The term freshet is commonly used to describe a large increase of water discharged in a river during spring months due to snow melt and sometimes rainfall. This can lead to seasonal flooding in low lying areas along rivers. The Ottawa River watershed, at approximately 146,000 km2, is an extremely large river system that experiences flooding to some degree every spring. The Ottawa River watershed conveys water from many rivers including the Rideau River. The Rideau River spring freshet typically peaks in advance of the Ottawa River. As Members of Council are aware, the Ottawa River basin experienced above average amounts of rainfall and snowpack during the peak of the freshet in past years, and as a result, the City experienced prolonged flooding events, which required large-scale responses from residents, City staff and community partners.
The City of Ottawa has established a Spring Freshet Taskforce each year since the 2017 freshet. The goal of the taskforce is to prepare for, monitor and respond to the needs of residents across the city. Much of the planning and operational response focuses on communities and city assets known to be impacted by seasonal flooding along the various rivers within the city, but especially along the Rideau River and Ottawa River.
Each year, sandbag filling stations are created for the benefit of residents who experience flooding on their properties. These stations are installed in locations that are convenient to affected communities. Updates on sandbag stations will be provided on both the Spring Maintenance and Flood Control and Spring Flooding 2023 pages of Ottawa.ca.
The City of Ottawa experienced significant flooding in 2017 and 2019. The freshets experienced in each of these years required the mobilization of a significant number of City resources, volunteers, provincial support, and in 2019, a request for support from the Canadian military. Based on the experience derived from previous planning, preparedness, and response activities since 2017, the City’s Spring Freshet Task Force is now led by the Public Works Department. The Office of Emergency Management within the City’s Emergency and Protective Services (EPS) Department is part of the Task Force. Should conditions in any year escalate, such that there is significant flooding requiring a City-wide emergency response, the lead department would pivot to EPS to coordinate that response through the Emergency Operations Centre. This approach ensures that operational control resides with the department responsible for the majority of the early seasonal freshet preparation activities (Public Works Department) and that operational responses are coordinated through an emergency response structure, if required (Emergency and Protective Services). The taskforce will partner with other City departments to ensure the needs of City services are considered, including Infrastructure and Water Services on flood protection of the Lemieux Island and Britannia water treatment facilities.
The Public Works Spring Freshet Taskforce is actively working with external partners to monitor water levels, which are currently normal or close to normal along the Ottawa River basin. Accordingly, there is no river flooding in the forecast right now, although this could change as we approach the pending spring freshet period. In preparing for the possibility of seasonal flooding, the taskforce is leveraging the lessons learned from previous freshet years.
The work of the 2023 PW Freshet Taskforce will also include:
▪ Completion of the Rideau River Flood Control program. The Rideau River Flood Control (RRFC) operations have begun in partnership with the Rideau Valley Conservation Authority, to closely monitoring ice conditions and water flow. Controlled blasting operations took place between the Minto and Sussex bridges which were at risk of ice jams, this will allow the water to flow unrestrictedly and to alleviate possible spring flooding. The team continues to monitor conditions.
▪ Developing communications in partnership with Public Information and Media Relations to ensure the PW spring flood control webpage, Spring Freshet webpage and freshet Twitter accounts are updated and shared with the public.
▪ Collaborating with other City services to ensure the protection of critical infrastructure including City Water Treatment Plants and City facilities are considered as part of preparedness activities; and
▪ Implementing revised operational and tactical procedures for the appropriate deployment of assets into communities for ease of access and early support as required.
Public Works will continue to deliver on all core services which include early freshet response activities. As mentioned previously, the Office of Emergency Management are directly engaged and will be prepared to mobilize and coordinate a City-wide response, as required.
With support from our partners in PIMR, Ottawa residents are encouraged to follow the City’s social media channels for updates, and to visit the Spring Flooding 2023 page for timely information.