The present study deals with the estimation of soil loss from the Upper Subarnarekha catchment in Odisha (India) using Soil and Water Assessment Tool (SWAT). Sequential uncertainty fitting (SUFI-2) algorithm of the SWAT calibration uncertainty programs (SWAT-CUP) was used for model simulation. The model was calibrated with the observed data for the period from 1996 to 2008 with first 3 years (1996–1998) as warm-up period. Further, validation of the model was done using 5-year data from 2009 to 2013. Reliable evaluation of the model performance during calibration has been substantiated by the coefficient of determination (R²), Nash–Sutcliffe efficiency (NSE), and percentage bias (PBIAS) as 0.81, 0.81, and −0.15, respectively, and the respective values for the validated model were found to be 0.79, 0.78, and −0.19. The values of P-factor and R-factor were found to be 0.80 and 0.75 and 0.66 and 0.74, respectively, for model calibration and validation. Average annual soil loss from the catchment was 4.84 Mg ha⁻¹. The watershed indexed as SW18 resulted in highest soil loss in the range of 10–15 Mg ha⁻¹year⁻¹. Further, prioritization was done at the level of sub-watersheds using the data of simulated sediment yield, soil texture, land use, and slope for identifying vulnerable sub-watersheds that need immediate attention. The study inferred that sub-watersheds having index numbers SW17, SW18, and SW19 are highly vulnerable, and hence top priority should be given to these sub-watersheds for reduction in soil erosion through the implementation of suitable soil and water conservation measures.

本研究使用土壤和水评估工具（SWAT）处理了印度奥里萨邦Subarnarekha上游流域的土壤流失估算。使用SWAT校准不确定性程序（SWAT-CUP）的顺序不确定性拟合（SUFI-2）算法进行模型仿真。使用1996年至2008年期间的观测数据对模型进行校准，以前3年（1996年至1998年）为预热期。此外，使用2009年至2013年的5年数据对模型进行了验证。通过确定系数（R ²），纳什-舒特克利夫效率（NSE）和百分比偏差（PBIAS）分别为0.81、0.81和-0.15，经验证的模型的各个值分别为0.79、0.78和-0.19。的值P-因子和R-因子被发现分别为0.80和0.75和0.66和0.74，进行模型校准和验证。流域的年平均土壤流失量为4.84 Mg ha ^-1。索引为SW18的分水岭造成的最大土壤流失范围为10–15 Mg ha - ¹年^-1。此外，使用模拟沉积物产量，土壤质地，土地利用和坡度等数据在子流域一级进行了优先排序，以识别需要立即关注的脆弱子流域。研究推断，索引号为SW17，SW18和SW19的子流域非常脆弱，因此应优先采取这些子流域，以通过采取适当的水土保持措施减少土壤侵蚀。