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angle of repcse of the bed material commonly assumed to be 30. for sa,d bed stream to get the side slope of the hole, Or use 2,75 y s. 2. Evaluate the Total Scour Deaths, o Are the scour depths reasonable and consistent with the design engineer's previous experience, with his/her engineering jcdgement? If not, modify the depths to reflect the ergineer's engineering judgement. o Do the local ~cour holes from the piers or atutments intersect bet~een spans? If so, local scour depths are larger and inceterminant, Therefore, the length of the bridge opening should be reevaluated and the opening increased or the number of piers decreased as necessary. o Are there other factors (lateral movement of the stream, scour hole arrr.oring, stream flow hydrograph, velocity and discharge distribution, moving of the thalweg, shifting of tte flow direction, channel changes, type of stream, etc.) to be considered? o Do the calcu12ted scour depths appear too deep for the conditions in the field, relative to the laboratory conditions (Abutment scour equations are for ::,e worst case conditio~s). Would riprap or spur dikes (guide bank) be a more cost effective solution, o Evaluate cost, safety etc. Also, account :0::: debris affects, o In the design of bridge foundations, the foundation elevation(s) should te at or below the total scour elevation(s) . 3. Reevaluate the Bridqe Desiqn, Reevaluate the bridge design on the basis of the foregoing scour analysis. REVISE THE DESIGN AS KECESSARY. This evaluation should consider: o Is the waterwCLY area large enough; 1. e., is contraction scour too larsre? o Are the piers too close to each other or to the abutments; i.e., do the scour holes overlap? The top width of a scour hole is about 2.75 times the depth of scour, If scour holes overlap, local scour can be deeper, 58