FLOOD SIMULATION USING GIS AND MIKE 11 - A CASE STUDY OF TEESTA RIVER BASIN

Abstract

Flood, a natural disaster in Bangladesh, affects the whole economy of the country. Teesta river basin of Bangladesh has been chosen _ as the study area where floods cause appreciable damages to life and properties every year. Flash flood generally occurs during monsoon in Teesta river basin and riverine flood occurs in Jamuna river. Like structural measure, non-structural n1eustire lllso plays 1111 Iinpor11111I role in improving the level of protection to lives and properties from floods by predicting the flood, identifying the flood prone areas and by educating the people to be prepared for the flood. An annual flood series (AFS) of 22 years of Kaunia gauging station in Teesta river has been used for estimating 25-, 50- and 100-year floods using flood frequency analysis method. Chi-square test, K-S test and D-index test have been applied for selecting the best-fit distribution. Three tests revealed that PT-IIl distribution is the best-fit distribution. That is how it can be assumed that annual maximum discharge on the Teesta river follows the PT-III distribution. The MIKE 11 NAM and HD model have been used for the simulation of i.he Teesta river network using 12 years historical hydrological time series (hut,1 to generate 11 time series of river stage and discharge along the river network. From the simulated result a stage-discharge curve and equation has been developed at Kaunia Guage site. By applying 25-, 50- and 100-year estimated discharges to the rating curve and its equation, the flood stages have also been computed as 32.66. 32.92 and 33.15 meter respectively. These computed stages may be useful for the hydrologist to prepare the flood extent and vulnerability of' that area to provide the inn rmation to the disaster management authority for proper integrated flood management. iv