Watershed Conditions Statements

Sporadic and random rainfall over the last week was not enough to bring the Rideau River watershed out of the Severe Drought status reached in mid-August Previous rain in August did cause flows and levels to increase but only for a brief period. With rain coming in small cells that affected very limited areas, levels have quickly declined again. Forecast for this week has a total of 20 millimetres possible that will not have a significant impact.
Despite the recent rainfall, the Rideau Valley remains in a Severe Drought Status. The 90-day accumulation of rainfall recorded at Environment Canada climate stations in and around the Rideau River watershed has increased to an average of 82 percent of the historical average. The 30-day accumulation is about 99 percent.
Based on the 30 Day Precipitation drought indicator, the Rideau River Watershed is in the “Severe” Drought category. There has been no rain recorded at the Ottawa Airport since July 25. Some rain has been recorded at other locations in and around the watershed but there have not been the several days of rain needed to restore the deficit that has accumulated. There is rain forecast through Friday and Saturday but that is expected as thunderstorms which will not produce the needed general rain over the whole watershed. Warm weather is forecast to continue through next week which will cause…
With little rain over the last two weeks, the Moderate Drought conditions continue in the Rideau watershed. The accumulated precipitation over the last 90 days is less than 60% of the long term average for this time of year which is the threshold for Moderate Drought. No significant rain is presently in weather forecasts for the next week but hot temperatures are. This means that evaporation will be a significant component of the water level decline process throughout the watershed.
The precipitation indicator for Moderate Drought of 60% of normal was reached last Sunday. Rainfall since then has had a minimal impact and conditions remain very dry. Flows in the Rideau River at Ottawa are at 25% of normal for the time of year. Two of the major tributary streams, Jock River and Kemptville Creek, are both flowing at about 6% of normal. The Tay River is in relatively better shape benefitting from outflow from Bobs Lake, one of the Rideau Canal reservoir lakes. Smaller streams are intermittent or dry and aquatic habitat is compromised for all species.
With no rain until Monday in weather forecasts, it is expected that the drought status for the Rideau River watershed will pass the threshold from Minor to Moderate Severity by Sunday. The amount of rain forecast for Monday will do little to reverse the trend of deepening drought. Flows in the Rideau River at Ottawa are 15% of normal for the time of year. Larger tributary streams are about 6% of normal and many small streams are intermittent or dry. Aquatic habitat is becoming limited for all species.
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Address:
Rideau Valley Conservation Authority
3889 Rideau Valley Drive
Manotick, Ontario K4M 1A5

Phone:
613-692-3571, 1-800-267-3504

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Monday to Friday, 8:30 a.m. to 4:30 p.m.

Member of: conservation ontario