Spectacle Pond is located in central Massachusetts just south of route 119 in Littleton, Massachusetts, with a portion of the pond and surrounding wetlands in the town of Ayer. The pond serves as a main source of the acquifer that provides drinking water to residents of Littleton and Ayer. It is fed from several brooks, some of which are un-named. The primary inlet is Bennetts Brook, which feeds the pond from the South. The outlet of the pond is Gilson Brook in the North. Gilson Brook flows out of the pond via a culvert underneath route 119. Gilson Brook feeds Forge Pond in Westford, the next body of water downstream from Spectacle Pond. These waters empty into the Merrimack River and eventually into the Atlantic Ocean.
The map above shows Spectacle Pond and highlights several key locations of important facilities in the area. The yellow area shows the approximate location of the Guilford Industries' proposed auto unloading site adjacent to their rail lines. The blue line roughly outlines the Zone II drainage area for Ayer town water wells at Spectacle Pond, and is also the approximate location of the Zone III drainage area for the Littleton town well at Spectacle Pond. The red circles show the locations of the Ayer and Littleton town water wells.
Groundwater in this Bennetts Brook drainage area travels generally from southwest(lower left) toward the northeast (upper right)in the area shown by this map. Both town's wells are down gradient from the proposed construction site, and any problem at the site could potentially affect both town's water supplies as well as fishing and recreational activities around Spectacle Pond.