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.

地下水水平因多种自然和人为应力（例如，季节性气候变异性，地下水抽水）的响应而有所不同。通过测量含水层系统对此类应力的响应，然后尝试建模响应（即使用基于过程或基于过程的数值模型），我们可以深入了解给定应力在地下水级别上会发生多快的变化以及效果将持续多长时间。在现场尺度上，通常可以使用足够的数据来限制和校准模型在短时间内。但是，对长期响应的观察（到千年来数十年）的获取更具挑战性，因为含水层的长期工具记录很少。这意味着我们需要是创新的，并开发新的建模方法，以探索含水层系统的长期响应。 我的研究计划将重点介绍两个至关重要的主题：干旱和盐水化。我们将研究含水层系统如何通过从树环记录中重建地下水水平以及使用一系列统计技术来表征地下水水平的响应，与气候周期的联系以及干旱的发生，并使用一系列统计技术来对含水层的干旱做出反应。我们将量化干旱繁殖率（例如，地下水水平的滞后时间和下降和恢复率），并将结果与​​观察到的数据进行比较。我们将进行场景建模，以归因干旱的原因，确定是否存在与干旱相关的临界点，其中系统恢复受到重大影响，量化系统恢复的速度，并探索不同的水管理选择。最后，我们将进行两项长期的地下水进化建模研究。第一个侧重于沿海三角洲的盐水古水发生，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流逝而变化，以响应海平面和补给的变化。 在加拿大和世界各地，水资源越来越受干旱和盐化的影响，因此对粮食和能源安全以及生物多样性产生了影响。在全球范围内，地下水越来越多地用于抵消淡水的需求，但是地下水戒断的长期影响很难数量，因为与地表水相比，地下水对压力源的响应速度较慢。我的研究将推动在地下水干旱研究中使用代理数据的方法，表征对干旱的含水层反应性并确定管理方案，并确定与气候变化相关的影响对沿海含水层中盐度分布的影响。获得的知识和我们开发的建模方法将是增强地下水资源可持续性研究并建立适当监视网络以检测变化的重要工具。