A Fragile Infrastructure: The Oroville Dam
February 15, 2017| By Martha Flanagan
Region: North America
Tim Pappas, co-leader of our Flood team, recently blogged about this exact issue, providing valuable information for underwriters. In light of current events in Northern California, it's worth rereading now.
The nation's tallest dam, the Oroville Dam in Northern California, has been in the news this week due to eroding spillways that forced the evacuation of just under 200,000 people. Due to heavy rainfall in Northern California, as well as water from the Sierra Nevada mountain range, Lake Oroville has been filled to the point of overflow. While the dam remains intact the emergency spillways, which allow the water to be diverted from the lake to prevent overflow, have been damaged.
Last week erosion on the primary spillway resulted in a massive hole in the lower part of the channel. The emergency spillway is only used if the water levels reach 901 feet in elevation. It was only when the water volume started to increase and the emergency spillway was needed that authorities discovered the emergency spillway was also damaged from the force of the water washing over the soil.
Environmental groups warned over ten years ago that the Oroville Dam was a disaster waiting to happen. They recommended that concrete be added to the spillway so that the hillside would not wash away.
As with many dams in the U.S., lack of repair, maintenance and upgrades have left our infrastructure in a fragile state.
Tim consults frequently with our clients on underwriting flood and storm surge exposure as well as evaluating risks. For more information please reach out to Tim directly.