Bell Ringer Runoff soaks into the ground through [ permeable / impermeable ] rock layers into an unconfined aquifer. It first flows through the zone of [ aeration / saturation ] and ends up with other water in the zone of [ aeration / saturation ].

Today 5.6 Notes – Water Use California Heist

Water Use

Freshwater Only 2.5% of Earth’s water is fresh water The rest (____%) is ____ water 97.5 salt

Freshwater Of the Earth’s freshwater: 70% is frozen in glaciers or ice caps (so not available for human use) 30% is groundwater 0.3% is surface water (lakes, rivers, etc.) Much of Earth’s fresh water is not available for human use

Freshwater Of all the water on Earth, only 0.003 % is available to humans, so we need to protect the water we do have! Water Conservation – the preservation and protection of water resources Using less water and keeping water free of pollution

Freshwater Use in the US Almost half of the US’s freshwater is used for thermoelectric power Review: The US’s main source of electricity is burning __________ To produce electricity, fossil fuels are burned to heat up a vat of ______ to produce steam to turn a ________ fossil fuels water turbine

Freshwater Use in the US Which of these energy sources could we use without having to heat up a vat of water? natural gas solar energy bacterial digestion coal petroleum/oil wind energy geothermal energy burning biomass hydroelectric power

Freshwater Use in the US Conservation – using alternative energy sources that do not require large vats of water

Water Usage About 1/3 of the US’s freshwater is used for irrigation Irrigation – watering crops to promote growth

Water Usage Irrigation is an extremely wasteful practice because nearly 80% of the water used is lost to evaporation or seeping into the ground rather than watering the plants

Freshwater Use in the US Conservation – using trickle irrigation Trickle irrigation – pipes trickle out small amounts of water over a long period of time instead of a burst of water in a short period of time Water is better able to soak into the roots However, trickle irrigation is significantly more expensive than traditional irrigation

Freshwater Use in the US Less than 10% is used domestically (in homes) However, this is the place where YOU can make the biggest change

Freshwater Use in the US The average American uses about 80-100 gallons of water a day! What are some ways we use water in our homes? In comparison, the average African family uses only 5 gallons a day!

Freshwater Use in the US Conservation Low-flow toilets use less water per flush (1.6 gallons instead of 5-7 gallons) However, most consumers find that it doesn’t effectively remove toilet paper or solid waste, so they end up flushing twice (1.6 + 1.6 = 3.2 gallons) Dual-flush toilets have two options for flushing: half flush for liquid waste and full flush for solid waste Uses less water than a traditional toilet, but is more expensive

Other Methods of Conservation: Use high-efficiency washing machines (determines how much clothes are in the washer and adjusts the water level accordingly) Only run full loads in dishwasher Take shorter showers Turn off faucets when not in use (like while you’re brushing your teeth) Fix any leaky faucets Just one leaky faucet can waste 350 gallons a year!

Overuse of Aquifers The current rate of freshwater use is greater than ever before This has put bodies of freshwater, especially underground aquifers, in danger

Overuse of Aquifers If groundwater is pumped faster than it is recharged (naturally refilled), the water table will drop below the drilled wells, creating a cone of depression Cone of Depression – sinking of a water table around a well

Overuse of Aquifers Subsidence – the sinking of the land around an overused aquifer (like a deflated balloon)

Overuse of Aquifers Saltwater Intrusion – when overpumping in coastal areas caused saltwater to be pulled into the freshwater aquifer Contaminates the fresh water, making the aquifer unusable

Overuse of Aquifers Possible Solution: Desalination – the process of removing salt from salt water in order to use the water However, not very effective and very expensive, so not a viable solution

Freshwater Availability Water is not evenly distributed around the world or even in the US, so some areas have abundant supply while others do not have enough to support their needs

Freshwater Availability Eastern US – abundant supply, so able to use water in a variety of ways (cooling, hydroelectric power, etc.) Western US – very little precipitation, so water is primarily used for irrigation

Freshwater Availability In California, cities have to get water shipped in from other locations to meet the needs of their populations

Freshwater Availability Worldwide, water availability is an even more serious situation, especially in northern Africa, the Middle East, India, and Australia

You have just bought a house and hire a company to drill a well for you. They come back with four proposals. Which one do you choose?

What is good about Well 1? Clean water, no pollution What is bad about Well 1? Shallow, won’t last long

What is good about Wells 2&3? Deep, won’t run out What is bad about Wells 2&3? Can become polluted (Well 2 from industrial waste, Well 3 from sewage)

Which well would you choose? What is good about Well 4? Clean water, no pollution What is bad about Well 4? Going to be really expensive to drill Which well would you choose?