Cost for impervious storm detention liner?
Cost for impervious storm detention liner?
(OP)
Has anybody had any experience with impervious liners for underground chamber type storm detention systems such as Stormtech? First, my reading of the Oregon UIC requirements seem to preclude any infiltration potential even from an open outlet detention system. This is for a fairly large 65,000 cf storage system serving a 10 acre industrial parking lot.
Stormtech recommends a 30 mill PVC liner with 8 oz non-woven reinforcement fabric under and over the liner. Does anybody have an idea what 15,000 square feet of this stuff would cost? Seems like it might be cheaper to go with a hard piped system.
Gary Van Dyke
Stormtech recommends a 30 mill PVC liner with 8 oz non-woven reinforcement fabric under and over the liner. Does anybody have an idea what 15,000 square feet of this stuff would cost? Seems like it might be cheaper to go with a hard piped system.
Gary Van Dyke





RE: Cost for impervious storm detention liner?
In the later case, a sealed system would not be required. You just omit any infiltration in your sizing and modeling calculations, thereby providing more conservative (oversized) storage.
If the infiltration itself is prohibited, there are many concrete and CMP storage options you could consider.
Peter Smart
HydroCAD Software
www.hydrocad.net
RE: Cost for impervious storm detention liner?
Mark
RE: Cost for impervious storm detention liner?
Peter, infiltration is strongly discouraged here. I fall to see the problem with a fully drained pond in class c soils but Oregon DEQ has everybody scared about ground water liability even for swales. For years we were perking everything and thinking we were being environmental. Now you need special permission and only if there are no other alternatives.
I'll try to do a cost analysis, but i really like the stormtech type system and HydroCAD makes it a breeze to model.
Gary Van Dyke
RE: Cost for impervious storm detention liner?
Anyway, if you're going with a closed system, you may want to consider round or arch-pipe, and avoid the cost of a separate waterproof membrane and stone backfill. There's a free chamber update for HydroCAD 8.5 that adds many common round and arch-pipe shapes to the chamber library. For details see www.hydrocad.net/chambers.htm
Peter Smart
HydroCAD Software
www.hydrocad.net