Arizona Water Resources and Issues Border Governors Conference

Arizona Water Resources and Issues Border Governor’s Conference - Water Table May 8, 2006

Geographic and Socioeconomic Profile • Area and geographic boundaries – 114, 000 sq mi – 6 th largest state in U. S. – Bordered on the south by Sonora, on west by California and Baja California, on north by Utah and on east by New Mexico – Elevation range 70 feet – 12, 633 feet – 51 groundwater basins in Arizona

Geographic and Socioeconomic Profile • Population – 15 counties; 87 cities and towns – 5. 9 million inhabitants (2005) – 2 nd fastest growing state in U. S. • Socioeconomic conditions – Principal activities: manufacturing, finance, commerce, mining, agriculture, tourism – 2. 9 million employed (4. 4% unemployment)

Hydrology • Climate – Characteristics: warm temperatures, aridity, seasonal precipitation, high year-to-year variability, strong decade-to-decade persistence – Average annual rainfall ranges from 3 inches in Yuma to >36 inches along Mogollon Rim – Average daily temperatures range from mid 90 s (F) below 500 feet elevation to the high 50 s (F) above 8, 000 feet elevation

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

Water Supply of Arizona Colorado River 2. 8 MAF Salt River 0. 9 MAF Groundwater 3. 5 MAF Gila River 0. 3 MAF

Hydrology • Surface Water – Colorado River Water 2. 8 maf • 1. 3 maf on River • 1. 5 maf Central Arizona Project (CAP) to central Arizona – Salt and Verde Rivers (Phoenix) • 0. 9 maf – Gila River • 0. 3 maf – Local surface water sources • Little Colorado River, San Pedro River, Upper Verde River

Hydrology • Groundwater – Recharge rates vary significantly by area – Deep, productive, good quality aquifers in many areas of central and southern Arizona – Thin, unproductive, deep or poor quality aquifers in many systems in northern Arizona (Arsenic, Total Dissolved Solids)

Arizona Water Supply Annual Water Budget Water Source Million Acre-Feet (maf) % of Total SURFACE WATER Colorado River CAP On-River 2. 8 1. 6 1. 2 In-State Rivers Salt-Verde Gila & others 36. 4 % 21% 16% 1. 2 0. 9 0. 3 15. 6% 12% 4% GROUNDWATER EFFLUENT 3. 5 45. 5% 0. 18 2. 3% Total 7. 7 maf

Arizona Reservoirs & Capacity Reservoir Capacity (million AF) Lake Powell 24. 5 Lake Mead 25. 9 Lake Mohave 1. 8 Lake Havasu 0. 65 Lake Pleasant 0. 81 Horseshoe Lake 0. 13 Bartlett Lake 0. 18 Roosevelt Lake 1. 6 San Carlos Lake 1. 3 Apache Lake 0. 25 Canyon Lake 0. 06 Saguaro Lake 0. 07 Alamo Lake 1. 05 Reservoir Capacity 58. 3 MAF

Arizona mean, high capacity and low capacity reservoir levels from 1971 through 2005, expressed in percent of total reservoir capacity Average Capacity High Capacity Year Low Capacity (2004) Colorado River System Lake Powell 70% 98% 1983 31% Colorado River System Lake Mead 77% 98% 1983 51% Colorado River System Lake Mohave 89% 92% 2003 91% Colorado River System Lake Havasu 92% 94% 1995 91% 56% 91% 1992 43% 59% 77% 1979 43% Reservoir Name Verde River Basin System Salt River Basin System (2005)

Demand Sources: ADWR, Uof. A, 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

GROUNDWATER DATA FOR THE YUMA BASIN (DRAFT) Basin Area, in square miles: 792 Name and/or Geologic Units Major Aquifer(s): Basin Fill Well Yields, in gal/min: Estimated Natural Recharge, in acre-feet/year: Estimated Water Currently in Storage, in acre-feet: Range 3, 186 -5, 271 Median 5, 098 (3 well reported) Measured by ADWR and/or USGS Range 10 -7, 000 Median 2, 456 (327 wells reported ) Reported on registration forms for large (> 10 -inch) diameter wells Range 500 -3, 000 ADWR (1990) Range 0 -2, 500 USGS (1994) 213, 000 Freethey and Anderson (1986) 49, 000 (to 1, 200 ft bls) ADWR (1994) 34, 0001 (to 1, 200 ft bls) Freethey and Anderson (1986) 35, 000 (to 1, 200 ft bls) Arizona Water Commission (1975) Current Number of Index Wells: 11 Date of Last Water-level Sweep: 1992 (587 wells measured) Reported Water Quality Exceedences: 1 Predevelopment Estimate bls=below land surface Arsenic, Cadmium, Fluoride, Lead, Nitrate, Organics, Solids, and Trace Elements (Antimony, Beryllium, and Thallium)

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 All water uses 10, 300 AF 8, 600 AF 7, 300 AF 1, 500 AF 25, 800 AF 537 AF

Upper San Pedro Basin Cultural Water Demand - 2003

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)

Government Framework and Management of Water Resources • Federal Agencies – Bureau of Reclamation • Administers Colorado River Basin Project Act and Colorado River Contracts. • Responsible for construction of major water supply development projects – Environmental Protection Agency • Federal oversight of surface water and drinking water quality programs • Oversight of state efforts to regulate solid waste landfills and hazardous waste sites – Army Corp of Engineers • Conducts flood control studies and dam, levee and channelization projects. Regulates placement of dredged or fill material into waters of the U. S.

