Lecture 5: Water Resources and Pollution Flashcards
Importance of Water
➝ Found in every living organism.
➝ Dissolves and transports many molecules (nitrates, phosphates, minerals).
➝ Quickly moves between three phases, transferring it (and heat) between the surface, atmosphere, and around the planet.
Distribution of Water
- Ocean 97%
- Freshwater 3%
> Ice Caps and Glaciers 70%
>Groundwater (Aquifers) 29%
>Easily Accessible Freshwater 1%
–> Lakes 52%
–> Soil Moisture 38%
–> Water Vapor 8%
–> Rivers 1%
–> Living Organisms 1%
Movement processes of water.
Hydrologic/Water Cycle
Liquid water is heated and converted to water vapor.
Evaporation
Evaporation from leaves
transpiration
Water vapor cools and liquefies.
condensation
Water droplets combine and fall from clouds.
Precipitation
Seeps through spaces in soil.
Infiltration
Flows downhill to a stream, then a lake or ocean.
Runoff
are underground formations of rock and sand that hold water.
Aquifers
The uppermost boundary of aquifers is called the
water table
is recharged from the ground surface directly above it.
unconfined aquifer
has an impermeable layer of clay or rock that limits recharging to a smaller area.
confined aquifer
the entire area of land where water runoff or infiltration
feeds a specific river
watershed
Withdrawal and consumption of water for agriculture, drinking, etc
water use
Amount of water diverted or removed from its source. A portion may be returned afterward.
Example:
Withdrawal
- Power plant coolant water
Water is withdrawn AND permanently removed from a source.
Example:
Consumption
- Irrigation
The three largest demands for water withdrawal include:
⇾ Power generation 38%: Coolant water and for generating steam.
⇾ Irrigation 39%: Watering crops.
⇾ Domestic 13%: Household water uses.
(others: industrial 6%, livestock 2%, mining 1%, commercial 1%)
the largest consumer of water worldwide, as most of
it is either taken in by plants or evaporated into the atmosphere.
Irrigation
__ occurs when the demand for water is greater than the supply. Leads to __.
water stress
- depletion of freshwater resources
Regions with water stress tend to be:
- Naturally arid
- Heavily populated
- Growing water-intensive crops and animals.
Environmental impacts of overconsumption of freshwater supplies:
⇾ Decrease in river flow.
⇾ Lowering of lake and reservoir levels.
⇾ Subsidence, or the gradual sinking of land.
Alternative water sources and reducing water consumption
water conservation
the removal of salt from ocean water, through two
possible methods: __, __
Desalination
- Distillation boils the water and collects the steam.
- Reverse osmosis passes pressurized water through a filter.