Evolution of Groundwater Systems: Effects of Long-Acting Natural and Superimposed Anthropogenic Stressors

地下水水位因各种自然和人为压力（如季节性气候变化、地下水抽取）而变化，这些压力作用于不同的时间框架。通过测量含水层系统对这种应力的反应，然后试图模拟这种反应（即使用分析或基于过程的数值模型），我们可以相当深入地了解给定应力在地下水位变化中表现出来的速度以及影响将持续多久。在现场尺度上，通常有足够的数据在短时间内约束和校准模型。但是，由于含水层的长期仪器记录很少，因此更难以获得长期（数十年至数千年）响应的观测结果。这意味着我们需要创新，开发新的建模方法，以探索含水层系统的长期响应。 我的研究计划将集中在两个至关重要的主题：干旱和盐碱化。我们将研究含水层系统如何在古记录和仪器记录中对干旱做出反应，通过从树木年轮记录重建地下水位，并使用一系列统计技术来表征地下水位响应，与气候周期的联系以及干旱发生。我们将量化干旱传播率（例如滞后时间和地下水位下降和恢复的速度），并将结果与观测数据进行比较。我们将进行情景建模，以归因于干旱的原因，确定是否存在与干旱相关的临界点，系统恢复受到显着影响，量化系统恢复的速度，并探索不同的水资源管理方案。最后，我们将进行两个长期的地下水演化模拟研究;第一个重点是在沿海三角洲的含盐古水的发生，第二个重点是如何海底地下水循环和盐度分布随时间变化，以响应海平面和补给的变化。 在加拿大和世界各地，水资源日益受到干旱和盐碱化的影响，从而影响到粮食和能源安全以及生物多样性。在全球范围内，地下水越来越多地被用来抵消淡水需求，但抽取地下水的长期影响难以量化，因为与地表沃茨相比，地下水对压力的反应更慢。我的研究将推进使用代理数据在地下水干旱研究的方法，表征含水层对干旱的响应，并确定管理方案，并确定气候变化对沿海含水层盐度分布的影响。所获得的知识和我们开发的建模方法将是加强地下水资源可持续性研究和建立适当的监测网络以检测变化的重要工具。

Groundwater levels vary in response to a wide range of natural and anthropogenic stresses (e.g. seasonal climate variability, groundwater pumping) that act over varying time frames. By measuring the response of the aquifer system to such stresses and then attempting to model the response (i.e. using an analytical or process-based numerical model), we can gain considerable insight into how quickly a given stress will manifest in a groundwater level change and how long the effects will last. At the site scale, sufficient data are often available to constrain and calibrate models over short time frames. However, observations of longer-term responses (decades to millennia) are more challenging to acquire, as there are few long-term instrumental records available for aquifers. This means that we need to be innovative and develop new approaches for modeling, in order to explore long-term responses of aquifer systems. My research program will focus on two critically important topics: drought and salinization. We will examine how aquifer systems have responded to drought in both the paleorecord and the instrumental record, by reconstructing groundwater levels from tree ring records and using a range of statistical techniques to characterize groundwater level responses, linkages with climate cycles, and drought occurrence. We will quantify drought propagation rates (e.g. lag time and rates of decline and recovery of groundwater levels) and compare the results to observed data. We will carry out scenario modeling to attribute the causes of drought, determine whether there are tipping points associated with drought where the system recovery is significantly impacted, quantify how rapidly the system recovered, and explore different water management options. Finally, we will carry out two long-term groundwater evolution modeling studies; the first focusing on the occurrence of saline paleowater in coastal deltas, and the second focusing on how submarine groundwater circulation and the salinity distribution change over time in response to changes in sea level and recharge. In Canada and around the world, water resources are increasingly impacted by drought and salinization, with consequent impacts on food and energy security, and biodiversity. Globally, groundwater is increasingly being used to offset freshwater demands, but the long-term impacts of groundwater withdrawal are difficult to quantity, because groundwater responds more slowly to stressors compared to surface waters. My research will advance approaches for using proxy data in groundwater drought studies, characterize aquifer responsiveness to drought and identify management options, and determine climate change-related impacts on the salinity distribution in coastal aquifers. The knowledge gained and the modeling approaches we develop will be important tools for enhancing groundwater resource sustainability studies and for establishing appropriate monitoring networks to detect change.