流域分块对汇流参数的影响

Effect of watershed subdivision on confluence parameter

选择屯溪、东湾及王快流域为典型流域,挑选合适的目标函数,采用单纯形法率定参数,研究流域分块对新安江模型SM、CS、CI及CG等参数的影响。结果表明,随着流域分块数增加:降雨资料均化程度减小,SM呈增大趋势,CS呈减小趋势,CI及CG基本保持不变;洪量、洪峰合格数及确定性系数均呈增大趋势,当子流域面积小于1000km2时模拟精度大幅度改善。

In this study, we took the Tunxi, Dongwan, and Wangkuai watersheds as typical watersheds and studied the effect of watershed subdivision on the Xin’anjiang model’s parameters, including SM , CS , CI , and CG . We used the simplex algorithm with suitable objective functions to calibrate the parameters of the model. The results of the study show that, with the increase of the number of watershed subdivisions, the homogenization degree of rainfall data decreases, SM has an increasing trend, CS has a decreasing trend, and CI and CG remain invariant. The number of qualified flood volume and flood peaks and the deterministic coefficient show an increasing trend with the increase of the number of watershed subdivisions. When the area of the sub-watershed is less than 1 000 km2 , the simulation accuracy improves significantly.