Climate study suggests flooding solutions for downtown Mystic

The New London Day 1/7/2024

Groton ― Improvements to the stormwater system, rain gardens, and a study of raising low-level roads are among potential solutions to help protect downtown Mystic from increased flooding in the face of climate change.

Draft recommendations from a study that the Town of Groton and consultant GZA GeoEnvironmental, Inc. conducted to improve the resiliency and sustainability of downtown Mystic were unveiled at a public forum Thursday at St. Mark’s Episcopal Church in Mystic.

Wayne Cobleigh of GZA GeoEnvironmental, Inc. said the focus of the study is on coastal flooding and sea level rise, heavy rainfalls that overwhelm the stormwater system, and extreme heat.

“These problems are going to become more frequent, and what we’ve got to try to figure out is what can we do to minimize the impact and be able to bounce back from these types of shocks,” he said.

Megan Granato, the town’s sustainability and resilience manager, said that during Superstorm Sandy in 2012, businesses were shut down for three weeks, people lost their HVAC systems, and basements were damaged.

But the area is also experiencing smaller storms: for two Decembers in a row, the town had to shut down roads right before Christmas due to standing water, and water flooded people’s homes and businesses.

The Connecticut Institute for Resilience and Climate Adaptation recommends preparing for up to 20 inches of sea level rise by 2050, and Granato pointed out that downtown Mystic already has some very low-lying roads.

In addition, the area historically had four days a year over 90 degrees, and by 2050 that number might be closer to 15 to 21 days per year, she said.

Cobleigh presented draft recommendations from the study. He said high-priority, short-term recommendations include installing green infrastructure, such as rain gardens, and improving the stormwater system by installing backflow preventers.

He said some of the roads in downtown Mystic are too low to be able to manage flooding. He said raising these roads is a potential solution, but it’s not easy and property owners along the roads would also have to elevate their driveways. He said it would require a coordinated effort between the town and private landowners to study the idea and find a way that is beneficial and makes financial sense.

Cobleigh said other high-priority, short-term recommendations include creating a stockpile of materials, such as sump pumps and back-up generators; adopting more stringent building standards; flood-proofing the Gravel Street pump station; creating a post-disaster response and recovery plan; and helping local businesses plan for floods.

Another recommendation is to study the feasibility of a stormwater authority that could levy fees that would benefit stormwater system maintenance and improvements.

Recommendations to help with extreme heat are to add trees and pop-up cooling stations on West Main Street and work with CIRCA on a heat study, according to the presentation.

The study also recommends best practices homeowners could implement for their properties: installing basement sump pumps in flood-prone homes; relocating mechanical systems above flood levels; undertaking flood-proofing measures in certain areas; and raising buildings on West Main Street, Gravel Street and Pearl Street, according to the presentation.

Cobleigh also presented low-priority measures: a downtown flood (hurricane) barrier, flood walls or levees along the Mystic River, and a below-surface floodwater detention system, but he said there are further questions to consider or studies needed about these ideas.

More information, a draft of the report’s chapter on recommendations, and a recording of Thursday’s presentation are available at:

The goal is to finalize the report by the end of the month. People can email comments by Jan. 15 to Granato at and David Leone at