Physical Simulation of Rainfall-Runoff System by a Hydrology Bench
Md. Nurul Kadir, Taznin Naher and Dr. M. Hassanuzzaman Khan
This study was conducted to simulate the rainfall-runoff system by a hydrology bench in a hydraulic laboratory. The hydrology bench consisted of a 210.8 cm long, 108.0 cm wide and 16.5 cm deep metallic tray with an overhead sprinkling system. A river network was created on the soil bed in the tray. Rainfall on the tray was simulated by supplying water by a pump through the sprinkling nozzles. There were two outlets, one to drain surface runoff and the other the subsurface runoff. Surface runoff hydrographs were developed for different rainfall durations on two different surface conditions, such as simple soil bed and gravel spread bed. The results were analyzed to verify the theories used in analysis of hydrographs, as available in relevant text books. Uniformity of rainfall distribution over the catchment was also analyzed. The results showed that the hydrology bench could simulate rainfall-runoff system quite satisfactorily. The simulation was better on the soil bed than the gravel spread bed. The rainfall distribution was not very satisfactory. However, the analysis of hydrographs showed that theories used in literature were in good agreement with the practical findings.