Improving our understanding and predictions of the impacts of groundwater extraction on small streams

在河流的上游，由于流量自然较低，且流量可能具有季节性，抽取地下水供水可能会引起基流量、河流阶段、湿润面积、流速和温度的显著变化。这种变化可能会减少下游地表水的可用性，并对敏感的水生生物产生负面影响。随着加拿大许多司法管辖区对更好地管理地下水开采对地表水的影响的认识和压力的提高，以及越来越多的证据表明气候变化的负面影响，迫切需要研究地下水开采与小溪流动状况之间的联系。NSERC Discovery研究的目标是提高我们对评估和预测地下水开采（通过抽水井）对水流条件和水温的影响的理解和方法。为实现这一目标，计划了三个短期综合项目，其中包括详细的实地研究和随后的数据分析和解释。实地项目将重点关注加拿大爱德华王子岛（PEI）的小溪，那里的公众和监管机构对从砂岩基岩含水层抽取地下水对小溪的影响有很高的认识和关注。该研究将产生一个独特的高分辨率数据集，包括主要流水力参数的变化，如水力梯度、宽度、湿润面积、速度和温度。这些实地研究的数据将使用三维变饱和流动和热输运模型以及在实践中仍然流行的分析模型进行数值解释。尽管存在各种复杂程度不同的数学模型来模拟水流枯竭，但令人惊讶的是，精确的现场实验数据可用于与各种概念和数学模型进行比较，特别是对于小的源头溪流。这项提议的发现研究预计具有重要的科学意义，并且非常适合同行评议的出版物，并且对目前正在努力解决这一水资源管理问题的司法管辖区的地下水开采许可的监管决定产生几乎直接的影响。

In the upper reaches of streams, where discharge is naturally low and flow may be seasonal, groundwater extraction for water supply may cause significant changes in base flow, stream stage, wetted area, velocity and temperature. Such alterations may reduce the availability of surface water downstream and have negative consequences for sensitive aquatic organisms. With heightened awareness and pressure in many Canadian jurisdictions to better manage the surface water impacts of groundwater extraction, and the increasing evidence of the negative effects of climate change, there is a significant need for research into the connection between groundwater extraction and flow conditions in small streams. The goal of the proposed NSERC Discovery research is to advance our understanding and methods for assessing and predicting the impact of groundwater extraction (by pumping wells) on the flow conditions and water temperature in small streams. To achieve this goal three short-term integrated projects are planned that include detailed field studies and subsequent data analysis and interpretation. The field program will focus on small streams in Prince Edward Island (PEI), Canada, where there is high public and regulatory awareness and concern surrounding the effects of groundwater extraction from the sandstone bedrock aquifer on small streams. The research will produce a unique high-resolution data set including changes in primary stream hydraulic parameters such as hydraulic gradients, width, wetted area, velocity, and temperature. The data from these field studies will be interpreted numerically using three-dimensional variably-saturated flow and heat transport models, and analytical models that remain popular in practice. Although various mathematical models, of varying complexity, exist for simulating stream flow depletion, accurate field experimental data that can be used to compare to various conceptual and mathematical models are surprisingly absent, especially so for small headwater streams. The proposed discovery research is expected be scientifically significant and highly suited to peer-reviewed publication, and have almost immediate impact on regulatory decisions for groundwater extraction permits in jurisdictions that are currently grappling with this water management issue.