Designing High Capacity Inlets above large Storm Interceptor

[patigerjet]

I'm working with a fairly large & complex 2.5 mile storm diversion pipe preliminary DESIGN project of twin 42" pipes with storm inlets placed every 300-400' along/above the twin interceptor. The twin interceptor is to be installed just above and parallel a very high stone quarry wall operation that may be failing from the high storm flows above the stone wall. The twin interceptors will first be largely fed above by a cheap but effective asphalt open-lined channel. The channel though has to be switched to an sub-grade pipe interceptor because of site limitations from building & equipment operations of the quarry.

What I need to determine is how to design an effective catch basin inlet system to feed the the sub-grade twin interceptor from above it. The key I assume will to largely sump the inlets with large volume grates since I am looking at large catchment areas (>300-500 acres total).

Any ideals guys on a effective/innovation inlet design approach along the interceptor. Am I also looking at combining the inlets by installing intercepting headwall culverts where I can track down locations where more heavily concentrated/channel flows are evident along the interceptor pipe and tieing these into the twin pipe interceptors.

Thanx

 

[civilperson]

Vertical square concrete area inlets with slots in the four sides and the top as a grate/manhole.

 

[saruman26]

Fairfax County, Virginia, has a standard concrete Yard Inlet detail that matches the description given by civilperson. The link to it is:

http://www.fairfaxcounty.gov/dpwes/publications/pfm/plates/6.htm

Scroll down to the 'YI-1' plates.