Appropriate Incorporation of Groundwater Flow Features and Processes in Small- to Large-Scale Hydrologic Models

地下水是可利用淡水的最大组成部分，在水文循环中起着至关重要的作用。GW是我们最重要的淡水资源，提供饮用水和粮食安全，维持地表水水体，并维持生物多样性。因此，用数值模式诊断和预报水文变化时，应适当考虑GW流及其与西南方向的相互作用。然而，由于模型结果可能对规划、水资源管理和政策产生重大影响，因此需要研究的现有建模软件在如何处理这种相互作用方面存在很大差异。这个为期3年的项目的总体目标是评估在安大略省南部两个具有代表性的流域(S-ON)的水文模型中适当纳入GW水流特征和过程的情况，方法是构建可能影响西南水流的不同复杂程度的模型。项目目标包括调查：1)水文模型应考虑的地下物质的总深度；2)应包括的地下地质非均质性的垂直和/或水平分辨率；以及3)在大型水文模型中如何表示GW提取/注入。这项研究将通过修改S最近建造的原型水文地球球体模型来进行，该模型是由项目合作伙伴Aquanty公司和加拿大地质调查局建造的。具体地说，奥尔德克里克流域和大河流域的嵌套和/或独立模型将从S-on HGS模型创建。项目目标将通过对不同复杂性的HGS模型进行性能评估来实现，方法是将模拟结果与来自监测井的现有数据和来自计量站的水位线进行比较。总体结果可供各利益攸关方用来评估在小型到大型水文模型中适当纳入全球水资源流动特征和过程的情况。所获得的知识将有助于实现该小组的总体目标，即利用前沿和创新的决策工具提供风险管理解决方案，以管理加拿大的淡水资源。

Groundwater (GW) plays a vital role in the hydrologic cycle as it is the largest component of available freshwater. GW is our most critical freshwater resource providing drinking water and food security, sustaining surface water (SW) bodies, and maintaining biodiversity. Therefore, diagnosing and predicting hydrologic changes with numerical models should appropriately account for GW flow and its interactions with SW. However, there are large differences in how this interaction is treated among existing modelling software requiring research as model results can have significant impacts on planning, water management, and policy. The overall goal of this 3-year project is to assess the appropriate incorporation of GW flow features and processes within hydrologic models for two representative watersheds in southern Ontario (S-ON) by constructing models of varying complexities that could impact SW flow. Project objectives include investigations of: 1) the total depth of subsurface materials that hydrologic models should consider; 2) the vertical and/or horizontal resolution of subsurface geologic heterogeneity that should be included; and 3) how GW extraction/injection are represented in large-scale hydrologic models. The research will be conducted by modifying the existing, prototype HydroGeoSphere (HGS) models of S-ON recently built by Aquanty, Inc. (Aquanty) and the Geological Survey of Canada (GSC), which are the project partners. Specifically, nested and/or standalone models for the Alder Creek Watershed (ACW) and the Grand River Watershed will be created from the S-ON HGS models. Project objectives will be achieved by performance assessment of HGS models of varying complexities by comparing simulation results with existing data from monitoring wells and hydrographs from gaging stations. The overall results could be utilized by various stakeholders to assess the appropriate incorporation of GW flow features and processes in small- to large-scale hydrologic models. The knowledge gained will help achieve the team's overarching goal to deliver risk management solutions informed by leading-edge and innovative decision-making tools to manage freshwater resources in Canada.