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Lecture 11

Lecture 11 .odt

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Department
Environmental Science
Course Code
EESA06H3
Professor
Nick Eyles

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EESA06 Planet Earth An Urban Planet: The Age of Construction Lecture 11 ➢ Exam  Amap will be on the exam  Know about Rodinia & Pangea  What collided with NorthAmerica during creation of Pangea ➢ Why do we do environmental science?  To apply that knowledge in the real world; make the planet more habitable  Understand how real world systems work and how WE are changing these systems; e.g. Climate  Planet is becoming a very “urban planet”  Chemical & industrial revolution  Almost 80% of world's population live in cities  Cities create urban shadow that reaches far beyond the city in terms of the need to provide resources to uban cities  Many environmental problems worldwide are due to these “supercities”  Supercities = Any city more than 10 million people  What has caused these cities to grow?  Proximity to harbor  Often a result of geology  They are often in plate tectonic areas that are active (earthquakes, volcanoes)  So the risk for natural hazards has increased  Not because there are more hazards, but because of fixed populations in active areas  Last year, more people were killed by earthquakes then by disease ➢ The Anthropocene: The Epoch of Man  Rapid Environmental Changes on the margins of urban areas  Our age is referred to as the Anthropocene = The epoch of man  We shift more sediment every year than rivers  We're changing the chemistry of the atmosphere  When did this begin to have an effect?  Industrial Revolution – late 18 century  Invention of steam engine is the real beginning of theAnthropocene ➢ Challenges of Change  Issues that environmental scientists are interested in  Hardening of water sheds  By building houses with roofs  You change the hydrology = the way in which the watershed functions  Water quantity/quality  Industrialization has contaminated huge volumes of water  Disposal of Wastes  Nuclear waste  Search for a new storage for nuclear/radioactive waste  Municipal waste (household waste) – not enough space to put it • We used to dig holes for them • But this leads to water contamination = leachate • This goes down into groundwater and thats why we dont drink groundwater in urban areas. We get water from the lake. Groundwater is not potable (water that can be safely consumed)  Industrial waste • Waterfront in Toronto • Old industrial sites with contaminants lying on the ground • They must be cleaned/remediated and this is expensive  Remediation of contaminants  Growing area in environmental science  Can't keep consuming agricultural land – we have to re-use old urban areas, some that have been uninhabited for a while  We can't drill on contaminated sites though = we might run into contaminants  You need to know what's down there first  Radon Gas  Radioactive, released from rocks like granite which contain uranium  End result is lead but in the process, radon is a daughter product  Granites are in the Shield (below us)  So there is radon beneath us seeping up through faults/fractures  Emerging problems  Natural Hazards  Landslides, tsunamis, volcanoes  Climate Warming  Biggest impact in Canada is not on urban areas since we live inside, but on the North  Permafrost = landscapes that are permanently frozen (stable for thousands of years)  Because of climate warming, the landscapes are thawing = landslides, etc  Environmental impact of resource extraction & energy supplies: oil sands, coal, etc  Alot of research is put into this – how do we get this stuff out in a reasonable manner  Environmental policy and planning  Many fields are involved: economics, business (not just geologists) ➢ Picture of 2 PhD students  Guy associated with a policy concerned with Earth effects – trying to model the geology across Toronto in 3D– for managing and protecting groundwater  Mandy  Girl is using a piezometer = a standpipe that is drilled down  Away of sampling groundwater (quality)  They have a steel casing ➢ Rate of Urbanization  1947 – Bluffs compared to 1962  HARDENING OF WATERSHED  The geographic area that contributes runoff to a stream. It can be outlined on a topographic map by tracing the points of highest elevation (usually ridge crests) between two adjacent stream valleys. The watershed of a large river usually contains the watersheds of many smaller streams. Also referred to as a "drainage basin".  The area of land that contributes water to a stream or river is called a watershed, or drainage basin. Small drainage basins generally contribute to streams, while the water from larger drainage basins come together to form large rivers  Hurricane Hazel in 1954 hit Toronto • Alot of flooding, deaths, different planning regulations • Instead of going into the ground, the water runs off into the creek  Problem with Highland Creek • Flash flooding • Flashy = means river increases after rainfall, so the whole river is eroding to it's bank • The area that contributes water to that river is completely hardened (75% urbanized) • Sediment is being moved, bridges being moved = it's expensive!  Frenchman's Bay in Pickering • Lagoon now surrounded by an urban area • The creeks that flow into the lagoon (watershed) has been truncated by urban structures (Hwy 401) • All the rivers flow towards Lake Ontario but the roads are going parallel to the shore • Once one of the creeks cross the transportation area(corridor), that water becomes brackish • Brackish = mixture of fresh water & salt water; not quite sea water; organisms can't live in it • Caused by road salt • Climate problem • This watershed receives 7000 tons of road salt every winter • Half of that gets flushed off and ends up as surface runoff directly into the lagoon • Other half goes down into the ground and mixes with groundwater – which is why you can't drink it because it has a high amount of chloride • If we stop using road salt now, it would take about 100 years for it to fully be cleared • You can go in summer and you can still measure brackish water in creeks because groundwater emerges as springs • In some areas sand is used instead of salt (salt won't work up North cause its too cold) • Salts are important though for road safety • Magnetic properties of sediments on the floor of the lagoon • Blue = not magnetic • Red = magnetic • Alot of these sediments are man-made that run off roads = these are more magnetic • Tire wear • Rubber contains cadmium • Everytime somebody breaks on that highway, the breakpads are wearing • It's all falling out on the surface and when it rains it all flushes down = problem •  Watersheds Under Pressure  Quality/Quantity  Quantity is especially problematic inAlberta (dry area)  Alberta experiences major droughts – characteristic of the climate  Scarce water supplies that will only
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