STYLIZED FACTS RELATING WATERBODY ACIDIFICATION TO HYDROLOGY, BEDROCK AND SURFICIAL GEOLOGY, SOIL AND ATMOSPHERIC POLLUTANTS IN THE LYE BROOK WILDERNESS, VERMONT

In this study, we revisit and expand upon prior results from the atmospheric and hydrological monitoring of the Lye Brook Wilderness Area (LBW). We focus on identifying stylized facts concerning waterbody acidification and characteristics of the hydrology, bedrock/surficial geology, soil and atmospheric pollutants of the region. Specifically, we continue the exploration of the effects of atmospheric pollutants that begun in 1980 by the Vermont Department of Environmental Conservation (VTDEC). We leverage the monitoring of several chemical and biological parameters that has been performed since 1993 in association with Vermont Monitoring Cooperative (VMC) and in conjunction with a partnership with the Green Mountain National Forest (GMNF).

Within the LBW, waterbodies are located in geologic areas that are resistant to chemical weathering. Many of the soils in the area were formed from glacial till, and the surficial geology also reflects glacial deposits. We hypothesized that these factors all have a strong effect on the LBW water chemistry, causing very low to negative alkalinity levels and low (~<5) pH levels. For the current study, conducted during summer 2017, we identified a total of 10 water sample sites for analysis. These sample sites included running brooks, rivers, ponds and lakes both within and surrounding the LBW.

Sampling rounds were conducted a total of four times at each site. Preliminary field measurements were conducted, noting the change in flow levels, water color, pH, temperature and conductivity. Results were analyzed in a lab for total nitrogen, total phosphorus, alkalinity and gran alkalinity. Separately, an intensive water gradient sampling procedure was also conducted on the Lye Brook River, which highlighted a response with elevation and changing bedrock and topography. A Vermont Rapid Assessment Method (VRAM), which uses hydrologic scoring matrices to evaluate Vermont wetland, was conducted within the Lye Brook Meadows, with the purpose of defining a baseline for the specific wetland condition of the area.

Based upon these analyses, we conclude that the low-to-medium buffering capacities of the bedrock geology, surficial geology and soil associations together make the LBW susceptible to surface water acidification, particularly given the observed high atmospheric levels of pollutants.