At their meeting on Tuesday, September 10, the Warren Select Board delved deeper into their discussion about adopting the Fluvial Erosion Hazard Overlay District first presented by the Warren Planning Commission on August 27.

The Fluvial Erosion Hazard Overlay District includes areas along the Mad River deemed vulnerable to erosion. In adopting the district, the town would restrict future development in those areas, but "what is the science that says [the district] should be here, rather than there?" board member Bob Ackland asked when first presented with the plan on August 27.

"I'm reluctant to remove development rights unnecessarily," board member Anson Montgomery said, so on Tuesday, the board invited Agency of Natural Resources (ANR) river scientist Gretchen Alexander, who was responsible for determining the Fluvial Erosion Hazard Overlay District in Warren, to their meeting to explain the science behind it.

Fluvial Erosion Hazard Overlay Districts, or "river corridors," as Alexander calls them, are areas in which "you might expect the river to adjust over time." Generally, the district surrounding a river channel is six times the width of the channel, a width that has been scientifically proven to be "the lateral area necessary for the river to reach a more stable condition," Alexander said.

According to Warren Planning Commission chair Craig Klofach, adopting the Fluvial Erosion Hazard Overlay District in this area would affect about 100 homeowners in Warren. "This eventually affects property value because you cannot build [in the district]," Klofach said.

Per the terms of the Fluvial Erosion Hazard Overlay District, property owners reserve the right to rebuild existing structures within the district but cannot build new structures. On Tuesday, the select board changed the language of the terms to show that the structures could be rebuilt with improvements, as long as they fell within "the existing footprint."

According to Alexander, Fluvial Erosion Hazard Overlay Districts are determined based on a "fairly rapid assessment," she said, and if the town could demonstrate that some area included in the district did not contain an erodible feature, the district could be reevaluated to reflect that.

The area in question on Tuesday was that of the Bobbin Mill, which was included in the Fluvial Erosion Hazard Overlay District. "I think we're all OK with every other [area in the district]," select board chair Andy Cunningham said at the start of the meeting. "It's just the Bobbin Mill we're dealing with tonight."

Before the district was presented to the select board, affected property owners had been notified about the proposal and had the opportunity to attend a public forum. When the district was presented to the select board, Bobbin Mill owner Barry Simpson and his attorney, Sheila Ware, attended the meeting to discuss the Bobbin Mill's inclusion.

In encouraging regulations like the Fluvial Erosion Hazard Overlay District, the ANR is interested only in environmental impact, Ware argued on August 27, while the select board must also consider the economic vitality of the town. The Bobbin Mill is "the only real industrial area in town," Ware said, and "there's absolutely no reason that this parcel couldn't be carved out so industrial use could continue."

Without the Fluvial Erosion Hazard Overlay District, Ware said, any future development in the area would still be subject to conditional use by the Warren Development Review Board, which does take into consideration environmental impact.

And in terms of environmental impact, Ware expressed concern that the overlay district surrounding the Bobbin Mill was "unnecessarily broad," and that areas included in the district have not been flooded. "If you don't have flooding, how can you have erosion?" she said.

On Tuesday, Alexander and the select board visited the Bobbin Mill to observe firsthand whether this could be true. "Does it look to you like a site that is likely to have a catastrophic event?" board member Matt Groom asked Alexander after the site visit.

Alexander responded that while she could not answer yes or no conclusively, she would be concerned about the first terrace bordering the river and the gravel pit behind it. According to Alexander, the site's "large degree of [human] manipulation" makes it a "very vulnerable location."

At the Bobbin Mill "there is some bedrock," Alexander said, "but the indicators ... of a static river are just not there." To prove the area was made up mostly of bedrock would require much more in-depth—and expensive—engineering.

That being said, the select board saw no reason that the area at the top of the Bobbin Mill could not be carved out of the Fluvial Erosion Hazard Overlay District, and they asked the planning commission to review the realignment in the area and provide a district map that reflects the change.