Storm Water Catch Basins
Storm Water Catch Basins
(OP)
Can anyone provide me with a reference for calculating the required length of a curb opening catch basin with gratings? The catch basin will be located at the bottom of a 15% slope access road. The catch basin has to collect 22 cfs, so that it does not flow directly into a main road thru a development.





RE: Storm Water Catch Basins
Hydraulic Design Series No. 4 "Introduction to Highway Hydraulics"
Hydraulic Engineering Circular No. 22 "Urban Drainage Design Manual"
These should give you the help you need.
RE: Storm Water Catch Basins
best, tincan
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
A grated street inlet will intercept approximately 2.5cfs/per foot of width on grade and approximately 4 cfs/foot of width in a sump.
RE: Storm Water Catch Basins
If this is an emergency/contingency design, you should cut a sump and drop an endwall and daylight a pipe outside the roadway, prior to the tank's overflow entering the road. The inlets along a curbed roadway should only be used to capture normal roadway runoff, plus a little from adjoining lands. They are not intended to capture huge concentrated flows like storage tank failures.
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
I've done this before myself - written a small excel program to look a various cases.
You can find discussion on such in any undergraduate fluid mechanics text.
n1cq
RE: Storm Water Catch Basins
1) When you refer to 1 "standard" grate + 1 std curb inlet having an inlet capacity of 1.6+2.5= 4.1 cfs, which standard are you refering to, and what are the dimensions? We're looking at APWA 302-2, which is ~3' long (add ~3'6" for each additional grate) and 2' wide with a curb inlet. So would an APWA 302-2 single grate with a curb opening have an inlet capacity of 4.1 cfs? Or were you refering to a smaller 'standard' inlet?
2) When you refer to a grated street inlet extending the width of the street (essentially a big trench drain), you say it has a capacity of 2.5 cfs per foot of width on grade. What length accompanies the 'foot of width' to give the 2.5 cfs capacity?
Thanks.
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
RE: Storm Water Catch Basins
The CICI are a nominal 2'-8" in length (2'-6" opening. The grates are2'-8" x 1'-8" (2'-6" x 1'-6" opening).
We use the x-street grated drainage in flat areas where we experience sheet flow or flooded street conditions.
Neenah has excellent cataglogs and data. As suggested above , contact them. Also as noted above, spacing the inlets along the road should work.