Colorado River Challenges Impacts to Southern Arizona
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Colorado River Basics 7 States, 2 Nations Annual Flow 15.0 MAF 40 Million People All of the Major Cities in Southwest 5.5m Irrigated Acres 250,000 mi 2 Basin Area Huge Topographic and Climatic Variability Apportioned: 50/50 Split Upper Basin Lower Basin Source: Colorado River Institute, Colorado State University
Central Arizona Project
CAP Service Area 3 counties 23,790 square miles < 8 annual rainfall 5 million people (approx. 80% of Arizona s population) 350,000 acres of irrigated agriculture 11 Native American tribes
How Much Water Does CAP Deliver? 1.6 million acre-feet each year = 521 billion gallons At Tucson s current per capita usage (90 gpd), this is enough to serve 16 million people
CAP Water Usage 2015 Cities - 33% 528,000 AF Farms (incl Tribes) 58% 927,000 AF Recharge Projects 6% More than 4 MAF since 1996
How Does Metro Tucson Use CAP Water? 178,000 AF/Year 10 Water Providers Both Public and Private Water Companies Recharge and Recovery Tucson s projects Rise in Groundwater Tucson Wheeling CAP water for Oro Valley, Vail, Metro, etc Others Using Recharge
Three Colorado River Challenges A Growing Gap Colorado River Water Supply and Demand Study
Three Colorado River Challenges An Extended Drought Historical Colorado River Flow 25 20 13 of the last 16 years (2000-2015) had below average Colorado River flow Flow (MAF) 15 10 Mean Flow = 10.73 5 0 2011 2005 2008 Year
Three Colorado River Challenges A Long-Avoided Risk Structural Deficit at Lake Mead Normal Inflow (Release from Lake Powell plus smaller rivers) 9.0 MAF Normal Outflow Evaporation Balance 9.6 MAF 0.6 MAF -1.2 MAF Approximately 12 foot decline in normal year
Probability of Shortage Year Probability of Shortage Probability of Tier 1 Shortage Probability of Tier 2 Shortage Probability of Tier 3 Shortage 2016 None 0% 0% 0% 2017 10% 10% 0% 0% 2018 52% 42% 10% 0% 2019 65% 47% 14% 4% 2020 59% 35% 18% 7% Source: BOR January 2016 24 month study
What Happens During a Shortage? The Secretary of the Interior reduces the amount of Colorado River water available to Arizona, Nevada and Mexico The amount of reduction depends on the elevation of Lake Mead Within Arizona, the reduction will be to CAP in the near term
Shortages within CAP Within the CAP system, water is distributed based on an internal priority scheme Long-term CAP water supply contracts have high priority, including: Municipal & Industrial Customers Native American Communities
Shortages within CAP The lowest priority within the CAP system is Excess Water water not ordered under long-term CAP contracts Excess Water has its own priority scheme 1 st Priority Agricultural Users 2 nd Priority Recharge and Other Excess Users
Shortage Impacts on CAP Customers Other Excess CAP Delivery Priority Low High Ag Pool Native American and Municipal & Industrial Priority Tier 1 Shortage Tier 2 Shortage Tier 3 Shortage Shortage amounts based on 2007 Lower Basin Shortage Sharing Guidelines
Impact on CAP Water Rates While cities will not experience significant cuts in their annual deliveries, shortage will impact CAP Water Delivery Rates Rate = Cost Volume With delivery reductions, CAP must collect fixed costs from a smaller number of customers Reduction of electrical power from Hoover Dam at Lake Mead will cause CAP to use some more expensive power
A Risk to All Colorado River Users Without equalization from Lake Powell or corrective action, Lake Mead could fall below elevation 1000 feet in <10 years If Lake Mead falls below 1000 ft: Southern Nevada Water Authority s ability to withdraw water is impacted Lake Mead has less than 4.5 MAF left in storage (<55% of normal flow) Power generation and efficiency at Hoover Dam is reduced and cavitation or vibration damage is possible
CAP Shortage Management Programs Storage and Recovery - 4 MAF of underground storage for future of CAP cities Lake Mead Reservoir Protection - Interstate plan to leave 740,000 AF in Lake Mead by end of 2017 - CAP has already stored more than 200,000 AF Innovative Conservation - Interstate funding to conserve 70,000 AF in the Colorado River Augmentation - Weather modification projects in the Upper Basin - Local and binational desalination
Banking Colorado River Water More than 4 MAF have been recharged in Underground Storage and Groundwater Savings Facilities since 1992 The stored water will increase the reliability of CAP subcontracts and certain on-river and Indian supplies CAP, in partnership with state agencies, customers and stakeholders has developed a recovery plan for the future retrieval of that stored water
Colorado River Sustainability Plan Memorandum of Understanding Reduce risks associated with low reservoir conditions by generating or storing additional water in Lake Mead United States Bureau of Reclamation AZ Department of Water Resources Central Arizona Project Colorado River Board of California The Metropolitan Water District of Southern California Southern Nevada Water Authority Colorado River Commission of Nevada
CAP Savings Plan Intentionally Created Surplus Voluntary Forbearance Agreements Alternate Deliveries to Phoenix Unused State Apportionment and changes in CAP operations
Pilot System Conservation Agreement Conservation Grants for River System Benefit $11 M Pooled funding $2 M each from CAP, MWD, SNWA, DW $3 M from BOR Basin-wide approach Lower Basin Upper Basin Mexico
Additional Regional Efforts Arizona, Nevada, California and the Bureau of Reclamation are working to develop a new set of tools and a shared strategy to go above and beyond what s already in place to protect Lake Mead
Options to Decrease Water Demand M&I Conservation Indoor residential Outdoor residential Commercial, industrial, & institutional Energy Water Use Efficiency Thermo-electric generation conversion to dry-cooling Agricultural Water Conservation Fallowing Conveyance system efficiency On-farm irrigation efficiency Improved irrigation management
System Conservation Yuma Desalting Plant Reduces the salts in drainage water so the water can be delivered to Mexico per U.S. treaty obligations Brock Reservoir Temporary storage which allows water that is ordered from Lake Mead but subsequently not used to be delivered later Vegetation Management Reduces non-native plants that consume river water and allows reestablishment of lower water using native vegetation
Options to Increase Water Supplies Water Importation and Exchange River imports to Front Range Desalination Pacific Ocean Gulf of California Brackish groundwater Yuma area Salton Sea drain water Reuse Municipal wastewater Industrial wastewater recycling Watershed Management Tamarisk control Weather modification
CAP is Preparing for the Future Colorado River Basin Working cooperatively with state, regional and national partners to address water supply challenges Supporting water conservation education and training for urban and agricultural customers Participating in efforts to address the gap between Colorado River supplies and anticipated demand Interacting regularly with customers and stakeholders about issues of mutual concern
Colorado River Challenges Impacts to Southern Arizona