Flood Routing of an Unmanaged River Basin Using Muskingum–Cunge Model; Field Application and Numerical Experiments

The accuracy of flood routing in the design of hydraulic structure and in the flood protection projects imposes a signi?cant modelling challenge. Most of river basins are unmanaged because of expensive tasks related to gauging stations establishing/maintaining and topographical surveys. Under these conditions, semi-distributed models such as Muskingum–Cunge procedure which express parameters of conceptual hydrological models in terms of physical system parameters can be used. In the present study, at first stage, the ?eld applications of Muskingum–Cunge flood routing model is performed using daily and hourly ?ood data available for Karun River, Iran. At the second stage, the performance of Muskingum–Cunge model are investigated in terms of the attenuation of the peak outflow, the lag of the peak outflow, and the volume-conservation by executing a total of 2,160 numerical routing experiments. In the experiments, a set of given hypothetical inflow hydrographs with different combination of the parameters which represent the channel, flood, and catchment characteristics are routed in uniform rectangular channel using Muskingum–Cunge procedure. The results are compared with the corresponding benchmark solutions (i.e. the dynamic wave model) and other simplified flood routing model (i.e. kinematic wave model). The consequences show that discrepancies between Muskingum–Cunge flood routing models and the corresponding benchmark solutions decrease with smaller roughness coefficient and/or steeper bed slope channel, and vice versa.