ESS NOTES 713 20131023
GET LANDSLIDE NOTES!!
Artificial levees (raised banks) are created for protection; can naturally occur
Diagram of Mississippi river (flood of Mississippi valley – infrequent 100 yr flood event in Mississippi river;
Flood frequency are predictable: not random at all.
Most rivers have a peak flow in Spring creating high level of discharge called Spring Flood.
100 Year Flood: can be statistically defined: much larger than annual event. Helps with planning –
about the farthest limit that citizens are willing to pay for through taxes.
Ex) Winnipeg/ Red River Manitoba flood of ‘97
Means on average within a 100 year period, a high magnitude flood could occur. All about statistical
Hurricane Hazel – Oct 1954
Most severe flooding on record in ON – Toronto ’54.
Damage: City council ordinance turned ravines into parks
Some small events since then: Aug 05
Heavy rain collapses roadway on Finch Calgary flood june 2013 – floods downtown; stampeded grounds.
Huge spreads of gravel on TransCan highway
Canmore worst affected area
Water and sediment movement beneath breaking waves:
Most waves hit the beach at an angle. This sets up a circulation patterns on the beach, which carries sand
by a circular route slowly along shore.
This process is called longshore drift. Tides generate currents moving in and out of inlets. The rising (flood)
tide moves water on to the tidal flats behind the barrier island (grey areas in Slide 13). The falling (ebb) tide
drains the tidal flats and moves sediment out of the inlet, where it may form an ebbtide delta. Note also the
movement of sand by longshore drift (at right, in Slide 13) to form a spit. In most areas, tides are said to be
semidiurnal. That is, they have a period or cycle of approximately onehalf of a tidal day. The predominant
type of tide throughout the world is semidiurnal, with two high waters and two low waters each tidal day. For
example, tides along the East Coast of Florida are semidiurnal. hurricanes 20131023
Tropospheric waves cause hurricanes
Caused by temp differences between hot African landmass and cooler ocean
Hurricane and typhoon – both strong tropical cyclone
Low pressure system that develops over subtropical waters
Starts by warm ocean waters and an atmosphere that is cooling – creates unstable conditions. Occur in
Atlantic/West Africa from July Oct.
Subtropical ridge – ridge of high pressure that occupies the Atlantic ocean
Range of hurricane strengths from 1 to 5.
Hurricane Sandy only 2
Storm surge – water is pushed towards the shore by the wind as it approaches the hurricane, creates a
huge amount of friction and a huge tide
Causes massage damage
Ex) Galveston Island 1900 deadliest natural disaster in US history. hurricanes 20131023
Gulf coast susceptible to hurricane damage – vulnerable coastline
Sinking of New Orleans during Hurricane Katrina:
ground water removed for domestic use/wetland areas drained – if you remove water, itll compact and
settle. Longterm: gulf coast is an area of slow geological subsidence – mississipi river dumps large
amounts of substance out
huge effect of Gulf Coast Oil production
Hurricane Stan Guatemala – triggers mudslides
Sandy – cuba, northward to New Jersey
Hurricanes are NOT becoming more frequent – no relationship between global warming and huricanes
Damage has increased Water 20131023
Water as a commodity
97.5 water in oceans
2.5 fresh water
74% in ice caps
25% is ground water
<1% is in surface rivers and lakes
Canada has 20% of global total of surface waters
Conflicts over water ensue since it is so limited
Desalination – removes salt from water
Can be used but it is very expensive and energy intensive NOV 4 20131023
The cleanup of Collingwood Harbour, the site of a major shipbuilding industry until 1986.
Problems of urbanization
Pressure for suburban development of greenfield lands (hitherto undisturbed agricultural land) around the
edges of the city of Toronto have become almost unstoppable. There is continuing demand for less
expensive housing, especially from new immigrants to Toronto, and the development industry is only too
happy to provide it.
The Oak Ridges Moraine exemplifies the problem. Environmental activists are concerned about the unique
ecology of the area (Slide 16, 17). There are unique assemblages of plants and animals here, which are
threatened by development.
Prevents efficient recharge
Moraine: ridge of sand and gravel fromed between two ice sheets during last ice age. Is good aquifer;
tapped into many wells in GTA.
The effects of urbanization:
reduce groundwater infiltration and recharge.
Covering large areas with concrete directs runoff into storm drains, decreases the area available for
Less runoff stored in soils and aquifers
Surface runoff increases
Flood levels more severe
More recently, concern and controversy have focused on the “Big Pipe”, a major new trunk sewerage pipe
to carry waste down to the Ashbridge’s bay treatment plant in Scarborough (Slide 18). Completion of the
pipe encourages more suburban sprawl.
Construction required pumping out groundwater NOV 4 20131023
Slides 19, 20:
The Walkerton tragedy
May 2000: 2300 cases of gastrointestinal illness and 7 deaths caused by the bacterium E. coli. – pig feces
polluting ground water
Agricultural wastes had been seeping into the groundwater close to the municipal water wells.
