Date of Award


Document Type

Honors Thesis (Colby Access Only)


Colby College. Geology Dept.


Jennifer D. Shosa

Second Advisor

Robert A. GastaIdo

Third Advisor

Bruce F. Rueger


Investigation of the physical and chemical processes that operate in small watersheds is one of the keys to understanding global hydrological and biogeochemical cycles. The Belgrade Lakes Watershed in Central Maine provides an idea1location for such an investigation because it is a well-defined system that is small enough to instrument and monitor at high resolution. This watershed also allows for the evaluation of seasonal changes in storage because a relatively large portion of the watershed is wetland and there is significant snow-pack during the winter months. The southern portion of Great Bog, covering 1.4 km2, is an excellent example of a freshwater northern peatland located in the Belgrade Lakes Watershed. It is flanked by local bedrock to the east, the Horse Point east to the west, and Great Pond to the north. Previous work has yielded a 14C date of about 8500 y BP at the base of the peat and has indicated that Great Bog was an open water embayment until about 6500 y BP. In an attempt to quantify the seasonal dynamics of the peatland hydrogeochemistry, 10 cores were pulled, the stratigraphy was correlated along two transects, and the water content of the sediments was determined. Three piezometers were installed in nests (with wells at -0.76 m, 1.52 m, and 3.05 m) at each core location and water levels, water chemistry, and major ion chemistry of these 30 wells were measured on a monthly basis. A model of the groundwater recharge-discharge characteristics of Great Bog was generated using measured hydraulic heads. Measured groundwater chemistry data (temperature, pH, conductivity, oxidation/reduction potential, and dissolved oxygen) support this model.


Full-text download restricted to Colby College campus only.


HYDROGEOCHEMICAL DYNAMICS, Complex wetland, central maine, Belgrade Lakes Watershed, Great Bog