A precipitation-runoff simulation model for flood forecasting of River Tel, Odisha, India

Abstract

Flood forecasting is considered as an important component of non structural measures for flood management planning. Hence it is of immense importance to accurately estimate the flood hydrographs resulting from storm events for all the tributaries of a river system which causes flood. In the present study simulation of precipitation-runoff process for the Tel Sub basin of Mahanadi Basin is carried out and various important parameters of the model are calibrated. It is pertinent to mention that Tel (catchment area 22800 km2) is an important tributary of Mahanadi system and contributes significantly to the flood peak at the delta head of Mahanadi at Munduli. Historical flood records show that the River Tel alone contributed 74.85% and 71.1% of the total flood peak at the delta head of Mahanadi during the floods of 2008 and 2009 respectively. For precipitation-Runoff simulation study of Tel Sub basin of Mahanadi Basin the HEC-HMS model, developed by Hydrologic Engineering Center of US Army Corps of Engineers is used. Using the model and available data some important model parameters which significantly affect precipitation-runoff process are calibrated considering the storm event of 29 August 2006 to 4 September 2006. Further, using the calibrated model parameters, the model is run to estimate the flood peak and time to peak for the storm event of Sept 2008 flood (14 Sep 2008 to 25 Sep 2008) and July 2009 flood (14 July 2009 to 25 July 2009). The observed and computed values of flood peaks and time to peaks are compared and it is seen that there is a close agreement between the observed and computed values. The result shows that there is an error of 4.8 % and 0.82% between the observed and computed flood peaks respectively for the storm events of 2008 and 2009.