ABSTRACT
ABSTRACT Study investigates the variation of the roughness values with flow depth, channel slope and geometry. Four types of experimental setup were prepared in the laboratory for the study, straight and curved channels with straight and trapezoidal cross sections. Variation of Mannings n and Chezys C with geometrical features and flow depth were studied. It is found that the roughness values varies significantly in case of curved channels and therefore prediction of discharge using this conventional roughness constants createdsignificant error in discharge estimation. Dimensional analysis is carried out to incorporate certain geometrical and flow parameters to the roughness equation. Roughness equations (Mannings n and Chezys C) were modified and validated with the stage discharge data of Vamanapuram river. It is found that modified equation gives more accurate discharge values in erodible bed channel flows.
