*4.4. Limitations and Potential Improvements*

While this study assessed the impact of terraces and vegetation practice on runoff and sediment routing process using the revised time-area method, it still has several assumptions and limitations in the method that need to be clarified and studied further. First, embankment height is a key indicator to evaluate the quality and storage volume of terraces. The assumption that all terraces in the Pianguanhe Basin are of good quality and set the embankment height with a fixed value may overestimate the runoff and sediment reduction efficiency of the terraces. This paper referred to the study of Xiong et al. [77] as the limitation of the flume test data. While the runoff and sediment retention function of vegetation is not independent of slope steepness or vegetation structure, these factors have not been considered yet. In addition, the effect of engineering measures such as check dam and human factors such as mining and road construction should also be considered to further improve simulation efficiency.
