AUGUST 13, 2019 – Council members and staff with the City of Kawartha Lakes received an update and presentation on the newly-completed Burnt River Flood Plain Mapping Tuesday afternoon.
Director of Planning, Development and Engineering, Ron Warne and GIS/Mapping Technician Galen Yerex made the presentation to Council.
The mapping was completed over 18-months and pulls 130 years of weather and hydrological data to provide the City and its residents with the most technically accurate flood plain information for the Burnt River area.
“Technology has improved dramatically since the flood plain mapping was last completed in 1991,” explained Mr. Yerex. “The updated flood plain mapping will provide better emergency management and planning information to the City and residents.”
With the dramatic flooding that property owners once again experienced this spring, the updated mapping will enhance the protection of people and property by clearly identifying flood-prone areas.
Staff surveyed high water marks during the Burnt River flood events that occurred in 2013 and 2016. These high-water marks were used to help calibrate the updated 2019 Burnt River hydraulic model. The model calibration was completed using a flood frequency analysis and the historic high flows measured by the Burnt River flow gauge station.
“The updated Burnt River flood study used several decades of historic flow gauge data, real flood event high-water marks as well as more accurate data compared to the 1991 Burnt River Flood study,” explained Mr. Yerex.
The resulting updated flood line yielded results that were largely similar to the 1991 Burnt River Flood Plain Mapping study in terms of the extent of the floodplain; however, the updated study references better information and almost 30 years of additional water flows, thereby providing greater reassurance of the quality of the updated flood line. This, in turn, helps instill greater confidence in the flood models and for planning purposes.
The 2019 Burnt River flood was higher, longer and contained more water than any other flood in the City’s history. The water levels in 2019 were 20 centimetres higher than the historic flood of 2013.
“What is perhaps even more alarming is that the water levels in a regulatory flood event – in this situation, based on the Timmins Flood from August 31, 1961 – would have resulted in twice as much water flowing through the Burnt River as what was experienced this spring,” explained Mr. Yerex.
Kawartha Lakes Mayor, and Vice-Chair of the Kawartha Conservation Board of Directors, Andy Letham noted the project is a critical update to the existing 1991 flood plain mapping.
“This updated mapping will be instrumental and invaluable in supporting our planning staff and the residents of Kawartha Lakes in understanding where issues currently exist and potentially could exist,” said Mayor Letham. “We appreciate the expertise and hard work of Kawartha Conservation in being able to provide this critical mapping to us.
“We share the same goal of helping to protect the people and property of residents in Kawartha Lakes and working together to identify flood prone areas through updated flood plain mapping is an important step in achieving that goal,” added Mr. Letham.
To learn more about the Burnt River Flood Plain mapping studies, or additional studies that have been completed visit Kawartha Conservation online at http://kawarthaconservation.com/permits-planning/flood-plain-mapping-studies.