Dam Design and Construction

Reclamation halts work on El Vado Dam upgrade, seeks alternative storage options

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Reclamation halts work on El Vado Dam upgrade, seeks alternative storage options
(photo courtesy Bureau of Reclamation)

The Bureau of Reclamation announced that construction to upgrade El Vado Dam has been halted and temporary alternative storage options are being developed.

The dam, on the Rio Chama in northern New Mexico, required structural modifications to ensure it can safely and reliably continue to function and serve its beneficiaries. It was completed in 1935 by the Middle Rio Grande Conservancy District and rehabilitated in 1955 by Reclamation. The dam provides irrigation water for the Middle Rio Grande Valley and impounds water for an 8 MW hydro powerhouse.

When constructed, El Vado Dam used a steel plate as the principal barrier to ensure its efficiency, making it one of the very few dams in the world using a steel faceplate. Results of regular inspections led to issue evaluations and corrective action studies through the Reclamation Safety of Dams program, as well as the modification work to be done to reduce the risk of failure due to seepage and failure of the spillway. As work progressed, additional evaluations revealed that the steel faceplate and underlying supports are in much worse condition than originally thought and cannot be relied on in upgrading the dam. These findings led to discontinuation of work and the reassessment of future actions.

“We started construction of the least cost viable alternative, but our experience during construction was that the alternative would not be effective in resolving our concerns,” said Reclamation’s Upper Colorado Basin Regional Director Wayne Pullan. “As a result, we are stopping construction on the ineffective alternative and working with Reclamation’s Technical Service Center and dam safety experts to develop new effective alternatives to address safety concerns and restore El Vado’s ability to safely store much-needed irrigation water for the Middle Rio Grande Valley.”

Reclamation has begun reservoir storage and monitoring criteria to determine a safe reservoir elevation to store some water while long-term alternatives to repair the dam are being developed. Water storage restrictions in recent years are a result of the seepage and spillway concerns identified though the Safety of Dams program. The reservoir has also naturally remained at lower levels for the past two decades due to prolonged drought.

Reclamation awarded the initial construction contract in 2021. Construction started in 2022 and required a lower reservoir water level to allow the contractor to install a foundation grout curtain along the left abutment, grout behind the existing steel faceplate on the upstream face of the dam and attach a geomembrane liner to the faceplate. A suspension of work was issued to the project contractor on March 20, 2024, due to unforeseen field conditions that posed numerous and unexpected challenges. Multiple attempts to apply backfill grouting have been unsuccessful, leading to this consideration of alternative solutions to reduce seepage.

Reclamation is committed to working with the MRGCD and other water management agencies to determine other storage options, while adhering to policies outlined in the Rio Grande Compact. The compact is an agreement between the states of Colorado, New Mexico and Texas, which equitably allocates the waters of the Rio Grande Basin. Current compact restrictions do not allow for alternate irrigation storage for the MRGCD.

“We will continue to do everything within our power to assist the MRGCD with determining the best alternative options for water storage while these restrictions remain at El Vado,” said Reclamation’s Albuquerque Area Office Manager Jennifer Faler. “We understand that this lengthened timeline is difficult news, especially for members of the community who rely on irrigation, but taking shortcuts is not the prudent path and we need to take the time to do this right.”