Existence of Swamps and Detention Tanks for Preventing Urban Flood—A Case Study

The change in land use is going in a faster way in order to accommodate the changes in lifestyle and other socio-economic and infrastructural developments. Rural areas are getting converted to urban areas. The agricultural, barren and other non-productive lands are now used for residential purposes. The basic morphology of land use of an area is under a rapid change. The basic conversion output is a land which was earlier a permeable/semi-permeable area now converted to impermeable or negligibly permeable. Also there is a drastic change in rainfall pattern. The occurrence of short duration and peaky rainfalls is more. These intense rainfalls are the root cause of urban flooding as very less scope of permeability in land is there in urban areas. Few years ago, cities were there with ample scope of drainage of rainwater. But the behavior of same city is different at present era with lot of water logging on the residential and industrial areas. The swamps in the older cities were the places to accommodate the surplus rainwater of the city. These are natural depressions, obviously these also behave naturally. But due to large developments, we are filling these lands in order to be utilized for residential purposes. With the present developments and higher runoff coefficients, the runoff generation is more in an urban area. In order to avoid a probable water logging scenario and to develop a sustainable preventative solution, detention tanks are to be placed for efficient drainage management as well as ground water recharging. The study relates to temporal changes in land use of Bhubaneswar city in connection to the rainfall and corresponding water logging problem in conformity to the temporal variation in temporal land use and land cover.