February 17, 2012
As the largest wholesaler of water in the country, the Bureau of Reclamation has been responsible for building various dams across the United States. The bureau now provides water for over 31 million people, and provides irrigation for one in five American farmers (1). However, in an effort to seek more and more sources of irrigation, the bureau began to choose dam sites that were less than desirable. As we read in this week’s reading of Cadillac Desert, all of the logical dam sites have already been built, leaving the Bureau to then begin damming up sites that have previously been rejected some forty years previously. As our population grows, and the sources of water diminish, the pressure on the Bureau of Reclamation to build more dam sites has increased as well. While many of these dams have turned out to be successful, disasters such as the failure of the Teton dam provide constant worry. The potential for a catastrophic disaster has only increased over time as multiple dams have been built on the same waterway. Now if one dam fails, the excess water will proceed to cause the next dam to also fail, with a domino effect capable of causing significant damage.
The bureau’s greatest disaster, the Teton dam, provides an interesting illustration of what can happen when bureaucracy transcends logical science to achieve an economic goal. The Teton dam was built in Northern Idaho, in order to provide irrigation to the many potato farmers in the region. It would provide irrigation to an area that already on average received 132 inches of irrigation a year, which amounts to five times the rainfall in the farmlands of Iowa. The dam’s original selling point was to provide a stable water source for these farmers, after two years of moderate drought (where ironically the crop yields were higher than normal) and a flood. While this certainly doesn’t provide sufficient reason to build a dam on a previously rejected site, everyone bought into the idea, and the construction was quickly underway. Aside from the Geologic Survey report presented to the Bureau, four regional geologists also submitted a statement that did in fact heed caution towards the safety of the dam, especially if an earthquake should arise, due to the semi-solid rhyolitic rock foundation. However, when the bureau calculated the cost and benefit analysis for building the dam, when factoring in the worst possible floods that could result without the dam; they ignored the concerns and decided to continue with construction. The project was officially finished in October of 1975, and they began to divert the river to fill the dam. Less than a year later, the excessively high water level, combined with insufficient outlets, eventually led to failure during the first filling of the reservoir. At 350 feet, this dam was the highest to ever fail, releasing billions of gallons of water. It resulted in 11 deaths, countless lost livestock, and nearly a billion dollars of damage (2).
It turns out that the chapter title, “Those who refuse to learn…,” is increasingly appropriate because just this year the Bureau of Reclamation has completed a study to assess the rebuilding of the Teton dam. While officials say the re-build is still in the distant future, it is certainly in the conversation as a solution to Idaho’s water storage problem. The new cost of the Teton dam is estimated around $550 million, but is compared to the $10 billion Idaho economy that may be in risk without water (3). Unfortunately, this discussion of the dams in this region is still centered primarily on the economic impact, rather than the geological and environmental consequences of another large-scale project. Additionally, many geologists expressed their concerns with the selection of this site for a dam, the first time it was built. Even if they rebuild the dam in a slightly different way, it is concerning to think they may try to rebuild the dam in a geologically inadequate location. It shall be fascinating to see how this plays out in the future, as the aquifer below Idaho is currently running a 600,000 acre feet water deficit, and the Teton dam provides the largest storage area, of 200,000 acre feet of water. Hopefully, regardless of their decisions, the Bureau of Reclamation will be able to avoid disaster this time.
This post was authored by Melissa Krigbaum ’12, a double major in Economics (BA) and Environmental Studies (BA).
- Bureau of Reclamation website http://www.usbr.gov/main/about/
- Teton Dam Failure http://web.mst.edu/~rogersda/teton_dam/
- Years after failure, Teton Dam continues to spark debate
- Teton Dam rebuild still option for water storage