One of the challenges associated with recovering imperiled species, such as Chinook salmon (Oncorhynchus tshawytscha), is identifying a set of actions that will ensure species

This report describes a study of spillway passage conditions for juvenile spring chinook salmon at Ice Harbor Dam in spring 2003. The Sensor Fish Device was used to measure conditions experienced by juvenile salmon passing over a deflector installed at the base of a spillway in the dam to mitigate total dissolved gas in the spill discharge as it enters the stilling basin. The Sensor Fish Device is a waterproof, nearly neutrally buoyant sensor package developed by Battelle with funding from the U.S. Department of Energy

With so many people affected [by the decimation of salmon runs in the Pacific Northwest], proposals for protecting salmon are highly contentious. Although the root causes of the problem have long been well documented, investigators are just beginning to understand that human activities have selectively eliminated some populations of salmon while favoring others, resulting in the loss of much of the genetic heritage in these amazing animals. So here we try to show the risks confronting salmon populations and salmon biodiversity with a focus on the potential for genetic loss.

This paper examines the effects of dam construction and operation in the Columbia River Basin on salmon populations. While the hydrograph of the Columbia River has been significantly impacted by dams, the seasonality of regulated flow on the Snake River has been less affected. The Snake River storage has been used for agricultural diversion while the Columbia has been for electrical generation. The reservoir system has effects on flow velocities, water chemistry (nitrogen supersaturation), habitat availability and reliability, and stream temperatures. Dams block about one third of the Columbia River watershed to access by anadromous fish.
Effects of Dams on Salmon;
Fish kills occur as a result of several characteristics of dams. Bruising, descailing, and stress caused by by-pass facilities; susceptibility to prey following delivery from by-pass to outfall; estuary damage; effects on the homing ability of fish; limited success in fish use of by-pass facilities. The effect of migration speed on smolt survival is uncertain but assumed to have an impact. More research is necessary.
Mitigation of Dam's Effects on Salmon:
Seven measures for mitigation of dams' effects on salmon are discussed
1. Fish passage facilities 2. Predator control 3. Transportation 4. Spill 5. Flow augmentation 6. Reservoir drawdown 7. Dam removal.

There is a highly polarized environment in which decisions balancing protection of fish populations and energy generation are made. Hydroelectric power accounts for 12% of U.S. electric supply and virtually all the nation's renewable enrage capacity. Yet, hydro is under increasing attack on environmental grounds, mostly for inputs on fish populations. The 1992 listing of sockeye salmon as endangered has intensified a long-running battle over restoring fish runs and sent mitigation costs skyrocketing. Further complicating the regulatory picture, a Supreme Court decision this spring appears to allow states to set minimum flows at hydroelectric facilities under the authority of the Clean Water Act. The real challenge for applied ecologists will continue to be: how best to put the right information on the table, in the right form, and at the right time to best incorporate ecological consequences in the decision making process.

Fish and hydroelectric dams are striving to coexist across the country. With conservation groups as well as state and federal agencies pressing for severe controls on water releases, hydropower production has been cut substantially in many cases. At the same time, dam operators have undertaken some sophisticated construction programs to meet the challenge. To date, many strategies employed on the Columbia and Snake Rivers have been both costly and ineffective. The Army Corps of Engineers is trying to address its problems partly with extensive model studies. But, they have found that "the more you learn, the more complicated it gets." Together the failures of the Corps, as well as other federal agencies have caused the power utilities to call for reductions in spending for all fish programs, which they say are ineffective.