Sizing a riprap basin for oversized box culvert outfall
Sizing a riprap basin for oversized box culvert outfall
(OP)
I am trying to find some reference material regarding the sizing of riprap outfall basins for larger diameter outfall culverts. The only references I can find provide sizing tables for pipes with diameters up to 96". However, due to lack of significant head on the lake outfall structure, the outfall culvert has to be a box that has a greater outfall orifice area. The velocities coming out of the culvert are low enough to allow for a riprap outfall, but I just can't find any materials that would detail how to size the basin. Any suggestions are greatly appreciated.





RE: Sizing a riprap basin for oversized box culvert outfall
http://www.dep.state.pa.us/dep/deputate/watermgt/w...
on pages 119-121 gives the equations in terms of D, so you can just use Deq of a rectangle =2L1L2/(L1+L2) to get D.
This will pass in PA, USA, so run it by the local reviewer first.