PLAINFIELD – Maps of four scenarios that could bring floodwaters to Plainfield homes and businesses were reviewed at a meeting of the Plainfield Hazard Mitigation Committee last Thursday, Jan. 15. Residents were invited to the meeting, billed as an opportunity to, “review newly completed (draft) Winooski, Great Brook and Molly’s Falls Dam #6 worst-case flooding projection maps, to help us all think about when to evacuate or stay put, and if neighbors might need extra help.”
map courtesy Plainfield Hazard Mitigation Committee
“These maps are also available for town disaster and housing projections, and evacuation route planning by emergency personnel,” said the agenda.
The recently compiled maps show the levels flood waters could potentially reach in a 100 year flood, which reflects a 1% chance of flooding, and in a 500 year flood, reflecting a 0.2% chance of flooding.
Two other sets of data showed scenarios for Marshfield Dam flooding, first on a sunny day, then during a 100-year-flood with the service spillway open. There has not been an issue with inundation at the dam, since May 26, 2011.
A red line showed the extent of recent floodwaters, which extended well beyond the 500-year mapping. It was explained that the maps do not account for debris washing down the river, or changes to the course of the river as it moves gravel downstream. Both of those issues affected flooding in 2024.
The committee discussed how to share information provided by the maps to families and business owners likely to be affected by future flooding in the area. Because emergency personnel are not likely to reach everyone who needs to be evacuated, they are looking to share the information provided by the maps. Those will be useful both to identify buildings at risk and the roads and bridges likely to offer safe travel to shelters, including a new one potentially at a church on the high side of Vt. Rte. 2., with which they hope to have a future conversation.
“Everybody needs to work out an individual evacuation plan because fire departments may not be able to reach homes [here and] also along Route 215 in Cabot.”
The number of buildings affected by floodwaters shown on the maps was close to 100 in Plainfield and considerably more when taking Marshfield into account. That number would be higher if not for the 27 buildings accepting buyouts to be demolished and turned into empty space, potentially creating floodplain to help reduce future flooding.
The mapping extended into Marshfield, which Plainfield Emergency Management Director Michael Billingsley explained is because, “Marshfield and Plainfield are interwoven in terms of shared risk from the dam and the river, ties between families going to school together for generations, and overlapping economies, social events and strategies. We share a Senior Center and a Health Center.
“Our Energy Coordinator and I attend Marshfield’s Energy Committee [meetings], and we invited a Marshfield resident to join our Hazard Mitigation Committee. Marshfield’s Emergency Management Director and I collaborate together, especially with regard to Twinfield”.
A change to plans for evacuation of the Twinfield school was noted. Where previously they were to go to Old Schoolhouse Common, the mapping shows earlier flooding happens along roads and bridges in that direction, so families are being directed to meet students on the former Goddard College campus. It will still be necessary to evacuate the school early, before flood waters reach roads and bridges offering access to that location.
Soon after the 2024 flooding the state, without discussion with town officials or emergency management personnel, removed woody debris and gravel from the river. The committee noted that likely increases the damage from future flooding because woody debris can cause high water to back up into fields and forests upstream from towns. Less obstructed and deeper channels left after gravel is removed can cause high water to move faster, causing more erosion and its associated damage. The maps are said to reflect that current state of the river.
Flooding in tributaries to the Winooski River were identified as sources of potential flooding in rainfall events away from the Winooski that can make it a more dangerous river.
Naismith Brook flooding in 2023 led to some evacuations and the 2024 flood involved inundation from the Great Brook.
The maps will be accessible on the Hazard Mitigation Committee page of the Plainfield town website when they are finalized.
Paul Fixx is editor of The Hardwick Gazette and lives in Hardwick.
