Floodwater Storage Report Released by Lake Champlain-Richelieu River Study Board

Floodwater Storage Report Released by Lake Champlain-Richelieu River Study Board

December 22, 2021 – The International Lake Champlain-Richelieu River Study Board has released its Floodwater Storage report. The report, one of several undertaken by the Study Board, explores using wetland and temporary farmland storage of flood waters to impede flows into Lake Champlain and the Richelieu River to reduce high water levels during floods.

The Study Board was appointed by the International Joint Commission in 2017 to respond to a request by the Canadian and US governments to explore causes, impacts, risks and solutions to mitigate flooding in the Lake Champlain-Richelieu River basin. The request was prompted by record-setting floods in the basin in 2011.

The full report, “Flood water storage using active and passive approaches - Assessing flood control attributes of wetlands and riparian agricultural land in the Lake Champlain-Richelieu River watershed,” can be found on the Study Board website here. A fact sheet also is available here.

Wetlands are natural landscape features within a watershed. They can help intercept floodwaters and slow their flow, reducing the timing and intensity of floods downstream. Upland storage is a nature-based approach for flood mitigation.

Study experts developed models to understand the role of existing wetlands on inflows to Lake Champlain and flows in the Richelieu River, and assess how adding wetland area to the basin and/or temporarily flooding farmland could create additional flood mitigation benefits.

This investigation assessed the potential of storing flood water on riparian agricultural landscapes and using current, restored, and constructed wetlands of tributaries in the Vermont and New York sub-watersheds to reduce runoff volumes, peak flows and net basin supplies to Lake Champlain.

This report illustrates how existing wetlands contribute to flood relief in the Lake Champlain-Richelieu River basin. When examining scenarios that could expand watershed storage, modelling shows additional wetlands could contribute to flood reduction and be an effective passive water storage practice. However, adding wetlands and/or flooding farmland would involve extensive surface area requirements and an elaborate implementation strategy. The report also points out that since there are significant flood reduction benefits from existing wetlands in the basin, it is very important to preserve these natural flood-moderating systems.

The authors conclude that given existing policies, programs and regulations in Canada and the United States, fostering restoration and construction of wetlands instead of flooding farmland might provide a socially acceptable framework to build resilience over time in the LCRR basin, at least at the local sub-watershed levels.

They also indicated that once the study is completed in 2022, the modelling tool developed for the LCRR Study will be available to interested parties to identify potential water storage areas and assess multiple scenarios for each sub-watershed within the basin.

For more information, contact:

Jeff Kart, US                                  989-372-1229           Jeff.Kart@ijc.org

Christina Chiasson, Canada         613-293-1031           Christina.Chiasson@ijc.org

-end-