Water testing procedures failed to detect the problem owing to local incompetence and cutbacks by the
Government of Ontario.
No quality difference; sustainability of rates of groundwater consumption; contaminants; not fluoridated;
plastic is a carcinogenic; plastic is wasteful use of petrochemical feedstock; pay 300 to 3000 times more
Things the individual can do.
Spread knowledge of water shortage impending
Support improved govt water testing
Oppose water exports
Drink tap Lecture 9 20131023
Metals, Minerals and Mining
mineral resource: is any element, compound, mineral, rock or aggregate that can be extracted from the
ground and has potential economic value
ore: is an aggregate from which a substance may be extracted profitably because of its concentration. It
typically consists of a body of rock, most of which has no value, but within which a valuable mineral is
present in greater than normal concentrations.
ore deposit: is therefore the body of rock containing a valuable concentration of a valuable mineral.
Gangue: is the nonvaluable rock in which the ore minerals occur. Typically this is discarded after ore
extraction and/or concentration as a pile of tailings left behind at the mine site.
Main minerals in Rockies and Canadians shield.
Biggest producer of many minerals – important to Canadian economy.
Developing economies in the world are hungry for these resources – huge amount of money inflowing from
China for example.
Major mineralforming processes
Occur in subduction zones
To do with the heat involved in plate tectonic processes
Hot groundwater (hydrothermal fluids) passes through host rocks and scavenged metals in host rocks and
is transported through hot water movement, settled in new location – crystallizes in more concentrated form
Ex) in mid oceanic spreading centers: black smokers are metal particulates from massive sulphide deposits
(copper, zinc) that comes up.
Some most important copper and zinc mines occur in these areas
hydrothermal solutions in stratovolcanoes (andesitic volcanoes) porphyry copper, plus concentrated
deposits in fractures, forming veins rich in gold, tin, silver.
The ore may still be highly disseminated, requiring the extraction of vast volumes of lowgrade ore for
processing and concentration. This is often achieved by digging vast openpit mines Lecture 9 20131023
crystallization of granite from magma (deep in magmatic arcs) concentrates remaining elements in
pegmatites , which are very coarsegrained versions of granites (crystals sometimes several centimeters
across), and may contain significant deposits of lithium, beryllium, plus veins rich in tin, tungsten, bismuth,
(pegmatites are the host rocks and do not necessarily contain useful ores, therefore it is incorrect to refer to
them as ore deposits unless they do, in fact, contain minerals).
Major Ore forming process – 5
explosive eruption of mantle rocks may generate kimberlites the host rocks for diamonds.
6) metamorphic recrystallization of limestone into marble – e.g. Carrara Marble, Italy.
7) —hydrothermal fluids circulating through muddy sediments, enrich the rocks in lead, zinc, copper,
forming stratabound ores. E.g., Pine Point (NWT) leadzinc, copper in Zambia, leadzinc deposits at Broken
Hill and Mount Isa, Australia
8) gold grains released from granites by surface weathering and erosion, concentrated by streams into
source of Cali and Klondike gold rushes in 19 c. Precambrian Gold S.Africa
9) Aluminum ore = oxide. Chemical weathering heavy rainfall causes bedrock to undergo heavy
weathering, leaching out insoluable materials
origin of laterite (iron rick) and bauxite (aluminum rich)
Waste dumps and tailing ponds
Mine site require remediation and clean up
—mountaintop removal literally removes entire hilltops, dumping the rock and soil into nearby valleys, in
order to expose coal seams for surface strip mining. The effects on the drainage network, downstream
loading of surface runoff with dust and with pollutants. Lecture 9 20131023
Acid mine drainage
Rocks stained by iron and other metals as groundwater and runoff drains through the old mine site
Toxic mining sludge bursts from a tailings pond (ex Hungary oct 2010)
At Sudbury (Slide 29), a serious local acid rain problem was managed by building higher smoke stacks,
which dispersed the pollutants more widely
Surface Scarring and reclamation
Abandoned mines are a serious issues but are expensive to clean
Canmore coal mines were closed in 1979 and remediation led to formation of Ski site used in Calgary
Valuable ore deposit areas interlap with many First Nation lands in British Colombia – i.e. oil pipeline
conflict; Windy Craggy copper deposit.
Protected lands – provincial parks
Increased pressure to exploit mineral field of wealth
China growing superpower – buying out mining and oil companies. Foreign control for a natural resource is
Curent developments: 1
Natural Resources, corruption and terrorism
Illegal income from natural resources has been used to fund activities by terrorists, drug gangs and
repressive governments worldwide.
Canadian diamond discoveries:
To prevent illegal trade, all Canadian diamonds are engraved with an invisible inscription.