Regional-scale groundwater recharge in fractured bedrock aquifers: Development of defensible water management tools

在加拿大的许多管辖区，水资源管理人员正试图在各种规模上为流域制定准确的水预算。在这些流域下面是浅基岩含水层的地方，使用主要为砂和砾石含水层开发的水预算方法的可行性被认为是错误的。例如，我们在安大略环境部、里多山谷保护局、卡塔拉基地区保护局和昆特地区保护局的合作伙伴最近的研究表明，估计多孔介质中地下水补给的传统方法在断裂基岩中可能非常不准确。不准确的补给估计的后果是可怕的，因为我们现在依靠这些来确定取水（即装瓶，工业需求和市政需求）对地下水和地表水供应的影响，并估计气候变化的潜在影响。在同类研究中，我们建议开发新的工具，更具体地设计，以准确地预测地下水补给断裂基岩含水层在当地和流域尺度。研究的重点将是实地研究和模型开发，利用以前的工作在位于东部安大略900平方公里的流域进行。我们的第一步将是确定在这种情况下，一年中实际补充了多少水。通过了解补给机制，我们建议开发一种新的数值模拟方法，新的地球化学方法和新的水力测量，以改善在浅基岩地区的补给估计。我们坚信，这项研究的结果将改变标准的工程和科学的做法，估计补给和防止过度开采，在这些设置，并将大大有利于其他地区在加拿大的基岩含水层利用，如在南部不列颠哥伦比亚省，魁北克，其他地方在安大略，并在加拿大大西洋。一名博士生和四名硕士生将在为期三年的研究过程中接受培训。

In many jurisdictions across Canada, Water Resources Managers are attempting to develop accurate water budgets for watersheds at a variety of scales. Where these watersheds are underlain by shallow bedrock aquifers, the feasibility of using water budgeting methods primarily developed for sand and gravel aquifers has been found in error. Recent studies by our partners in the Ontario Ministry of the Environment, the Rideau Valley Conservation Authority, the Cataraqui Region Conservation Authority and the Quinte Region Conservation Authority for example have shown that the traditional methods for estimating groundwater recharge in porous media are potentially highly inaccurate in fractured bedrock. The consequence of inaccurate recharge estimates is dire, as we now depend on these to determine the impact of water abstraction (i.e for water bottling, industrial requirements, and municipal needs) on groundwater and surface water supplies, and to estimate the potential impacts of climate change. In the first study of its kind, we propose to develop new tools more specifically designed to accurately predict groundwater recharge in fractured bedrock aquifers at the local and watershed scales. The focus of the research will be on both field study and model development, taking advantage of previous work conducted in a 900 km2 watershed located in eastern Ontario. Our first step will be to determine how much water is actually recharged during the year in this setting. By understanding the recharge mechanisms we propose to develop a new numerical modeling approach, new geochemical methods and new hydraulic measurements for the improvement of recharge estimates in areas of shallow bedrock. We strongly believe that the results of this study will change the standard of engineering and scientific practice for estimating recharge and preventing overexploitation in these settings and will greatly benefit other regions in Canada where bedrock aquifers are utilized such as in southern British Columbia, Quebec, elsewhere in Ontario, and in Atlantic Canada. One PhD student and four MSc students will be trained over the course of the three-year study.