From Minutes to Millennia: Transient Responses in Groundwater Systems

从几分钟到几千年：地下水系统的瞬态响应

• 批准号: 203028-2013
• 负责人: Allen, Diana
• 金额: $ 2.91万
• 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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=593745
• 关键词: Minutes; Millennia; Transient; Responses; Groundwater

Globally, groundwater is the source of one third of all freshwater withdrawals. In many environments, natural groundwater discharges sustain baseflow to rivers, lakes and wetlands during periods of low or no rainfall. Despite these vital contributions to human welfare and aquatic ecosystems, a paucity of studies on the relationship between climate and groundwater severely restricted the ability of the Intergovernmental Panel on Climate Change (IPCC) to assess the interactions between groundwater and climate change in both its third and fourth assessment reports. Most climate change impact studies conducted to date have modeled groundwater systems as a snapshot in time (2020s, 2050s) over a 100-year projection window. Little research has been undertaken on the transient (time-varying) responses of these systems, and even less on the computationally challenging problems involving episodic and very long-term change. Moreover, most groundwater models continue to be calibrated using time-averaged observations (representing assumed steady-state conditions) or short-duration transient data (e.g. pumping tests) and, therefore, the uncertainty in long-term predictions is high. This research will explore the dynamics of groundwater systems using transient modeling in order to better understand aquifer responses to climate stresses that act over short and long time frames, from minutes to millennia, and attempt to better constrain the range of hydraulic properties suitable for regional-scale hydrogeological studies through model calibration to transient datasets. Significant insight will be gained concerning the sensitivity of the system to the parameters that control the aquifer response, and thus, aid in quantifying the uncertainty in future projections. This contribution is crucial for determining the sustainability of the groundwater resource as noted by the Council of Canadian Academies' report in 2009 on "The Sustainable Management of Groundwater in Canada" and for establishing appropriate monitoring networks to detect change.

在全球范围内，地下水是所有淡水戒断中三分之一的来源。在许多环境中，在低降雨期间，自然地下水排放为河流，湖泊和湿地的基础。尽管对人类福利和水生生态系统做出了重要贡献，但对气候与地下水之间关系的研究很少，严重限制了政府间气候变化（IPCC）评估其第三和第四次评估报告中地下水和气候变化之间相互作用的能力。迄今为止进行的大多数气候变化影响研究都将地下水系统建模为100年投影窗口的时间（2020年代，2050年代）的快照。关于这些系统的短暂（时变）响应的研究很少，甚至在涉及情节性和长期变化的计算挑战性问题上更少。此外，大多数地下水模型继续使用时间平均的观测值（代表假定的稳态条件）或短期瞬态数据（例如泵送测试）进行校准，因此长期预测中的不确定性很高。这项研究将使用瞬态建模探索地下水系统的动力学，以更好地了解含水层对气候应力的反应，这些应力在短时间内（从几分钟到千年）在短时间内起作用，并试图通过模型校准对跨性别数据集的模型校准来更好地限制适用于用于区域尺度水理学研究的水力特性范围。关于系统对控制含水层响应的参数的敏感性的敏感性，将获得重要的见解，从而有助于量化未来预测的不确定性。这项贡献对于确定地下水资源的可持续性至关重要。