基于改进White方法的地下水蒸散发研究

Using the improved White method to quantify groundwater evapotranspiration

在依赖地下水的植被广泛分布的干旱半干旱地区,蒸散发是地下水排泄的主要方式,因而准确计算地下水蒸散发量,对地下水资源评价具有重要意义。目前水量残差法、地下水极限埋深法和地下水水位日动态法可以用于计算地下水蒸散发量,由于地下水动态信息容易获取,长期以来得到广泛关注。分析了利用地下水动态信息的White方法在计算地下水净补给量方面的不足之处,提出了改进的White方法,即利用相邻两天地下水位上升段的平均斜率计算地下水的净补给量,并利用数值模拟方法对改进的White方法的计算精度进行了评价,表明改进后的方法较原始方法精度提高了16%。最后利用苏贝淖流域实测的地下水动态数据,采用改进的White方法计算了地下水蒸散发量。研究成果对干旱区水资源可持续开发利用具有一定的科学意义和应用价值。

Ecosystems that depend on groundwater are widely distributed in arid and semi-arid areas.Evapotranspiration（ETG） is a significant component of the groundwater discharge.Water balance methods,experience equation methods and groundwater regime methods are commonly used to calculate ETG.Because the groundwater table record can be easily obtained,it is widely adopted to estimate ETG.It has been proved that the White method incorporates a significant source of errors due to the problematic assumptions.In this paper,an improved White method is proposed.The method was verified using the simulation data.The result indicates that the accuracy is increased by 16%.The improved method was used to estimate groundwater evapotranspiration in the Subeinao watershed using the measured groundwater level.The proposed method plays a significant role in groundwater sustainable development in arid environments theoretically and practically.