Environmental assessments of aquifer storage and recovery for decentralized wastewater management

在2022财年，我们利用综合地表-地下流建模方法来评估干井在流域规模上减少城市径流的有效性。开发了HydroGeoSphere三维模型，描述了被一层低渗透材料覆盖的合成无承压含水层。对地表条件、含水层性质、干井设计和降雨条件等参数进行了敏感性分析。模型结果表明，当地表具有较高的曼宁粗糙度系数或含水层材料具有较高的水力导电性时，干井在减少径流方面更有效。为了达到最佳性能，干井应位于径流通量高的排水路线下方。增大干井半径或深度可提高入渗能力，但较深的干井会通过渗入雨水污染地下水。干井的性能随着降雨强度的增加而下降，这就强调了需要当地降雨强度、持续时间、频率（IDF）数据来为特定流域的干井设计水平提供信息

During FY2022, we utilized an integrated surface-subsurface flow modeling approach to evaluate the effectiveness of drywells in reducing urban runoff at a catchment scale. A 3D model with HydroGeoSphere was developed, characterizing a synthetic unconfined aquifer covered by a layer of low-permeability materials. Sensitivity analyses of parameters such as land surface conditions, aquifer properties, drywell designs, and rainfall conditions were performed. Model results indicated that drywells are more effective in reducing runoff when the land surface has a higher Manning roughness coefficient or the aquifer material has a higher hydraulic conductivity. To achieve optimal performance, drywells should be situated beneath drainage routes that have high runoff flux. Increases in drywell radius or depth enhance the infiltration capacity, but deeper drywells can contaminate groundwater through infiltrating stormwater. Drywell performance declines with higher rainfall intensity, emphasizing the need for local rainfall intensity, duration, frequency (IDF) data to inform the design level of drywells in specific catchments