STEADY FLOW SIMULATION IN IRRIGATION CANALS

A mathematical model is developed for the analysis of spatially varied steady flow in irrigation canals. The model accounts for canal seepag e and effect of control structures at the upstream and downstream ends of the canal. Two computational methods developed to solve the spatia lly varied steady flow equations for the irrigation canals are present ed here. The governing differential equations are solved iteratively u sing fourth order explicit Runge-Kutta method. The model results are v erified with experimentally observed water surface profiles available in literature. The effects of bed seepage, canal condition and backwat er curves on the discharge carrying capacity and variation of flow dep th are studied through model application on a canal reach. It is found , that in most of the situations the backwater curves spread sufficien tly upstream and significantly affect the performance of the control s tructure at the upstream end. In many situations, it may not even be p ossible to operate the canal at design discharges.