CENTRAL ARIZONA PROJECT

P.O. Box 43020

Phoenix, Arizona 85080

PHYSICAL ADDRESS

23636 North 7th Street

Phoenix, Arizona 85024

CONTACT INFORMATION

info@cap-az.com

623-869-2333

WEB

CentralArizonaProject.com 

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YOUR WATER. YOUR FUTURE. 

March 25, 2024

Submitted via e-mail to LTEMPSEIS@usbr.gov

Bureau of Reclamation

LTEMP SEIS Project Manager

125 South State Street, Suite 800,

Salt Lake City, UT 84138

RE: Comments on the Long Term Experimental and Management Plan (LTEMP) Draft 

Supplemental Environmental Impact Statement (DESIS)

Dear LTEMP SEIS Project Manager,

The Department of the Interior (Interior) through the Bureau of Reclamation (Reclamation) has 

published the DSEIS to the December 2016 Record of Decision for the Glen Canyon Dam LTEMP. 

The DSEIS analyzes additional flow options to disrupt smallmouth bass and other warmwater 

invasive nonnative fish from establishing below Glen Canyon Dam and analyzes new information 

regarding the sediment accounting window associated with the LTEMP High Flow Experiment 

(HFE) Protocol to improve Reclamation’s ability to implement HFE releases. See 89 FR 9148

(February 9, 2024).

The Central Arizona Water Conservation District (CAWCD) is a political subdivision of the State 

of Arizona, established pursuant to Arizona Revised Statutes § 48-3701 et seq., that operates the 

Central Arizona Project (CAP) pursuant to various contracts and agreements with Reclamation. 

The CAP canal is a 336-mile system that brings Colorado River water to central and southern 

Arizona, delivers the State of Arizona’s single largest renewable water supply, and provides water 

to municipalities, tribes, and agriculture. CAWCD, therefore, has a keen interest in the wise 

administration of the Colorado River system reservoirs, including Lake Powell and Lake Mead, 

and a particular interest in avoiding potential negative impacts from Glen Canyon Dam operations. 

CAWCD offers the following comments on the LTEMP DSEIS:

Water Deliveries: Operations to protect, mitigate and improve resources in Grand Canyon 

National Park and Glen Canyon National Recreation Area downstream of Glen Canyon Dam must 

remain consistent with and subject to the existing laws governing allocation, appropriation, 

development and exportation of the Colorado River resource. See Grand Canyon Protection Act
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YOUR WATER. YOUR FUTURE.

(GCPA), Pub. L. 102-575, 106 Stat. 4602, 4669, § 1802(b). The priority given to water storage, 

allocation and delivery under the GCPA substantially limits the Secretary’s ability to change other 

elements of Glen Canyon Dam operations. Accordingly, under existing LTEMP framework, water 

deliveries must be made “in a manner that is fully consistent with and subject to the Colorado 

River Compact, the Upper Colorado River Basin Compact, the Water Treaty of 1944 with Mexico, 

the decree of the Supreme Court in Arizona v. California, and the provisions of the Colorado River 

Storage Project Act of 1956 (CRSPA) and the Colorado River Basin Project Act of 1968 that 

govern allocation, appropriation, development, and exportation of the water of the Colorado River 

Basin, and consistent with applicable determinations of annual water release volumes from Glen 

Canyon Dam made pursuant to the Long-Range Operating Criteria (LROC) for Colorado River 

Basin Reservoirs, which are currently implemented through the 2007 Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead” (2007 Interim 

Guidelines). See Record of Decision for the Glen Canyon Dam Long-Term Experimental and 

Management Plan (Dec. 2016) at 1.

Infrastructure concerns at Glen Canyon Dam: During the February 28-29, 2024, meeting of 

the Glen Canyon Dam Adaptive Management Group, Reclamation shared the knowledge they had 

gained by operating the Glen Canyon Dam at low elevations (near 3,520’) in March 2023, as well 

as knowledge gained regarding the condition of the River Outlet Works (ROW) from operating 

the ROW during the April 2023 experimental high flow releases. Reclamation also expressed the

potential for unknown issues from operating the ROW for extended periods of time. CAWCD

cautions against the use of ROW for experimental operations if such operations may result in any 

diminishment of the rights afforded to the Colorado River Basin States through the Colorado River 

Compact, the CRSPA, or any other law to which the GCPA is subject. It is crucial that Reclamation 

complete its evaluation of infrastructure vulnerabilities and take immediate actions to develop and 

implement solutions. Protection of Glen Canyon Infrastructure may involve a host of strategies 

including infrastructure modifications, strategic releases from CRSPA units, and water use 

reductions in the upper basin, among others. Infrastructure modifications should be prioritized to 

ensure compliance with required water deliveries under the Colorado River Compact. 

Action Alternatives: Given the significant infrastructure concerns that currently exist at Glen 

Canyon Dam, and the pervasive issue of invasive species, CAWCD believes that flow-related 

actions are only one tool and a myopic way to address the issue and that additional actions like 

the installation of fish exclusion device(s) are necessary and urgently needed for the long-term 

prevention of establishment of invasive species from Lake Powell into the reach below Glen 

Canyon Dam. In addition, CAWCD believes that a permanent solution to the persistent issue of 

invasive species lie in an assortment of flow and non-flow related treatments rather than a singular 

alternative or solution. Rather, solutions to invasive species must be dexterous such that a 

treatment option can be chosen from an assortment of tried-and-true options based on a decision 

tree or tiers of treatment needed using the existing adaptive management process. 
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YOUR WATER. YOUR FUTURE.

CAWCD appreciates the opportunity to provide comments on the LTEMP DSEIS. Should there 

be any questions or concerns regarding this letter or any aspect of CAWCD’s interests regarding 

the DSEIS, please contact Vineetha Kartha or Greg Adams at your earliest convenience. 

Sincerely,

Brenda Burman

General Manager