How do dams impact the river and its tributaries?
There are several dams on the mainstem of the Ipswich River, and many more on the tributaries that feed into the Ipswich. The mainstem dams include the Ipswich Dam in downtown Ipswich; the Willowdale Dam and a smaller dam of the United States Geological Survey, also in Ipswich; and the South Middleton Dam, adjacent to the Bostik-Findley industrial site. Many of the Ipswich River tributaries have at least one dam, and several have a series of dams. What are the effects of these dams on the river? The first effect is to alter the flowing nature of the river, creating ponded habitat instead, and reducing (or stopping) flows downstream. The change from flowing to ponded conditions is very significant to the river’s ecology. Important fish species, such as brook trout and fallfish, must have flowing conditions for their survival, and cannot survive in ponds. The downstream river reaches may dried up completely, and also become “starved” for sediments, which help distribute nutrients through
