Sahoo, Dr. Bharat ChandraPanda, ChinmayaPanigrahi, Dr. Balaram2018-09-112018-09-112018http://krishikosh.egranth.ac.in/handle/1/5810072692Land capability, erosion status and water resources potential of a watershed are some of the basic and important factors need to be considered in watershed planning and development. Empirical models /methods available for estimation of these parameters are more assumption based than actual field values. Intervention of remote sensing and GIS in identifying and assessing the parameters and estimation of their potential has been widely accepted in watershed planning. Thus, a physical based GIS supported model called Soil and Water Analysis Tool (SWAT) has been used in the present study to estimate the runoff and sediment yield from the upper catchment of Subarnarekha basin. ArcSWAT embedded with ArcGIS interface was calibrated using observed data for a period from 1996 to 2008 which includes three years of warm up period from 1997 to 1998. Further, the validation of the model was accomplished using the observed data on flow and sediment yield from 2009 to 2013. In both the instances, the R2 values were above 0.85 to 0.90 with low percent of bias (-)12 to (-)19%. Interestingly, the modelling efficiency of SWAT is found to be excellent (NSE = 0.83 to 0.90) as far as stream flow and sediment yield estimation is concerned. The model sensitivity analysis was carried out with 10 sensitive parameters recognized for stream flow and 17 sensitive parameters for sediment yield. The Base flow alpha factor (ALPHA_BF) among them was adjudged as the most sensitive factor for influencing stream flow and similarly, Manning’s n value for the main channel (CH_N2) was the most sensitive one for sediment yield. Finally, the model was run to simulate the stream flow and sediment yield on monthly time step. Monthly sediment yield was simulated with R2 values of 0.78 and 0.76 during the calibration and validation period and NSE values of 0.76 and 0.75 for the respective periods. Further, an attempt has been made in the study address the prioritization issue of the watershed. The model outputs such as sediment yield, erosion class of the soil, soil slope and type of land use have been clubbed together with assigned weightage values in ranking the watersheds based on their vulnerability status. The study is also identifying the sub-basins where installation of proper soil and water conservation structures can reduce both sediment and runoff losses from the watershed. Overall, based on the model performance and its prediction efficiency, SWAT model can be reliably used for stream flow and sediment yield estimation and watershed planning at sub-basin and basin scale in eastern Indian region.ennullThesis