Estimation of Surface Run-off for Urban Area Using Integrated Remote Sensing and GIS Approach

Urban run-off increases significantly due to increased impervious area and reduced drainage network. Evaluation of land use in urban area plays a vital role as input to the estimation of runoff. The hydrological design standard for urban water resources planning and management is commonly based on the frequency of occurrence of heavy rainfall events. In the present study, the occurrence of most frequent heavy rainfall event is investigated for Thanjavur town, located in the State of Tamilnadu, India and used for estimation of run-off depth. The Soil Conservation Service Curve Number (SCS-CN) is used for evaluating run-off depth value for event rainfall starting from 10 mm to 400 mm. The land use detail for the study area was obtained by integration of GIS and remote sensing. The spatial variation of event rainfall is considered with certain percentage of deviation from base rainfall for each triangle area that contributes to the run-off. The results of the analysis indicate that the study area can produce the run-off volume more than that required for urban water management at an average seasonal rainfall.