Unit 8 Exam - Chapter 13 Flashcards
How long is the Colorado River?
Flows 2,300 km through seven U.S. states
How many days and reservoirs does the Colorado River have?
14 dams and reservoirs
From where is the Colorado River supplied?
snowmelt of the Rocky Mountains
What four places does the Colorado River supply electricity and water to?
Las Vegas, Phoenix, Los Angeles, and San Diego
Also irrigates crops
What three issues is the Colorado River experiencing?
Very little water is reaching the Gulf of California
System has experienced severe drought since 1999
Lake Mead fell to record low water level in 2015
Freshwater …
One of the earth’s most important forms of natural capital
Used inefficiently and polluted
Low cost encourages waste
Not accessible to many people
Why is access to freshwater a GLOBAL HEALTH issue?
Over 4,000 people die each day from lack of access to safe drinking water - water borne diseases and diarrhea
Why is access to freshwater an ECONOMIC issue?
Water is vital for producing food and energy
Why is access to freshwater an ENVIRONMENTAL issue?
Excessive withdrawal
Why is access to freshwater a NATIONAL AND GLOBAL SECURITY issue?
“Amidst ever-growing geopolitical tensions, economies experience added pressure on precious natural resources. And as water scarcity forces people to seek resources elsewhere, they risk being exploited or harmed as countries react to the increased migratory flows.”
What percent of the water supply in the world is available freshwater?
0.024% of water global supply
Where does freshwater come from?
Groundwater, lakes, rivers, and streams
Hydrologic Cycle
Movement of water in the seas, land, and air
Distributed unevenly
How do humans alter the Hydrologic Cycle?
Withdrawing and polluting water, and causing climate change
Why is there freshwater scarcity?
More than enough renewable freshwater
Unevenly distributed and polluted
Water footprint
Rough measure of all the water an individual uses
Virtual Water
Virtual water is water used indirectly to produce products and food, but is considered part of a person’s water footprint depending on what they consume
Virtual water = Water used to produce food and other products
Where does much of the water from precipitation go?
Seeps underground and into aquifers
What are some of the biggest example of water use in US households?
Washing clothes
Showers
Toilets
Leaks
Faucets
Electric Power Plant Cooking
Irrigation
What do the Nile, Jordan, Yangtze, and Ganges have in common?
Many of the world’s major river systems are highly stressed
How many countries face water scarcity / what is the prediction for the future?
More than 30 countries face freshwater scarcity
Estimate: 60 countries by 2050
What percent of Earth’s land experiences drought?
30% of the earth’s land area experiences severe drought
Research predicts this will worsen
Is groundwater use sustainable?
Groundwater withdrawals are Unsustainable in Some Areas
Groundwater
Groundwater - water under ground - like aquifers
Can drop a well if there’s one under your house - it is legal!
Withdrawing Groundwater : Advantages
Useful for drinking and irrigation
Exists almost everywhere
Renewable if not over pumped or contaminated
Cheaper to extract than most surface waters
Withdrawing Groundwater : Disadvantages
Aquifer depletion from overpumping
Sinking of land (subsidence) from overpumping
Some deeper aquifers are nonrenewable
Pollution of aquifers lasts decades or centuries
Ogallala Aquifer
OVERPUMPED
largest known aquifer
Irrigates the Great Plains
Very slow recharge
Water table dropping
Water pumped 10–40 times faster
than recharge rate
Government farm subsidies result in further depletion
Biodiversity threatened in some areas
Groundwater Depletion : Prevention
Use water more efficiently
Subsidize water conservation
Limit number of wells
Stop growing water-intensive crops in dry areas
Groundwater Depletion : Control
Raise price of water to discourage waste
Tax water pumped from wells near surface water
Build rain gardens in urban areas
Use permeable paving material on streets, sidewalks, and driveways
What does overpumping aquifers do to food production + the economy?
