiction before executing any plan to alter that drainage pathway.

 

Never thought of that. Thanks

 

What is the distance you are looking at and what is your climate, frost depth.

Cold climates can easily freeze up a buried pipe rendering the drainage useless until late spring thaw.

I converted mine to a shallow swale to maintain the drainage yet make the space usable. That same flow path went under my driveway with a 14" culvert and every year the slow trickle of water would freeze it solid. I had to divert the majority of the water to another above ground path around my driveway.

Bud

 

I am not a big fan of French drains. They can work but with most the water has to get into the ground before it can get to the drain. This severely limits how much water it can accept. Swales are often constructed to handle those surges of water from a heavy downpour that run off and don't have time to soak in.

 

You all have me rethinking this. The swale works. I suspected there could be a downside with the french drain. I was afraid of sizing it wrong or getting plugged. Maybe what I will do is like Bud and just make the swale more shallow.

Thanks for your thoughts.

 

A French drain may be installed down the middle of a swale or in lieu of a swale to channel water away from the yard or area more quickly. But it is not worthwhile to put in a French drain to take surface water if water is still going to back up and pond in the area in question.

A "French drain" within which water is expected to end up and persist and soak into the soil is more properly called a leach field.

 

Eh, wild guess, but generally a suburban residential drainage system is going to require 2' diameter reinforced concrete pipe, because it has to accomodate the 100 year storm, (think hurricane or torrential downpour) without backing up.

That becomes expensive; and is probably why the initial builder went with a swale in the first place.

Why do you want that area level?

Swales are often a pain to mow, but you can often get state-DOT wildflower mix to use in damp areas.
For example, I've got a swale and damp spot where the yard drains into a wooded area.
One spring i grabbed some fern seed heads from the woods, seeded the area, and now it looks great as a ribbon of green ferns running across the lawn.