Land-Use and Land-Cover Change in Dhaka Eastern Region and Its Impact on Surface Run-off

Abstract

The aim of this study is to identifythe impending urbanization-led land-use and land-cover (LULC) change of Dhaka Eastern Region (DER) and assessing its impact on surface runoff. Remotely sensed image data and proposed land-use plans for DER isanalyzed and mapped in this study to detect the changes of LULC. A faster pace of land transformation was observed during2016-17from unpaved to the paved surface. Four post-developed LULC scenarios were predicted from the classified Landsat imagery of 2016-17with increasing imperviousness. Runoffwas estimated by SCS-CN method integrating RS and GIStools. LULC changes according to land cover classes were assimilated with the hydrologic soil groups and then runoff depths were estimated for annual rainfall events in DER. Like the slower trend of urbanization, area-weighted 퐶푁also increased slowly during2016-17but followed a moderate leap in RDP and scenario-1. However, 퐶푁dropped in scenario-2 mainly due to the change in land-cover by infilling of highly permeable hydrologic soils. Predicted scenario-3 and 4 resulted in higher 퐶푁respectively because of increasing imperviousness inLULC. Higher 퐶푁resulted in higher runoff and more drainage requirements. RDP scenario or the predicted scenario-1 with 퐶푁84is potentially a viable LULC option for DER by 2035 and beyond that may cause more than 30%to 50%runoff comparing tothe representative 2010 LULC condition.