American River (March 13, 2024) – On December 23, 1964, the State Route 49 bridge over the North Fork American River just below Auburn was washed away. Hell Hole Dam, being built for Placer County Water Agency (PCWA) on the Rubicon River, failed during an extreme precipitation. The failure of the partially built dam sent a wave of water and debris downstream into the Middle Fork American, where it eventually reached the Confluence and destroyed the Georgetown Bridge.
Remnants of the Georgetown Bridge Failure Finally to be Cleared from American River After 60 Years
After nearly six decades submerged beneath the tranquil waters of the American River, remnants of a devastating dam failure are set to be extracted from the riverbed within the Auburn State Recreation Area. But what led to their submersion in the first place?
Before the current State Route 49 bridge spanned the American River, a bridge of similar alignment served as a crucial link between Auburn and the communities of northwest El Dorado County. This bridge, christened the Georgetown Bridge, was erected in 1948 and met its demise on December 23, 1964.
The Catastrophic Breach and its Aftermath
The Association of State Dam Safety Officials (ASDSO) recounts a grim tale of the Hell Hole Dam’s breach, unleashing a torrent of 30,000 acre-feet of water down the Rubicon River, coursing through the Middle Fork of the American River, and culminating at the confluence with the North Fork of the American River near Auburn.
Triggered by an atmospheric river and exacerbated by the dam being only halfway completed before the onset of the rainy season, this breach wrought havoc, hurtling 700,000 cubic yards of rock along with the deluge, eventually reaching Folsom Lake some 60 miles downstream in a mere four hours.
In the wake of this catastrophe, five bridges, including the Georgetown Bridge, were swept away. However, despite the widespread destruction, no fatalities were recorded.
Post-Deluge Assessment and Reconstruction Efforts
Following the subsidence of the floodwaters, authorities were confronted with the arduous task of rebuilding essential infrastructure. The Mountain Quarries Railroad Bridge, resilient amidst the chaos, emerged as a temporary crossing point for motorists while plans for a new bridge upstream took shape.
Submerged remnants of the Georgetown Bridge remained beneath the waters, their fate entwined with the uncertainties of subsequent construction projects. Congress’s approval in 1965 for the Auburn Folsom South Unit, encompassing the construction of a towering double-curved dam, altered the trajectory of the debris from the 1964 disaster.
However, as construction commenced in 1975, seismic concerns, compounded by environmental activism, impeded progress. The project was ultimately abandoned, prompting renewed discussions about the fate of the submerged remnants.
Current Clean-Up Endeavors
Recent announcements by the Placer County Board of Supervisors signal a concerted effort to rid the American River of this enduring scar. Dokken Engineering, commissioned for environmental consultation, is tasked with formulating a meticulous removal plan and navigating the regulatory landscape.
With a substantial budget exceeding $900,000, Dokken Engineering is poised to spearhead the endeavor, overseeing water quality assessments and land management strategies crucial to securing the requisite permits.
“Funding was secured in February 2023 through an $8 million transfer of Priority Legislative Budget Project Funds from Caltrans to Placer county,”
the county disclosed in a press release, underscoring the significance of this long-awaited initiative.
https://www.parc-auburn.org/bdr-project.html
Anticipated to commence in 2026, this endeavor represents a pivotal step towards restoring the American River to its pristine state, while also honoring the legacy of those bridges lost to the annals of time.
