Contents preface (VII) introduction 1—37

10.6.2. Ribbed Pitching
Projections on the sides of the channel for the purpose of dissipating surplus energy of the flow can be provided in the form of ribbed pitching which consists of bricks laid flat and on edge alternately (Fig. 10.9). Bricks laid on edge project into the stream and thus increase boundary friction and dissipate the surplus energy.

Flow

Fig. 10.9 Ribbed pitching
10.6.3. Provisions at the Downstream End of Cistern
If high velocity stream continues up to the end of the cistern, a baffle wall or a deflector [Fig. 10.10 (a)], or a dentated cill [Fig. 10.10 (b)] or a biff wall [Fig. 10.10 (c)] may be provided
Dentated sill

Apron
Flow

(a) Deflector (b) Dentated sill (c) Biff wall

Fig. 10.10 Roughening devices at the downstream of cistern

CANAL REGULATION STRUCTURES

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at the downstream end of the cistern. The baffle wall provides a deep pool of water upstream of itself in the cistern. This pool of water is helpful in the dissipation of residual energy. Other devices (i.e., deflector, dentated cill, biff wall) produce a reverse roller which results in a limited scour away from the toe and piles up material against the toe of the structure. A dentated cill, in addition, breaks up the stream jet.