DETERMINING GROUNDWATER FLOW AND RECHARGE RATES IN THE WETLANDS AT FISH LAKE ENVIRONMENTAL EDUCATION, LAPEER COUNTY, MICHIGAN

Wetlands are hydrologic-dependent, intricate ecosystems that offer vital ecological services. Understanding the functionality of these ecosystems and their interactions with the surrounding environment is crucial for conservation efforts. The Fish Lake Environmental Education Center near Lapeer, Michigan is dominated by glacial topography and contains a kettle lake (Fish Lake) and several wetlands, including a large bog and multiple kettles in the northern region of the property. In the spring, snowmelt and precipitation form ephemeral ponds called vernal pools in the kettles. A combination of groundwater and precipitation sources each of the kettles in varying amounts, while the bog is primarily sustained by precipitation. A previous study conducted in the southern portion of the site indicated that groundwater is flowing southeastward toward the lake. Groundwater flow direction on the northern portion of the site was undetermined. The purpose of this research was to assess the flow of groundwater in the northern wetlands and to determine the rate surface water recharges groundwater in the vernal pools.

Shallow groundwater and surface water sampling took place monthly or biweekly from April 2023 to September 2024. Sample collection using a disposable bailer occurred in monitoring wells with depths ranging from 8 to 12 feet below the ground surface. Pressure transducers in several wells continuously record water levels. Field data collection included manual water level measurements, electrical conductivity, pH, and temperature. Hand augering allowed for the collection of soil samples in the kettles. In laboratory analysis, water samples were tested for nitrite, nitrate, sulfate, phosphorus, iron, and turbidity. Permeameter testing determined soil hydraulic conductivity values in order to estimate recharge. With the calculated well elevations and other data, it can be inferred that groundwater initially flows towards the bog then as it infiltrates deeper into the ground it flows towards the lake. The data also suggest that each kettle functions differently in terms of recharge and groundwater interactions. This project supports other research conducted at Fish Lake and will be added to a digital field guide.