Simulation of runoff and sediment yield from a hilly watershed in the eastern Himalaya, India using the WEPP model

• Published in: Journal of hydrology (Amsterdam) 2011-08, Vol.405 (3), p.261-276
• Main Authors: Singh, R.K., Panda, R.K., Satapathy, K.K., Ngachan, S.V.
• Format: Article
• Language: English
• Subjects: Calibration; Computer simulation; conservation practices; control methods; corn; crops; cultivators; drainage; Earth sciences; Earth, ocean, space; Exact sciences and technology; Freshwater; highlands; Hilly watershed; Hydrology; Hydrology. Hydrogeology; Management; Management strategies; Marine and continental quaternary; Mathematical models; model validation; monsoon season; paddies; peanuts; plows; rain; Reduction; Runoff; Sediment; sediment yield; Sediments; simulation models; soybeans; storms; students; Surficial geology; sustainable agriculture; tillage; topographic slope; traditional farming; Water Erosion Prediction Project; Watersheds; WEPP model
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2011.05.022

► The WEPP model was tested in high rainfall and steep slope conditions of eastern Himalaya using field-measured data. ► The calibrated and validated WEPP model was used to develop conservation strategies for agricultural sustainability. ► Soybean, peanut and maize intercropped with soybean could replace paddy in upland for 27% sediment yield reduction. ► Porous rock-fill check dams and trash barriers in drainage lines could reduce the sediment yield by 54.67%. ► Soybean – drill-no-tillage – structural controls combination has potential to reduce sediment yield by 78.40%. A study was undertaken to develop appropriate vegetative as well as structural measures to control sediment yield from a 239.44 ha small multi-vegetated watershed in high rainfall and high land slope conditions of eastern Himalayan range in India using a physically based distributed parameters Water Erosion Prediction Project (WEPP) model. The model was calibrated and validated using field-measured data pertaining to 86 storms of monsoon season 2003 and 98 storms of 2004. The daily simulated runoff and sediment yield of the Umroi watershed for the calibration and validation periods were found to match with their measured counterparts at 95% significance level as shown by the Student’s t-tests. The model simulated daily runoff quite well as corroborated by reasonably high Nash–Sutcliffe simulation coefficients of 0.94 and 0.87, low root mean square errors of 1.42 and 1.77 mm, and low percent deviations of −1.71 and −3.01, respectively for calibration and validation periods. The performance of the model for simulating daily sediment yield was also quite good with Nash–Sutcliffe simulation coefficients of 0.95 and 0.90, root mean square errors of 0.08 and 0.09 Mg ha −1 and percent deviations of 3.05 and −5.23, respectively for calibration and validation periods. Subsequently, the calibrated and validated model was used to simulate vegetative (crop, level of fertilization and tillage) and structural (rock-fill check dam and trash barrier) measures and combinations of vegetative and structural control to evaluate their impacts on runoff and sediment yield reduction. Simulations of different vegetative management scenarios indicated that replacing traditional bun agriculture and upland paddy crop with maize, soybean, and peanut would reduce sediment yield by 18.68, 29.60 and 27.70%, respectively. Field cultivator and drill-no-tillage systems have the potential to reduce sediment yield by 13.14