The Colorado River · The Colorado River: A quick look at a complex system Eric Kuhn, General Manager Gunnison Basin State of the Rivers – June 1, 2015

The Colorado River:A quick look at a complex system

Eric Kuhn, General Manager

Gunnison Basin State of the Rivers – June 1, 2015

Colorado River Basin Today• Seven Basin States• Almost 300,000 square miles• 35 Million People and growing• Up to 5.5 Million Irrigated Acres• 10 Autonomous / Sovereign Tribes• 2 Countries

Colorado River Basin Tomorrow• Seven Basin States• Almost 300,000 square miles• 80 Million People (increase of 91%?)*

• 4.6 Million Irrigated Acres (decrease of 15%?)*

• 10 Autonomous / Sovereign Tribes• 2 Countries

* Source USBR Colorado River Basin Study, 2012

Law of the River Allocations 7.5 MAF to Upper Basin (by %’s to CO, UT, WY, NM)1

7.5 MAF to Lower Basin (4.4 CA; 2.8 AZ; 0.3 NV)2

1.0 MAF additional to Lower Basin3

• (i.e., tributary development, e.g., Little Colorado and Gila Rivers in AZ)

1.5 MAF to Mexico4__________________________

17.5 MAF Total Allocated ‘on paper’1 1922 Colorado River Compact, 1948 Upper Colorado River Compact

2 Colorado River Compact, 1929 Boulder Canyon Project Act, 1964 AZ v. CA3 1922 Colorado River Compact

4 Treaty of 1944

1922 Colorado River Compact• Divides Colorado River (incl tributaries), into

Upper & Lower Basins and defines Divisions• Boundary between the two basins is Lee

Ferry, Arizona (i.e., compliance point)

• Lower Division: Nevada, California & Arizona • Upper Division: Wyoming, Colorado, New

Mexico & Utah• Arizona, Utah and New Mexico have lands

within both basins

Colorado River Compact of 1922Colorado, like all Upper Division states, shares obligations to the Lower Division

III (d) the Upper Division shall “not cause the flow of the river at Lee Ferry to be depleted below an aggregate of 75,000,000 acre-feet for any ten consecutive years.”

III (c) regarding Mexico…the Upper Division must “deliver at Lee Ferry water to supply one-half of the deficiency so recognized in addition to that provided in paragraph (d).”

Sources of Uncertainty1. What is the obligation and safe yield for the

Upper Basin States under the 1922 Compact? (Article III)

2. What water supply conditions should we plan for in the future?

Based upon: Climate change (warmer and drier?) 19TH century (above average), previous 30 years (below average), tree rings?

3. What is the future demand for water of all four states of the Upper Basin?

Population and economic growth? Technology? Values? Uses? Conservation?

Basic Trade-off Certainty vs. Development

• The higher the level of development the higher the risk of curtailment

• Pre-compact uses (primarily West Slope ag) not subject to Compact curtailment

• Existing post compact users desire Compact protection

– i.e., less development to minimize threat of a future curtailment

Long Term Questions • Future water supplies - drier? • Overuse of the water supply• Operation of Lake Powell after 2026? • How do we avoid a curtailment? • Future of agricultural water use? • Allowance for new water uses?• Will compacts, agreements and

management of reservoirs change?

Upper Basin uses incl. reservoir evap. 4.0 - 4.5

Lower Basin mainstream uses 7.5 - 7.5Lower Basin reservoir evap. 1.0 - 1.5Lower Basin tributaries 2.0 - 2.5Total Lower Basin 10.5 - 11.5

Subtotal 14.5 - 16.0Add Mexico 1.5 1.5TOTAL 16.0 – 17.5

Current Use EstimatesMAF/ year

Hydrology comparisonaverage annual inflows at Lee Ferry

• 2000-2014 12.3 MAF/year• 1988-2014 13.2 MAF/year • 1906-2014* 14.8 MAF/year • 1120-1172 T 12.7 MAF/year• Basin Study CC 13.7 MAF/yearCC = climate change* = gage period T = paleo-hydrology based upon tree rings

Data from Reclamation’s Naturalized Flows database

2000-2015 Water Budget

• Supply = 13 MAF/yr (12.3 at LF + .7 inflows LB)

• Use = >15 MAF/yr (not including LB tribs like Gila)

• Deficit = >2 MAF/yr

Observed storage change• December 1999: Mead + Powell > 50 MAF• December 2015: Mead + Powell < 18 MAF

2015 Another Dry Year!In spite of “Miracle May”• System storage will continue to decline• Lake Mead deliveries could see first

shortage in 2016 or more likely 2017• Lake Powell levels will continue to decline

moving us closer to minimum power• California is still in an historic drought• Pressure on the states will intensify to

implement contingency plans

Contingency Planning • Challenge from US Dept of Interior:

• What if the current drought were to continue into the future?

• Have a plan in place by 2015 (MOA or similar)

• The Goal: • Identify actions that can reduce the risk of losing

power production or being unable to deliver water• Possible Solutions:

• Extended Operation of CRSP reservoirs• Demand Management• Cloud seeding / other augmentation

Lake Powell Releases • Controlled by the 2007

Interim Guidelines

• Based on storage levels in both Powell & Mead

• What happens in the LB impacts Powell and what happens in the UB impacts Mead

• As long as Powell has storage - NO compact problems for UB

975

1,000

1,025

1,050

1,075

1,100

1,125

1,150

1,175

1,200

1,225

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

24 Month

2014

2015

Projected2016

2017

2018

2019

2020

Lake Mead Elevation Since 2000

Lake Mead Elevation (EOM) Projected 24 Month 8.23 MAF Releases First Shortage Tier

January 200091% Active Storage

12.52 MAF ReleaseWY 2011

Hydrology

Structural Deficit