PROVINCIAL LOW WATER LEVELS CONDITIONS REPORT

PROVINCIAL LOW WATER LEVELS CONDITIONS REPORT

Update for December 31, 2003

Region	Precipitation (monthly)¹		Flows (monthly)²
MNR Southern (previously referred to as Southcentral)	To date (Jan 6, 2004), watersheds in 3 Conservation Authorities (CA) are in a Level I³ confirmed Low Water condition: (Catfish Creek, Grand River, Kettle Creek). Southern Ontario overview: Most stations reported above 80% of the average precipitation for December¹. In the west (west of Toronto Region, north to Georgian Bay) Several stations reported precipitation below 80% of the average precipitation for December, with an additional site reporting below the 60% threshold. Centrally, (north of the west half of Lake Ontario) All but one station reported above 80% of the average precipitation for December. In the east (north and east from Prince Edward Region) All stations reported above 80% of the average expected precipitation for December. 18 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period July 1, 2002 through December 31, 2003, with the exception of one station in the Aylmer and Midhurst District. 3 month precipitation: All stations reported above 80% of the average expected precipitation for the period October 1 through December 31. As of January 6, the Provincial Response Centre is forecasting 10 to 20cm of snow and 10 to 20cm in local accumulations 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 December. Flood Potential: Moderate to high due to rapid freezing and super cooling of water leading to the formation of frazil ice.
	Average Historical Precipitation Overall average December precipitation ranges from 60 mm to 115mm (water equivalent) Most stations range from 80mm to 105mm 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	All but one station reported greater than 80% of the average precipitation expected for December¹ 18 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period July 1, 2002 through December 31, 2003. 3 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period October 1 through December 31. Northeastern Ontario is forecast to receive 5 to 10cm of snow and 5 to 15cm in local accumulations over the next 5 days.	All stations reported flows well above 70% of average using the criterion² for streamflow. Flood Potential: Moderate to high due to rapid freezing and super cooling of water leading to the formation of frazil ice.
	Average Historical Precipitation Ranges from 55 mm to 75 mm for December 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 remains are in a Level I³ confirmed Low Water condition: Dryden Most stations reported above 80% of the average precipitation expected for December¹. One station in the west reported below 80% and one station 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 July 1, 2002 through December 31, 2003, with the exception of one station in the west. 3 month precipitation: Several stations across the west reported below 80% of the average expected precipitation for the period October 1 through December 31, with one station in Fort Frances and Thunder Bay area each reporting below 40%. Northwestern Ontario is forecast to receive 1 to 4 cm of snow over the next 5 days.	Most stations reported flows above 70% of average using the criterion² for streamflow with the exception of one in each of Dryden and Sioux Lookout. Flood Potential: Moderate to high due to rapid freezing and super cooling of water leading to the formation of frazil ice.
	Average Historical Precipitation Ranges from 25 mm to 40 mm for December 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
December Conditions	Levels of Lake Superior declined by their usual amounts during December. An above average supply of water to the Great Lakes resulted levels rising on Lakes St. Clair, Erie and Ontario more than their normal amounts, while Lake Huron-Michigan did not decline by as much as anticipated. Great Lakes basin precipitation for December was about 96% of average. Lakes Superior, Huron-Michigan, Erie and Ontario basins received 83%, 89%, 123% and 113% of average precipitation, respectively. During December, with the exception of Lake Ontario, the monthly mean levels of all of the Great Lakes remained below average. Only Lake Superior remained significantly lower than one year ago. Lake Huron-Michigan remains significantly below chart datum despite the December 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 2 months. Lake Superior will continue to seasonal decline over the next 3 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.

^{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
January 6, 2003}