In 1994, the pipeline was in trouble. An erosion of the structures built to support the twin penstocks due to decades of water runoff was noticed. Winter was just around the corner and engineers looked for a solution before further erosion threatened the pipeline.
“Our greatest challenge was access in and around the pipeline,” explained Ron Lee, project engineer for the State of California’s Department of Water Resources. He continued, “As the pipeline travels down the mountain, it covers some very steep sections. The grade goes from flat to nearly 45%. Several sections are easily accessible with vehicles, while others on the steepest portions are only reachable on foot.” The project needed to be completed within 30 to 40 days, before harsh winter rains set in. Return trips would make the project costly and time consuming. Finding a long-term solution was now made even more difficult.