Scott Dam is 103 years old, and its partner in the Potter Valley Project, Cape Horn Dam, is even older. Both were designed during a time when engineers assumed and built for a stable, predictable climate with reliable water resources. Both structures are also rated as “high hazard” structures, meaning that loss of life is likely in the event of dam failure. Over the years, PG&E has been required to report the declining condition of Scott Dam’s aging structure to FERC. Several reports suggest serious issues that may be associated with Scott Dam’s aging structure. These include decaying concrete, cracks in the structure’s face, pipes with unknown connections, spraying leaks, and the vulnerability of the dam’s only low-water outlet to clog with sediment. Worldwide, most dams constructed in the last century were built to last 50 – 100 years. These older dams are often not engineered with modern safety standards or constructed to withstand intensified weather events of our changing climate - nor are they built to withstand significant seismic events. Scott Dam is located right next to the Bartlett Springs Fault Zone, capable of generating a magnitude 7 earthquake. Why was Scott Dam constructed in a fault zone? Stay tuned for part 5 of our dam safety series tomorrow. #DamSafety #EelRiverDams #FreeTheEel #NationalDamSafetyAwarenessDay (fb)

Sediment has been piling up in the Lake Pillsbury reservoir for far too long. If these piles of sediment slough off and fall in, they can irreparably clog the needle valve - the only way to release water when the reservoir isn't completely full. PG&E has no plan to fix this valve if it becomes clogged. The kicker? All this sediment piling up against the dam is part of the reason why PG&E can never again completely fill or empty the reservoir. What other concerns should we have in regards to Scott Dam's aging infrastructure? Tune in tomorrow for part 4 of our dam safety series. #DamSafety #EelRiverDams #FreeTheEel #NationalDamSafetyAwarenessDay (fb)