Local municipalities share experiences with floods
More than 30 people attend annual Flood Emergency Planning Meeting hosted by Ausable Bayfield Conservation Authority; Municipalities, conservation authority share flood response experiences
Municipal staff presented to this year’s Flood Emergency Planning Meeting about their responses to major flood events in 2019.
Ausable Bayfield Conservation Authority (ABCA) hosted the meeting at the Masonic Hall in Exeter.
Coastal flooding along Lake Huron’s shoreline has become more frequent as lake levels reach and even set all-time record levels for a given month. Monthly average lake level for Lake Huron in January 2020 set a record high for the month but was below the overall record high level for Lake Huron, said Davin Heinbuck, ABCA Water Resources Coordinator. It is predicted Lake Huron levels will continue to set monthly records through spring and possibly summer, he said. Lake Huron may experience all-time record highs this year. Shoreline dunes and bluffs are being eroded by wave action during this period of high lake levels, the Water Resources Coordinator said. The erosion problem is worse during large storm events in autumn and winter. Strong northwest winds produce storm surges that increase water levels and wave action. Bank failures along bluffs can occur at any time during a storm event or even days, weeks, or months later.
Ausable Bayfield Conservation Authority provides flood forecasting and warning messages, to municipalities, in advance of major weather systems likely to cause flooding and that contribute to bank failures and erosion along the Lake Huron shoreline. The May 25, 2019 flood event hitting Parkhill and other communities, however, was an example of an intense local event that was not predictable based on forecasts. This heavy, intense, localized rainfall event occurred in the southern portion of the Ausable Bayfield watershed.
Tommy Kokas, ABCA Water Resources E.I.T., shared how the Cameron-Gillies Diversion Channel is designed to divert water away from the town of Parkhill, and into the reservoir, during severe runoff events. “The diversion channel bypassed about 50 per cent of the flow from this event, that would have normally gone into the town of Parkhill,” said Kokas. “You can imagine if all that extra flow had gone into Parkhill, the issues that would have occurred.”
Floods do happen, said Kokas, and we need to be prepared. “There is a need for continued vigilance, staying alert,” he said. “This can happen at any time.” The conservation authority stream gauges, river watch and snowpack water-equivalent monitoring, modeling, and other tools help to provide municipalities with better information before and during flood events. Structures such as the Parkhill diversion channel also help.
Municipality of North Middlesex Chief Administrative Officer (CAO) Jonathon Graham shared about costs from the flood event including repairs to infrastructure. He also said the flood had other impacts such as bypasses of sanitary pumps. He said the flood underlined the importance of planning and maintaining communication before and during events. The municipality and ABCA were in regular contact during the May 25, 2019 event, he said.
Lines of communication were open with conservation authority staff and that was important as information provided by ABCA during the flood gave him information council and staff needed, Graham said. Even when the flooding began to recede there were weather forecasts with a potential for 30 millimetres more of rain and the municipality had to be prepared for that possibility.
Other local flood events in 2019 included flooding in Port Franks and Grand Bend areas in October and November. Flood waters remained for two whole days during the October 17, 2019 event and high lake levels contributed to drainage problems. Chris Martin, Lambton Shores Community Emergency Management Coordinator (CEMC), said high lake levels have created challenges for Lambton Shores. In a period of about six years, Lake Huron has gone from record lows to almost record highs. The impacts of these high lake levels include reduced beach size at Grand Bend beach and increased traffic to the beach as other beach areas have receded. He said beaches are smaller during times of high lake levels so crowds of people are concentrated in smaller areas. The municipality has had to adapt to respond to this increased density. Creating policies for the size and location of beach umbrellas, to ensure sight lines for lifeguards, was an example of a response to this challenge.
Another issue was wave action and energy eroding the Mud Creek shoreline. The sustained impact resulted in the loss of dunes along the shore. The Lambton Shores Community Emergency Management Coordinator described the cleanout the municipality conducted at the mouth of Mud Creek. The high lake levels make it challenging to provide an outlet in order to open up Mud Creek, he said.
Steve McAuley, Director of Community Services, Municipality of Lambton Shores, said the municipality worked with residents and the property owners’ association and was able to dig out the mouth of Mud Creek but for emergency purposes only as roads were flooded and to preserve emergency access. The Director of Community Services said continued increases in the Lake Huron water level would have major impacts to Mud Creek, Grand Bend, and River Road. “The information we get from ABCA is really imperative to understand what is going on (during a flood event),” he said.
ABCA Water Resources Coordinator Davin Heinbuck shared photos from recent and historic flooding events throughout the watershed. Common types of local flood events include heavy rains, rain and snowmelt, and ice jams. A lack of river ice means the risk of ice jams is relatively low at this time but the risk can change depending on weather. Also, the depth of the snow pack, and the ‘water equivalent’ in the snow pack, is about half of what is normally expected at this time of year. This also lowers the risk of flooding. A heavy snowfall followed by rapid warming and rain would increase flood risk, however. Flooding could still be a factor if heavy spring rains fall on saturated ground, Heinbuck said. The risk of a melt and runoff event in the next week or two after the meeting was predicted to be “slight,” based on a two-week outlook.
Heinbuck also presented about the roles and responsibilities of different levels of government and agencies during a flood event. He also discussed the conservation authority’s Flood Emergency Plan.
Geoffrey Cade, ABCA Water and Planning Manager, thanked the presenters and said flooding and high lake levels demonstrate how important it is to ensure development takes place outside of the most hazardous areas. He thanked the municipal staff for having worked closely with ABCA during the recent flooding and for having kept lines of communication open.
PHOTO: MUNICIPALITIES PRESENT AT FLOOD EMERGENCY PLANNING MEETING: Presenting about local flood response, at the February 11, 2020 Flood Emergency Planning Meeting in Exeter were, from left to right in photo: Jonathon Graham, Chief Administrative Officer (CAO) and Director of Operations with the Municipality of North Middlesex; Davin Heinbuck, Water Resources Coordinator with Ausable Bayfield Conservation Authority (ABCA); Tommy Kokas, ABCA Water Resources E.I.T.; Steve McAuley, Director of Community Services, Municipality of Lambton Shores; and Chris Martin, Lambton Shores Community Emergency Management Coordinator (CEMC).