Technical Release 210-39: Hydraulics of Broad-Crested Spillways
From ASDSO Dam Safety Toolbox
Natural Resources Conservation Service, 1968
This technical release pertains to the hydraulics of broad-crested spill- ways, both trapezoidal and rectangular. Such spillways usually function as emergency spillways and mw be earth, vegetated, rock, or structural. Broad-crested spillways may or may not have a control section. Although this technical release is primarily directed toward the evaluation of certain parameters for a spillway having a control section, it contains information concerning the hydraulics of a spillway without a control section.
Procedures are presented for:
- The evaluation of the permissible critical specific energy head, Hec, corresponding to a permissible velocity, vp, and exit channel bottom slope, so;
- The evaluation of the head, Hp, in the reservoir over the crest of the spillway corresponding to the critical specific energy head, Hec;
- The evaluation of the required spillway bottom width, b, corresponding to the critical specific energy head, Gc, and the required discharge, Q; and
- The evaluation of the critical slope corresponding to the discharge Q/4 where Q is the discharge corresponding to Hec
Revision ID: 5327
Revision Date: 12/13/2022