ROLE OF URBAN IMPERVIOUSNESS AND DIRECTLY CONNECTED IMPERVIOUS AREAS ON URBAN DRAINAGE SYSTEMS

摘要

Urbanisation brings significant changes to the extension of total impervious areas (TIA) Since many decades impervious area (DCIA) which is more important rather than TIA to bring the aesthetic hydro-environment in urban areas. The present study aims to delineate DCIA for a small sub-urban area. The impervious surface connectivity to drainage conveyance and overland flow directions are the essential tools in identifying DCIA from TIA. Primarily the computed from land use map and GIS data (22%) obviously; the results of GIS data set along with field assessment are well in agreement with the models developed by other researchers. The average percentage of connectivity (% DCIA with respect to TIA) is 63.45 % which lies below the line of optimal connectivity (1:1) prescribed for a medium density residential area and attributed the probable reason of water-logging in many locations over the study area.