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 Freshwater 97 % of all water is saltwater. – Saltwater in lakes – Seas – Oceans 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 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 x.html x.html Rivers, lakes, streams, ponds, lakes ½ drinking water comes from surface water Collect in a watershed

Surface waters create a watershed

AZ Surface H2)

February 8, Where does Arizona’s water come from? – Colorado River – Other surface water (Salt, Verde, Gila Rivers) – Groundwater – Effluent

February 8, Where does Arizona’s water come from? Total statewide demand: ~7.87 maf/year – About 40% supplied by groundwater pumping – More than 50% supplied by Colorado & Gila River systems – Use of reclaimed water is increasing – currently 7% Groundwater Colorado & Gila Rivers Colorado & Gila Rivers

Salt River mi long Verde River and Black River are tributaries Ends in Gila River Challenges: Turbidity (sediment) Fecal Coliform Mining

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 h_aquifer.html h_aquifer.html Filtration h_filtration.html 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)

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February 8, Arizona’s Future

February 8, Current Lower Basin Reservoir Stats * * As of 1/1/08 Current Storage Percent Full Million Acre-Feet 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

February 8, The Colorado River system is facing the worst drought on record. Lake Mead's water level has dropped approximately 70 feet since January When full, Lake Mead contains enough water to cover the state of New York with water one foot deep. Lake Mead’s Water Level

February 8, 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, 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

Solutions? Arizona Farmers on the Verde River 2/05/smarter-irrigation-returns-water-to- arizonas-verde-river/ 2/05/smarter-irrigation-returns-water-to- arizonas-verde-river/

February 8, What if an extended drought is normal? – Hydrological studies indicate that cyclical wet/dry periods of years are normal – Supply calculations might be overly optimistic – What does this mean for water management?

February 8, 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, 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