Significance of conceptual rainfall runoff model over synthetic unit hydrograph in simulating high flow

Abstract

This study evaluates the performance of both synthetic unit hydrograph (SUH-SCS method) and conceptual rainfall – runoff simulation (CRRS-HBV96 model) in estimating annual highest flow, using Jiangwan catchment as the study location with hydrological data from 1957 – 1969. The result explicitly shows the significance of CRRS over SUH method, as well as expresses the importance of qualified hydrological data series. Although SUH method requires simpler data demand, CRRS is principally found to be more accountable in delivering flow simulation. In HBV96 model simulation, hydrological characteristic annual changes are found through parameters alteration that goes in line with the actual catchment physical condition. The high flow simulation delivers average and standard deviation of the relative error respectively at 0.2123 & 0.2048. By applying the same concept using SCSSUH method, optimum Curve Number (CN) parameter value increases from 50 to 52, delivering average and standard deviation relative error at 0.5514 & 0.3864 respectively. It is clear to see that CRRS produces better result compared to SUH method, due to its consideration to more variable expressed by numerous parameter. Further, it leads to evidence and expectation that developing countries should pay more attention and priority to their hydrometric system.