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: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=569845
• 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，地下水是所有淡水提取的三分之一的来源。在许多环境中，在降雨量较少或没有降雨量的时期，天然地下水排放维持向河流、湖泊和湿地的基流。尽管对人类福祉和水生生态系统作出了这些重要贡献，但政府间气候变化专门委员会(气专委)在其第三和第四次评估报告中评估地下水和气候变化之间相互作用的能力受到严重限制，因为缺乏关于气候和地下水之间关系的研究。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模拟为100年预测窗口内的时间快照(2020年代、2020年代)。对这些系统的瞬时(时变)响应的研究很少，对涉及间歇性和非常长期变化的计算挑战问题的研究就更少了。此外，大多数地下水模型继续使用时间平均观测值(代表假定的稳定状态条件)或短期瞬变数据(例如抽水试验)进行校准，因此，长期预测的不确定性很高。这项研究将利用瞬变模型探索地下水系统的动态，以便更好地了解含水层对短期和长期、从几分钟到几千年的气候压力的反应，并试图通过对瞬变数据集的模型校准，更好地约束适用于区域尺度水文地质研究的水力特性范围。将获得关于系统对控制含水层反应的参数的敏感性的重大洞察，从而有助于量化未来预测中的不确定性。正如加拿大科学院理事会2009年关于“加拿大地下水的可持续管理”的报告所指出的那样，这一贡献对于确定地下水资源的可持续性以及建立适当的监测网络以发现变化至关重要。