Limits food production and raises prices
Widens gap between rich and poor
Land Subsidence examples for overpumped aquifers examples
San Joaquin Valley in California
Mexico City
Groundwater pollution/overpumping : coastal
Groundwater overdrafts near coastal regions
Contamination of groundwater with saltwater
How can we increase freshwater supply?
Large dam-and-reservoir systems
Greatly expanded water supplies in some areas
Disrupted ecosystems and displaced people
EX: Chatfield Reservoir, Reallocation Project
What is the main goal of a dam and reservoir system?
Capture and store runoff
Release runoff as needed for:
Flood control
Generating electricity
Supplying irrigation water
Recreation (reservoirs)
Reservoirs - advantage
Increase the reliable runoff available for use
Reservoirs - disadvantages
Displace people
Impair ecological services of rivers-
What are some ecological services of rivers?
Endanger plant and animal species
Fill up with sediment within 50 years
Oroville Dam - California
Oroville dam in California was compromised by extremely heavy rainfall after a severe drought
Main spillway was damaged which almost caused the weir to collapse
180,000 people were evacuated with only an hour’s notice.
What is a weir? (dams)
Weir? is a small barrier built across a stream or river to control and raise the water level slightly on the upstream side. It generally allows the water to flow over the crest (which is the top) or sometimes underneath some sections.
How does climate change intensify weather extremes?
Mountain snowpack will be reduced, making less freshwater available downstream
When water levels drop, hydroelectric dams cannot function
Colorado River will not be able to meet water needs in Arizona, New Mexico, and California
How can dams kill an estuary?
Only a small amount of Colorado River water reaches Gulf of California
Threatens aquatic species in river and species that live in the estuary
Current rate of river withdrawal is not sustainable
Inefficient use of irrigation water for agriculture
Proposed actions for states using the Colorado River
Enact strict conservation measures
Phase out agricultural subsidies
Shift water-thirsty crops to less arid areas
Raise the price of freshwater
Dam that opened up in the documentary in order to fill the delta temporarily
2014: Morelos dam near Yuma, AZ opened for two months to release water through the delta to the Gulf of California
Dramatic short-term results
What is National Environmental Policy Act (NEPA)?
National Environmental Policy Act (NEPA) requires that an environmental impact statement be developed for every federal project likely to have an effect on environmental quality
Impact on water, soils, air quality, wildlife habitat, etc
Desalination methods (for turning saltwater to freshwater for drinking)
Distillation
Reverse osmosis
More than 17,000 desalination plants currently operating in 150 countries
Most in arid nations of Middle East, North Africa, Caribbean, and Mediterranean
Desalination Issues
Issues: high cost, high energy use, and large amounts of salty wastewater
Water Transfers: Advantages
Transferring water from one place to another has greatly increased water supplies in some areas
Has also disrupted ecosystems
Water transfers: Issues/Disadvantages
Has also disrupted ecosystems
Water loss through evaporation and leaks
Ecosystem degradation
Water Transfers : Real Life Examples
China -
South-North Water Diversion Project
Diverts six trillion gallons of water per year
California central valley -
Aqueducts
The Aral Sea Disaster: Water Transfer Issue
Large-scale water transfers in dry central Asia have led to:
Wetland destruction
Desertification
Greatly increased salinity
Fish extinctions and decline of fishing
Blowing salt and dust destroying wildlife and crops
Increased glacial melting in the Himalayas
How has the shrinkage of the Aral Sea disrupted the local climate?
Hot, dry summers, colder winters, and a shortened growing season
Aral Sea : Restoration Efforts
Cooperation of neighboring countries- Kazakhstan and Uzbekistan
More efficient irrigation
Dike construction raised level of Northern Aral Sea
Ways to use Freshwater More Sustainably
Cut water waste
Raise water prices
Slow population growth
Protect aquifers, forests, and other ecosystems that store and release freshwater
How much of the world’s water supply is wasted and why?
