Wilton’s Historic District and Historic Properties Commission (HDHPC) devoted most of its Wednesday, Jan. 13 meeting to an interim progress report from a study currently underway about historic Cannondale.
The study, led by consultant Michelle Boyd of Building Conservation Associates (BCA), was designed to inform the Cannondale Master Plan that will eventually be undertaken by the Planning and Zoning Commission.
An earlier interim report, presented to HDHPC on Nov. 11, included a review of Cannondale’s development evolution.
The latest BCA presentation focused on environmental risks — specifically from flooding.
“The biggest environmental risk that we have here in the village is the flood potential from the Norwalk River,” said Azure Dee Sleicher of RACE Coastal Engineering, who conducted the engineering analysis.
Sleicher explained that much of the historic Cannondale area is located in a FEMA AE Zone, meaning properties have a 1% annual risk of flooding — from the so-called 100-year flood event.
She emphasized that FEMA’s updated flood maps, expected to be approved this year, will only expand the area believed to be at risk.
That may not come as a surprise to anyone who witnessed the devastating flooding that occurred in Cannondale and many other areas of Wilton on August 18, 2024, when at least eight inches of rain fell in just a few hours.
While the main hall of the historic Cannon Grange managed to evade flooding that day, Sleicher suggested it might not fare so well again. Her analysis concluded that the property could be flooded in three feet of water in another significant event — even a 10-year storm.
Sleicher calculated the vulnerabilities for the Grange as well as a number of other prominent buildings, including the historic schoolhouse, the buildings known as the Gregory barns, the former gristmill, and other recognizable locations in the area.
They each were shown to have estimated flood levels of at least two and in some cases five feet in significant flooding events. Like the Grange, some of the structures, such as the historic schoolhouse, would be at risk even in a 10-year storm, Sleicher said.
The entire presentation can be seen on the Zoom meeting video which is posted on the Town website. The presentation document is also posted.
Sleicher highlighted the fact that many historic properties are exempt from certain FEMA restrictions, but as a result, are often less resilient when flooding events occur.
She found the former gristmill, which was constructed partially over the river, particularly remarkable.
“This is a building that could never be built today based on today’s standards,” Sleicher said, citing its low elevation, over‑water footprint and basement.
Sleicher also outlined some mitigation strategies for the historic buildings, such as moving mechanical systems and valuable contents to higher floors, using more flood‑resistant materials in repairs, and considering temporary, deployable barriers, for example.
Sleicher noted two potential infrastructure projects that could improve conditions over time: the planned replacement of the Cannondale Rd. bridge, which now traps some flood debris due to its design, and the removal of a dam in the area, both of which could help reduce floodwaters through the village.
HDHPC Chair Lori Fusco praised the level of detail in the presentation and observed that the flood risks pose a real challenge for both preservation and development in the area.
“It’s really fascinating. On the downside, we’ve got a 2026 revision of the flood map, which is really just reality — it’s the reflection of the way the conditions are now, and it looks like more of that area is going to be more at risk,” Fusco mused. “But on the bright side, there are things that can be done to offset and mitigate those situations.”
“It’s good information, it’s important information, and it’s good to understand the dynamics,” Fusco continued. “It’s a very unique location for this beautiful historic village, right next to that river. Rivers are quaint and lovely, but they can also create some challenges. So it’s important, especially if they’re looking to possibly develop there, you’ve got to think about what those challenges are, and really what’s realistic.”
The study’s third and final presentation is expected at the commission’s Mar. 10 meeting. The deliverable will include a “revitalization roadmap” including economic impacts of historic preservation, conceptual strategies, considerations for adaptive re-use, case studies and recommendations.