Development of a Tool to Identify Groundwater Recharge Areas Vulnerable to Sodium Chloride Contamination in Well Head Protection Areas

在加拿大，经常使用岩盐来管理冬季驾驶条件，以及需要在城市环境中实施雨水管理(SWM)做法，导致地表水和地下水中含有大量的氯化钠。高浓度的氯化钠正在影响水的肥力和生态系统的可持续性。因此，圭尔夫大学和城市流域集团有限公司的一家合资企业将开发一个集成的模拟框架，其中包括开放建模接口(OpenMI)中广泛使用的地表水模型(SWAT)和地下水模型(MODFLOW)，该模型可以模拟氯化钠通过土壤剖面进入地下水含水层的运移机制，也可以通过陆上进入河流的运移机制。滑铁卢市银湖上游的月桂溪子流域被选为试点研究区域之一。综合模型将利用将在地表水和地下水采样活动中收集的监测数据进行校准和验证。一旦校准和验证，将制定各种方案来评估各种雨水管理做法及其对地下水质量的影响以及对生态系统的影响。最后，遗传算法(GA)将与地表水-地下水模型相结合，以优化最佳SWM实践的选择，并在月桂溪子流域的井口保护区确定易受氯化钠污染的地下水补给区。

In Canada, frequent application of rock salt for managing winter driving conditions and the need to implement stormwater management (SWM) practices in urban environment result in large volumes of sodium chloride in surface and ground water. High concentrations of sodium chloride are affecting the potability of water and sustainability of ecosystems. Therefore, a joint venture between University of Guelph and Urban Watershed Group Ltd. will develop an integrated modelling framework involving a widely used surface water model (SWAT) and ground water model (MODFLOW) in Open Modelling Interface (OpenMI) which can simulate the transport mechanisms of sodium chloride through soil profile into ground water aquifer and also through overland into streams. The Laurel Creek sub-watershed upstream of Silver Lake within the City of Waterloo was selected as one of the pilot study areas. The integrated model will be calibrated and validated using monitoring data which will be collected in both surface and groundwater sampling campaigns. Once calibrated and validated, scenarios will be developed to evaluate various stormwater management (SWM) practices and their impact on groundwater quality as well as impacts on ecosystems. Finally, a genetic algorithm (GA) will be integrated with the surface water-groundwater model to optimize the selection of best SWM practices and to identify groundwater recharge areas vulnerable to sodium chloride contamination in well head protection areas of the Laurel Creek sub-watershed.