Test 2 Flashcards
What do we value more than water?
Land
How much of the world’d water is in the great lakes?
20%
St. Lawrence Contamination
- Half of beluga whales have cancer
- Not from chemicals dumped in St. Lawrence, river was already dirty when they got there
How long does it take for water to get from Lake superior to St. Lawrence, and what is this times significance?
- Takes 350 years for water to get from lake superior to St. Lawrence
- when European settlers came (something so long ago affects lakes now)
What is a ‘great lake’
Lake over 500km^2
How many great lakes are there worldwide?
250, but now only 241 in the modern world because some shrinking, therefore losing their categorization
What fraction of water in Canada is made up by the Great Lakes?
1/3
Why are the great lakes called the Laurentian great lakes?
because laurentian ice sheet created them
What are the great lakes in Canada?
HOMES
Huron, Ontario, Michigan, Erie, Superior
Watershed
Area which river flows into great lake (area around lakes)
Outside of basin -> river flows to other little lakes
295,000 miles^2, or 764,051 km^2
Shoreline
12,100 miles, or 20207 km
6850 (about half) in Ontario and Quebec
5270 miles in the 8 US states - therefore have to make regulations with these 8 states
Volume of Water in The Great Lakes
23 000 km^3
Surface Area of Great lakes
244 000 km^2
What is the largest system of fresh surface water on Earth
The Great Lakes, provides 18% of worlds fresh water supply
Outflows in the great lakes basin
less than 1% per year, therefore pollutants that enter system stay in the system
Where does pollution occur first before affecting the water?
occurs on watershed, and then affects water
What percent of the worlds total water is fresh water vs salt water?
- 5 % salt water
2. 5% is fresh water
Distribution of Fresh Water (2.5% of Global Water)
69% glaciers and permafrost snow cover
30% fresh water
0.9% other, including soil moisture, ground ice/permafrost and swamp water
0.3% freshwater lakes and river flows
Drainage
Lake Superior and Lake Michigan, east through Lake Huron, Lake St. Clair, Lake Erie, Lake Ontario, to the St. Lawrence and Atlantic Ocean.
(West to East) !!
- superior and Michigan simultaneously into Huron
The Great Lakes Basin
- edge of watershed is the border around lakes
- anything in great lakes gets around watershed
- how pollution eventually end up in St, Lawrence and hurt whales
Where does London get its water? Describe the cycle.
From Erie and Huron
Water goes homes -> sewage plants -> cleaned into thames river
How were the great lakes formed? - The Wisconsin Period
- began 70,000 years ago
- ice picked up clay, sand, gravel, boulders
- As ice moved it shaped the landscape
withdrew 14,000 and 15,000 years ago
massive meltwater = ancestral lakes - clay, sand, gravel and boulders formed hills, ridges and moraines
Shape of the lakes has evolved due to:
- Retreat of Glaciers
- Topography surrounding the lakes
- Gradual tilting of the earth’s crust (major factor since glaciers retreat)
Ongoing Evolution of the Great Lakes (continue to alter the shape and size of the Great Lakes:
- crustal tilting, shore erosion, climate change
- climate change: more storms, more erosion, more erosion, more evaporation (warmer weather, less season changes where lakes freeze (if water isnt frozen, it can evaporate)
