stormwater storage
stormwater storage
(OP)
I am researching different types of underground stormwater storage, and am wondering which is perferred pipe or chambers? Any comments and/or insights as to why one is better then another would be greatly appreciated.





RE: stormwater storage
RE: stormwater storage
RE: stormwater storage
Chuck
cgopperton@stantec.com
http://www.stantec.com/
RE: stormwater storage
RE: stormwater storage
I have found that most city officials will appove a concrete system with little hesitations and that my clients like the idea of concrete and not plastic or steel.
Justin
RE: stormwater storage
you will need 1-10'x10' box 433 feet long. That is alot
of cost. While excavation of 1 ac-ft averages about $5000.
RE: stormwater storage
RE: stormwater storage
2) The conventional vault system uses concrete block walls and a precast concrete deck. This is simply an underground vault with a minimum of 4' vertical clearance for maintenance and a minimum of (1) 30"x30" accessway, usually placed under the pavement. AVOID UNDER BUILDING STORAGE AND PERCOLATION, unless a special analysis is performed. Make sure that there is adequate access for maintenance to all areas of the vault. This system is usually the most expensive, but the smallest area. A variant is to vault a buffer area and use a wood deck (pedestrian loading only) to cover the vault. This system also requires maintenance.
3) Infiltrator (semi-elliptical HDPE pipe) systems. These systems are very difficult to maintain, but not very expensive. Picture a ~15" high span, maybe 30" wide connected by a 4" diameter pipe nipple. These can be stacked into numerous perpendicular rows, but pay attention to the distribution system. The bottom is a non-woven fabric (mirafi 140n or approved equal). The inlets should be via the catch basins with a 2' minimum sump and bottom opening.
4) Alternate such as large diameter plastic pipe (usually HDPE). See the rock bed system w/o the rock.
We design these systems with a 50% percolation safety factor based upon a double ring infiltrometer percolation test and ground water mounding analysis unless the seasonal water table is 10' under to bottom of the underground system (5' for CA<2.0 acres)
RE: stormwater storage
Infiltration could be factored into the design of a subsurface storage system if the site's soils have adequate percolation rates. It is both conservative and conscientious to design a subsurface system without taking into account the loss of volume through infiltration but none-the-less infiltration should be a design initiative when appropriate.
Replicating the pre-developement infiltration, with an appropriate design, maintains the subsurface hydrology. Many times the focus of stormwater management plans only target the issues imposed from changing surface hydrology while they neglect the chnages in subsurface hydrology.
RE: stormwater storage
RE: stormwater storage
RE: stormwater storage
I used this product to detain over 30,000 cf. It is <$10 per 3.5 cf storage (module only), the modules are 94% void making the detention area nice and compact. I preceded it with a stormceptor to reduce settlement. Don't forget to oversize for the volume lost to sediment as the units are non-accessible after construction.