Why are dams important?Dams have long served an important function for human civilization. They create artificial water reservoirs that store vast amounts of water. This maintains a consistent and reliable water supply for drinking, industry, and agriculture. Dams can also be crucial for flood control. They capture excess water during storms to protect downstream communities and infrastructure from damage and can also be used to generate power. Historically, dams have been built for very specific functions. Some of these functions have changed over time. More than 40 dams were once built along the Blackstone River. By the mid 1900s, much of the large-scale industry had left the area, leaving dams that served little purpose. Although efforts have been made to convert some of these historic dams to modern hydro-electric operations, many dams remain underutilized. Unlike dams in other parts of the U.S. that generate large amounts of clean, renewable electricity, dams along the Blackstone River tend to be much smaller-scale and better suited for older technology. 
NPS/Rodriguez How long have dams existed?Dams have existed in the U.S. for centuries. Beavers have naturally dammed rivers as a way of creating a new habitat and home. Native Americans built earthen dams and complex irrigation systems for water management long before European settlement. In the Blackstone Valley, Indigenous peoples including the Narragansett, Nipmuc, and Wampanoag tribes, used water management techniques to help with fishing. European colonists used dams to power early mill operations. In 1792, a dam was built to power Old Slater Mill in Pawtucket, RI. This marked the start of the Industrial Revolution. In the following decades, dozens of dams were built along the Blackstone River. By the 1900s, the Blackstone River was nicknamed “America’s Hardest Working River.” 
NPS/Rodriguez Modern eraDams have long been a cause of resentment and concern. Growing awareness of the ecological harm dams can cause has led to removal efforts. Hundreds of dams have been removed in the U.S. since 1990. Dams disrupt ecosystems by blocking fish migration, trapping important sediments, and altering the natural flow of water. This leads to changes in temperature and volume that can affect water quality by removing oxygen and nutrients. These changes break up habitats, reduce animal fertility downstream, promote invasive species, and harm native aquatic life. This causes a loss of biodiversity by simplifying ecosystems. As a result, efforts to remove dams from rivers across the U.S. have been accelerated in the last few years. Along the Blackstone River, the Blackstone Watershed Collaborative and other advocates are working to reduce the negative effects of dams on our ecosystem. Dams can also pose a threat to people who are interested in utilizing the river for recreational purposes. Dams, particularly low-head dams like the smaller ones along the Blackstone River, generate powerful hidden currents. Many groups and people in the Blackstone River Valley are working to reduce some of the negative impacts of dams. For instance, the Blackstone Watershed Collaborative created a river paddle guide to help paddlers navigate the river safely. Efforts to create fish passage and to remove dams are also ongoing. Learning to balance the historic and economic value of dams while mitigating their negative effects will help humans, plants, animals, waterways, and ecosystems thrive.
Blackstone Watershed Collaborative. (2025). Gaining Fish Passage over the Lowest Four Dams on the Blackstone. Retrieved from Blackstone Watershed Collaborative: https://www.blackstonecollaborative.org/fishpassage Collaborative, B. W. (2025). https://www.blackstonecollaborative.org/. Retrieved from blackstonecollaborative.org. National Geographic. (2025). Hydroelectric Energy: The Power of Running Water. Retrieved from National Geographic: https://education.nationalgeographic.org/resource/hydroelectric-energy-power-running-water/ Smithsonian. (2025). National Museum of the American Indian. Retrieved from Education: https://americanindian.si.edu/support/giving?s_src=KFY26PXPSEARCH&s_subsrc=OutrightGift_Web&utm_source=google&utm_medium=ppc&utm_campaign=gt&gad_source=1&gad_campaignid=23086001692&gbraid=0AAAABBbDHLP1gaKKX4MiofzMAP9d4zVPP&gclid=Cj0KCQiA9OnJBhD-ARIsAPV51x
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Last updated: January 24, 2026