Fact Sheet

O&M - Alamo Lake Dam, AZ

U.S. Army Corps of Engineers, Los Angeles District
Published April 19, 2023

Located 25 miles North of Wenden, AZ and 120 miles NW of Phoenix, AZ. The dam was placed in full operation in   July 1968. Project condition is good and has a proposed dam safety action class rating of DCAC 2 (high urgency). Project elements being operated and maintained include Dam (earth fill: 283-ft high; 975-ft long) Outlet Works Spillway Service Roads Reservoir (1,045,300 acre-ft cap, spillway crest - 1977) One Recreation Area with annual visits estimated at 35,000.

AUTHORIZATION: Flood Control Act of 1944

ACTIVITIES FOR FY 2023: Funds will be used for legal or policy mandated minimum level operational activities, including Construction monitoring of the bulkhead gate fabrication, completion of the upper conduit inspection, awarding a contract to refurbish the service gates, biological survey work (Northern Mexican Garter Snake) to support our upcoming Biological Opinion, water quality sampling, water control and management, including data analysis and review of potential modifications to operations; environmental stewardship activities and recreation management. Additional funds could be used for continuing the work on the EIS to support the Water Control Plan update, support the geotechnical boring investigation required to support the design of the new bulkhead gate installation system, construct the elevator replacement designed in FY22, and complete the hydraulic system refurbishment designed in FY22. IIJA ACTIVITIES: Continuing the design on a new bulkhead gate installation system, designing, and constructing required infrastructure updates to the existing spillway access road, designing the repair of the plunge pool and riprap apron, and design and installation of a new a-frame crane within the control tower.

FY 2024 PLANNED ACCOMPLISHMENTS: Optimal funds could be used for rehabilitation of the upper conduit including emergency gate rehab as well as structural repairs within the conduit; completion of an ARC-Flash survey at the Dam control tower; completion of the elevator modernization, rehabilitation of the dams hydraulic systems; completion of the design of the H2S gas ventilation system repairs and implementation of the repairs; completion of the designed plunge pool and riprap apron repair, completion of the Water Control Manual update, water control and management, including data analysis and review of potential modifications to operations; environmental stewardship activities; and recreation management. Legal or policy mandated maintenance activities, including highest priority ARC-Flash survey and structural needs for elevators and dam facilities.

The latest studies indicate that during a probable maximum flood event, the spillway would be incapable of handling the discharge, resulting in overtopping and possible failure of the Dam. Further studies are planned to better understand increased flood risk at the dam and potential consequences downstream. Several protected species occur within the vicinity of Alamo Dam, including the endangered southwestern willow flycatcher, the threatened yellow-billed cuckoo, and the northern Mexican garter snake. The Bill Williams River Corridor Steering Committee, consisting of stakeholder agencies concerned with operations of Alamo Dam, has made operational recommendations proposing to modify the 2003 water control manual. The Corps supports some of these recommendations and is currently updating the water control manual for more efficient flood risk management purposes. After 50 years, there is a need to rehabilitate the dam operator compound structures as well as significant dam components to reduce the risk of structural and component failure. Efforts are underway to complete an inspection of the upper outlet works, which has not been inspected in more than 20 years and cannot be inspected until the bulkhead gate fabrication is completed.
The upper outlet works will be inspected once the bulkhead gate, bulkhead gate installation system, and sill are in the condition required to safely place the bulkhead gate. It is highly likely the upper outlet works will require repair/rehabilitation. The Corps will continue to pursue funding to complete the required repair/rehabilitation to the upper conduit and gate systems. The current method used to install the bulkhead gate is no longer structurally up to par and is exceptionally challenging and unsafe to use in its current submerged condition. The structure will be replaced in FY24. The ventilation system for the control house needs to be redesigned and modified to provide adequate capacity and to discharge H2S gases away from the entrance to the tower. The Corps is working on obtaining funding to complete an upgrade to this system to increase ventilation capacity and creating positive pressure in the areas frequented by dam staff to prevent H2S gas exposure. Electronic and telephone communication can be unreliable between the LA District office and operators at the Dam, particularly during inclement weather events. Funding is required to complete a communication study. The study will focus on identifying the best technology to improve communication issues.

As of 01 MAR 23

Estimated Federal Cost            $ 8,931,830

Estimated Non-Federal Cost                               0
Total Estimated Project Cost            $ 8,931,830

Allocation thru FY22            $ 1,914,000

President’s Budget for FY23        $ 6,352,830 1/
Conference Add for FY23                             $0
Approved IIJA FY23            $  1,369,000
Workplan for FY23                1,210,000
President's Budget for FY24        $ 4,603,500 2/
Approved IIJA FY24            $15,197,000
Workplan for FY24                          TBD
Balance to Complete After FY24                           N/A
1/ Decreased 1% from $ 6,417,000
2/ Decreased 1% from $ 4,650,000

CONGRESSIONAL INTEREST: Senators Kelly and Sinema, Representative Gosar (AZ-09)



Congressional Liaison