Scour Potential near a Spillway

[fish1]

Hello All,
I would like to determine the potential scour depth at the entrance to a fish ladder located near a small dam's spillway. The fishway protrudes into the path of the spillway flow about 9 ft. The structure extends from the abutment (about 2 ft downstream of the spillway) at a 45 deg angle with the end about 10 ft downtream of the spillway.

Can anyone provide some guidance to the appropriate method to estimate potential scour depth around the structure? I have looked at various equations for bridge abutments (Laursen, Froehlich, and HIRE) but i am not sure they apply to my situation.

Thanks,

 

[sam74]

http://www.fhwa.dot.gov/engineering/hydraulics/software/softwaredetail.cfm

This is a link to some free energy dissipation software. Check out the program HY8Energy. It will automate design methods outlined in HEC 14. It has a module that will estimate scour dimensions. Much easier than doing hand calcs.