Original Creation: From creating the lakes to providing power for the mill owners the damming of Stony Brook has created a place of natural beauty as well as a diverse lake ecosystem. The dam creating Upper Lake was built in 1829 followed in 1847 by the building of the dam that created Lower Lake. Both dams were built to provide the mills with a more regular source of water power than the stream could provide. (27) The dams not only created sources of power but also created a place of natural beauty. Upper Lake even became a bird sanctuary in 1970. The area around Upper Lake was bought by Mount Holyoke in 1884 from the mill owners. (32)
The middle dam, by the bridge that now leads to the Willets Howell Center, has a more interesting background and for some reason tends to be mentioned less often. It was created in 1852 by the seminary to provide energy for the pumping of hot and cold water through the seminary building. This is also where the pump house, also know as the “Cat House” is located to house the pumping apparatus and which is today the oldest building on campus. The pumping of hot and cold water was an incredible luxury for this time period and shows just how up and coming Mount Holyoke really was. (27)
Renovations: In 1912 the concrete dam built at the foot of Upper Lake was renovated to increase the height of the dam by 18 inches and subsequently increase the capacity of the lake. (19) This was done due to the build up of sediment that was taking place which eventually lead to the more drastic measures of dredging the lakes. In 1940 the dam by Upper Lake was repaired and improved to make the opening wider which would in turn allow a higher water flow and prevent the meadows from flooding after every heavy rain storm. (20) The dam by Upper Lake was again repaired during the summer of 1957 (26).
Ecological Implications: Ecologically the dams created natural boundaries which would prevent migratory species from following their normal roots and would also separate populations of species that may influence them into evolving into two different species if the conditions in the two lakes were significantly different. This can be seen with the eel population today in that there are very few eels found above the dam of Lower lake. The dams also created new habitats by creating both a large area of relatively still water (the lakes) as well as an area that has a relatively high flow rate most of the year. This probably increased the diversity of the South Hadley area. On the more negative side the damming of Stony Brook most likely degraded some of the surrounding environment during construction as well as having a negative impact on the wildlife that depended on the natural cycle of the flooding meadows and the previously existent wetlands.