Transcript Title

Arizona Water Resources
And Issues
Border Legislative
Conference
December 7, 2006
Average statewide Arizona monthly precipitation, (bars; left-hand
scale) and temperature (line; right-hand scale) 1971-2000
2.5
100
80
1.5
60
1
40
0.5
20
temp (F)
precip (in.)
2
0
0
jan
feb
mar
apr
may
jun
Precip (in.)
jul
aug
Temp (F)
sep
oct
nov
dec
Water Supply of Arizona
Colorado River
2.8 MAF
Salt River
0.9 MAF
Groundwater
3.5 MAF
Gila River 0.3
MAF
Arizona Water Supply
Annual Water Budget
Water Source
Million Acre-Feet (maf)
% of Total
SURFACE WATER
Colorado River
2.8
36.4 %
CAP
1.6
21%
On-River
1.2
16%
In-State Rivers
1.2
15.6%
Salt-Verde
0.9
12%
Gila & others
0.3
4%
GROUNDWATER
EFFLUENT
3.5
45.5%
0.18
2.3%
Total
7.7 maf
Demand
Municipal
1.37 maf
18%
Industrial
.41 maf
5%
Agriculture
5.9 maf
77%
Sources: ADWR, UofA, USGS
Border Profile
• Two thirds of Arizona’s border is under federal
jurisdiction as national monuments, forests,
wildlife refuges, bombing ranges or are tribal
lands
• Significant agricultural and urban water use is
therefore restricted to area near Yuma and to
the communities of Nogales, Sierra Vista and
Douglas
Border Profile
Groundwater
Basin
2003
Population
2003
Surface
Water
Demand
(acre-ft)
2003
Groundwater
Demand
(acre-ft)
2050
Population
Yuma
176,000
788,000
304,000
502,000
Santa Cruz
AMA
37,000
Upper San
Pedro
82,000
4,500
34,000
110,000
Douglas
28,500
0
95,000
36,500
20,000
58,500
(2025)
Yuma Basin
Cultural Water Demand-2003
• 1.09 million acre-feet used in 2003 by agricultural,
municipal and industrial sector
– Well pumpage and diversion of Colorado River contract water
– 96% Agricultural Use
• Use not expected to increase
• 72% surface water
– 3.5% Municipal Use
• Rapidly growing communities of San Luis, Yuma and Fortuna
Foothills
• 85% surface water
– .5% Industrial Use
• 69% surface water
Santa Cruz AMA
Demographics
Amado
PIMA
SANTA
COUNTY
Tubac
CRUZ
COUNTY
Rio Rico
Nogales
• 37,000 people;
population concentrated
in Nogales and along
the Santa Cruz River
• Large fluctuations in
temporary residents
• Nogales, AZ population
23,000
• Nogales, Mexico
population 300,000
Santa Cruz AMA Demand
Use by Sector
All water uses
Underflow to
Tucson AMA
16%
8,600 AF
Agricultural
19%
10,300
Industrial
8%
AF
Municipal
13%
7,300 AF
Industrial
3%
1,500 AF
Riparian
48%
25,800 AF
Domestic
1%
537 AF
Municipal
40%
Agricultural
52%
Upper San Pedro Basin
Cultural Water Demand - 2003
20,000
18,000
Acre-Feet
16,000
14,000
12,000
Surface water
10,000
Groundwater
8,000
6,000
4,000
2,000
0
Municipal
Industrial
Agricultural
Water Use Sector
Douglas Basin
Cultural Water Demand - 2003
• 60,400 acre feet of groundwater
• Irrigation Non-expansion area
– Most of basin is an Irrigation Non-expansion area
– no new lands can be irrigated with groundwater
• 89% Agricultural Use
– Water use is increasing
• 11% Municipal Use
– Demand is increasing slowly
Government Framework and Management
of Water Resources
Laws governing surface water are distinct from those
governing groundwater
– Surface water
•Prior appropriation doctrine
– “First in time, first in right”
“Subflow”
subsurface water
subject to surface
water law
– Groundwater
•Beneficial use doctrine
– Unlimited ability to pump, so long as use is
“beneficial” and “reasonable” (outside AMAs)
– Ability to pump constrained by system of rights
and permits (inside AMAs)
Water Management Areas
Prescott AMA goal:
safe-yield by 2025
Harquahala INA: No
new irrigated lands
Pinal AMA goals:
- allow development of nonirrigation uses
- preserve agriculture as
long as feasible
Santa Cruz AMA goal:
- maintain safe-yield
- prevent decline of water table
Joseph City INA: No
new irrigated lands
Phoenix AMA goal:
safe-yield by 2025
Tucson AMA goal:
safe-yield by 2025
Douglas INA: No
new irrigated lands
Challenges: Future Water Supplies
• Underground Storage
–
–
–
–
CAP and effluent
55 Active Permits
Permitted volumes 150 af to 200 kaf/year
Most recharge facilities are located within AMAs;
especially the Phoenix AMA
• Conservation
• Reuse
• Augmentation
Future Water Supplies
Underground Storage - Benefits
• Long-term storage
• Large capacity
• Little evaporative loss
• Reduces risk of
subsidence
Water Management Initiatives
• Conservation
– Technology Transfer
– Education and Public Information
• Effluent Reuse
• Augmentation and Water Transfers
– Agriculture to Urban Water Transfers
– Desalinization in the Future?
Challenges: Indian Water Settlements
• 28% of Arizona Land held in Trust for the
benefit of Native Americans
• Recently Settled:
– Gila River Indian Community and
Tohono O’odham
635,000 acre-feet/year to Gila River
Indian Community
-- Fort Yuma – Quechan
• Pending settlements; Navajo, Hopi, White
Mountain Apache and San Carlos Apache
Challenges - Surface Water Adjudications
Definition: “A general stream adjudication is a
judicial proceeding in which the nature, extent,
and relative priority of water rights is
determined.”
Gila & Little Colorado cases are still in Phase 1
after 30+ years
Gila River
Little Colorado River
•Court must define the legal
difference between surface water and
ground water before rights can be
determined
Challenges - Colorado River
•Arizona’s Central Arizona Project water
supply has the most junior priority.
•Drought may cause water supply shortage
•Discussions are underway on supply
augmentation, conservation and system
management to meet demands and
obligations
Colorado River Compact &
Treaty Allocations
Upper Basin (7.5 maf)
Lee Ferry
Lower Basin (7.5 maf)
California – 4.4 maf
Arizona – 2.8 maf
Nevada – 0.3 maf
Mexico 1.5 maf
Arizona
Upper
Basin –
50 kaf
Challenges -Drought
• Arizona Drought Preparedness Plan
adopted in 2004 to identify drought
impacts, prepare drought response and
reduce drought impacts
• Water providers must prepare drought
plans
• Drought monitoring is ongoing
Challenges - Border
• Colorado River - federal jurisdiction and international
treaty
• Population growth is impacting shared and limited
water supplies
• Limited hydrologic information for many border basins
hinders water planning and management
• Water quality issues in the Douglas/Agua Prieta and
Ambos Nogales pose a threat to local water supplies
• Lack of access to renewable water supplies to support
increasing demand