Water Distribution and Properties

• 70% of Earth’s surface is covered in water.

• 97% of water is located in the oceans.

• 3% of water is freshwater, most of the freshwater is located in the ice caps and glaciers.

• Unique properties of water

  • Water has a high boiling point

  • A lot of energy is needed to evaporate water

  • Water dissolves many compounds

  • Water expands as it freezes

  • Water adheres to many solid surfaces

Freshwater

• Freshwater

  • The places with the highest amount of freshwater are the places with high precipitation and small populations.

  • The places with the lowest amount of freshwater are the places with low precipitation and large populations.

  • The use of freshwater is growing at twice the rate of population growth.

Aquifers

• Aquifers

  • Geologic feature that contains water in quantities sufficient to support a spring or well.

  • Holds 30 times more water in the US than all US lakes and rivers combined.

• Important terms

  • Confined Aquifer - an aquifer below the land that is saturated with water.

  • Recharge Zone - The area above an aquifer that supplies water.

  • Unconfined Aquifer - An aquifer where the upper water surface is at atmospheric pressure

  • Unsaturated Zone - The zone immediately below the land surface that is not totally saturated with water.

  • Water Permeability - The ability of a material to allow passage through rocks with water

  • Water Table - The level below that ground is saturated with water.

Types of Ice

• Glaciers

  • Body of dense ice that only forms on land.

  • 99% of glacial ice is contained in ice sheets in polar regions.

  • Largest reservoir of freshwater in the world.

• Ice Sheets

  • Mass of glacial ice that is greater than 20,000 square miles in area.

  • The only ice sheets are Antarctica and Greenland.

• Ice Shelves

  • Thick floating platform of ice that forms when a glacier or ice sheet flows down to a coastline and onto the ocean surface.

  • Only found in Antarctica, Greenland, and Canada

• Sea Ice

  • Frozen seawater.

  • It floats on the ocean surface.

  • It is found primarily in the Northern Hemisphere.

Oceans

• 71% of the Earth’s surface is covered in oceans.

• More than half of this area is under 10,000 feet.

• Oceans have a significant effect on the biosphere, because oceanic evaporation is the primary source of precipitation.

• Oceanic Circulation

  • Heat is transferred to the equator by ocean currents.

  • Warm waters near the surface and cold water deeper in the ocean move by convection currents.

• The Great Ocean Conveyor Belt

  • There is constant motion in the form of a global ocean.

  • Cold water sinks to the bottom of the ocean

  • Warm water rises to the surface.

  • Cold water will go south towards the Antarctic

  • Warm water will come back up to the Pacific

  • This conveyor belt helps regulate the amount of sea ice in polar regions.

Agricultural, Industrial, and Municipal Use

• There are 3 types of water withdrawal

  • Agricultural

  • Industrial

  • Municipal

• Water Shortages

  • The rate of water consumption is growing twice as fast as population growth.

  • Water is a limited factor as it limits the amount of food that can be produced in a region.

• Water Diversion

  • Groundwater is the largest source of freshwater in the world.

  • Freshwater is being diverted into many different purposes.

  • Environmental consequences from this diversion can be

    • Concentration of salts and minerals and pollutants may increase

    • Can reduce the habitat for fish and can impact feeding and spawning success

    • Temperature and oxygen levels can increase.

    • A reduction of the native populations of animals and plants.