Future of Large Dams

The Future of the Bonneville Dam

As with the Glen Canyon Dam, the construction of the Bonneville Dam proceeded with little consideration of possible adverse ecological and sociological consequences. This unfortunate lack of foresight has all but destroyed native salmon runs and has inflicted extreme hardships on Native American communities. The damage is done, and though it may no longer be possible or desirable to return the area to its original state, we cannot, as conscientious stewards of this planet, ignore the wrongs imposed on the Columbia River ecosystem by the Bonneville Dam. But short of taking down the dam, what can be done? There are several structural modifications and new technologies, such as salmon ladders and Minimum Gap Runner turbines, which are designed to facilitate the migration of mature and juvenile salmon. However, it is still uncertain whether such improvements really accomplish their purposes. For example, fish ladders cannot be used by migrating smolts, and 5-15% of these are killed at each dam (Columbia River Inter-Tribal Fish Commission, 1997). The future must involve investing money into researching restoration methods, such as bypass systems and drawdowns, and developing a system which will save natural salmon from extinction in the Northwest.
If the primary ecological goal is to restore healthy native salmon and steelhead runs on the Columbia River, it would be necessary not only to decommission the Bonneville Dam but also the other dams on the Columbia River and the four dams the lower Snake River (National Marine Fisheries Service, 1995). So many communities depend on the power and jobs produced by these dams that this is not a viable option at the present time, and therefore, it would do little good to remove just the Bonneville Dam. However, there are many groups which depend on healthy salmon populations in the Columbia River system for their livelihood. In the future, as with the Colorado River, it would be ideal to develop viable power alternatives and lessen the need for products provided by dams. Then, perhaps, there will be conditions conducive to the removal of the dams plugging the Columbia and its tributaries. However, transportation and irrigation issues would have to be addressed.
A more viable option at this point in time with regard to restoring salmon and steelhead runs may be to perform natural river drawdown by breaching the four lower Snake River dams. The National Marine Fisheries Service (1995) and the Columbia River Inter-Tribal Fish Commission (1997) believe that this is a necessary modification and would be beneficial for salmon runs, but other organizations, mostly those which have an investment in the products of the dams, debate whether the gains to salmon are worth the economic costs and loss of benefits to surrounding communities. It seems, however, that these are selfish objections. The lower four Snake River dams are responsible for the majority of smolt deaths in the mainstream river system, but they provide only about 5% of the Northwest’s hydropower (The Oregonian, 1998). Other modifications to irrigation systems of the few farms which use water from these dams, would essentially eliminate the need for the dams. This seems to be an alternative which could satisfy all parties: salmon runs would be rehabilitated, and little power generation would be lost. Although these drawdowns would be expensive initially, the economic benefits provided by the regeneration of a salmon fishery would be extensive. More information regarding the debate on the decommissioning of the four lower Snake River dams can be viewed at http://www.cyberlearn.com/remove.htm

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