With rainstorms getting worse, town toughens erosion controls

Rain’s been falling — often a lot all at once, with 14 storms dropping half an inch or more measured from April through late August by the Aquarion Water Company, which tracks rainfall at its reservoir in Greenwich. The town of Ridgefield is responding to the weather trend by requiring builders to double-up on erosion and sedimentation controls at vulnerable areas of construction sites.

“The intensity of the storms,” said First Selectman Rudy Marconi, “when you get a site that has lost its vegetation, is under construction, there’s no question it’s vulnerable to these storms.

“There’s no question, the amount of rain and the intensity of it, that the previous erosion and sedimentation measures need to be modified,” he said.

“In June or July, we had over two inches of rain in 45 minutes. In those types of storms, it’s almost impossible to control a site 100%. But it’s also obvious we can do a lot more.”

Planning and Zoning Director Richard Baldelli has issued new rules, effective Sept. 1, for the control of erosion and sedimentation at construction sites — and said permits could be revoked for projects that fail to comply.

“Due to the increasing number and intensity of major storm events (1/2” or greater) erosion and sediment control plan minimum requirements are being increased to help mitigate significant negative impact to all wetlands, watercourses, roadways and properties,” Baldelli wrote.

“All erosion and sedimentation control plans submitted after Sept. 1, 2018 showing a ‘single line’ erosion control barrier will no longer be accepted by the land use office,” he said.

“All Erosion and Sedimentation Control Plans will be required to show, at a minimum, multiple layers of erosion control barriers at the most vulnerable points, and, when applicable, additional enhanced measures.”

Baldelli offered some examples of other “enhanced measures” to limit the ill effects of erosion and sedimentation.  

Entrances to construction sites “will be required to be ‘flared-out’ at the construction entrance's intersection with the roadway,” he said, and must be set up so that “all vehicles will have to travel the full length of the construction entrance when entering and exiting the site.”

Additional enhanced measures to control erosion and sedimentation include: “the use of fore-bays, stone check dams, diversion swales, settling basins, etc.”

There could be more.

“Erosion and Sedimentation Control Plans submitted for properties that contain steep slopes, inland wetlands, watercourses, water-bodies, floodplains, aquifers, and other sensitive site features, may be required to provide additional erosion control measures,” the planning and zoning department’s release said,

“Erosion and Sediment Control Plans shall be designed so that no silty water leaves the immediate work site, and or creates a negative impact to all wetlands, watercourses, roadways and properties.

“Any Erosion and Sediment Control Plan that is designed to allow water that has contact with any earth disturbed area to leave the Erosion Control protected area, will have to show how the water will be treated to ensure that only clean water will outflow.

“Failure to properly maintain Erosion and Sediment Controls may result in the immediate revocation of permits.”

Aquarion’s graph of major rain events also shows more than 20 storms dropping over a half-inch of precipitation so far in 2018, and 31 storms of at least half-inch in the last year, back to August 2017.

Baldelli told The Press that the new program reflects both the changing weather patterns and the town applying what has been learned about erosion control.

“The enhanced erosion control standards are mainly based on two items,” he said. “One, the increased number of intense storms. And, two, the town's continual quest to mitigate construction site negative sediment impacts from storm events.

“We are taking what we have learned from large projects that have had erosion control peer review input and bringing those lessons in mitigation to smaller projects throughout the town.”

Baldelli said the action is an administrative change under authority from the state Department of Energy and Environmental Protection (DEEP) and doesn’t require a vote for either the local Planning and Zoning Commission or the Inland Wetlands Board.

“Because the town’s current regulations are based on DEEP’s 2002 Guidelines for Soil Erosion and Sediment Control,” he said, “there is no need to amend the regulations to institute additional enhanced erosion controls.”