engleski

A COMPARISON OF FLOOD ROUTING BY MODIFIED LINEAR MUSKINGUM AND KINEMATIC WAVE APPROACHES ON THE DRAVA AND MURA RIVERS

During flood events hydrographs may experience significant transformation in the downstream reaches due to translation, physical dispersion and lateral inflow/outflow. The overland flow is more complex than the in-channel flow and routing is usually calculated by non-linear approaches. This paper presents the development of modified linear Muskingum-McCarthy (MM) and kinematic wave (KW) approaches for routing of flood hydrographs and the results of hydrograph calculations on the Mura and Drava rivers. The original MM and KW approaches were modified so that inflow hydrograph to a reach is separated based on a flow rate, and separated hydrographs are then routed independently in a reach. In such a way the overland flow is routed independently and differently from the in- channel flow but is transformed by using linear approximation. This idea is applied in HEC-HMS model by using different K, x parameters (MM approach) and Manning’s roughness coefficients n (KW approach) for the in-channel and overland flows. Such approach is physically based as the overland attenuation is significantly larger than the in-channel flow. The modified linear Muskingum-McCarthy and kinematic wave models were applied for the calculation of flood hydrographs on the Drava and Mura rivers. The subject area covers the 106.6 km long section of the Mura river (from g.s. Gornja Radgona in Slovenia to its confluence into the Drava river in Croatia) and the 27.5 km long section of the Drava river in Croatia (from hydroelectric power plant Dubrava to g.s. Botovo). Input dataset included hourly discharges on several gauging stations for 19 historical flood events in period 1996-2018. Model calibration was performed for 4 events on trial-and-error basis by comparing measured and calculated hydrographs on six hydrological stations, and model verification is done for other 15 events. The goodness of fit was evaluated for peak discharge, time of peak discharge and volume of hydrograph by using mean absolute error (MAE), relative mean absolute error (RMAE), root mean square error (RMSE) and Nash-Sutcliffe efficiency coefficient (NSE). It was shown that the modified Muskingum-McCarthy model performs better for routing of flood waves on the Mura and Drava river than the modified kinematic wave approach.

Muskingum-McCarthy method, kinematic wave method, flood routing, HEC-HMS, Drava river, Mura river

nije evidentirano