Arizona Water Resources And Issues

1. ArizonaWater Resources And Issues Border Legislative Conference December 7, 2006

4. Average statewide Arizona monthly precipitation, (bars; left-hand scale) and temperature (line; right-hand scale) 1971-2000

5. Water Supply of Arizona Colorado River 2.8 MAF Salt River 0.9 MAF Groundwater 3.5 MAF Gila River 0.3 MAF

6. Arizona Water SupplyAnnual Water Budget 7.7 maf

7. Demand Sources: ADWR, UofA, USGS

8. 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

9. Border Profile

10. Yuma BasinCultural 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

11. 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 Demographics Amado PIMA COUNTY SANTA CRUZ COUNTY Tubac Rio Rico Nogales

12. Santa Cruz AMA Demand All water uses 10,300 AF 8,600 AF 7,300AF 1,500AF 25,800 AF 537 AF

13. Upper San Pedro BasinCultural Water Demand - 2003

15. Douglas BasinCultural 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

17. 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” • 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) “Subflow” subsurface water subject to surface water law

18. Water Management Areas Prescott AMA goal: safe-yield by 2025 Joseph City INA: No new irrigated lands Harquahala INA: No new irrigated lands Phoenix AMA goal: safe-yield by 2025 Pinal AMA goals:- allow development of non-irrigation uses- preserve agriculture as long as feasible Tucson AMA goal: safe-yield by 2025 Santa Cruz AMA goal:- maintain safe-yield- prevent decline of water table Douglas INA: No new irrigated lands

19. 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

20. Future Water SuppliesUnderground Storage - Benefits • Long-term storage • Large capacity • Little evaporative loss • Reduces risk of subsidence

21. 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?

22. 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

23. 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

24. 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

25. 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 Arizona Upper Basin – 50 kaf Mexico 1.5 maf

26. 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

27. 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