The state of a 99-year-old dam on private property near the city of Jackson is dangerously precarious, leaving 169,000 cubic yards of arsenic-contaminated tailings at risk of flooding into the city from expected heavy winter rain, according to state officials.
Charles Ridenour, of the California Department of Toxic Substance Control, told local NBC News affiliate KCRA that the Eastwood Multiple Arch Dam, built in 1916, was showing cracks. He noted that the state has initiated a $1 million emergency repair operation, which is expected to finish by November 23.
In 2013, the California Department of Toxic Substances (DTSC) contacted the EPOA about its concerns with the dam. A June 2015 report by the U.S. Army Corps of Engineers revealed the dam was structurally unsound.
Ridenour added that rain storms posed the greatest threat to the dam’s stability, adding that if the dam collapsed, a 15-foot high mudflow could hit downtown Jackson in two minutes, causing as much as $100 million in damage. A storm in 2006 was heavy enough to send water flowing over the dam.
A permanent fix for the dam would cost $8 million and would take at least two years to finish. The state wants to obtain reimbursement from Marilyn Van Horn, of Palo Alto, who owns the property on which the dam sits. State officials claim that Van Horn refused to allow access to the land unless a judge issued a court order. Ridenour said if Van Horn refuses to reimburse the state, the state will place a lien on her property.