THE EFFECTS OF BEAVER DAMMING ON GROUNDWATER FLOW THROUGH A WETLAND SYSTEM, BEAVER MEADOW, NY

The North American beaver acts as an ecosystem engineer, in that it has the ability to greatly alter its surrounding ecosystem by changing the hydraulics of a system. Specifically, the beaver is a dam builder, it uses available materials to build a dam and alter the flow of water in a stream in order to create a suitable living environment. This activity results in increased hydraulic head behind the dam, which can change the distribution of water in a system and disrupt groundwater flow paths. Beaver dams can have long term effects on an ecosystem, especially in areas with low topographic gradients, such as wetlands. A wetland that functions as an area of groundwater discharge can potentially undergo a reversal of flow and become an area of groundwater recharge with the addition of a beaver dam. This project focuses on a wetland environment that has been altered by a beaver dam, the Buffalo Audubon Society’s Beaver Meadow nature preserve in western New York.

Calibrating to water levels collected before, during, and after the construction of a beaver dam, a groundwater model was created with MODFLOW to examine the hydrologic changes that occurred in a beaver modified wetland system. Specifically, this model allowed for the quantification of changes in groundwater flux through, and immediately surrounding, the wetland. Changes in the extent of the capture zone of this wetland were also examined. This information can be helpful to those considering using beaver introduction as a low cost and natural wetland restoration technique.