What if I told you that this dam standing before you is more than just a structure? The Amelia Earhart Dam is a vital piece of infrastructure. It protects us from the sea’s relentless surge.
Welcome to the Amelia Earhart Dam. This earth-fill dam spans the Mystic River. It sits near the river’s mouth between Somerville and Everett. Built in 1966, it serves a critical purpose. It regulates tidal effects and stops saltwater from invading the upstream river basin.
Amelia Earhart Dam features three locks for marine traffic. The largest lock stretches 325 feet long and 45 feet wide. Two smaller locks measure 120 feet long and 22 feet wide. Sadly, public access to the dam is not permitted.
Have you ever wondered about the name? The dam is named after Amelia Earhart. She was the aviation pioneer. Her plane vanished in 1937. Earhart once lived in nearby Medford, Massachusetts in the 1920s.
Now let’s talk about the future. Somerville’s 2017 Climate Change Vulnerability Assessment paints a concerning picture. By 2035, a 100-year flood could flank the Amelia Earhart Dam. By 2070, it might even overtop the dam. This would lead to significant impacts on low-lying areas. Assembly Square is one such area.
In 2018, 21 cities and towns near the Mystic River united. They requested flood prevention and mitigation funding. They sought about $20 million for an extra pump.
The Amelia Earhart Dam stands at a modest 22.2 feet. Storms will soon eclipse that height given current extreme weather trends. Already in 2018, Winter Storm Grayson brought the harbor water to 21.3 feet.
Catastrophic flooding from a “100 year” storm is a warning. It shows the permanent changes to come. That is unless major investments elevate or rebuild the Amelia Earhart Dam. A short-term fix is estimated at $45 million. A longer-term fix is around $121 million. Rebuilding could cost $800 million to $1.2 billion.
Scientists predict that in about 20 years, storm surges will regularly exceed 22 feet. This will damage the Amelia Earhart Dam’s integrity. It will lead to flooding of the Mystic River. Flooding threatens to displace thousands in Medford, Somerville, and Arlington. Rising water will reclaim repurposed marshland. It will destroy homes and create climate refugees.
Both the New Charles River Dam and the Amelia Earhart Dam are about 50 years old. They regulate water levels to roughly mid-tide. Under normal conditions, gates close at high tide. This prevents the ocean from raising basin water levels. At low tide, the river flow drains out.
The dams have pumps. The pumps throw river flow over the walls into the ocean. This happens when rain-driven flooding coincides with high tide. The pumps have handled all storms over the past 50 years.
The dams were built to survive the highest harbor water levels observed to date. That was the flood of 1851 plus another foot and a half. Their decks sit about 8 feet above normal high tide. This seemed safe when built. With rising seas, there’s a risk the ocean will surge over these dams.
Ocean storm surge flows are too big for the pumps. A flanking or overtopping event means severe flooding. It will affect the Charles and Mystic basins.
Even a brief overtopping event could damage the dams’ pumping systems. Saltwater could flood critical electrical and mechanical areas. Repairs could reach $150 million.
Fortunately, projects are in motion to harden the dams. This will help them handle over-topping events. Once these fixes are in place, the focus will shift. Raising these structures will push the urgent threat further into the future. Even without increased elevation, flood risk remains low for the next few decades.
Remember Amelia Earhart Dam. It’s not just concrete and steel. It’s a shield. It’s a testament to our resilience. It’s a call to action.