Bosserelle Amandine L, Morgan Leanne K
Department of Civil and Natural Resources Engineering, Faculty of Engineering, University of Canterbury, Christchurch, New Zealand.
Waterways Centre, School of Earth and Environment, University of Canterbury, Christchurch, New Zealand.
Ground Water. 2025 Jul-Aug;63(4):551-569. doi: 10.1111/gwat.13489. Epub 2025 May 2.
Coastal shallow groundwater is susceptible to adverse sea-level rise (SLR) impacts. Existing research primarily focuses on SLR-induced salinization of coastal aquifers. There is limited understanding of the magnitudes and rates of water table rise in response to SLR, which could lead to groundwater flooding and associated infrastructure challenges. This study used a variable-density groundwater flow model to quantify the transient movement of the water table in response to various SLR scenarios and rates, considering a range of aquifer parameters for both fixed-head and fixed-flux inland boundary conditions. The SLR scenario based on realistic and progressive SLR projections resulted in a smaller water table rise than the instantaneous or gradual SLR scenarios at 100 years, despite a final identical SLR. Rates of water table rise were always less than SLR, decreased with distance from the coastline, and were proportional to SLR. The magnitude and rate of water table rise in response to SLR were largest for fixed-flux conditions. It also took longer for the rate of water table rise to equilibrate after the commencement of SLR for fixed-flux conditions than for fixed-head conditions. As such, fixed-flux conditions represent a greater hazard for water table rise, and the maximum impact may not be experienced for decades. This delayed response poses challenges to planners and managers of coastal groundwater systems. Introducing a drain reduced water table rise more on the inland side of the drain than on the coastal side. Subsurface infrastructure may limit SLR impacts, but further effects need to be carefully considered.
沿海浅层地下水易受海平面上升（SLR）的不利影响。现有研究主要集中在SLR导致的沿海含水层盐渍化。对于因SLR导致的地下水位上升幅度和速率的了解有限，这可能会引发地下水洪水及相关基础设施挑战。本研究使用可变密度地下水流模型，针对固定水头和固定通量内陆边界条件下的一系列含水层参数，量化了地下水位对各种SLR情景和速率的瞬态响应。尽管最终海平面上升幅度相同，但基于现实和渐进海平面上升预测的情景在100年时导致的地下水位上升幅度小于瞬时或逐渐海平面上升情景。地下水位上升速率始终小于海平面上升速率，随离海岸线距离的增加而减小，且与海平面上升速率成正比。对于固定通量条件，地下水位因海平面上升而上升的幅度和速率最大。固定通量条件下，地下水位上升速率在海平面上升开始后达到平衡所需的时间也比固定水头条件下更长。因此，固定通量条件对地下水位上升构成更大的危害，且几十年内可能不会感受到最大影响。这种延迟响应给沿海地下水系统的规划者和管理者带来了挑战。引入排水设施后，排水设施内陆一侧的地下水位上升幅度比沿海一侧减小得更多。地下基础设施可能会限制海平面上升的影响，但需要仔细考虑进一步的影响。
