平原区地表水-土壤水-地下水转换机理实验与模拟

The varied groundwater table depth in the plain area，as a result of the impact of climate change and human activities, causes the change of the unsaturated zone thickness and soil water storage，and subsequently alters the runoff production, soil water distribution, groundwater recharge and evapotranspiration. The compositions of the sources of different water components (streams, groundwater, and soil water) further complicate the hydrologic cycle in the plain area. Through the systematic observation of surface water-soil water-groundwater on a typical small watershed in the plain area, and environmental Isotopes (O-18 and deuterium) technique, this project conducted the experiments of precipitation-soil water-groundwater conversions with unsaturated zones of different thicknesses using the lysimeter, studies the mechanism of the surface water-soil water-groundwater conversion and simulates the hydrologic processes in a watershed of the plain area with distributed hydrological models. A physically-based distributed hydrological model, which can reproduce the impact of the thickness of unsaturated zones using the variable soil water storage and runoff parameters, is developed for integrated the simulations of surface water-soil water-groundwater dynamics. Based on the principles of water balance and mass conservation of isotopes, the mechanism of the surface water-soil water-groundwater conversion is examined. The effects of the thickness of the unsaturated zone are quantitatively evaluated on the surface water resources and groundwater resources.

由于气候变化和人类活动影响，平原区地下水埋深变化导致包气带厚度以及土壤蓄水容量的变化，从而改变了地表产流、土壤水分布、地下水补给和潜水蒸发等水文过程以及各种水分转化关系；平原区各种水分（河道径流、地下水、土壤水）的来源组成使得平原区水循环过程更加复杂。本项目通过水文实验站和淮河平原小流域地表水-土壤水-地下水系统观测实验，结合稳定同位素（氧-18、氘）技术，开展不同包气带厚度的蒸渗仪降雨-土壤水-地下水转换实验研究、平原小流域地表水-土壤水-地下水转换机理实验和平原流域水文过程分布式模拟研究。建立能够反映平原区包气带厚度变化的变动蓄水容量参数产流模型，根据水量平衡和同位素质量守恒原理，分析各种水分来源组成，揭示地表水-土壤水-地下水转换机制，构建具有物理基础的平原区分布式水文模型，实现地表水-土壤水-地下水动力过程耦合模拟。定量评价包气带厚度变化对地表水资源和地下水资源的影响程度。

由于气候变化和人类活动影响，平原区地下水埋深变化导致包气带厚度以及土壤蓄水容量的变化，从而改变了地表产流、土壤水分布、地下水补给和潜水蒸发等水文过程以及各种水分转化关系。本项目通过水文实验站和淮河平原小流域地表水-土壤水-地水系统观测实验，在五道沟实验站设置不同深度的蒸渗仪，开展不同包气带厚度的蒸渗仪降雨入渗、产流、土壤水、地下水转化的实验，结合稳定同位素（氧-18、氘）技术，揭示包气带厚度变化下地下水由降雨入渗补给和河道径流补给过程以及组成规律；分析河道径流-地下水相互转换过程，建立能够反映平原区包气带厚度变化的变动蓄水容量参数产流模型，根据水量平衡和同位素质量守恒原理，分析各种水分来源组成，揭示地表水-土壤水-地下水转换机制，构建具有物理基础的平原区分布式水文模型，实现地表水-土壤水-地下水动力过程耦合模拟，定量评价包气带厚度变化对地表水资源和地下水资源的影响程度，具有重要的理论意义和实用价值。迄今为止，本课题发表学术论文38篇（其中SCI检索10篇，核心刊物28篇）均标有基金资助，培养博士研究生10名，硕士研究生17名，参加国际会议5次，获得大禹水利科学技术奖一等奖和高等学校科学研究优秀成果科技进步一等奖各1项。