Water Use and Management

Chapter 17

Water Resources

• The hydrologic cycle constantly redistributes water• Total: 370 billion billion gallons

• 500,000 km3 evaporates from oceans; 90% return

• Solar energy drives the cycle

• Water supplies are unevenly distributed• Global atmospheric circulation

• Proximity to water sources

• topography

Major Water Components

• Oceans hold 97% of all water• Regulates our planet’s atmosphere

• Glaciers, Ice, Snow = most surface fresh water• Quickly disappearing

• Groundwater stores large resources

• Rivers, lakes, wetlands = cycle quickly• Small, constantly need to be replenished

• Wetlands = vital

• Atmosphere = among the smallest of compartments

Water Availability and Use

• Renewable water is made up of surface runoff and infiltration

• While readily accessible water supplies are large, water scarcity still occurs when there is a great demand for water or poor water quality

• Droughts can be caused by the introduction of domestic animals, and is exacerbated by land use

• Water use divided into 3 parts: agricultural, domestic, and industrial, with agricultural having the greatest consumption

• Irrigation can be insufficient, with much water being lost through evaporation and run off (drip irrigation is a much better solution)

Water Use Cont. and Freshwater Shortages

• Wealthy countries use far more water than developing countries, which usually lack access to clean water

• Water shortages are usually caused by natural deficits, over consumption by agriculture or industry, and inadequate funds for purifying and delivering good water

• Ground water is being depleted by diversion projects, dams and canal systems, which have damaging effects on the environment

• Sedimentation and climate change affect reservoirs greatly

• Eventual lack of resources may lead to fights over water supplies

Conserving

• Getting by with less water• Farmers are starting to follow the “land bank” plan, they agree to a 10-25%

reduction in their water usage. Due to the depleted amount of water availability this plan benefits farmers in a way that their access to water is not shut off completely.

• Increasing the water supply• Farmers used to pay “rain makers” in an effort to save their crops

• “rain makers”- person who attempts to make rain fall through rituals or scientific techniques (via seeding clouds- dry ice or KI particles)

• What we can do now!• Shorter showers, stopping leaks, switch to drought resistant lawns.

Did you know…

• The largest US water use is toilet flushing

• US today is now conserving 144 million liters of water per day as opposed to 20 years ago

• Growing recognition that water is a precious and finite resource has changed policies and encouraged conservation across the US