200 likes | 343 Views
What do you know about Lake Michigan?. " Michi-gama " "large lake”. How were the Great Lakes formed?.
E N D
How were the Great Lakes formed? • The Great Lakes were formed nearly 20,000 years ago when the earth's climate warmed and the last glacial continental ice sheet retreated. The glacier, up to 2 miles thick, was so heavy and powerful it gouged out the earth's surface to create the lake basins. Meltwater from the retreating glacier filled the newly created basins. Approximately 3,500-4,000 years ago, the Great Lakes attained their modern levels and area.
What a Relief! • With the weight of the heavy glaciers gone, the bed of the Great Lakes continues to rise at a rate of 7.5 cm every 100 years!
Lake Michigan Water Levels • http://www.doorcountyadvocate.com/article/20130109/ADV01/301090304/Lake-Michigan-sets-new-record-low
Great Lake Facts • The Great Lakes have 90% of US fresh water, and 18% of the worlds fresh water (only the polar ice caps hold more of the worlds fresh water). • Provides drinking water for 40 million people. Provides 56 billion gallons of water per day for municipal, agricultural, and industrial use. • Spread evenly across the contiguous 48 states, the lakes' water would be about 9.5 feet deep.
Great Lakes Watershed Covers an area the size of France
The Lake Michigan basin is the area of land where rivers and streams all drain into Lake Michigan.
37 million people live in this area • Chicago processes almost a billion gallons of Great Lakes water each DAY! Wastewater is sent to the Gulf of Mexico • Only 1% of the water in the Great Lakes system is replenished each year; the remaining is a one time gift from the glaciers.
The Chicago Sanitary & Ship Canal drains 2.1 billion gallons of water from the Lakes into the Gulf of Mexico every day!
Lake Michigan Facts • Lake Michigan is the third largest of the Great Lakes and ranks as the fifth largest lake in the world. • Deepest Point is 923 feet • Lake Michigan beach closings • 2003 – 1,473 • 2002 – 919 • 1996 – 182
Deepest Point • 923 feet
Lake Effect Weather • Keeps Chicago • Cool in the summer • Warm in the winter • Lake Effect Snow
Invasive Species • Since the 1800s, more than 160 aquatic invasive species have become established in the Great Lakes.