Shortage on the Colorado River: Analysis of Impacts to Water Users in Central Arizona. Ken Seasholes

Transcription

1 Shortage on the Colorado River: Analysis of Impacts to Water Users in Central Arizona Ken Seasholes Manager, Resource Planning & Analysis AWRA Annual Conference, Denver November 19, 2015

2 Colorado River Lower Basin 7.5 MAF California 4.4 MAF Arizona 2.8 MAF Nevada 0.3 MAF Mexico 1.5 MAF Nevada Colorado River Basin Utah Wyoming Colorado Arizona California New Mexico Mexico

3 Basin Project Act (1968) Authorized construction of the Central Arizona Project (CAP) Made CAP s right junior to most others in the Lower Basin, including all of California s 4.4 MAF and most of the rights in Nevada and On-River users within Arizona Diversion is ~1.6 MAF (2.8 MAF 1.2 MAF On-River) CAP supply is subject to reduction when Shortage is declared by the Secretary of the Interior Impacts depend on depth of shortage and how the CAP supply is being used

4 Arizona Shortage Strategies Conservation & Water Management Long-term programs Drought response provisions Tiered Priorities of CAP Water Shortage Sharing With Nevada and Mexico Within Arizona between CAP and On-River Water Banking & Recovery

5 Comprehensive Management 1980 Groundwater Management Act Created the Arizona Department of Water Resources Established Active Management Areas Hydrologic boundaries Stringent regulations Long-range water management goals Ensured funding of the Central Arizona Project

6 Central Arizona Project 336 mile aqueduct system 15 pumping plants 8 siphons, 3 tunnels 2,900 ft. of lift 2.8 million MWH/yr.

7 Priorities of CAP Water o The first distinction in priority is between Long-Term Contracts and Excess Water o Total Long-Term Contracts = MAF Non-Indian Subcontra cts 54% Indian Contracts 46%

8 Priorities of CAP Water o Any CAP water available after filling Long-Term Contracts is Excess Water Agricultural Settlement Pool is 1 st priority 400,000 AF through ,000 AF 2017 to ,000 AF 2024 to 2030 Remaining Excess Water is primarily for underground storage and replenishment

9 CAP Deliveries 2014 Prior to Long-Term Contracts

10 1,600, Deliveries Low 1,400,000 Other Excess 132 KAF 1,200,000 Excess Water 530,000 AF Excess Ag Pool 400 KAF CAP Delivery Priority Acre Feet 1,000, , , ,000 NIA Priority 177 KAF Long-Term Contract Water Indian 995,000 M&I AF Priority Priority 431 KAF 318 KAF 1,525,000 AF High 200,000 0 Priority 3-68 KAF

11 Priorities of CAP Water o There is an additional priority scheme among the Long-term Contracts that further insulates cities and tribes from many of the impacts of shortage Highest Equal Lowest o Priority 3 (P3) Priority o Indian Priority o Municipal & Industrial (M&I) Priority o Non-Indian Agricultural (NIA) Priority

12 1,600, Deliveries Low 1,400,000 Other Excess 132 KAF 1,200,000 Excess Water 530,000 AF Ag Pool 400 KAF CAP Delivery Priority Acre Feet 1,000, , , ,000 NIA Priority 177 KAF Indian Long-Term Contract Water 995,000 M&I Priority AF Priority 431 KAF 318 KAF 1,525,000 AF High 200,000 0 Priority 3-68 KAF

13 1,600, Deliveries Low 1,400,000 1,200,000 Other Excess 132 KAF Excess Water 530,000 AF Ag Pool 400 KAF Ag CAP Delivery Priority Tribes Acre Feet 1,000, , , ,000 NIA Priority 177 KAF Indian Long-Term Contract Water 995,000 M&I Priority AF Priority 431 KAF 318 KAF Cities High 200,000 0 Priority 3-68 KAF

14 Shortage Sharing Lower Basin shortages shared based on 2007 Guidelines Mexico separately agreed to reductions at the same elevations Lake Mead Elevation Arizona Reduction Nevada Reduction California Reduction Mexico Reduction ,000 AF 13,000 AF 0 AF 50,000 AF ,000 AF 17,000 AF 0 AF 70,000 AF ,000 AF 20,000 AF 0 AF 125,000 AF

