STILLING BASINS 255
levels than conventional hydraulic jump basins and, in the case of gated
spillways, symmetrical gates operation (to prevent side rollers which could
bring sediment into the bucket which, in turn, could damage the dissipator).
The stilling basin with a surface regime hydraulic jumpuses a sub-
merged small shallow flip bucket (Fig. 5.8(b)); the theory and its application
Fig. 5.6 Stilling basin with chute blocks and baffles, USBR Type III (after
US Bureau of Reclamation, 1987)
Fig. 5.7 Plain and slotted roller buckets (US Bureau of Reclamation, 1987)