One-half to two-thirds of water is wasted
Evaporation, leaks, and inefficient use
On the True Cost of water
The cost of water to users is low
Government subsidies mask the true cost of water
No subsidies for improved efficiency
Raising the price of water: disadvantage and solution
Raising prices could hurt lower-income farmers and city dwellers
Solution: establish lifeline rates for low income users
Solutions: Reducing Irrigation Water Losses
Avoid growing thirsty crops in dry areas
Import water-intensive crops and meat
Encourage organic farming and polyculture to retain soil moisture
Monitor soil moisture to add water only when necessary
Expand use of drip irrigation and other efficient methods
irrigates at night to reduce evaporation
line canals that bring water to irrigation ditches
irrigates with treated wastewater
Flood irrigation: Problems/Issues/Disadvantages
Flood irrigation -
45% of water lost
Not efficient / efficiency needs to be improved
More efficient Flood Irrigation Techniques
Center pivot, low pressure sprinkler
Low-energy, precision application sprinklers- LEPA
Drip or trickle irrigation, micro irrigation
—– Costly
—– Less water waste
Poor Farmers Conserve Water Using Low-Tech Methods
Human-powered treadle pumps bring water into irrigation ditches
Harvest and store rainwater
Capture water from fog
Use polyculture to create canopy vegetation
Reduces evaporation
Use no till agriculture- leaving plants on soil reduces runoff and keeps the temperature down which reduces evaporation and transpiration
Solutions: Reducing Water Losses
Redesign manufacturing Process to Use Less Water
Recycle water in industry
Fix water leaks
Landscape yard with plants that require little water
Use drip irrigation for gardens and lawns
Use water-saving showerheads, appliances, and toilets (or waterless composting toilets)
Collect and reuse gray water in and around houses, office buildings, and apartments
Raise water prices and use meters, especially in dry urban areas
More : Cutting Freshwater Losses in Industry and Homes
Recycle water used in industry
Use low-flow toilets, showerheads, and front-loading washing machines
Fix leaks in the plumbing systems - A leaky faucet that drips at the rate of one drip per second can waste more than 3,000 gallons per year. That’s the amount of water needed to take more than 180 showers
Use native plants in landscaping
Use gray water
Water meters reduce water use
Gray Water
water that already has been used domestically, commercially and industrially. This includes the leftover, untreated water
What can You do? : Water use and Waste
use water saving toilets, showerheads, and faucets
take short showers instead of baths
turn off sink faucets while brushing teeth, shaving, or washing
wash only full loads of clothes or use the lowest possible water-level setting for smaller loads
repair water leaks
wash your car from a bucket of soapy water, use gray water, and use hose for rinsing only
if you use a commercial car wash, try to find one that recycles its water
replace your lawn with native plants that need little of any watering
water lawns and gardens in the early morning or evening and use gray water
use drip irrigation and mulch for gardens and flowerbeds
Freshwater and waste
Large amounts of freshwater used to flush away wastes
Wastewater reusing
Only about 7% of wastewater is currently recycled- some of our clean treated sewage water is put back in McLellan reservoir for reuse
How can we reduce the threat of flooding?
Protecting more wetlands and natural vegetation in watersheds
Not building in areas subject to frequent flooding
Floodplain
Area flooded when a stream overflows its channel
Fertile soils for farming
Recharge groundwater and refill wetlands
Human Activities that Damage Floodplains
Vegetation removal
Draining of wetlands
Rising sea levels from global warming means more coastal flooding
Case Study: Living Dangerously on Floodplains in Bangladesh
Dense population on coastal floodplain
Moderate floods maintain fertile soil
Recent increased frequency of severe floods
Destruction of coastal wetlands
Mangrove forests cleared
Increased storm damage
Adapting: using more flood-tolerant crops
Solutions: Reducing Flood Damage – PREVENTION
preserve forests in watersheds
preserve and restore wetlands on floodplains
Increase use of floodplains for sustainable agriculture and forestry
Solutions: Reducing Flood Damage – CONTROL
Strengthen and deepen streams (channelization)
Build levees or floodwalls along streams
Build dams
