David B. McCoy is on the board of directors of the Environmental Defense Institute.
By DAVID B. McCOY
What do the residents of Mackay, Idaho, have in common with the townsfolk of Fukushima, Japan? They believe they are safe and they believe what their government tells them. They believe what the nuclear industry tells them. They have no idea of the catastrophic danger they are in. Like the residents of Fukushima, Mackay residents will have no advance warning of an imminent dam collapse. At this time, there is no electronic or human warning system in place to allow evacuation.
Mackay Dam was built nearly a century ago without any thought given "to conform to seismic or hydrologic design criteria." The Utah Construction Co. had no previous experience in reservoir construction. No one knows how safe the dam will be during the next earthquake or major flood. Mackey Dam lies 11 miles from the Borah earthquake fault, which caused a magnitude 7.3 earthquake in 1983.
The state of Idaho classifies Mackay Dam as Category 1 "high hazard." The dam receives safety inspections every two years. Since the last inspection was in 2009, the Idaho Department of Water Resources report does not reflect that Mackay Dam was overtopped in 2010 and 2011 from high runoff.
The Idaho 2009 dam inspection report states: "Much about this dam is not known due to poor documentation during initial construction and subsequent modifications. The amount of leakage observed at the right-center toe of the dam is cause for concern despite claims by the owner that 'it has always leaked like that.'"
The flow of water from the base of the middle of the dam is now leaking at a rate greater than 1 cubic foot per second, enough water to fill a backyard swimming pool about every 30 minutes.
Mackay Dam, should it not hold, threatens to send an 80-foot wall of water toward the town of Mackay within 20 minutes. Further, there are 13 300,000-gallon underground tanks filled with high-level nuclear waste at the Idaho National Laboratory. The floodwater would spread the contamination across the Snake River Plain. Should Mackay Dam not hold, the safety systems for a nuclear reactor at INL may not function. A nuclear meltdown could occur, spreading an enormous amount of radiation.
On the west side of the dam, the emergency spillway lies beneath a large mass of rock with a continuous crack from top to bottom. This area is susceptible to massive rock movement should an earthquake occur. The steep cliff above the spillway constantly sheds rock into the spillway channel. There is no abutment on the east side of the dam. The concrete spillway channel has numerous cracks throughout.
The state of Idaho has a history of ignoring potential disasters. In 1976, the earthen Teton Dam began eroding due to a leak at its base, then burst, resulting in 11 deaths and over a $1 billion in property damage. Teton Dam, built during the same era and of similar design, was only 125 miles from Mackay Dam.
Can a similar occurrence be prevented? Recommendations to consider are:
- Install an electronic warning system and 24-hour monitoring.
- Create an emergency plan for evacuation.
- Make annual inspections and an action plan to correct deficiencies.
- Repair leakage.
- Do spillway repairs.
- The federal government should take over ownership of Mackay Dam due to national security issues.
- The current owner must carry adequate liability insurance for loss of life and property damage.
- Access to the dam should be blocked to prevent sabotage.
Ideally, the U.S. Department of Energy should purchase the site and provide a well-constructed dam that can withstand natural disasters and protect existing nuclear facilities.
The town of Mackay does not have to be another Fukushima.
