PROVINCIAL LOW WATER LEVELS CONDITIONS REPORT

PROVINCIAL LOW WATER LEVELS CONDITIONS REPORT

Update for November 30, 2003

Region	Precipitation (monthly)¹		Flows (monthly)²
MNR Southern (previously referred to as Southcentral)	To date (Dec 4, 2003), watersheds in 5 Conservation Authorities (CA) are in a confirmed Low Water condition - All are at Level I³: (Catfish Creek, Grand River, Kettle Creek, Long Point Region, Quinte). Southern Ontario overview: Most stations reported above 80% of the average precipitation for November¹. In the west (west of Toronto Region, north to Georgian Bay) Most stations reported above 80% of the average precipitation for November. Centrally, (north of the west half of Lake Ontario) All stations reported above 80% of the average precipitation for November. In the east (north and east from Prince Edward Region) All but three stations reported above 80% of the average expected precipitation for November. 18 month precipitation: Almost all stations reported greater than 80% of the average expected precipitation for the period June 1, 2002 through November 30, 2003 with the exception of 2 stations in the Aylmer District. 3 month precipitation: Most stations reported above 80% of the average expected precipitation for the period September 1 through November 30. As of December 4, the Provincial Response Centre is forecasting 2 to 4mm of water equivalent in mixed precipitation over the next 5 days.		All stations reported flows well above 70% of average using the criterion² for streamflow. Several stations experienced flows at or near critical levels during the month of November. Flood Potential: Immediate flood threat is currently MODERATE to HIGH through the eastern portion of the region. Rainfall in combination with frozen ground/saturated soil conditions and high streamflows or rapid melt of accumulated snow pack could lead to flooding in some water courses.
	Average Historical Precipitation Overall average November precipitation ranges from 60 mm to 120mm Most stations range from 70mm to 100mm Environment Canada Winter Outlook (December, January, February)⁵ Near normal precipitation for all of southern Ontario with below normal in the eastern most portion of the province. Near normal temperatures for all of southern Ontario.
MNR Northeast	Most stations reported greater than 80% of the average precipitation expected for November¹ 18 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period June 1, 2002 through November 30, 2003. 3 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period September 1 through November 30. Northeastern Ontario is forecast to receive 4 to 6 cm of snow over the next 5 days.	All stations reported flows well above 70% of average using the criterion² for streamflow. Flood Potential: Immediate flood threat is currently MODERATE to HIGH for the southern portion of the region. Rainfall in combination with frozen ground/saturated soil conditions and high streamflows or rapid melt of accumulated snow pack could lead to flooding in some water courses.
	Average Historical Precipitation Ranges from 60 mm to 100 mm for November for most stations Environment Canada Winter Outlook (December, January, February)⁵ Above normal precipitation for the western most portion of the northeast, near normal for the remainder. Near normal temperatures for all of northeastern Ontario.
MNR Northwest	One MNR District is in a confirmed Level I low water condition: Dryden Most stations reported above 80% of the average precipitation expected for November¹. Two stations in the west and several in the Thunder Bay area reported below 40%. 18 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period June 1, 2002 through November 30, 2003. 3 month precipitation: Most stations reported greater than 80% of the average expected precipitation for the period September 1 through November 31. Northwestern Ontario is forecast to receive 4 to 10 cm of snow over the next 5 days.	All stations reported flows above 70% of average using the criterion² for streamflow with the exception of one in Fort Frances. Flood Potential: Immediate flood threat is currently low. Long term flood threat would be from significant or heavy rainfall.
	Average Historical Precipitation Ranges from 35 mm to 55 mm for November for most stations. Environment Canada Winter Outlook (December, January, February)⁵ Near normal precipitation for all of northwestern Ontario. Near normal temperatures for all of northwestern Ontario.
Great Lakes⁴
November Conditions	Levels of Lake Superior, St. Clair and Erie declined by their usual amounts during November. An above average supply of water to the Great Lakes resulted in a rise for Lakes Huron-Michigan and Lake Ontario rather then the expected seasonal decline. Great Lakes basin precipitation for November was about 134% of average. Lakes Superior, Huron-Michigan, Erie and Ontario basins received 81%, 164%, 117% and 146% of average precipitation, respectively During November, with the exception of Lake Ontario, the monthly mean levels of all of the Great Lakes remained below average. The levels of Lakes Superior, St Clair and Huron-Michigan remained significantly lower than one year ago, while the level of Lakes Ontario and Erie (only slightly) were higher than 1 year ago. Lake Huron-Michigan remains significantly below chart datum despite the Novembers rise.
Outlook⁵	Lakes Huron-Michigan are not expected to rise above chart datum until late spring/ summer. Lake Superior is expected to drop below chart datum in December. Levels of Lakes Huron-Michigan, St. Clair and Erie are expected to remain relatively static rather than follow their seasonal decline over the next 3 months. Lake Superior will continue to seasonal decline over the next 4 months. With the exception of Lake Ontario, levels of all the Great Lakes are expected to remain below the monthly mean over the next 6 months. Lake Ontario levels are expected to rise above average in January/February .

^{1Environment Canada’s synoptic stations are equipped to measure snow. Precipitation gauges from dataloggers often are not set up to measure snow adequately. The resulting errors plus the elimination of many of the readings for these gauges means our precipitation coverage is poor during months with snow.

²For each gauge used in the analysis the average flow is calculated for July, and August and September from the historical record. The minimum of these three values is compared to the past month’s average flow. During the winter months most streams are partially filled or covered over with ice. This ice reduces the cross-section of the stream resulting in flow readings that are higher than actual. This error is corrected in the historical record. Thus the observed, relative to the historical minimum, is also higher than the actual in streams with significant ice conditions.

³ Level I conditions initiate the formation of a Water Response Team (WRT) which encourages a voluntary 10% reduction in water use. At Level II the WRT encourages a further 10% reduction by restricting non-essential water use; level III represents the condition where there is insufficient supply of water to meet all needs which July result in regulation of water use.

4Great Lakes summary includes information from Environment Canada, Great Lakes - St. Lawrence Regulation Office and the Detroit District U.S. Army Corps of Engineers.

5Outlook provided by Environment Canada. Environment Canada has assigned very low confidence to this season’s precipitation Outlook across the province and medium confidence to the temperature Outlook.

Brent Smith
Surface Water Policy and Program Officer
December 4, 2003}