Where does water come from?
Water Vocabulary
• Tributary- a small river that joins a larger one
• Head water- the source of a river
• River Basin- the land area that contributes water to the
river (drainage)
• Dam- a man made structure to alter the flow of the
river
• Effluent- treated- or untreated- waste water
71% of the earth is covered in water
Saltwater
• 97 % of all water is
saltwater.
– Saltwater in lakes
– Seas
– Oceans
Freshwater
• 3% of all water
– 2% not available for it is
frozen or in deep aquifers.
– 1% is available for human
consumption.
Brackish Water
–Mixture of saltwater and fresh
water.
–Found where fresh water flows
into saltwater @ oceans and lakes.
Sources of water
• Water that we use for daily use comes from a
variety of sources including:
• Surface water
–Rivers, streams, snow and ice melt, ponds,
lakes
• Underground water
–aquifers
Surface Water
• Rivers, lakes, streams, ponds, lakes
• ½ drinking water comes from surface
water
• Collect in a watershed
• http://www.fcwa.org/education/watershed/inde
x.html
Surface waters create a watershed
AZ Surface H2)
Where does Arizona’s water come from?
– Colorado River
– Other surface water
(Salt, Verde, Gila Rivers)
– Groundwater
– Effluent
1
0
February 8, 2008
Where does Arizona’s water come
from?
• Total statewide demand: ~7.87 maf/year
– About 40% supplied by
groundwater pumping
Groundwater
– More than 50% supplied by
Colorado & Gila River systems
Colorado &
Gila Rivers
– Use of reclaimed water is increasing – currently 7%
February 8, 2008
11
• 200-300 mi
long
• Verde River
and Black
River are
tributaries
• Ends in Gila
River
Challenges:
Turbidity (sediment)
Fecal Coliform
Mining
Salt River
Gila River
• 649 miles
• Salt river is main
Tributary
• Ends in Colorado River
• Has several dams
– Coolidge ( AZ)
– Painted Rock Dam (AZ)
Colorado River
• 1450 miles long
• Main source of water in SW
US
Ground Water
• A few feet to a few thousand feet
underground
• Stored water from underground rivers, filtered
surface water
• Can drill wells to access
• Generally clean
• Aquifers- large underground storage of water
aquifer
• http://www.epa.gov/safewater/kids/flash/flas
h_aquifer.html
• Filtration
• http://www.epa.gov/safewater/kids/flash/flas
h_filtration.html
AZ Ground water supplies
Uses for Water
• Domestic
– drinking, bathing, cleaning, cooking, watering
lawns, washing cars, etc
• Agricultural Usage
– Irrigating fields (food, fiber)
– Raising livestock
• Industrial Usage
– Manufacturing, mining, etc
Threats to Water Security
• Water Security- the ability to access clean,
safe water
– Population Expansion
– Urbanization
– Pollution
– Warming waters
– Destruction of Forest/vegetation
Water Scarcity– Not having access to adequate clean drinking
water
– 1.2 billion people, almost 1/5 of the population
live in areas of where they don’t have access to
clean water
– 500 million are approaching this situation
– 1.6 billion, ¼ population face economic water
shortage (lack of infrastructure to take water from
rivers and aquifers)
http://www.un.org/waterforlifedecade/scarcity.shtml
https://www.youtube.com/watch?v=8STrs78yx
O0#t=36
Arizona’s Future
February 8, 2008
27
Current Lower Basin Reservoir Stats *
Current Storage
Percent Full
Million
Acre-Feet
Lake Powell
46%
11.8
Lake Mead
50%
12.5
Total System Storage
53%
31.8
Total System Storage
Last Year
55%
34.2
* As of 1/1/08
2
8
February 8, 2008
Lake Mead’s Water Level
The Colorado River system is facing the worst drought on record.
Lake Mead's water level has dropped approximately 70 feet since
January 2000.
When full, Lake Mead contains enough water to cover the state of
New York with water one foot deep.
February 8, 2008
29
Growing Needs
• Can the Colorado River meet the growing
needs of Arizona, California, & Nevada?
– Lower basin is fully appropriated
– Southern California cities must buy water from farmers & improve
efficiencies
– Southern Nevada Water Authority is storing water in Arizona & retiring
agricultural uses in Nevada
– Mexico & environmental demands threaten existing users in the
Colorado Basin
February 8, 2008
30
Current Water Regulation Programs
–
•
•
–
•
•
•
–
•
•
Inside AMAs
Assured Water Supply Rules
Conservation programs
Outside AMAs
Adequacy program
New 100-year Adequacy Requirement
Rural watershed studies
Across Arizona
Well-drilling & well-spacing rules
Surface water rights adjudication
February 8, 2008
31
Solutions?
• Arizona Farmers on the Verde River
• http://voices.nationalgeographic.com/2013/1
2/05/smarter-irrigation-returns-water-toarizonas-verde-river/
What if an extended drought is
normal?
– Hydrological studies indicate
that cyclical wet/dry periods of
20-30 years are normal
– Supply calculations might be
overly optimistic
– What does this mean for water
management?
February 8, 2008
33
Climate Change: Can we manage our
water supplies in response?
Will the future bring more or less precipitation?
The evidence is inconclusive
More heat means –
Higher evaporation rates &
increased water demands
February 8, 2008
34
Active Management Areas (AMAs)
– AMAs comprise
• 80% of population
• 75% of water consumption
• 13% of land
– 4 of the 5 AMAs have a mandated
goal of
safe yield by 2025
– All new irrigation banned in AMAs &
INAs after 1980
February 8, 2008
35