Numerical experiment on water and soil losses for the application in ungauged basins

摘要

Water and soil losses are dominated by the conditions of regional geomorphologics, land-uses, and landcovers, in addition to strong influences of rainfall characteristics in the region. An ideal approach to deal with the problem of water and soil losses in the study should consider all conditions together. Therefore, a coupled 2-D numerical model of water, sediments, and morphological change based on the governing equations of 2-D shallow water, 2-D unbalanced sediment transportation, and ground surface variation in elevations was proposed in this study. Considering the general complexities of regional land covers and land-uses, the coupled 2-D numerical model was developed by an unstructured FVM method based on irregular polygonal mesh systems. Throughout its application the experimental station of water and soil losses in Suining Prefecture, Sichuan Province, the coupled 2-D numerical model was validated. Results indicate that the model can perform stably and reliably with satisfactory accuracy for the evaluation of the distribution of water and soil losses, both in temporal and spatial domains. Furthermore, the results also imply that the model can be applied to ungauged basins for the evaluation of the sources of water and soil losses coming from within a basin so that adequate and practical methods for treatment can be adopted.