Storm pipes can be a part of a regional basin?
Storm pipes can be a part of a regional basin?
(OP)
Whenever I design storm drain basins, I come up with a question.
Is it appropriate that storm drain pipes connected to a new basin can be included as a part of the basin capacity?
Some municipalities say "No" for conservativeness, some say "OK".
I know that conservative design of the basin is really great to prevent "flooding" in case of a big storm event, but it's hard to ignore it if the capacities of the underground pipes are huge.
I am wondering how the design criteria are in other areas....?
I am in Northern California. Thanks and have a wonderful day!
Is it appropriate that storm drain pipes connected to a new basin can be included as a part of the basin capacity?
Some municipalities say "No" for conservativeness, some say "OK".
I know that conservative design of the basin is really great to prevent "flooding" in case of a big storm event, but it's hard to ignore it if the capacities of the underground pipes are huge.
I am wondering how the design criteria are in other areas....?
I am in Northern California. Thanks and have a wonderful day!





RE: Storm pipes can be a part of a regional basin?
RE: Storm pipes can be a part of a regional basin?
In highly urbanized developments designers in this part of the country sometimes just upsize all their storm drain pipes and put the entire detention volume in them. This causes other issues, such as the need for good access to maintain them against sediment accumulation. Some municipalities down here (City of Atlanta) will not allow CMP stormwater detention unless it's "offline." Anything they consider to be "online" has to be RCP. That's basically an artifact of how they broke out their rules for storm drain design vs their rules for detention design. Some others don't want detention in CMP at all.
I'm not sure what sort of topography you've got to work with, but in my experience, it's best to have the last stick of pipe in your network at 1% or flatter and in the invert of your pond, for energy dissipation reasons, and keep every other stick in your pipe network as high as you can get it, both to reduce installation cost and to keep it as dry as you can for future maintenance reasons. That's presuming you've got enough fall in your system to work with.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Storm pipes can be a part of a regional basin?
They didn't say whether or not it worked as intended or even if it had been built yet.
"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928
RE: Storm pipes can be a part of a regional basin?
I did some masters degree work on urban stormwater infiltration, and it has fascinating potential. I have an article around here somewhere about a Japanese pilot project where they had pervious concrete, had a stone underdrain, still had catch basins that weren't really used, tied the stone underdrain in with the base course rock of the storm sewerlines, and made them perforated as well. It was one contiguous subsurface flow. They said they noticed streams that had previously dried up due to urbanization spontaneously return to base flow in the basin. There's also some French research that says infiltration through the base course acts as an aerobic bioreactor for water quality treatment.
All that said, I'd be worried about putting a stormtech chamber "on line," particularly on grade. I'm not sure the inverts of those things are designed to carry peak flows, and they only really work properly when they're flat, so using the chambers themselves as stormwater conveyance would bother me as the engineer. I've done that sort of thing with exfiltration trenches in Miami, but I wouldn't touch it in other areas.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: Storm pipes can be a part of a regional basin?
RE: Storm pipes can be a part of a regional basin?
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com