Stormwater Management in Begunbari Canal Catchment of Dhaka, Bangladesh: Fid-Bau Portal

Stormwater Management in Begunbari Canal Catchment of Dhaka, Bangladesh

Ahammad, Muneer / Tarek, Mehedi Hasan / Khan, Md. Sabbir Mostafa

Stormwater management is a challenging task in urban areas, particularly in relatively densely populated cities having weak water governance and a lack in the institutional arrangement. It is even more challenging when the natural drainage system experiences relatively high water levels in the peripheral rivers during the rainy season, or if the system capacity is compromised due to encroachment of the runoff detention areas. Having these problems, flooding during the monsoon season is a regular phenomenon in Dhaka, the capital of Bangladesh. The situation of Eastern part of this city is more complex as it also faces external flood from the Balu River. Begunbari canal is the main canal that carries most of the stormwater of Eastern Dhaka as well as pumped discharge from Central Dhaka. But the canal section is inadequate to carry the river water and stormwater. The river water has to be prevented to enter into the canal to manage the stromwater efficiently. An embankment along the river would serve this purpose with pump regulation at the canal outlet. In this study, Begunbari canal catchment (47.67 square km) area of Eastern Dhaka has been modeled in GeoSWMM. The model was calibrated with the observed data and drainage study was carried out for keeping the flooding level in the area below 4.5 m PWD under design storm of 2 day 1:5 year return period draining within 2 days. It was found that 55 cumec capacity pumps with 1.5 square km retention area are required to keep the water level in desired limit.