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

地下水系统的演变：长效自然和叠加的人为压力源的影响

• 批准号: RGPIN-2020-07228
• 负责人: Allen, Diana
• 金额: $ 4.44万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741670
• 关键词: Evolution; Groundwater; Systems; Effects; Long

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.

地下水位随着各种自然和人为压力(如季节性气候变化、地下水抽水)的变化而变化，这些压力在不同的时间范围内起作用。通过测量含水层系统对这种压力的反应，然后尝试对这种反应进行建模(即使用分析性或基于过程的数值模型)，我们可以相当深入地了解特定压力在地下水位变化中体现的速度和影响将持续多久。在现场范围内，通常有足够的数据可以在短时间内约束和校准模型。然而，对较长期(几十年到几千年)响应的观测更具挑战性，因为可用于含水层的长期仪器记录很少。这意味着我们需要创新，开发新的建模方法，以便探索含水层系统的长期反应。我的研究计划将集中在两个至关重要的话题上：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，方法是根据树轮记录重建地下水位，并使用一系列统计技术来描述地下水位响应、与气候周期的联系以及干旱发生。我们将量化干旱传播速度(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，以确定干旱的原因，确定是否存在与干旱相关的临界点，即系统恢复受到重大影响的临界点，量化系统恢复的速度，并探索不同的水管理选项。最后，我们将开展两个长期的地下水演化模拟研究，第一个重点是沿海三角洲咸水古水的出现，第二个重点是海底地下水循环和盐度分布如何随着时间的变化响应海平面和补给量的变化。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，从而对粮食和能源安全以及生物多样性造成影响。在全球范围内，地下水越来越多地被用来抵消淡水需求，但地下水开采的长期影响很难量化，因为与地表水相比，地下水对压力源的反应更慢。我的研究将推进在地下水干旱研究中使用替代数据的方法，确定含水层对干旱的反应并确定管理方案，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发现变化的重要工具。