sub drain 1

[johnlai]

Has anyone designed a perimeter sub drain system for a pond?

The water table is below the bottom of the pond.

 

[ccor]

They are common for the water quality component now required in many ponds.

 

[LHA]

There is usually no "design" capacity to them. You just don't want them to clog, or create excessive outlet velocity.

Use 3" Perforated Sch 40 PVC is OK for rigid, corrugated HDPE for flexible. Lay pipe at 1%. Wrap in filter cloth, backfill with 6" of AASHTO #3, wrap that in geotextile.
Then cover with clean stone, if bottom of basin is flat. You can cover with topsoil and plant, if you can pitch the basin at 2% toward the trench. Outlet to a stable area...riprap apron is OK, into an inlet box or manhole is better.

Remember, amateurs built the ark...professionals built the Titanic. -Steve