WATER resources AP Environmental Science The amount of water in the earth is constant

Imporantant Resource Water is essential and maintains all life and ecosystems It regulates the temperature of the planet Redistributes heat Cycles essential nutrients through land, air and all living things.

Renewable Resource Fresh water is a renewable resource because of the hydrologic cycle which returns water to both surface and groundwater sources from the atmosphere.

Earth’s Distribution of Water Figure 15-01 Title: Only 2.5% of Earth's water is fresh water. Caption: Of that 2.5%, most is tied up in glaciers and ice caps. Of the 1% that is surface water, most is in lakes and soil moisture. Data from United Nations Environment Programme (UNEP) and World Resources Institute. Notes: Keywords: fresh water, streams, rivers, groundwater, oceans, atmosphere

Natural Capital: Surface Water Fresh water that exists above ground Streams Rivers Ponds Lakes Wetlands Watershed Area of land drained by a river system Drainage basin

Natural Capital: Surface Water Almost ¾ of all water used in the U.S. comes from surface water and is used for electric power generation, municipalities, industrial use, and irrigation South Platte River, Colorado

Natural Capital: Surface Water Productivity classification Oligotrophic Low nutrients High oxygen Eutrophic High nutrients Low oxygen Eutrophication usually results from human-caused excessive nutrient pollution.

Natural Capital: Wetlands Surface water systems in which the soil is saturated with water Generally feature shallow standing water with lots of vegetation Marsh Swamp Bog

Natural Capital: Wetlands Vernal Pool Seasonal wetlands containing water only at a specific time of the year. Wetlands are extremely valuable as habitat for wildlife Wetlands provide important ecosystem services Slowing runoff Reducing flooding Recharging aquifers Filtering pollutants

Natural Capital: Wetlands Extensive damage of wetlands has occurred throughout the U.S. Less than half of all wetlands remain Ramsar Convention on Wetlands (1971) Seeks protection of wetlands worldwide

Natural Capital: Ground Water Systems Water beneath Earth’s surface, held within the pores of soil and/or rock. Account for ¼ of all water used in the U.S. Supplies almost ½ of all drinking water Important source of irrigation for Midwest

Natural Capital: Ground Water Systems Evaporation and transpiration Evaporation Stream Infiltration Water table Unconfined aquifer Confined aquifer Lake Well requiring a pump Flowing artesian well Runoff Precipitation Confined Recharge Area Aquifer Less permeable material such as clay Confirming permeable rock layer

Natural Capital: Ground Water Systems Aquifers Underground reservoir contained in porous, sponge-like formations of rock, sand or gravel. Largest know aquifer is the Ogallala, located under 8 U.S. Great Plains states

Natural Capital: Ground Water Systems unconfined aquifer is an aquifer with a permeable water table. confined aquifer is bounded above and below by less permeable beds of rock where the water is confined under pressure. Some aquifers are replenished by precipitation; others are not.

Natural Capital: Ground Water Systems As aquifers are withdrawn, they recharge VERY slowly; average rates are only about 1 m per day.

Natural Capital: Ground Water Systems Water Table The upper limit of groundwater held in an aquifer Drops when aquifers are overdrawn Result= becomes more difficult and expensive to extract.

Natural Capital: Ground Water Systems In parts of Mexico, India, China and many Asian and M.E. nations, water tables are falling 3-10 feet per year. In coastal areas, saltwater can intrude, making the water undrinkable and land can subside, creating sinkholes

Sustainability ONLY if water is used and managed sustainably can water be realized as a renewable resource. Currently, in many industrial nations, concerns over water quantity dominate In developing countries, concerns over both water quantity and quality persist

Where Does It Rain? Humans are not distributed across the globe in accordance with water availability.

Where Does It Rain? A growing number of heavily populated countries are located in arid lands

Global Water Conflicts Two main factors for water shortage: dry climate and too many people. Many people live in hydro poverty – can’t afford clean water.

Sharing Water Resources Among Countries

Potable Water Safe Drinking Water Nearly 1 billion people do not have access to safe drinking water 80% of human illness result from poor drinking water Increasing populations put additional stress on water supplies

What is the Trend? Over the last century Human population has increased 3x Global water withdrawal has increased 7x Per capita water withdrawal has increased 4x About one-sixth of the world’s people don’t have easy access to safe water Most water resources are owned by governments and are managed as publicly owned resources

Usage?

Annual Precipitation of the Continental U.S. A person needs about 1 gallon water/day for hydration In the US each person uses about 188 gallons/day An additional 657 gallons/person/day are used for irrigation, industrial use. Total per capita use is about 2000 gal/person/day US has highest per capita water withdrawal, followed by Canada, Australia, Russia, Japan

Too Little Water Problems in the West Dry climate Drought Desiccation US has plenty of water. Much of it is in the wrong place at the wrong time. Most serious problems are flooding, pollution, and occasional urban shortages Acute shortage Adequate supply Shortage Metropolitan regions with population greater than 1 million

Too Little Water Growing Problem

Population Growth Supply & demand are in growing conflict – supply is finite water management driven by values and needs In the western US, irrigation makes up 85% of all water use 50% to grow food for livestock 35% to grow crops Not sustainable…cost of water is heavily subsidized by the federal government

Supply and Demand Agriculture uses approximately 70% of the Earth’s annual fresh water withdrawn from our streams and rivers

Supply and Demand Amount of land currently being irrigated has doubled in the last 50 years to meet the demand for food.

Supply and Demand Most irrigation remains highly inefficient Crops end up using only 40% of the water applied by “flood and furrow” methods

Supply and Demand Over-irrigation leads to waterlogging and the salinization of agricultural lands World-wide, about 15-35% of water withdrawals for irrigation are thought to be unsustainable.

Supply and Demand Industry Residential Accounts for approximately 20% of Earth’s annual fresh water use Residential Accounts for approximately 10% of Earth’s fresh water use.

Bottled Water Bottled drinking water production now represents a significant groundwater extraction and depletion problem Nestle, Pepsi-Cola, Coca-Cola have begun extracting ground water, bottling and selling it for a profit, and then moving on , leaving the community from which the water was taken with a degraded resource base.

Bottled Water Bottled water exerts substantial ecological impact because it is heavily packaged and transported long distanced using fossil fuels. Bottled water is not demonstrably safer or healthier than tap water In fact, often the source is not as strictly regulated as drinking water by the EPA

Supply and Demand Change in land use changes permeability Areas with 15 to 75 percent impervious surface are characterized as moderately developed. Areas with greater than 75 percent impervious surface are considered urban or highly developed.

Supply and Demand Areas with greater than 10% impervious surface have been proven to have a negative affect on groundwater and storm water.

Water Rights Water collectively belongs to the public Cannot be owned by individuals Individuals or groups may be granted rights to use water Legal authorization to use a predefined quantity of public water for a designated purpose. Irrigation, domestic water supply, power generation

Water Rights State law requires certain users of public waters to receive approval from the state prior to using water. Any use of surface water which began after 1917 requires a water-right permit. Withdrawals of underground water from 1945 requires a water-right permit.