Water Resources 101

Arizona’s Water:

Supp

lies

and

Usa

ge

Water Resources 101

Where does Arizona’s water come from?

Three basic sources:1. Groundwater2. Surface Water3. Effluent

Water Resources 101

GroundwaterFarmers in Tucson

area began drilling GW wells in early 1900’s1902: DTW 10’-20’1922: DTW ~ 100’2006: DTW ~ 300’

There are now ~ 7,000 production wells in AZ (without private wells)

Water Resources 101

Groundwater Use in AZ

Total GW Pumpage in 2005 was 2.9 MAF

Accounts for approximately 40% of AZ’s water supply

Groundwater mining (overdraft) is a statewide problem – its not just for AMA’s anymore

Tucson AMA 220 KAF

Phoenix AMA 800 KAF

Pinal AMA 460 KAF

Santa Cruz AMA 21 KAF

Non AMA Areas 1.4 MAF

Prescott AMA 21 KAF

2005 DataHistoric GW use in AZ

0

1

2

3

4

5

6

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Year

MA

F/y

r

Water Resources 101

Surface WaterHistory:

Pre-Hohokam irrigation system found in Tucson – 1200 BC

Hohokam developed first canal in Phoenix area in 800 AD

AZ’s largest source of renewable waterAbout 50% of AZ’s water

supplyOver 4 MAF per year

Availability varies from:year to yearseason to seasonplace to place

2005 Data

Colorado River 2.8 MAF

Gila River 0.4 MAF

Salt/Verde River 1.0 MAF

Water Resources 101

Salt River Project (SRP)1902 – National Reclamation Act

(Provided funding for SRP)1903 – SRP established: 1st

multipurpose reclamation project in the US (water & power)

1908 – Granite Reef Diversion completed

1911 – Roosevelt Dam Completed (later expanded in 1996)

From 1925 – 1946 SRP built 5 more dams 3 on the Salt River 2 on the Verde River Total capacity ~ 2.3MAF

2007 - delivered ~ 1MAF of water 80% Ag in 1965 – 15% Ag in 2007

Water Resources 101

1928 – Boulder Canyon Project Act (Allocated Colo. River Water)

1946 – Formation of CAPA (Lobbying group for CAP)

1968 – Colorado River Basin Project Act (CAP Authorization)

1973 – Construction started1993 – Project completion

335 miles, 2,400’ lift 1.6 MAF/yr of deliveries (26% Ag in

2008) Construction cost >$4 billion Largest water transfer project ever

constructed in the US

Central Arizona Project (CAP)

Water Resources 101

EffluentLong history of reuse in AZ

Grand Canyon – 1926Phoenix/Peterson Farms –

1932Tucson Reclaimed System -

1983Direct reuse accounts for ~

2.5% of AZ’s water supply (200 KAF)~ 70% for turf/ag irrigation

In 2006, we directly reused about 20% of the effluent produced in AZProbably higher in 2008

Remainder is recharged – directly & indirectly

Water Resources 101

How Is Arizona’s Water Used?

Agriculture 74%

5.8 MAF

Industrial 6%

Municipal 20%

1.6 MAF

0.5 MAF

2005 Data

Total Water Usage = 7.9 MAF

Water Resources 101

How Has Our Water Use Changed Over Time?

In general, water consumption has increased with increasing populations (except recent AMA activity)

Water use between sectors has changedUse between water sources has shiftedWater use changes vary by geographical

region

Water Resources 101

The AZ Water AtlasADWR project – overview of

water supply and demand in Arizona

Divides state into 7 Planning Areas

When complete – 8 VolumesGoal – Provide regional

perspective on supply, demand and water resource issues

Water Resources 101

Active Management Areas(AMAs)