15 Water Banking Water banking recharging water for later use has become an important part of Arizona s strategy for mitigating impacts from Colorado River shortages Stored water will be pumped from wells ( recovered ) to supplement ( firm ) the Colorado River supply Arizona has created an elaborate physical, institutional, financial and regulatory framework to accomplish this goal

16 Arizona Water Banking Authority The AWBA was established in 1996 To mitigate the impacts of Colorado River shortages To create water management benefits To allow interstate storage To help settle Indian water rights claims Water will be recovered when Colorado River shortages affect users that are firmed by the AWBA Primarily municipal users, and specific tribes 16

17 AWBA Storage 3.9 MAF in storage 3.3 MAF for AZ 0.6 MAF for NV In the Phoenix, Pinal and Tucson Active Management Areas 10 Underground Storage Facilities (USFs) 14 Groundwater Savings Facilities (GSFs) GSF USF NV AZ 17

18 Shortage: Near-Term Near-term shortage impacts are based on baseline CAP projections that are developed annually to assist operations and planning 3 to 10-year forecast duration Generally assume no major changes in customer orders Gradual increase in long-term contract orders Similar rates of recharge activity by long-term contractors that are banking for themselves 18

19 2017 Projected Deliveries 1,600,000 Low 1,400,000 1,200,000 Other Excess 175 KAF Ag Pool 300 KAF Excess Water CAP Delivery Priority Acre Feet 1,000, , , ,000 Indian Priority 326 KAF NIA Priority 222 KAF M&I Priority 448 KAF Long-term Contract Water High 200,000 0 Priority 3-68 KAF

20 1,600,000 Tier 1 Shortage Impact Low 1,400,000 Other Excess Shortage Ag Pool Shortage 143 KAF 320,000 1,200,000 Ag Pool 157 KAF CAP Delivery Priority Acre Feet 1,000, , , ,000 Indian Priority 326 KAF NIA Priority 222 KAF M&I Priority 448 KAF High 200,000 0 Priority 3-68 KAF

21 1,600,000 Tier 2 Shortage Impact Low 1,400,000 1,200,000 Other Excess Shortage Ag Pool Shortage 223 KAF 400,000 CAP Delivery Priority Acre Feet 1,000, , , ,000 Indian Priority 326 KAF Ag Pool 77 KAF NIA Priority 222 KAF M&I Priority 448 KAF High 200,000 0 Priority 3-68 KAF

22 Projection Uncertainties o CAP supply & demand uncertainties o On-river use total available CAP delivery supply o Changes in customer ordering patterns o Availability of other supplies o Additional uncertainties during shortage o Drought-related conservation or behavioral changes affecting long-term contract orders o Impact of rate increases

23 Shortage: Long-Term Longer term projections must account for higher levels of uncertainty At the Basin scale, the Reclamation s Colorado River Simulation System (CRSS) model is used Hydrology (Observed, Paleo, Downscaled GCMs) Upper Basin depletions Reservoir operations, including shortage Policy changes The supply outputs from CRSS are then used as inputs for further modeling and analysis

24 Service Area Analysis Example CAP Water Use by Destination Actual Projection Recharge Basins Total Recharge (GSF+USF) Crops Other Treatment Plants

25 Service Area Analysis Example CAP Water Use by Destination with Shortage Actual Projection Recharge Basins Shortage Crops Total Recharge (GSF+USF) Other Treatment Plants

26 AWBA Recovery Planning In 2014, a Joint Recovery Plan was developed by CAP, AWBA and ADWR Describes basic framework, methods, timing, volume, and potential partnering opportunities 26

27 Recovery Timing A scenario planning approach was taken to evaluate shortage, and the magnitude and type of AWBA recovery needed Based on shortage tiers from guidelines

28 Summary Near-term shortages will primarily affect CAP agricultural users and recharge Some increase in groundwater pumping is likely Shortage will likely increase CAP delivery rates Medium and longer-term projections indicate more frequent and extensive shortage impacts Over-allocation and poor hydrology could create instability in the Colorado River system The impact of shortage to Central Arizona will ultimately rest on how successful the Basin States and Mexico are in addressing the projected imbalances in supply and demand

29 Questions? Ken Seasholes Jessica Fox