ABSTRACT
Across the globe, urban population is increasing at an alarming rate. The increase in urban population causes the increase in impervious areas due to the changed land use land cover (LULC). This in turn significantly influences the hydrology of the area causing flooding in urban areas. In this research, an attempt has been made to adopt low impact development (LID) measures to increase infiltration in the study area. The present study analyzes flooding in the west zone of Ahmedabad city with 100% urban land use and served by the stormwater network connection. The study comprises verifying the network capacity followed by identification of the areas that get flooded during the monsoon season since past few decades. The appropriate LID structures for such locations are identified and their impact to reduce the flooding is analyzed. The study uses spatial data such as stormwater drainage network, ground level and invert level of catch basins, digital elevation, and contour map. The network efficiency to carry the stormwater was done using Bentley CivilStorm and was found to be 67%. It was derived that the flooding occurred primarily due to two reasons—insufficient capacity of network, and other local features existing in the area such as natural topography/ slope, LULC, and vicinity to existing network. The analysis indicated that 4after implementing the LID structures such as vegetated swale, infiltration trench, and bioretention in the identified 11 sites, 7.73 million L of water may be infiltrated into the ground out of 11.34 million L of flooded water. This would in turn retain the quality and quantity of water in urban areas. The study finally demonstrates that the flooded water can be reduced by 68% by using these practices in west zone of Ahmedabad.
