TR-80 : Application of flood routing procedure incorporating lateral inflow

Abstract

The treatment of lateral inflow in flood routing has been a matter of concern to the hydrologists. However, most of the studies have considered the lateral inflow as the volumetric difference of outflow and inflow and the shape being as that of inflow/outflow hydrograph and then adjusting it with either inflow/outflow before/ after routing, respectively. These methods, thus, do not take lateral inflow into account implicitly.

O'Donnell (1985) developed a methodology named Three Parameter Muskingum type procedure which incorporates the lateral inflow with the assumption that it is of the shape of inflow. This has the advantage that it is very simple, efficient and needs less computation efforts in application.

In this study, the above-said model has been applied to nine flood events of three sub-reaches of river Tapti with magnitude of floods varying from 933 cumecs to 9592 cumecs. The computed and observed outflow hydrographs compare well in all the cases. The model efficiency in simulation of outflow hydrograph varies from 70.98% to 98.82%, indicating satisfactory performance of the methodology in routing of flood events in different reaches of river Tapti.