RVCA - Watershed Conditions Statement - March 9, 2023

Spring Outlook - With High Snowpack, Be Prepared for Spring Flooding Across the Rideau Valley

RIDEAU VALLEY, March 9, 2023 – The winter of 2022-23 is quickly coming to an end, and RVCA’s Flood Forecasting team is working closely with its municipal and agency partners to prepare for potential spring flooding. As discussed below, it is important to be prepared for possible flood conditions over the next few weeks as spring returns to the Rideau Valley watershed.

Current conditions:

• This winter has been unusually mild with some rain events and approximately 300 cm of snow fallen to date in the Ottawa area. The snowpack varies throughout the Rideau Valley Watershed, but in general the water content in the snow is near average for the upper and middle parts of the watershed and above average for the lower part of the watershed (Ottawa area).
• Due to the mild weather and rain throughout the winter, water levels on some upper watershed lakes are presently above normal for this time of year (i.e., Wolfe & Christie Lakes). Parks Canada staff who manage water levels for the Rideau Canal will closely monitor these water levels and have indicated that the levels are expected to rise in the upper watershed lakes as the snowpack begins to melt.
• The current short-term forecast indicates limited precipitation and seasonal temperatures (slightly above zero temperatures during the day and below zero at night); however, we know the daily temperature will begin to increase and there will likely be some rain as we move through March.
• City of Ottawa crews have begun the annual ice removal program on the Rideau River between Rideau Falls and Bronson Avenue. Crews will work to keep the ice from reforming until the spring freshet occurs (For more information: call City of Ottawa’s information line at 311).

What does this mean for flood potential?

• Based solely on the fact we have above-average snow water content and above-normal water levels in some upper watershed lakes, there is potential for above-average flooding this spring across the Rideau Valley watershed, especially in low-lying areas which have flooded in the past.
• Precipitation and temperature are two other key factors influencing actual flood conditions as we move through March and into April, which staff will monitor closely.
• The short-term forecast suggests a slow melt with little precipitation, which is favourable for limited flooding for at least the first half of March.

With changing levels expected over the coming weeks, ice cover on lakes, ditches, local streams and rivers will continue to be unstable. Extreme caution should be exercised by everyone when near local waterbodies. Parents should inform their children of the risks and provide appropriate supervision. 

As the temperatures start to warm up, ice jams are possible in local streams and rivers, as flows could quickly increase before the ice can melt. Residents are advised to monitor their local waterbody closely for signs of ice jams as spring progresses. RVCA staff will be monitoring conditions, but we always welcome observations from watershed residents.

Potential flooding along roadways is also a concern due to current snow/ice buildup on roadside ditches and some roads.

Residents in flood-prone or low-lying areas historically susceptible to flooding should take the necessary precautions to protect their property, such as:

• Ensuring sump pump is clear, in good working condition and has a backwater valve
• Ensuring easy access to a portable backup generator and pump
• Ensuring downspouts are clear and the outlet is at least 3 metres from the dwelling
• Securing items that might float away as flows increase
• Removing valuable items from basements or lower floors that could be subject to flooding
• Keeping emergency phone numbers handy
• Familiarizing yourself with your municipality’s Emergency Preparedness Plan

More information including our Flood Contingency Plan and real-time water level and stream flow data can be found at www.rvca.ca/watershed-conditions.

This watershed conditions statement is in effect until March 24, 2023 at 5 p.m. and may be updated at that time unless the forecast or conditions change.