Field Study Report Course No. : WFM 6306 Course Name: Urban Water Management Submitted to Dr. M. Shah Alam Khan Professor IWFM, BUET Submitted by Uthpal Kumar Roll No. 0411284003 Institute of Water and Flood Management Bangladesh University of Engineering and Technology February, 2012 Detention and Retention Function of Hatirjheel Integrated Project and Its Management Aspect By Uthpal Kumar, PhD Candidate, IWFM, BUET, Dhaka-1000.
[email protected] 1. Introduction Detention and retention basin are important component of stormwater management in the cities. The Hatirjheel-Begunbary detention basin is the largest stromwater detention basin in Dhaka which drains stormwater from one-third catchment area of the city. Dhanmondi, Gulshan and Banani lakes are hydrologically linked with this detention basin, and the combined outfall of the whole catchment area (about 30 km2) falls at Rampura, where Begunbary Khal meets to receive total drainage discharge, and finally drained into the Balu river by gravity flow. After the severe flood in 1988, a regulator was constructed at the Rampura outfall and this regulator is kept close as the external river water level reach at 5 m PWD. At that time a total of 50 (30 pumps are of 25 cusec and 20 are of 5 cusec capacity) pumps are used to drain stormwater from entire catchment area and the total process is maintained by the DWASA. The detention capacity and function of the Hatirjheel basin have been reduced significantly due to illegal encroachment. Moreover, solid waste dumping, illegal households’ and industrial sewerage connections have also been polluted the total system for its subsistence uses.