Glen Canyon Dam Detonation Cord Prompts Closures

National Park Service workers found detonation cord near the Arizona dam, leading officials to close a service road and day-use area.

Updated on Nov. 4, 2026 in National Parks

Photograph of a weathered concrete dam face and spillway above turquoise reservoir water, with red sandstone canyon walls in the distance under a clear desert sky. — National Park Service workers found detonation cord in boreholes near Glen Canyon Dam in Arizona, prompting officials to close Chains Road and The Chains day-use area. AI Illustration. Upload story photo >

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National Park Service workers discovered detonation cord in boreholes along a restricted service road near Glen Canyon Dam in Arizona. Officials closed Chains Road and The Chains day-use area while evaluating mitigation options and said there was no threat to public safety.

Why it matters

The cord was traced to the dam's original construction in the 1950s and 1960s, showing how remnants of major federal projects can surface decades later. Visitors to Lake Powell and the dam area face temporary access restrictions while the situation is assessed.

Park Service inspection identified several boreholes containing detonation cord, with the dam standing 710 feet tall and construction dating to 1956. The number of boreholes and the full extent of remaining material have not been disclosed.

The players

National Park Service

The federal agency that manages Glen Canyon National Recreation Area and oversaw the inspection and closures at the dam.

Glen Canyon Dam

A 710-foot-tall concrete dam on the Colorado River whose construction began in 1956 and which impounds Lake Powell.

The details

Workers found the boreholes along a restricted service road, and an explosive ordnance disposal team traced the cord to the dam's original construction. Officials closed Chains Road and The Chains day-use area while they evaluate options for removing it.

Oct. 15, 1956: President Dwight D. Eisenhower remotely triggered the first dynamite blast at the dam site.
1956: Construction on Glen Canyon Dam began.
1950s and 1960s: Dam construction period when the detonation cord was likely left in place.

Seasonal Patterns

The discovery ties directly to the 1956 blasting that began dam construction, when President Dwight D. Eisenhower triggered the first dynamite charge. Decades later, remnants of that construction work are still being found at the Arizona site.

Visitors planning trips to Lake Powell or the Glen Canyon Dam area should expect Chains Road and The Chains day-use area to remain closed while officials evaluate mitigation. Checking Park Service updates before traveling will help avoid unexpected access restrictions.

The takeaway

Remnants of major construction projects can persist for decades, so federal land managers continue to find and address legacy hazards. Travelers to Arizona parks should verify current access rules before visiting.