Government Framework and Management of Water Resources • State of Arizona Agencies – Arizona Department of Water Resources • Groundwater management and administration of water rights • Technical and administrative support to the surface water adjudication court • Authority to consult, advise and cooperate with the U. S. Secretary of Interior on certain matters related to the Colorado River • Supervision of safety of dams under state jurisdiction – Arizona Department of Environmental Quality • Administers water pollution control, monitoring and assessment, and contamination site cleanup programs • Effluent reuse, groundwater recharge projects and discharge of water to aquifers or streambeds must meet water quality standards

Government Framework and Management of Water Resources • State of Arizona Agencies – Central Arizona Water Conservation District • Tax-levying public improvement district of the state responsible for Central Arizona Project system maintenance and operations, repayment obligations and creation of water resource management programs – Arizona Water Banking Authority • Stores Arizona’s unused Colorado River allotment in groundwater basins to firm up urban water supplies for Arizona to be used during times of shortages on the Colorado River or during CAP service interruptions. • May enter into interstate agreements with entities in Nevada and California to store water in Arizona

Government Framework and Management of Water Resources • Local Agencies – Have certain authorities to obtain and manage water resources locally in accordance with state and federal laws – Public water utilities • Set water rates, can enact local water conservation and water use ordinances. For example, can require effluent use on golf courses, time of day lawn watering, etc. – Private water utilities • Regulated by the Arizona Corporation Commission, which regulates water rates and authorizes curtailment tariffs when demand is greater than production • Cannot pass ordinances affecting water use or rates

Groundwater Management • There are different programs and regulations in Active Management Areas (AMAs), Irrigation Non-Expansion areas (INAs) and in areas outside of AMAs and INAs. • Statewide, all wells must be registered and drilled by a licensed well driller • Statewide, transportation of groundwater between groundwater basins is prohibited except as allowed specifically by statute

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

Groundwater Management – Active Management Areas • 1980 Groundwater Management Act: – Established Active Management Areas (AMA’s) – Currently 5 – Established a system of groundwater rights based on historic use and permits for new uses subject to specific conditions – Set long-range water management goals for AMAs • Will AMAs achieve their goals? What other actions are needed? • Requires management plan for each AMA – Created the Arizona Department of Water Resources to administer the provisions of the Act • Department has regulatory, permitting and enforcement power; it does not control water supplies or infrastructure

Groundwater Management – AMA Management Plans – New plan every 10 years, though 2025; developed through a public process – Increasingly stringent conservation requirements – Include long-range water demand supply projections – Conservation programs for agriculture, municipal and industrial water users – Recharge/augmentation program and water quality assessment

Groundwater Management – Irrigation Non-Expansion Areas • Irrigation non-expansion areas – Established in areas of critical groundwater overdraft-but not as severe as in AMAs – Prohibition of new agricultural irrigation acreage – Management objective to protect existing water users – 3 INAs: Douglas, Harquahala, Joseph City

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

Future Water Supplies-Conservation • Public outreach: • Teach Good Water Habits Statewide • Provide information on the best available conservation technologies • Provide incentives – tax credits • Voluntary local conservation goals • Promote low water use designs in landscaping • Local government initiatives: • ‘Toilet to tap’ • Domestic/commercial water-harvesting and use of ‘graywater’ • Encourage water-efficient appliances, fixtures, ordinances • Ordinances for use of effluent for large turf areas such as golf courses, parks and sports facilities

Future Water Supplies - Effluent Reuse and Augmentation • Improve treatment quality or match quality to use • Turf and Landscape Uses - some municipal and county ordinances require effluent for new golf courses and turf areas. There also regulatory incentives • Recharge excess for later recovery • Direct Reuse – considered but must overcome public perception issues • Augmentation includes importing water where legally available, cloud seeding, constructing necessary infrastructure, securing water sources and rights, desalination

Challenges: Indian Water Settlements • 28% of Arizona Land held in Trust for the benefit of Native Americans • Many areas of the state are affected by Indian Water Rights settlements with significant implications for water management and access to water • 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 • Of the 7. 5 million acre-feet of water available to the lower basin states, Arizona’s Central Arizona Project water supply has the most junior priority. • River is over-allocated • 16. 5 maf allocation vs. 13 - 15 maf actual • Drought impacts on water supply • 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) 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

Mexican Water Treaty of 1944 Allots to Mexico 1. 5 maf of Colorado River water per year, plus 200, 000 acre-feet if the Secretary determines that surplus water is available.

Colorado River Flows Legally allocated Tree rings, Upper Basin (1512 -1961) 16. 5 MAF 13. 5 MAF Lowest 20 -year average (1579 -1598) Tree rings, Upper Basin (1512 -2000) 10. 95 MAF 14. 7 MAF Isotopes, Delta clams (1500 -1950) 12. 5 MAF

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

Average water year (October –September) temperature and total water-year precipitation in Arizona from 1930 -2002. Figure Author: Ben Crawford, CLIMAS

Challenges - Border • Issues related to the Colorado River are under federal jurisdiction and international treaty • Increasing 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 • Need for an integrated binational groundwater model to effectively manage the Santa Cruz AMA water resources to meet the management goal • Uncertainty about the future use of effluent generated by Mexico and treated at the Nogales International Wastewater treatment plant in Arizona and concerns about the quality of the effluent. Effluent is an important supply for riparian areas and groundwater recharge