In this session we will explore topics incdluing the formation of the Great Lakes watershed & current threats to the Great Lakes ecosystem. The Great Lakes will also be discussed in terms of global freshwater & challenges facing the world's freshwater supply.

1. Great Lakes & Global Freshwater INLAND SEAS EDUCATION ASSOCIATION Protecting the Great Lakes Through Education

2. Picture by Google Earth

3. Distribution of Earth’s Water Icecaps & Glaciers68.7% Ground Water 30.1% Salt Water 97% Fresh Water 3% Other 0.9% Rivers 2% Surface Water 0.3% Lakes 87% Swamps 11%

8. The Great Lakes Superior Michigan Huron Erie Ontario

9. Lake Superior Largest of the Great Lakes & 2 nd largest lake in the world. Deepest (max = 1,333 ft.) and coldest of the Great Lakes. So large that it could contain all of the other Great Lakes PLUS three more Lake Eries! Retention time of 191 years . Soo locks – first Canadian built 1797 (destroyed War of 1812), US built 1855 (now there are 4 locks) Superior

10. Lake Michigan Michigan Second largest Great Lake by volume. Shores lined by the worlds largest freshwater sand dunes. Maximum Depth 925 ft. Retention time of 99 years. Chicago Ship & Sanitary Canal (1887-1922)

11. Lake Huron Huron Third largest Great Lake by volume. Longest shoreline of the Great Lakes, including the shorelines of its 30,000 islands Maximum Depth 750 ft. Retention time of 22 years.

12. Lake Erie Erie Smallest Great Lake by volume. Warmest, shallowest, & most biologically productive of the Great Lakes. (part of the central basin goes anoxic in summer). Most densely populated Great Lake & is exposed to the greatest effects from urbanization & agriculture. Maximum depth 215 ft (average depth only 62 ft). Retention time of 2.6 years. Erie Canal (1825) connects Lake Erie to Hudson River.

13. Picture by Google Earth Niagara Falls

14. Lake Ontario Ontario Smallest Great Lake by surface area but much deeper than Lake Erie (average depth 283 ft, maximum depth 802 ft). Lies 325 feet below Lake Erie at the base of the mighty Niagara Falls. Welland Canal (4 canals built 1829-1932) connects Lake Ontario to Lake Erie, Trent-Severn Waterway (44 locks built 1833-1920) connects Lake Ontario to Georgian Bay. Retention time of 6 years.

16. Map provided by The Watershed Center Grand Traverse Bay

22. Map provided by the EPA Great Lakes National Program Office

25. What Can We Do?