Mean Instantaneous Unit Hydrographs of Random Channel Networks

Authors: BEYHAN OĞUZ

Abstract: The IUH (instantaneous unit hydrograph) of a channel network is still used as a component in rainfall runoff modeling. There are two approaches to determine the IUH in relation to geomorphological basin characteristics. One of these approaches is Rodriguez-Iturbe and Valdes, approach known also as Exponentially Distributed GIUH (geomorphologic instantaneous unit hydrograph); the alternate approach is that of Gupta and Waymire, known also as Linear Routing GIUH in the literature. A model developed in a previous study which relates the geomorphological IUH of one of these approaches to the diffusive approximation of the momentum equation is used for obtaining the IUH s the networks will produce. Also the concept of junction configuration is made use of. A simulation study has been carried out for 6-source channel networks with a certain junction configuration. Here the aim is to see the distribution of the IUH s which these networks produce. The relationships between mean IUH properties and non-dimensionalized mean interior link length of the network are obtained for a Froude number of 0.2 and for all possible junction configurations of 3, 4, 5, 6-source channel networks. The average relationships between IUH properties and dimensionless mean interior link length are obtained for 3-8 source channel networks.

Keywords: mean instantaneous unit hydrograph, river network, topology, dimensionless response.

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