Displaying items by tag: snowmelt

WCS – R03/2021

March 8, 2021 –The winter of 2020-21 is quickly coming to an end. After a mild start, February brought cooler temperatures. The watershed saw a significant rain event in late December, followed by below normal precipitation in January and above normal precipitation in February. Current conditions recorded at several RVCA and Parks Canada snow course sites are indicating normal water content amounts in the snow for this time of year. In general, water levels on lakes and flows in the streams are presently below normal for this time of year.

The current short-term weather forecast indicates a warm week ahead with daytime high temperatures well above zero from Tuesday through at least next weekend and night-time low temperatures also above zero on Wednesday and Thursday. The forecast indicates some but no significant precipitation this week.

If the temperatures come as forecast, a significant amount of the snow is expected to melt across the Rideau Valley watershed which will make water levels and flows rise quickly and may result in flooding for low lying areas along all waterways, especially near small creeks and streams. Parks Canada staff who manage the water levels for the Rideau Canal have indicated that the levels in lakes are expected to rise in the upper watershed lakes as the snowpack begins to melt.

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: City of Ottawa information at 311).

With the rising water levels that can be expected over the coming weeks, ice cover on lakes, ditches, local streams, and rivers will 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. 

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

This watershed conditions statement is in effect until March 31, 2021, at 5 p.m. and will be updated at that time unless the forecast or conditions change.

"Rideau Valley Conservation Authority is a partnership of municipalities within the Rideau Valley watershed created under the Conservation Authorities Act to deliver a range of programs in watershed management and natural resource conservation."

 RVCA Watershed Conditions Statements:

• Water Safety – High flows, unstable banks, melting ice or other factors that could be dangerous for recreational users such as anglers, canoeists, hikers, children, pets, etc. Flooding is not expected.
• Flood Outlook – Early notice of the potential for flooding based on weather forecasts, calling for heavy rain, snow melt, high winds or other conditions that could lead to high runoff, cause ice jams and/or lakeshore flooding or erosion.
• Flood Watch – Flooding is possible in specific watercourses or municipalities. Municipalities, emergency services and individuals in flood prone areas should prepare.
• Flood Warning – Flooding is imminent or already occurring in specific watercourses or municipalities.

March 25, 2021­ - Above normal temperatures in March have melted most of the snow across the Rideau Valley watershed. The snow melt was quite rapid at first causing water levels and flows to rise quickly in some areas. This was followed by a more gradual melt of the remaining snow. For the most part, water levels and flows are about normal for this time of year and are well below flood thresholds.    

The short-term forecast is calling for rainfall amounts of between 40 to 50 millimetres between Thursday and Sunday, with heaviest rain on Friday, and cooler temperatures but still above zero. If the rain comes as forecast, water levels and flows will increase again across the Rideau Valley Watershed. As such, an updated FLOOD OUTLOOK is in effect due the possibility of flooding for all low-lying areas along all waterways, especially near small creeks and streams. Parks Canada staff who manage the water levels for the Rideau Canal have indicated that the levels in the upper watershed lakes are currently below average and expected to rise but not to flood levels.

Further to the above, a FLOOD WATCH is in effect for the low-lying areas along Stevens Creek and Taylor Drain in the Village of North Gower. If the rain comes as forecast, water levels may be similar too, or possibly higher than, those already observed this spring.

With the rising water levels expected over the coming days, the remaining ice cover on lakes, ditches, local streams, and rivers will be unstable. In addition, ice cover in the rivers and streams may breakup as a result of warm temperatures and higher flows, increasing the risk of ice jams and associated overbank flooding. Extreme caution should be exercised by everyone when near local waterbodies. Parents should inform their children of the risks and provide appropriate supervision. 

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

This watershed conditions statement is in effect until April 15, 2021, at 5 p.m. and will be updated at that time unless the forecast or conditions change.