Humans and Water

Humans and Water Objectives: Explain why fresh water in one of Earth’s limited resources. Describe the relationship between groundwater and surface water in a watershed. Identify how water is used in homes, industry, and agriculture. Describe water management practices. Identify ways that water can be conserved. Compare point source pollution and non-point source pollution. Explain groundwater pollution. Explain eutrophication

Humans and Water Important Vocabulary: Surface water Desalination Watershed Groundwater Aquifer Recharge zone Irrigation Canals Dams Desalination Point Source Pollution Non-point Source Pollution Runoff Eutrophication Thermal Pollution Wastewater

Global Water Distribution 71% of the Earth’s surface is covered with water 97% of Earth’s water is salt water 77% of fresh water is frozen in glaciers and polar ice caps

Surface Water Freshwater is found in lakes, rivers, streams, and wetlands Watershed – the area of land that is drained into a body of water

Groundwater Most freshwater available for human use comes from groundwater Groundwater is stored beneath the Earth’s surface in rock formations Rain percolates through the soil and into the rock beneath it to recharge the groundwater supply

Aquifers Aquifers are underground formations that contain groundwater The water table is the upper boundary Aquifers consist of rock, sand, and gravel that have spaces where water accumulates

Aquifers, cont. Recharge zone – the area of the Earth’s surface where water percolates down into the aquifer Well – a hole that is dug or drilled to reach groundwater

Example - Ogallala Aquifer One of the largest known aquifers in the world – holds about 4 quadrillion liters of water Supplies about 1/3 of all groundwater used in the U.S. Water is used for irrigation in the Midwest Water is being withdrawn 10 – 40 times faster than it is replaced Conservation methods are being promoted to protect the Ogallala Aquifer

REMEMBER THIS!!! Only 3% of the world’s water is freshwater! Most freshwater for human use comes from groundwater! In some areas, water from aquifers is being withdrawn faster than it is being replaced!

Questions??? Question 1: What is the main source of water for human use? Question 2: The area of land drained by a river is known as a _______________. Question 3: What is the largest known aquifer in the U.S.?

Water Use and Management Industrial 19% Agricultural 67% Residential 8% Differs from one country to the next U.S. uses more than other countries Example: U.S. uses about 300 liters of water a day; India uses about 41 liters

Industrial Use Used to: Manufacture goods Dispose of waste Generate power/cool power plants Example: Calvert Cliffs Nuclear Power Plant pumps water from the Bay, carries the water through pipes to use during energy production before it is sent to a cooling tower, and then pumps it back into the Bay

Agricultural Use Irrigation – method of providing plants with water from sources other than precipitation Example: overhead sprinklers, water filled ditches It can take nearly 300 L of water to produce one ear of corn As much as 80% of the water used evaporates and never reaches the roots

REMEMBER THIS!!! The U.S. uses much more water than many other countries! Agriculture uses the most water! It takes hundreds of gallons to produce food because crops must be irrigated!

Water Management Projects Canals, man-made rivers, supply water to dry areas Dams Positive Aspects include: Creates Reservoirs; lake that forms behind the dam can be used for recreational purposes Controls flooding Supplies potable (safe to drink) water Generation of electricity Drawbacks: impedes fish migration for spawning; fewer nutrients downstream;expensive to build

Water Conservation Drip irrigation system – reduces evaporation Recycling cooling water in power plants Things you can do to conserve water: Take shorter showers Low-flow shower heads and toilets Turn off water while brushing teeth Wash only full loads of laundry Water lawns late in the day to reduce evaporation

Solutions for the Future Transporting water – ships tow enormous plastic bags full of fresh water to areas that don’t have a lot of fresh water Desalination – process of removing salt from salt water Both are expensive solutions CONSERVATION

REMEMBER THIS!!! Dams can be used to create electricity, provide recreation, potable water, and control flooding! There are many simple things you can do to conserve water! Water conservation is the best way to ensure that people have enough water in the future!

Questions??? Question 4: What are the three major uses of water? Which uses the most water? Question 5: List three benefits of a dam. Question 6: List three ways you can conserve water.

Water Pollution . The introduction of a chemical, physical, or biological agents that enter into water and degrades the water quality as well as adversely affects the organisms that depend on the water.

Point-Source Pollution pollution discharged from a single source - you can POINT at the source Example: From a pipe Example: Smokestack Example: Tailpipe

Non-point Source Pollution - comes from many sources - often in the form of runoff

Groundwater Pollution Pollutants enter groundwater when polluted water percolates down from the Earth’s surface Saltwater can enter groundwater when water is removed from an aquifer

Eutrophication Overabundance of nutrients builds up in the water causing algal blooms SAV below dies due to lack of sunlight Decomposers use up the oxygen in the water as they eat the SAV causing other aquatic organisms to suffocate and die Process is accelerated with the addition of detergents (phosphorus) and fertilizers (phosphorus and nitrogen) – called “artificial eutrophication”

Other Water Pollutants Thermal pollution – temperature of the water increases due to human activities can change the ecosystem and kill aquatic organisms Oil spills – responsible for only 5% of oil pollution in the oceans; most other oil pollution comes from non-point sources on land Wastewater – water that contains waste from homes or industries

REMEMBER THIS!!! Point Source pollution comes from a single source! Non-point Source pollution comes from many sources in the form of runoff. Saltwater can enter an aquifer from excessive pumping of groundwater! Eutrophication may cause dead zones that are initiated by excessive nutrients being added to an aquatic ecosystem!

Questions??? Question 7: Describe point source pollution. Question 8: Provide an example of non-point source pollution. Question 9: Artificial eutrophication is caused by excess ___________________ and ________________. Question 10: Where does most oil pollution come from?

THE END!!!