Session1: River Engineering and Management
Title: MORPHOLOGICAL IMPACT OF BRIDGE CONSTRUCTION ON SUNSARI MORANG IRRIGATION INTAKE
Bijay Shrestha, Sanjay Giri, Alessandro Cattapan, Mario J. Franca
In this paper, we present the results of a morphological study revealing the impacts of river intervention during bridge construction phase in Koshi River near Chatara (Nepal). We demonstrate how such intervention in the river reach resulted in morphological changes that subsequently had an impact on the intake of Sunsari-Morang Irrigation Project (SMIP), located downstream of the bridge. We carried out image analysis to detect the problem and attempted to replicate it using a two-dimensional morphological model (Delft3D). The study revealed how flow and geomorphological feature and processes as well as intervention on these processes lead to adverse impacts on the river system on one hand, and safety and functionality of water infrastructures on the other. The paper demonstrates how a process-based modelling tool can be useful for a rapid assessment of morphological impacts caused by interventions in highly dynamic and sediment-laden river like Koshi.