Water Resources Chapter 13

Questions for Today  Why is water so important?  Does everyone have access to clean and healthy water  Describe the three major zones of Groundwater.  What are the major problems associated with Freshwater in the US?  What is Drought and what are the problems associated with Drought?  Who owns all the freshwater?

Freshwater Is an Irreplaceable Resource That We Are Managing Poorly (1)  Why is water so important? Earth as a watery world: 71% (mostly Salt) 60% of yourself is made from water Freshwater availability: 0.024%  Hydrologic cycle Movement of water in the seas, land, and air Driven by solar energy and gravity  Water pollution Degradation of the World’s Water Supply Partly Because it’s Cheap Taken For Granted

Freshwater Is an Irreplaceable Resource That We Are Managing Poorly (2)  Access to water is A global health issue Sanitation 1.6 million people died in 2007 An economic issue Helps reduce poverty and produces food and energy A women’s and children’s issue In developing countries, it is their job to carry water back home A national and global security issue Tension between shared resources

Girl Carrying Well Water over Dried Out Earth during a Severe Drought in India

Most of the Earth’s Freshwater Is Not Available to Us  People divided into: Water haves Those that have a readily availably clean and healthy water supply For instance: Canada has 0.5% of the world’s people but has 20% of the world’s water Water have-nots Those that do not access to clean, fresh water For instance: China has 20% of the world’s people, but only 7% of the world’s supply of freshwater

We Get Freshwater from Groundwater and Surface Water (1)  Ground water Water found in the pores between soil, gravel and rock held between an impenetrable rock layer  Zone of saturation The point at which the groundwater is completely filled  Water table The Top of the Ground water zone Falls in dry weather or unsustainable harvesting Rises in Wet Weather  Aquifers Natural recharge – from precipitation and percolation Lateral recharge – from a nearby river or stream Both Recharge slowly

We Get Freshwater from Groundwater and Surface Water (2)  Surface Water – Most Important Water Resource Lakes, Rivers, Streams Surface runoff – non-evaporated precipitation Watershed (drainage) basin A collection area for Surface water

Natural Capital: Groundwater System: Unconfined and Confined Aquifer

Fig. 13-3, p. 316 Unconfined Aquifer Recharge Area Precipitation Evaporation and transpiration Evaporation Confined Recharge Area Runoff Flowing artesian well Well requiring a pump Stream Infiltration Water table Lake Infiltration Unconfined aquifer Less permeable material such as clay Confined aquifer Confining impermeable rock layer

We Use a Large and Growing Portion of the World’s Reliable Runoff  2/3 of the surface runoff: lost by seasonal floods  1/3 runoff usable Domestic: 10% Agriculture: 70% Industrial use: 20%  Fred Pearce, author of When the Rivers Run Dry Takes 450,000 liters or 2,400 bathtubs of water to produce a car 140 liters to produce a cup of coffee 25 bathtubs to produce a T-shirt

Case Study: Freshwater Resources in the United States  More than enough renewable freshwater, unevenly distributed Eastern states have more rain than western and southwestern states The three rainiest cities are: Mobile, AL Pensacola, FL New Orleans, LA  What are the most serious water problems in the US? Floods Pollution Drought – when precipitation is at least 70% lower and evaporation is higher than normal.

Average Annual Precipitation and Major Rivers, Water-Deficit Regions in U.S.

Fig. 13-4a, p. 317

Fig. 13-4b, p. 317

Long-Term Severe Drought Is Increasing  Causes Extended period of below-normal rainfall Diminished groundwater  Harmful environmental effects Dries out soils Reduces stream flows Decreases tree growth and biomass Lowers net primary productivity and crop yields Shift in biomes

In Water-Short Areas Farmers and Cities Compete for Water Resources  2007: National Academy of Science study Increased corn production in the U.S. to make ethanol as an alternative fuel Decreasing water supplies Aquifer depletion Increase in pollution of streams and aquifers

Who Should Own and Manage Freshwater Resources? (1)  Most water resources Owned by governments Managed as publicly owned resources  Veolia and Suez: French companies Buy and manage water resources Successful outcomes in many areas

Who Should Own and Manage Freshwater Resources? (2)  Bechtel Corporation Poor water management in Bolivia  Potential problems with full privatization of water resources Financial incentive to sell water; not conserve it Poor will still be left out