Flood depth analysis for the district of Sylhet

Abstract

The study was undertaken to develop a flood depth map of Sylhet district corresponding to floods of 10 years and 20 years return' periods. T he study was carried out as follows: i) Determination of total flooded area under different flood depth classes correspondi~g to floods of 10 years and 20 years return period. ii) Comparison between computed flood depth distribution values with existing informations On flood depth to develop flooded depth area CUrves for the study area. iii! Development of a computer program for determination Of flood depth distribution values from river stage and topography data.

Two flood depth maps were prepared for the study area. Areas under different flood depth classes were planimetered and presented in tabular form. Comparison between computed flood depth distribution for 20 yrs return period with flood depth map prepared by Master Plan Organization in 19B5, shows that results are in good agreement. A computer program was developed to determine the flood depth distribution Of a simple case Of a single channel chatchment. The program was applied to an independent catchment of the study area. Results obtained from the program were in close agreement with that obtained from analytical method.