City officials updated City Plan commissioners about two major long-term efforts to contain flooding near the train station and in the Hill, and got the go-ahead to keep pursuing them.
The City Plan Commission gave that support at its latest monthly meeting, with two separate unanimous votes by commissioners.
The commission first authorized the mayor to accept a federal pass-through to the state funding for a $35.8 million tunnel and embankment project. The money would become available if the city is successful in a national competition for a FEMA [Federal Emergency Management Agency] grant. The ten-foot wide “micro tunnel” would run 30 feet underground and be capable of carrying heavy rain and surge water from the Union Avenue rail yard areas to the harbor.
In a separate vote, a favorable unanimous referral was given for the mayor to sign an agreement with the U.S. Department of the Army to design a flood wall and pumping station “to address the storm surge floods and shoreline erosion at the I‑95 corridor, rail yard, business district, and public park.” The flood wall would go up along I‑95 at Long Wharf, along with movable flood gates and a super pumping station that can heave out 1,185 cubic feet of water per second during significant storm surges.
The pumping station design work, said Deputy City Engineer Dawn Henning, will cost $9.6 million, with “65 percent to be funded by the Army Corps and 35 percent by the state and local partners.”
She said that the city and state will split their portion: $1.69 million has already been bonded in Hartford, and the city’s portion to come out of existing municipal funds.
Henning said both these applications are based on years of work her department and the city have done in trying to understand downtown and Hill flooding and devising a workable, affordable solution.
“I’ve been working on this for seven years, all my time here,” she said in her presentation to the commissioners at the meeting, which was held this past Wednesday evening over Zoom. “Part of what we’ve done is the 200 plus bioswales, but we’re still left with a flooding problem and how to address the stormwater to the harbor.”
The heart of the problem is that “the areas are all trying to drain through three pipes into the harbor. We’re low-lying, so we need to build more capacity under the rail yard where the pipes go, but we can’t dig under a rail yard!”
The solution: Add more capacity through building the “micro tunnel” 3,200 linear feet long and 30 to 40 feet below ground. It would start near the Knights of Columbus building, pass under the post office on Brewery Street, and have its outfall in the harbor near where the three above-ground pipes have theirs.
“With micro-tunneling 30 to 40 feet below ground, we can support the pipe without traditional structures,” Henning said. Such structures, like pilings, would be expensive and difficult if a traditional pipe went across Long Wharf, which is basically a marsh.
“The pump station would increase the capacity for this pipe,” Henning added.
Commissioner Josh Van Hoesen pronounced the prospect “a good financial deal.” Commissioner (and Alder) Adam Marchand called the project important. “If we can get a lot of federal dollars to help us, it’ll be really good.”
Commission Chair Leslie Radcliffe came at her enthusiasm touched with skepticism. “I live in the Hill, and we do have a lot of flooding. I trust you know what you’re doing. I wouldn’t want to see all the trash that comes down my street when it floods end up in the harbor,” she said. “I trust you will make sure it works.”