Water Resources 101

Tucson AMA Changes By Sector

1986

By Source

2006

270 KAF

344 KAF

518K People

1.0M People

* GSF = 100% CAP

*

Water Resources 101

600

Tucson Active Management AreaWater Use by Sector: 1940-2000

0

100

200

300

400

500

1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995Year

Wat

er U

se(t

ho

usa

nd

s o

f A

cre

Agricultural Municipal Industrial Total

100

200

300

400

500

1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995Year

Fee

t)

Agricultural Municipal Industrial Total

2000

Water Resources 101

Phoenix AMA Changes By Sector

1986

By Source

2006

2.2 MAF

2.2 MAF

1.9M People

3.6M People

* GSF = 80% CAP/20% Effluent *

Water Resources 101

Pinal AMA Changes By Sector

1986

By Source

2006

783 KAF

1.0 MAF

40K People

148K Ppl

* GSF = 100% CAP

*

Water Resources 101

Prescott AMA Changes By Sector By Source

2006

1986

22 KAF

46 KAF

40K Ppl

95K People

Water Resources 101

Santa Cruz AMA Changes By Source

20061986 By Sector

21 KAF16 KAF

19K People 22K People

Water Resources 101

Eastern Plateau Planning Area

Water Resources 101

Eastern Plateau Planning AreaGW use increased by

13% from 1986 to 2005SW use decreased by

40% from 1986 to 2005Water Use by Sector:

Industrial = 49%Municipal = 26%Agricultural = 25%

Population increased from 209K in 1990 to 279K in 2006 (33%) 61%

9%

30%

Average Annual Water Use per Sector (2001-2005)

Total ~ 170 KAF

Water Resources 101

Southeastern AZ Planning Area

Water Resources 101

Southeastern AZ Planning Area

Water Use by Sector

AG 85%

Muni 8%Ind 7%

Total Water Use (2001-2005) = 515,000 AF/YR

• Agricultural demand increased by 4% from 1995 – 2005

• Industrial demand decreased by 38% from 1995 – 2005

• Effluent reuse < 1% of total water use (11% of total amount generated)

• Groundwater use accounts for about 84% of total water use

Water Resources 101

Upper Colorado River Planning Area

Water Resources 101

Upper Colorado River Planning AreaWater Use by Sector (2003):

SW 38%

Effluent 2%

GW 60%

Water Use By Source (2003)

Total Water Use (2003) = 173,650 AF

Agricultural = 95,850 AF (55%)Municipal = 55,200 AF (32%) Industrial = 22,600 AF (13%)

Water Resources 101

Central Highlands Planning Area

Water Resources 101

Central Highlands Planning AreaWater Use by Sector (2003):

SW 38%

Effluent 2%

GW 60%

Water Use By Source (2001 – 2003)

Total Water Use (2003) = 77,650 AF

Agricultural = 38,000 AF (49%)Municipal = 22,600 AF (29%) 92%

GW Industrial = 17,100 AF (22%)

Water Resources 101

Western Plateau Planning Area

Water Resources 101

Western Plateau Planning AreaWater Use by Sector:

Agricultural = 4,500 AF (51%) 44% from GWMunicipal = 3,400 AF (39%) Industrial = 900 AF (10%)

Water Use By Source (2001-2003)

SW 39%

Effluent 3%

GW 57%Total Water Use = 8,800 AF

Water Resources 101

Lower Colorado River Planning Area

Water Resources 101

Lower Colorado River Planning AreaWater Use by Source:

Groundwater = 1,027,250 AF (34%)Surface Water = 2,010,500 AF (66%) CAP = 88,187 AFEffluent = 680 AF (0.02%)

Water Use By Sector (2001-2003)

Total Water Use = 3,038,400 AF

Agriculture 98%

Municipal 2%Industrial <1%

Water Resources 101

So, What Have We Learned?Water Use Patterns have changed over time:

by Sectorby Sourceby Geography

Conjunctive use Works! Diversity is a good thing!Combination varies by region, but sources are the

same: Groundwater Surface Water Effluent

Planning (Long-Term) + Investment = Reliability