Impact of topography on groundwater salinization due to ocean surge inundation
Impact of topography on groundwater salinization due to ocean surge inundation
复制标题
DOI：
10.1002/2016wr018814
复制
发表时间：
2016-08
影响因子：
5.4
通讯作者：
Xuan Yu;Jie Yang;T. Graf;Mohammad Koneshloo;M. O'Neal;H. Michael
中科院分区：
文献类型：
--
作者：
Xuan Yu;Jie Yang;T. Graf;Mohammad Koneshloo;M. O'Neal;H. Michael
气候变化引起的海平面上升以及海浪频率和强度的增加可能会加剧对低洼沿海地区的不利影响。海洋涌动期间，水向陆地流动，将盐引入沿海表层含水层，威胁地下水资源。沿海地形特征（例如池塘、沙丘、障壁岛和河道）可能对过度冲刷和盐碱化过程产生强烈影响，但在建模研究中通常被高度简化。为了了解地形对地下水盐化的影响，我们使用完全耦合的地表和地下数值模拟器 HydroGeoSphere 对理论溢出事件以及可变密度地下水流和盐输送进行了 3D 建模。该模型将沿海含水层模拟为一个综合系统，考虑了地表水流、耦合的地表和地下交换、可变饱和流和可变密度地下水流。为了代表各种沿海景观类型，我们模拟了美国特拉华州的合成场和真实世界的沿海地形。地下水盐碱化评估表明，促进地表水流的地形连通性控制了盐碱化含水层的体积。相反，地表凹陷处可储存的水量决定了渗入地下的海水量以及海水从含水层冲走的时间。我们的研究表明，由于海洋涌动过度冲刷，地形对地下水盐化有重大影响，对沿海土地管理和地下水脆弱性评估具有重要意义。
Sea‐level rise and increases in the frequency and intensity of ocean surges caused by climate change are likely to exacerbate adverse effects on low‐lying coastal areas. The landward flow of water during ocean surges introduces salt to surficial coastal aquifers and threatens groundwater resources. Coastal topographic features (e.g., ponds, dunes, barrier islands, and channels) likely have a strong impact on overwash and salinization processes, but are generally highly simplified in modeling studies. To understand topographic impacts on groundwater salinization, we modeled a theoretical overwash event and variable‐density groundwater flow and salt transport in 3‐D using the fully coupled surface and subsurface numerical simulator, HydroGeoSphere. The model simulates the coastal aquifer as an integrated system considering overland flow, coupled surface and subsurface exchange, variably saturated flow, and variable‐density groundwater flow. To represent various coastal landscape types, we simulated both synthetic fields and real‐world coastal topography from Delaware, USA. The groundwater salinization assessment suggested that the topographic connectivity promoting overland flow controls the volume of aquifer that is salinized. In contrast, the amount of water that can be stored in surface depressions determines the amount of seawater that infiltrates the subsurface and the time for seawater to flush from the aquifer. Our study suggests that topography has a significant impact on groundwater salinization due to ocean surge overwash, with important implications for coastal land management and groundwater vulnerability assessment.