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)

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

Arizona Water Supply Annual Water Budget Water Source Million Acre-Feet (maf) % of Total SURFACE WATER Colorado River % CAP1.621% On-River1.216% In-State Rivers % Salt-Verde Salt-Verde0.912% Gila & others Gila & others0.34% GROUNDWATER % EFFLUENT % 2.3% Total 7.7 maf 7.7 maf

Sources: ADWR, UofA, USGSDemand

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 Yuma176,000788,000304,000502,000 Santa Cruz AMA 37,00020,00058,500 (2025) Upper San Pedro 82,0004,50034,000110,000 Douglas28,500095,00036,500

Yuma Basin Cultural Water Demand 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 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 Nogales Tubac PIMA COUNTY Rio Rico SANTA CRUZ COUNTY Amado Demographics

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

Upper San Pedro Basin Cultural Water Demand

Douglas Basin Cultural Water Demand ,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

“Subflow” subsurface water subject to surface water law Laws governing surface water are distinct from those governing groundwater Government Framework and Management of Water Resources –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)

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

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 Challenges: Future Water Supplies

Future Water Supplies Underground Storage - Benefits Long-term storageLong-term storage Large capacityLarge capacity Little evaporative lossLittle evaporative loss Reduces risk of subsidenceReduces risk of subsidence

Water Management Initiatives ConservationConservation –Technology Transfer –Education and Public Information Effluent ReuseEffluent Reuse Augmentation and Water TransfersAugmentation 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 Americans28% of Arizona Land held in Trust for the benefit of Native Americans Recently Settled: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 ApachePending settlements; Navajo, Hopi, White Mountain Apache and San Carlos Apache

Challenges - Surface Water Adjudications Gila River Little Colorado River Definition: “A general stream adjudication is a judicial proceeding in which the nature, extent, and relative priority of water rights is determined.” Court must define the legal difference between surface water and ground water before rights can be determinedCourt must define the legal difference between surface water and ground water before rights can be determined Gila & Little Colorado cases are still in Phase 1 after 30+ years

Challenges - Colorado River Arizona’s Central Arizona Project water supply has the most junior priority.Arizona’s Central Arizona Project water supply has the most junior priority. Drought may cause water supply shortageDrought may cause water supply shortage Discussions are underway on supply augmentation, conservation and system management to meet demands and obligationsDiscussions are underway on supply augmentation, conservation and system management to meet demands and obligations

Upper Basin (7.5 maf Upper Basin (7.5 maf) 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 Lee Ferry Colorado River Compact & Treaty Allocations

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 -Drought

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 Challenges - Border