考虑土壤膨胀性的流域水文模型应用研究

目前分布式水文模型在进行流域水文过程模拟时,还未考虑土壤膨胀性对降雨入渗的影响,这会造成模型模拟失真,制约着流域分布式水文模型的适用性。对传统降雨入渗产流模型(TGAM)进行修正,引入膨胀性土壤导水系数和膨胀性土壤饱和含水量,提出考虑土壤膨胀性影响的降水入渗产流模型(GJGAM),并将其应用到流域分布式水文模型WEP-L模型中。最后,以南小河沟流域作为研究区域,选择十八亩台断面为控制断面,分别利用改进前、后的WEP-L模型模拟研究区的降水径流过程,对比验证WEP-L模型改进后的适用性。结果表明,利用改进前后的WEP-L模型,率定期内研究断面的月径流模拟值与实测值的相对误差变化不大,但Nash-Sutcliffe效率系数显著提高。验证期内相对误差减小,Nash-Sutcliffe效率系数提高。通过考虑土壤膨胀性对降雨入渗的影响,WEP-L模型对南小河沟流域降雨入渗过程的模拟效果明显改善,具有较好适用性。

The Application of Basin Hydrological Model Considering Soil Swelling Effect

At present, the distributed hydrological model does not consider the influence of soil swelling on rainfall infiltration when it is used to simulate the hydrological process of a river basin. This will cause the distortion of model simulation and restrict the applicability of the distributed hydrological model in the basin. In this paper, revised traditional Green-Ampt model(TGAM), introduction of expansive soil hydraulic conductivity and expansive soil saturated water content, a rainfall infiltration model(GJGAM) considering the effects of soil swelling is proposed and applied to the distributed hydrological model WEP-L model. Finally, taking the Nanxiaohegou River Basin as a research area, the Shibamutai Section is selected as the control section. The improved WEP-L model is used to simulate the precipitation and runoff process in the study area. The results show that using the improved WEP-L model before and after the improvement, the relative error between the simulated and measured values of monthly runoff at the regular-period study section does not change much, but the Nash coefficient increases significantly. The relative error decreases during the verification period and the Nash-Sutcliffe coefficient increases. By considering the effect of soil swelling on rainfall infiltration, the WEP-L model has significantly improved the simulation effect of rainfall infiltration process in the Nanxiaohegou Drainage Basin, and is highly applicable.