The Bachelor Brook runs through Granby and South Hadley before discharging into the Connecticut. It is dammed only once within South Hadley and that is the Pearl City Dam making the Pearl City Reservoir. This is a small concrete dam. The Bachelor Brook is dammed twice more in Granby at Aldrich Lake and Forge Pond.
The Elmer Brook is a tributary of the Bachelor Brook. It has one dam – the Lithia Springs Dam and its reservoir. The dam is a medium sized concrete structure with a large earthen dam alongside.