Reviving Our Rivers

The South River was once a free-flowing tidal estuary, stretching just 15 miles inland from the Atlantic Ocean on the coast of Massachusetts. In 1640, the South River became the centerpiece of the newly established town of Marshfield. Around this same time, a dam was constructed on the river to power a gristmill for local farmers. From this point on, the natural flow of the South River was blocked. Over the next few hundred years, the dam eventually became a sawmill that operated from the mid-1800s to the early 1900s. As the times shifted and industries moved away, the site eventually became a park in 1949. The river wound through grassy salt marshes, under bustling roads, and past quiet neighborhoods. Yet, the dam remained.

This dam proved especially damaging to the natural ecological processes of the South River. River herring, which had been migrating upstream to spawn for millennia, were unable to reach the waters where they were born. While a fish ladder had been installed in an attempt to help the river herring travel past the dam, very few were able to use it successfully. In turn, river herring populations in the South River declined drastically over time. Recognizing this issue, local nonprofits, park owners, and government organizations collaborated to remove the dam, which was no longer needed for industry. Finally, in February 2025, the dam was demolished. The removal had almost immediate results, and only a few short months later, in July 2025, river herring populations in the South River started to increase.

The story of the South River is just one example of how dams harm rivers, an often underdiscussed ecological issue that plagues freshwater ecosystems throughout the United States. According to the U.S. Army Corps of Engineers, there are over 90,000 dams in rivers and streams across the country. This number could be even larger, since many dams are too small or remote to be counted. In addition to blocking fish migration, dams have other harmful effects on rivers and streams. These include changing natural flow rates, negatively impacting water quality, and altering aquatic habitats. Yet, one of the most overlooked and devastating residual effects of dams is their impact on Indigenous peoples.

The arrival of colonists brought dam construction to rivers and streams, aiming to control flooding, provide hydropower, and manage water for irrigation and storage, all to support settler colonialism. This was enabled by the forced displacement of Native communities away from free-flowing rivers and out of their ancestral homelands. As dams were constructed, rivers and surrounding environments were severely altered. This impacted the lived experiences and histories of Native communities that view water as a sacred and divine foundation of life for both humans and ecosystems. Dams also created reservoirs that flooded the fertile land surrounding rivers and streams used by Native peoples, destroying their livelihoods. Today, many remaining dams are effectively a symbol of colonization, representing how the U.S. government stole land from Native communities and used rivers as a tool for economic expansion.

Displacement of Native communities due to dams has long lasting impacts. A study from 2023 found that 56 of the 326 federal reservations in the U.S. have experienced a loss of land from reservoirs created by dams. Impacts of climate change, including warming temperatures and increased flood events, have further exacerbated dam-related issues. In the wake of these harms, Native communities have long been fighting for dam removals and promoting free-flowing rivers and streams.

In fact, the largest dam removal project, located on the Klamath River in Oregon and California, was largely driven by Native nations, activists, and leaders. For over 100 years, the 263-mile-long Klamath River was restricted by four hydroelectric dams that provided irrigated water to nearby farms and communities. Salmon populations in the Klamath River that supported local Native nations, including the Yurok, Karuk, and Hoopa, were decimated due to large and frequent fish kill events caused by the dams. After many years of Native and local advocacy, as well as litigation with the dam owners and the government, all four dams were demolished in 2024. The revival of the Klamath River was celebrated by the local Native nations, and has since served as a prime example of restoring natural ecosystems for both the benefit of the people and the planet.

In our ongoing work to restore environments in the face of climate change, dam removals must be included as part of these efforts. By reviving our rivers and streams through dam removals, we can ensure ecosystem health and longevity, support migrating fish populations, and honor Indigenous history. Whether rivers are as small as the South River or as large as the Klamath River, dam removals provide quantifiable positive benefits that can inspire further social and environmental movements.

RCC National Environment Leadership Fellow Avery Sands – Trinity College

Avery Sands is a senior at Trinity College in Hartford, Connecticut, majoring in Environmental Science with a minor in Legal Studies. She has experience working with environmental nonprofits, including an internship with the North and South Rivers Watershed Association on the South Shore of Massachusetts. At Trinity, Avery has worked as an undergraduate research assistant studying how trace metal concentrations affect urban pond ecosystems and assessing the water quality of streams flowing into the Connecticut River.