Effect of Variable Slopes on the Flow Conditions for Side Channel Spillway.

Abstract

Spatially varied flow occurred in many hydraulic structures with the variable discharge including the main spillways designed for normal flood discharge and head above the sill at the crest, where hydraulic analysis of flow conditions have established through the research work carried at various laboratories, Efforts have been made here in this paper to assessment the flow in the receiving channel of a side channel spillway which is required to be provided to byepass the excess discharge above FRL during high floods. The present conditions particularly occur with earth dams where a conventional spillway cannot be used due to the settlement of the wall. The experimental studies were carried out for side channel spillway by using 3-D physical model to the scale of geometric similar scale (1/100). Experiments were carried out at Department of Civil engineering hydraulic laboratory, B.V.D.U.C.O.E, Pune. Side channel bottom was kept at the same level of spillway. Various experiments were carried out on the model of trapezoidal side channel spillway model, for different discharges varying from 1 lit/sec to 3 lit/sec for the different slopes from 0° to 20°. Coefficient of correlation varies from 0.80 to 0.98 which is fairly good. Maximum water depths for the higher discharge when channel is horizontal and depths decrease as slope of channel increases. Water surface profiles and discharge versus depths graphs were drawn from the hydraulic studies which may provide the guidelines related to flow conditions at side channel spillway.