Water Resources 101 Arizona’s Water: S upplies and Usage
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