PROVINCIAL LOW WATER LEVELS CONDITIONS REPORT

PROVINCIAL LOW WATER LEVELS CONDITIONS REPORT

September 30, 2003

Region	Precipitation (monthly)¹		Flows (monthly)²
MNR Southern (previously referred to as Southcentral)	To date (Oct 6, 2003), watersheds in 12 Conservation Authorities (CA) are in a confirmed Low Water condition - 10 CA’s have watersheds in Level I³only: (Kettle Creek, Quinte, Ausable Bayfield, Kawartha Region, Lower Thames Valley, Nottawasaga Valley, Upper Thames Region, Long Point Region, Hamilton Region, Otonabee Region); and 2 CAs have watersheds in Level II: (Catfish Creek, Grand River) Southern Ontario overview: Most stations reported above 80% of the average precipitation for September¹. In the west (west of Toronto Region, north to Georgian Bay) Most stations reported above 80% of the average precipitation for September. Centrally, (north of the west half of Lake Ontario) Most stations reported above 80% of the average precipitation for September. In the east (north and east from Prince Edward Region) Most stations reported above 80% of the average expected precipitation for September. Two stations reported below 60%. 18 month precipitation: Almost all stations reported greater than 80% of the average expected precipitation for the period April 1, 2002 through September 30, 2003 with the exception of 3 stations in the Aylmer District. 3 month precipitation: Most stations reported above 80% of the average expected precipitation for the period July 1 through September 30. As of October 6, the Provincial Response Centre is forecasting no rain over the next 5 days.		Most stations reported flows above 70% of average using the criterion² for streamflow. Six stations reported flows below 30%. Flood Potential: Immediate flood threat is currently low. Long term flood threat would be from widespread significant rainfall.
	Average Historical Precipitation Overall average September precipitation ranges from 50mm to 100mm Most stations range from 75mm to 90mm Environment Canada Fall Outlook (September-October-November)⁵ Above normal precipitation for the eastern most portion of S. Ontario, normal elsewhere. Near normal temperatures for all of southern Ontario.
MNR Northeast	Most stations reported above 80% of the average precipitation expected for September¹ 18 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period April 1, 2002 through September 30, 2003. 3 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period July 1 through September 30 Northeastern Ontario is forecast to receive 8 to 12 mm of rain over the next 5 days.	Most stations reported flows above 70% of average using the criterion² for streamflow. One station reported flows below 30%. Flood Potential: Immediate flood threat is currently low. Long term flood threat would be from widespread significant rainfall.
	Average Historical Precipitation Ranges from 85mm to 115 mm for September for most stations Environment Canada Fall Outlook (September-October-November) ⁵ Above normal precipitation Below normal temperatures
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 September¹. Two stations in the Thunder Bay District reported below 40%. 18 month precipitation: All stations reported greater than 80% of the average expected precipitation for the period April 1, 2002 through September 30, 2003 with the exception of 1 station in the Thunder Bay District. 3 month precipitation: Most stations reported greater than 80% of the average expected precipitation for the period July 1 through September 30. Northwestern Ontario is forecast to receive 5 to 9 mm of rain over the next 5 days.	Most stations reported flows above 70% of average using the criterion² for streamflow. Two stations reported flows below 50%. Flood Potential: Immediate flood threat is currently low. Long term flood threat would be from widespread significant rainfall.
	Average Historical Precipitation Ranges from 85 mm to 90 mm for September for most stations. Environment Canada Fall Outlook (September-October-November) ⁵ Above normal precipitation Below normal temperatures

Great Lakes⁴
September Conditions	All of the Great Lakes continued their seasonal decline in September with the exception of Lake Superior which rose slightly. Lakes Michigan-Huron have not been this low at this time of year since the record lows of 1964. Great Lakes basin precipitation for September was about 106% of average. The Lakes Superior, Michigan-Huron, Erie and Ontario basins have received 102%, 90%, 166%, and 116% of September average precipitation, respectively. During September, with the exception of Lake Ontario, the monthly mean levels of all of the Great Lakes remained below average. The levels of Lakes Superior and Michigan -Huron remained significantly lower than one year ago, while the level of Lake Erie remained the same as 1 year ago. The level of Lake Ontario was higher than 1 year ago. Lake Michigan-Huron is below chart datum.
Outlook⁵	Lake Michigan-Huron is expected to stay below chart datum for the foreseeable future and there is concern that it may reach record lows by February 2004 under continued low inflow conditions (low precipitation high evaporation). Lake Superior is expected to drop below chart datum in December. Levels of all the Great Lakes are expected to continue their seasonal decline over the next 5 months. With the exception of Lake Ontario, levels all of the Great Lakes are expected to remain below the monthly mean over the next 6 months. Lake Ontario levels are expected to stay near average for the next 2 months and then drop below average for the following 4 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.

Valerie von Zuben
Surface Water Monitoring Intern

October 6, 2003}