Rarely has anyone thought about a dam in Everett, but with huge, historic coastal surges as were seen this year on March 2 and Jan. 4, some are drawing attention to the Amelia Earhart Dam on the Mystic River – which spans from Everett to Somerville and holds the Boston Harbor out of areas like the Mystic and Malden rivers.
In the most recent flooding event on March 2, red flags were raised when the dam – to the naked eye – appeared very close to overtopping the dam. Indeed, such a close call had rarely been seen in the area.
Patrick Herron, director of the Mystic River Watershed Association (MyRWA), said it might be time to think about the Dam and simple resiliency project that could protect properties along the Malden River in Everett if the Earhart Dam were to ever be overtaken by the Harbor surge.
“On March 2, you could see the water very close and our back of envelope calculations based on what we saw was they had about two or three feet of freeboard left,” he said. “We think there is a good opportunity when the Draw 7 Park on Somerville is constructed soon to include some coastal resiliency aspects to protect things that are upstream…The Dam may not be at risk right now for overtopping frequently or at all, but it could overtop or go around the Dam in 2020 or 2030. We think this is a very appropriate time right now, given what we’ve seen lately, to ask questions about coastal resiliency for this Dam.”
He said MyRWA and its partners are not only worried about water going over the Dam from the Harbor, but also going around the Dam over land separately or at the same time.
“When you’re talking about water overtopping the Dam in a small area by about six inches, that’s not as severe of an impact,” he said. “But if you were talking about a foot overtopping much of the Dam and circumventing the Dam, then you have a very serious issue on your hands.”
The seriousness of it for Everett could lie along the Lower Mystic and the Malden River, where the new GE Park, the Main Street neighborhoods and the Gateway Mall area could be at great risk for flooding – all in areas that have really never experienced such disasters. On the Medford side, the newly developed Preotle properties along the Malden River could also be at risk.
The Department of Conservation and Recreation (DCR), which operates and owns the Earhart Dam, said they monitor levels with their Flood Control Management staff very closely, especially in events like happened on March 2.
DCR officials said the Earhart Dam was not in any critical danger on either March 2 or Jan. 4, but did say both of those two tidal events were two of the highest ever recorded at the Dam. The other instance was on Feb. 7, 1978 during the Blizzard of `78.
On March 2, they reported that there was more than 2.5 feet of freeboard at the Dam on the Harbor side, and the Dam was not under and distress. The March 2 tide was a 14.67-foot tide, and the Jan. 4 – the highest recorded at the Dam – was 15.16-foot. On Feb. 7, 1978, the tide recorded was 15.10-feet.
The Dam works to actually create a calm area on the Mystic and Malden more for ease of recreation than anything else. The Dam keeps the major tidal influence from the Harbor out of those areas and creates a calmer area – while also having controlled releases of water from the upper Mystic River areas during large rain events. While most worry about water inundating the Dam from the reverse side coming from rainwater, few have yet thought about the Harbor tides actually being the threat.
Herron and other advocates said there might be a lot of measures the DCR could implement now that may not be multi-million dollar improvement project.
He said there are improvements that could be implemented during construction projects, and there are also measures like temporary blockades that could be put in place if need be.
“We believe there is a lot of low-hanging fruit that could help the situation,” he said. “We should begin to look at that…The Draw 7 Park just over on the Somerville side will be re-built soon for the next 50 years, and the design could have some coastal resiliency built into it. If you think that for every $1 million in design that you put in now, you might be saving $10 million through those protections because that is a pinch point.”
DCR officials said they will continue to review weather reports, make necessary system adjustments and monitor water levels at the Dam in the future.