Rainfall Runoff Modeling for Urbanized Watersheds

Abstract

Rainfall is a major natural water resource, when it falls on the surface of the earth, due to newlinedifferent earth surface characteristics and climatic processes, it undergoes various newlineprocesses where some part of this lost in various type of abstraction like evaporation, newlineinterception, infiltration and remaining flows into drainage system as surface runoff which newlineeventually joins receiving water bodies. Runoff is the most basic and important information newlineneeded for assessment of available water resources for various uses, optimum planning, newlinemanagement and design of water related infrastructure facilities and services. Rainfall to newlinerunoff conversion is a function of many catchment and meteorological characteristics. newlineWatershed characteristics including land use/land cover (LULC) in addition to newlinemeteorological parameters are very vital information for hydrological behavior of newlinewatersheds. There are various methods, approaches and models are available for the newlineassessment of runoff and water availability from a particular area. These models and newlinemethods are conceptualized to deal with rainfall-runoff processes at a level of complexity newlinein term of mathematical treatment of processes, data required, spatial and temporal newlineresolution of input data to achieve a desired accuracy. For different application like for newlinefeasibility studies, planning level, design level and operation level, we need to use suitable newlinemodel/method ensuring achievement of required accuracy and maintaining cost newlineeffectiveness. Further, rainfall-runoff processes are quite different and dynamic in newlineurbanized catchments as compared to rural catchments due to dynamic land use land cover, newlinemore human interventions and landscape disturbances. Change in land use/cover newlinecharacteristics in a watershed alone may lead to significant changes in hydrological newlinebehavior of a watershed which includes increase in peak runoff, reduction in time to peak, newlineless groundwater recharge and more pollution. Such adverse changes may leads to lot of newlinehydrological problems in urban areas like flooding, soil erosion and contamination of newlinereceiving water bodies. Remote sensing data and other geospatial analysis techniques can newlinebe used to extract correct land use land cover information at required spatial and temporal newlineresolution.