Drop Spillways

15 percent AGRICULTURE SOIL CONSERVATION approach channel APRON DESIGN backfill bars buttress cantilever channel bottom coefficient compute concrete CONSERVATION SERVICE ENGINEERING contact pressures crest elevation critical depth cutoff wall DEPARTMENT OF AGRICULTURE depth of weir design discharge determined discharge capacity downstream face drainage drop spillway earth fill Engineering Handbook equal example feet floor blocks flow foot foot length foundation material freeboard ft lbs ft² given H₁ H₂ headwall extension horizontal resisting Hydraulic Design hydrostatic pressure in² lbs/ft² Length of weir longitudinal sills maximum minimum moments and shears nappe permeability piping pitrun ratio Req'd required discharge riprap scour SERVICE ENGINEERING DIVISION SHEET sidewall and wingwall sliding SOIL CONSERVATION SERVICE steel required stilling basin Structural Design submergence tailwater depth toewall transverse sill type B drop U. S. DEPARTMENT Unexposed face uplift pressures va² values of h W₂ water table weir notch Σο