Green water defense as flood mitigation approach for Dhaka district

Abstract

Dhaka is prone to flood hazard due to its location, topology, climate and proximity to rivers. The main objectives of this study are to delineate the flood extent, find out the flood duration during monsoon, identify the change in land use and find out mitigation measures to reduce the impact of flood hazard in Dhaka. In this report, the flood types, causes of flood, flood history and flood control, and flood mitigation measures for Dhaka district are discussed. The study is based on review of literature, analysis of satellite images and water levels, and interviewing of some key informants. Due to its location, Dhaka is found to be susceptible to both fluvial and pluvial types of flooding. Drainage congestion is another major problem in Dhaka during the monsoon due to unplanned rapid urbanization, poor drainage system and improper maintenance of sewerage and drainage system. At present, Dhaka does not have any integrated long term flood risk management plan. A multi-scale, delta perspective flood mitigation focus, which involves long term adaptive management, is not yet in place. Green water defense, which is an adaptive management approach for delta regions, can be one of the best flood mitigation approaches, for Dhaka, both in city and district scales.