Determine the discharge rating curve for the following ungated overflow spillway. A bridge over the spillway will be supported on round-nosed piers 1.8 m thick, with a maximum span width of 12 m between the centerline of the piers.

Assuming a head of 8m, enter the discharge for the maximum flood elevation of 110m.

Reservoir and flood data are as follows:

Maximum flood discharge = 3000 m3/sec
Maximum flood pool elevation = 110 m
Maximum normal pool elevation = 100 m
Approach channel invert elevation = 80 m
Downstream channel elevation = 20 m
Maximum flood tailwater elevation = 40 m