Watershed Conditions Statements

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.
The last significant rainfall in the Rideau River watershed on June 5 caused streamflows to increase and helped crop growth, but the effect has worn off and the lack of rain since has once again left flows dropping and crops in need of more water. Rainfall recorded at Kemptville indicates that the Moderate Drought severity has been reached in the southern parts of the watershed. However, the drought severity overall in the watershed is still Minor but is expected to reach Moderate status late next week. Forecast rain next week is not expected to have a significant impact. Streamflows increased…
Rain on June 5 was sufficient to improve the drought status to minor severity on the Rideau watershed. Streamflows and water levels increased as a result of the rain from about 10 percent of normal for the time of year to 50 percent. However, such flows are typically seen in mid-July to early August. Little rain is forecast for the next two weeks which means that water levels can be expected to drop noticeably throughout the watershed again.
With little effective rainfall on the Rideau watershed for the last two months, the drought status is now moderately severe. Except for some intense rainfall in the downtown core of Ottawa last Friday and Saturday, conditions have continued to be very dry in the Rideau River watershed. Rainfall recorded at Environment Canada climate stations over the last three months is now at 60% of normal for the time of year. This means that Moderate Drought status has been reached.
With no rain over the last ten days and less than 30% of normal for the last 30 days, the Rideau River watershed is on the verge of minor drought conditions. Precipitation measured at Environment Canada climate stations in and around the watershed show that about 80% of normal for the time of year has fallen in the last 90 days. This means that minor drought status has been reached. Municipal watering restrictions could be imposed to limit the volume of water extracted from groundwater and surface water sources. It is recommended that those living in residences served by private…
With a definite declining trend of the water levels of Bobs Lake and Christie Lake, the Flood Watch that has been in effect specific to those lakes since April 11 is now cancelled. With little precipitation over the last two weeks and, therefore, declining inflow to contend with, Parks Canada staff have been able to gradually bring the levels of both lakes back down to target operating ranges. Water levels in the rest of the watershed are also decreasing and are close to averages for the time of year. However, the water is still relatively high and is cold. Caution…
The focus of this message is potential flooding issues on Bobs and Christie Lakes in the upper end of the Tay River watershed, part of the Rideau River/Canal system. Bobs Lake has levelled off over the weekend as inflows were reduced by colder temperatures. Runoff from the snow that fell overnight along with rain showers today and Tuesday will prolong the high water levels. No precipitation along with more spring-like temperatures are forecast for the rest of the week beyond Tuesday. This can be expected to bring a decline in levels on both Bobs and Christie Lakes.
An unusual amount of snow for this time of year is expected to cause lake levels in the upper part of the Rideau River watershed to rise as the snow melts over the next several days. Water levels can be expected to increase throughout the watershed but levels to flood stage could occur on Bobs and Christie Lakes. With the level of Bobs Lake close to the Full Supply Threshold, water has to be released. However, the release is being done as gradually as possible to minimize the impacts on both lakes. While levels are likely to increase downstream of…
Flows in all watercourses in the Rideau River watershed can be expected to increase through today as a result of a significant rain event. Forecasts of heavy rains today in the province east of Georgian Bay will have an impact on the Rideau River watershed. With rainfall in the order of 30 mm possible, flows can be expected to increase again to similar flows as what was reached earlier in March. This could once again bring flooding of the lowest lying areas along rivers and streams and on lakes and ponds.
Flows in all watercourses in the Rideau River watershed increased through the weekend and may have peaked on Monday. However, with rain forecast for tomorrow, flows may rise slightly higher by Wednesday night than what was reached yesterday. This could bring flooding of the lowest lying areas along streams. Below freezing temperatures are forecast for Friday and into next week. This freeze-up will cause water levels to decline quickly. With the changing water levels and ice formation due to the colder temperatures, caution around water is advised and children need to be warned of the risks.
An unusually warm string of temperatures that are forecast to continue through next week are rapidly reducing the snowpack. Flows in all watercourses have increased significantly over the last two days. This increase will continue through the weekend until the snow cover is gone on Sunday night. Further increases in water levels will depend on whether or not the 10 to 20 millimetres of rain presently forecast for Monday to Wednesday occurs and when it falls. The impact of the melt and rain is expected to be a peak flow on March 17 in the order of 280 cubic metres…
March 03, 2016

Spring Outlook

Winter 2016 took an unusually long time to arrive and has had trouble staying. Now it looks like it may be leaving early. A record snowstorm on February 16, some rain on the 24 followed by cold has made for a frosty start to March. Conservation Authority staff measured the snow on the ground on March 1 finding the depth and water equivalent to be slightly above the historical average. The snow that fell on Tuesday night and into Wednesday has increased the snowpack to about 25 percent above normal for the time of year. Weather forecasts indicate that temperatures…
A mix of precipitation forecast for tonight through to Thursday can be expected to cause some increase in levels in in all watercourses throughout the Rideau River Valley. It is unclear what will be the predominant form of precipitation that will fall over the next two days. If it is mainly rain, much of that will be retained in the snowpack but some runoff can be expected to occur and water levels will increase on all watercourses.
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Contact Us

Address:
Rideau Valley Conservation Authority
3889 Rideau Valley Drive
Manotick, Ontario K4M 1A5

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

Email:
info@rvca.ca

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

Member of: conservation ontario