Elise Leduc of the Woods Hole Group on Monday, July 8, presented selectmen with the first look at what roads and structures are subject to flooding and damage during a major storm.
Ms. Leduc was before the board to present the findings of a vulnerability assessment that looked at the potential for flooding of Falmouth’s assets following significant storms today, in 2030 and in 2070. It also showed what would happen to the building or road in the event of a 20-year or 100-year storm.
“I think the most telling thing here is the vulnerability of Falmouth’s roadways,” Ms. Leduc said. “When you put this together with all the other assets and all of the buildings, it is really a number of roads and bridges that pop out as most at risk.”
Through their analysis, the group assigned a composite risk score to Falmouth’s roads and assets, how likely a property is to flood, as well as the consequences of its flooding, such as the impact on public safety and emergency services, the cost of damage and how much of the town is impacted by losing the asset.
The most vulnerable road, with a composite risk score of 6,635, is the section of Water Street between Luscombe Avenue and the drawbridge. Other vulnerable roads include Chapoquoit Road between Little Neck Bars Road and the bridge, Clinton Avenue between Swing Lane and Scranton Avenue, and Scranton Avenue from Lowry Road to Clinton Avenue.
The most vulnerable building or structure is the Park Road Sewer lift station. Given its location and elevation, the Woods Hole Group determined there is 100 percent change of flooding at this location under current conditions.
“As you go forward in time, the probability you cross that critical elevation increases,” Ms. Leduc said, referring to sea level rise.
Other at-risk assets include the Old Dock Road Pier upweller pumps, the Woods Hole Drawbridge hut and the Old Dock Road Pier shed.
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“Not surprisingly, a lot of these are marine related because they are so close to the ocean,” Ms. Leduc said. “However, town hall actually ranks number six.”
The final report, which should be completed by October, will include recommendations alongside these rankings.
“We have a lot of data, we have a lot of results, some of which is a little shocking in terms of the water levels we might have to deal with,” Ms. Leduc said. “The goal here is to start developing short-, mid- and long-term adaptation strategies to address these flooding impacts. These could include anything from infrastructure repairs to recommendations for regulation and policy updates to land acquisition and conservation.”
In addition to inundation maps, the Woods Hole Group developed three visualizations that show how vulnerable the Mitchell Bathhouse, Green Pond Bridge and Water Street are to a 100-year storm today, in 2030 and in 2070.
If a 100-year storm were to happen this year, floodwaters would reach an elevation of 8.6 feet in the area of the Green Pond Bridge, causing waters to push up against the base of the bridge.
“By 2070, the whole bridge would be over-topped in a 100-year flood,” Ms. Leduc said, presenting selectmen with a picture that showed water where the bridge is.
In addition to a final report to selectmen, the Woods Hole Group will conduct a public presentation regarding its findings and recommendations.
She noted these recommendations will vary from structure to structure.
“In no case will one solution be the solution for the whole town,” Ms. Leduc said. “Each asset will have its own set of solutions.”
Selectmen Chairwoman Megan E. English Braga described the data as “phenomenal.”
“We have this conversation as a board all the time,” Ms. English Braga said. “We recently just talked about this issue, how do we know where we have to focus our town’s efforts? This really is just a tremendous product.”