SECTION 2: High Lake Ontario Water Levels Q 2.1: What were Lake Ontarios levels prior to regulation, and since regulation?
• Regulation began in 1960. From 1918 to 1959, the long-term mean Lake Ontario level was 74.70 m (245.1 ft), with a maximum monthly mean of 75.76 m (248.6 ft) and a minimum monthly mean of 73.74 m (241.9 ft) making the total range 2.02 m (6.6 ft). From 1960 to 2008, the long-term mean level was 74.80 m (245.4 ft), with a maximum monthly mean of 75.73 m (248.5 ft) and a minimum monthly mean of 73.83 m (242.2 ft) making the total range 1.90 m (6.2 ft). The higher long-term mean level since 1960 is attributable to higher water supplies received in this period than received in the period before regulation. Had regulation not been in place, these increased supplies would have resulted in a long term mean from 1960 to 2008 of 75.09 m (246.4 ft), with a maximum monthly mean of 76.07 m (249.6 ft) in June 1973 and a minimum monthly mean of 73.78 in (242.0 ft) in December 1964, yielding a total range of 2.29 m (7.6 ft).
Related Questions
- SECTION 3: High Water Levels and Flows in the St. Lawrence River Q 3.1: Does regulation of Lake Ontario outflows make spring flooding conditions worse in the Montreal area?
- Why can Lake Ontario water levels be reduced in the fall of each year to provide a buffer against high water supplies the next spring?
- How can high or low Lake Ontario water levels affect domestic and sanitary uses?
