Soaking up stormwater solutions

CORNWALL — Wild weather in recent years has come with a price tag and put the squeeze on small towns.

Cornwall spent hundreds of thousands repairing culverts, roads and retaining walls after a summer of heavy rain in 2023. The expenses took a toll on the town’s undesignated funds balance and prompted the addition of $100,000 to a newly created storm damage line item in the 2024-25 budget.

To address the impact of a turbulent climate and better plan for the future, Cornwall Planning and Zoning Commission hosted Trinkaus Engineering’s Steven D. Trinkaus for an info session at Cornwall Library July 10.

“Rainfall patterns are changing,” said Trinkaus. “What we are getting are these short duration, high intensity rainfall events. Storms that drop three inches in two hours or less.”

Trinkaus’s presentation offered advice on “low impact sustainable development” methods that are designed to mimic nature. He has shared this information internationally with many trips to Korea and China, as well as throughout Connecticut and the United States.

When not properly managed, runoff can cause water quality issues, habitat loss, and damage to infrastructure. Erosion, flooding and landslides can occur as a result of mismanaged stormwater.

Cornwall experienced this last year with considerable erosion to a retaining wall on River Road, flooding on Jewell Street, and a landslide on Essex Hill Road.

Trinkaus cited impervious surfaces as the prime enemy of runoff. Aside from disrupting watercourses, unnatural environments lead to contaminated runoff that can severely harm organisms.

“The major issue we’re trying to address is pollutants and non-point source runoff,” said Trinkaus, citing solids, trash, oils, and metals as contaminants. “The fish and other wildlife are left to deal with this.”

Densely vegetated habitats soak up rainwater at much higher rates compared to environments cleared of vegetation. Deep-rooted plants enable water to penetrate down beneath the soil and minimize runoff.

The ideal time to address stormwater management is at the start of a new project. Trinkaus suggested the best designs are ones that maximize retention of the natural environment.

“The goal really is to have a site ... that acts like a forest or a meadow, which is what it was before you put a shovel in the ground,” said Trinkaus.

Controlling water at the source is the most reliable way to prevent excess runoff. Trinkaus suggested utilizing rain barrels, water gardens, and detention ponds to trap water where it falls.

New advancements like permeable pavement and porous concrete can help address the issue, but costs of these materials remain high. Trinkaus praised the new technology while noting the old fashioned way is tried and true.

“Mother Nature does a great job of treating water and filtering it.”