Impact of temporal changes of land use on surface Run-off A case study on musi basin using soil and water assessment tool (SWAT)

Land and water are the two most vital natural resources of the world. Proper planning and management of these two most vital natural resources is, therefore, of utmost necessity. For proper planning and efficient utilization of the land and water resources it is necessary to understand the hydrological cycle and estimate the hydrological parameters. In the present study SWAT2012 (Soil and Water Assessment Tool, ArcSWAT10.2.2), a physical based semi distributed hydrologic model having an interface with ArcGIS 10.2.2, GIS software was applied for Musi Basin, a sub-basin of river Krishna, covering an area of 11268.54 sq.km in order to model the various hydrological components and to assess the impact of land use/land cover on the surface flow. In order to study the impact of land use/land cover on surface runoff, simulations were carried out for the crop periods of kharif 2005-06 and kharif 2010-11 using the same precipitation file. Results indicated that with an increase in irrigated land and increase in urban land, during the period from 2005 to 2010 surface runoff has increased by 8.47mm (18.6% to 19.6% of precipitation) showing that the land use/land cover has an impact on the hydrological regime. Then the simulations were carried out for the land use of 2005-06 kharif with and without irrigation operation for a time period of 35 years (1979-2013) and the simulations showed that the surface runoff was more for the model under irrigation by 7.6%. Runoff had increased from 24.8% to 32.4 % of precipitation. These results clearly show how land use changes and agricultural management practices impact hydrological parameters like runoff.