Wetland Modeling in PCSWMM: Exploring Options to Define Wetland Features and Incorporate Groundwater Exchanges

Abstract

Wetlands in Southern Ontario are experiencing degradation from urban development. Hydrologic analysis is important to demonstrating that a development will not have negative impacts on wetlands. A wetland water balance study has been conducted to develop reference hydrologic regimes for two wetlands in Pickering, Ontario. Knowledge gained from wetland water balance analysis informed the development of PCSWMM models. The objective of this study was to explore options for incorporating and defining wetlands in PCSWMM, select groundwater interaction parameters, and optimize the process for creating a calibrated catchment-wetland model using known seasonal wetland water levels. Continuous monitoring data was used for calibration and validation of the models. Methods, calibration targets, and challenges encountered when defining groundwater interactions and stage-storage relationships will be highlighted. The study will identify areas where increased data collection could improve the model parameterization. The discussion will address the value of a model which can both adequately represent the development and the wetland by incorporating infiltration-runoff effects, evapotranspiration changes, LID practices, groundwater regimes, and dynamic feedbacks between the wetland water level and the system.