A Muskingum-Cunge Channel Flow Routing Method for Drainage Networks

Abstract

A Muskingum-Cunge channel flow routing scheme is modified for application to large drainage networks with compound cross sections and for continuous long-term simulation. The modifications consist of a decoupling and separate routing of main and overbank channel flow, an introduction of a variable time step to increase model efficiency during periods of steady flow, and an interval determination of the numerical increment. The resulting hydrologic model is verified by comparing its flow routing results with those of hydraulic benchmark models solving the full unsteady flow equations. Test conditions consist of hypothetical flood hydrographs, long prismatic channels with simple and compound sections, and a third order drainage network. For the tested conditions, the model produces hydrograph peaks, times to peak and shapes that compare well with those of the hydraulic benchmarks. Hydrograph distortions due to overbank floodplain storage and multiple peaks from complex drainage networks are also well reproduced. The execution time of the model is generally one order of magnitude faster than that of the hydraulic benchmark models.