Environmental Science 1021F/G Lecture Notes - Physical Water Scarcity, Economic Water Scarcity, Water Scarcity

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Water Lecture Notes
Hydrologic Cycle
Always exists, changes in form & location
o Solid liquid gas
o Cloud, land, ocean/lake, soil
Infiltration = soil surface into soil
Percolation = mvt through soil layers
Cause of BC temperate forests: Rocky Mountains - clouds gather off ocean, move up over
mountains & come down to release moisture on warm other side
Water Supply
We only have groundwater supply available for use
o A potentially renewable resource
Recall watershed concept - topographically-determined area where water drains into land
Zone of Aeration = soil has space for air, and some water in between
Zone of Saturation = soil is 100% filled with water in between spaces
Water table = delineation between aeration & saturation zones
Aquifer = required for sustenance in communities relying on well-water
Porous, water-saturated soil where groundwater flows
Naturally occurring, created through time by geological changes
Unconfined = large surface area where water supply can be recharged
Confined = only one small point of recharged (soil is impenetrable along most of aquifer length)
Fossil = ancient aquifers; no recharge
Lateral = recharged by open body of water
Natural = recharged by precipitation
Types of water use
Withdrawal
o Water is taken out and at least some is returned within same watershed (at point of origin)
o Thermal pollution = water is warmed, changes certain species habitat (hurts temp-sensitive
fish)
Can prevent natural freezing in winter required for ecosystem
Consumptive
o Water isn't returned at point of origin
Domestic use of water = everything you encounter on daily basis (home, school, work, restaurants,
recreation)
Our next big crisis after the fossil fuel issue at present will be a water crisis
We have never lived w/o water
What water used for:
Industrial use
Power plants for cooling purposes (leads to thermal pollution)
Domestic use (water used to run daily life, house usage = water used in home)
Showers/bathing
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Toilet flushing (30% of home water use)
o One area use of freshwater can be reduced significantly
Use of Water in Canada
Transportation
o Mostly West & East coasts, into St. Lawrence Riv.
o Will open up into Arctic waterways with sea ice melting
Has its own implications
We`re a water-rich country (in terms of groundwater, wetlands - 25% of all in the world, protects
from flooding)
Water scarcity
Greater pop. Affected by water scarcity
Causes:
1. Dry climate
2. Drought
Unexpected reduction in precipitation
3. Dry soil
Doesn't hold water
May not all water infiltration
No plants = no clouds
4. Demand
Water stress = overuse of water
Water scarcity = more extreme demand, overuse & abuse of resource
Situations
US west coast & farther east, physical water scarcity (no water there)
Economic water scarcity = not able to get water (but it's available physically) by cost or politics
Diverted waters for other purposes & overuse lead to major rivers drying up
Ways to increase freshwater supplies
1. Dams & reservoirs
Provide recreation areas
Controls water, able to access power
Downstream control of flooding
Increases water lost to evaporation
Land flooded for reservoir is lost
People displaced
Pesticide residue released - soil isn't scraped out - into water source
Release of GHG from plant material now flooded
New physical barrier between land wildlife populations
Less genetic diversity in populations
Less protection from disease
Lead to inbreeding
Nutrient-rich sediments displaced when waters released from dam
Sediment build-up elsewhere
Soils lost upstream
2. Transferring water one area to other
Displaces people
Changes ecosystems
3. Tapping groundwater
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