Flood Inundation Maps & Report Released for Lake Champlain & Richelieu River

In the last post, information was provided about the draft report prepared by a working group of the International Joint Commission (IJC) about flood inundation and forecasting in the Lake Champlain-Richelieu River watershed.  The IJC is a a collaboration between the US and Canada to provide coordination, management and protection of shared watersheds. Here in Vermont, we have representatives that have been appointed to the International Lake Champlain-Richelieu River Technical Working Group.

Today, the final report that came out of the Lake Champlain-Richelieu River Technical Working Group was released.  The report, A real-time flood forecasting and flood inundation mapping system for the Lake Champlain-Richelieu River watershed, was an outcome of a 2013 comprehensive Plan of Study.

From the press release:

"The IJC endorses the TWG observation that enhanced coordination among agencies involved in real-time forecasts is necessary to support the development and maintenance of forecast models and quality-controlled joint water level predictions. The Commission endorses the TWG recommendation that a binational coordination body be mandated and funded to consolidate and synthesize flood forecasting work undertaken domestically into a single binational flood forecast. This body would also be charged with developing and disseminating consistent messaging to emergency responders and the public.

"Consequently, the new IJC report does not evaluate potential flood mitigation measures as this was outside the terms of reference provided by governments.

"The Commission reiterates its strong recommendation that governments implement the full scope of the 2013 Plan of Study (PoS) to evaluate past impacts, flood plain management practices and adaptation strategies, and to assess soft (i.e., low impact and cost) to moderate flood mitigation measures and their impacts."

An outcome of the report was a series of inundation flood maps that show the areas of the Lake Champlain and Richelieu River shorelines that would be inundated when the Lake flood waters are at a certain height. Again, from the press release:

"The inundation maps show flooding potential under different flood scenarios and are not designed for regulatory purposes. A preview of these maps is available on the IJC web site at: http://arcg.is/1MhXui2."

Please take some time to explore the inundation maps, as well as read through the final report which can be found at http://ijc.org/files/publications/Lake-Champlain-IJC-Report-to-Govts-Dec-2015-NEW.pdf 

IJC invites public comment on draft flood forecasting and mapping report for Lake Champlain and Richelieu River

IJC invites public comment on draft flood forecasting and mapping report for Lake Champlain and Richelieu River and previews flood inundation maps

The International Joint Commission (IJC) is requesting comments from the public on a draft report to enhance flood preparedness and warnings for Lake Champlain and the Richelieu River by December 10, 2015.  Specifically the IJC asks if the report’s recommendations are sound and whether the recommendations address real needs for enhanced flood preparedness and warnings for Lake Champlain and the Richelieu River.  The Commission is also inviting the public to preview the associated flood inundation maps.

Following the submission of IJC’s  July 2013 Plan of Study “The Identification of Measures to Mitigate Flooding and the Impacts of Flooding of Lake Champlain and Richelieu River” (POS), the governments of the United States and Canada asked the IJC to address two issues associated with the system wide flooding in 2011:
a. closing the gaps in the data needed for a future real-time flood forecasting and inundation mapping system, and
b. the creation of static flood inundation map products.

The IJC appointed the International Lake Champlain-Richelieu River Technical Working Group (TWG) comprised of technical experts from United States, Canada, Quebec, Vermont, and New York to address the two issues. The IJC is now inviting public comment on the TWG’s draft report Toward an operational real-time flood forecasting and flood inundation mapping system for the Lake Champlain and Richelieu River.

The TWG report includes six recommendations addressing the need to:

1. Implement an operational probabilistic approach for forecasting floods, including modelling of wind set up and wave action;
2. Keep the Henry and Grand Isle water level station to maintain water level calibration and also install wave buoys to assist in wave model calibration;
3. Institute a binational coordination body such as an IJC Board to support agencies involved in real time forecasting;
4. Acquire new bathymetric data for the Richelieu River between Sorel and Saint-Jean-sur-Richelieu;
5. Create a single consistent Digital Elevation Model (DEM) for the entire Lake Champlain-Richelieu River basin following the completion and quality control of LiDAR and bathymetric data acquisition; and
6. Generate static flood inundation maps for the entire Lake Champlain Richelieu River system.

The current effort has significantly advanced the creation of flood-inundation maps for the Lake Champlain-Richelieu River system. These maps provide an emergency planning tool for authorities and the general public on land that may flood during high water events. Static inundation maps were created for the Vermont side of Lake Champlain and a portion of the New York northeastern shoreline on the US side, and for the Richelieu River from the border to downstream of the Fryers Rapids on the Canadian side. A preview of these maps is available on the IJC web site at: http://arcg.is/1MhXui2 , however, the site is under construction and the text accompanying the maps is in French only at this time. A complete LiDAR Digital Elevation Model available in Canada also allowed for the representation of inundation depths for the 11 flood scenarios.  The inundation maps are not designed for regulatory purposes, but rather to show flooding potential under different conditions.  Furthermore the report does not evaluate potential flood mitigation measures as this was outside of the scope of the reference from governments.

This public comment period is being held from November 16 to December 10, at which time the IJC will consider public comments before submitting its final report to governments.


Contacts:

Nick Heisler  (English)  Ottawa 613-992-8367 Heislern@ottawa.ijc.org

Sarah Lobrichon (French)      Ottawa 613-992-5368 LobrichonS@ottawa.ijc.org

Frank Bevacqua Washington 202-736-9024 Bevacquaf@washington.ijc.org

                                             
Sarah Lobrichon
Policy and Communications Analyst | Analyste des politiques et des communications
International Joint Commission | Commission mixte internationale
234 Laurier Ave. West, 22nd Floor, Ottawa, Ontario, Canada K1P 6K6
234, avenue Laurier Ouest, 22e étage, Ottawa (Ontario), Canada K1P 6K6
Telephone | Téléphone 613-992-5368 / Facsimile | Télécopieur 613-993-5583

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