Compliance Engineering Journal
ISSN NO: 0898-3577
SURFACE RUNOFF ESTIMATION USING SCS- CN METHOD AND GIS TOOL FOR THE PALAR WATERSHED, KARNATAKA Amritha Thankachan1, Mohammed Badiuddin Parvez2, Chalapathi K3, M. Inayathulla4, Chithaiah.E5 1,2,3 Research
Scholar, Department of Civil Engineering, UVCE, Bangalore University
4 Professor, 5Guest
Department of Civil Engineering, UVCE, Bangalore University
Faculty, Department of Civil Engineering, UVCE, Bangalore University
Abstract: Adequate knowledge about the hydrology is very much required for the proper planning and management of water resources in an area. Rainfall and runoff are the important constituents in determining the hydrology of an area to determine the water management strategies. SCS- CN method is a widely used method for the calculation of surface runoff considering the land use pattern, soil type and antecedent moisture condition. In the present study runoff of the Palar watershed, Karnataka state, South India has been calculated using the SCS-CN method. The watershed consists of a total area of 2872.357 km2. The maximum rainfall of 1231.67 mm in the year 2005 and a minimum of 418.7 mm in the year 2003. The average annual runoff is calculated as 218.26 mm and 626.91MCM. The rainfall- runoff correlation value is 0.8253. The study results can be effectively coordinated for the watershed management activities.
Key Words: Antecedent Moisture Condition, Hydrological Soil Group, Runoff, SCS- CN method Introduction: A watershed is defined as an area of land that feds all the water running under it and draining off into a waterbody. Rainfall and runoff are important processes involved in hydrologic cycle. Rainfall is the common form of the precipitation in which liquid water is received from the condensed atmospheric water vapour. Where ever rainfall is involved in that region’s hydrologic cycle, it serves major role not only to serve the needs of the humanity, but also for the existence of the life. Surface runoff is the term used to mention the flow of excess water through the surface of earth. Runoff depends on many factors like meteorological factors, physical characteristic of the basin etc. in which rainfall and its characteristics have major influence. Also it is very much important to study how the runoff varies with rainfall under the prevailing conditions as rainfall- runoff studies are very essential for the construction of hydraulic structures, watershed management, flood forecasting, water harvesting and also for any hydrologic studies. Soil Conservation Services Curve Number method abbreviated as SCS-CN method is a widely accepted and used method for the calculation of runoff. This method was developed
Volume 11, Issue 2, 2020
Page No: 258