Groundwater Modeling of Montandon Marsh: A Five Year Analysis of Water Budget

Montandon Marsh is a significant wetland area in the Lower West Branch of the Susquehanna River Region in West Chillasquaque Township, Pa. Montandon Marsh is unique in its region because of its large size and diverse ecosystem; it is particularly valuable as habitat for migratory waterfowl and other bird species. While the marsh is a priority for local conservation groups and is legally protected from development, the marsh's existence is dependent on its receiving an adequate water supply. Without water, a wetland becomes a meadow or a forest. The goal of this research project is to study the sources of water that sustain Montandon Marsh by creating a water budget. Data collected from 2003 to 2007 will be used to determine if the size of the marsh's water sources are changing over time and confirm if the groundwater is truly the largest source, as suggested by a previous study (Woolever 2004). The water budget study will quantify the amount of water entering and leaving the marsh by measuring the following components: precipitation, evapotranspiration, surface inflow and outflow, and groundwater inflow and outflow. This study is complemented by a groundwater modeling system. The groundwater simulation model will be used to characterize the site, calibrate the model and visualize the subsurface flow.