GEOLOGICAL AND HISTORICAL INVESTIGATION OF THE BELGRADE LAKES WATERSHED

The Belgrade Lakes watershed includes six interconnected lakes and represents an important water and recreational resource in central Maine. The present geographical configuration of this watershed has been significantly modified by the construction of seven dams for water control and the generation of hydroelectric power over the past 100 years. The purpose of this investigation was to understand and document the impacts of these dams on the evolution of this lake system.

Preliminary data on each dam was obtained from the Maine Emergency Management Agency and included date of construction (1896 to 1989), length (6.7-76.1 m), structural height (0-7 m), and hydraulic height (0.3-5.5 m). Longitude and latitude of each dam was obtained in the field using GPS. These data were integrated into a GIS mapping program and depth maps for each of the six lakes were constructed. Using hydraulic height values to the closest meter for the dams the original geographic extent, volumetric changes ranging from 1.0 x 10⁶ to 14.0 x 10⁶ m³ and changes in surface area percent ranging from 12 to 43 % for each lake were determined. Adding dates of dam construction, changes to aerial extent of the lakes in the watershed were mapped in a historical context.

It is clear that this region would have looked significantly different had the dams, beginning in 1896, not been constructed. Results of this investigation provide a historical context and an important foundation for long-term hydrogeochemical and geochemical investigations of this watershed.