Along with the many environmentally friendly benefits that hydropower brings to the Northwest, most significantly clean and renewable energy, the inevitable change that is brought about by dams has impacted salmon.  Since the first dam was built in the 1930s, scientists, state and federal agencies, tribes, utilities, nonprofit organizations and dozens of special interest groups have been working to help protect one of the Northwest’s most valued natural and economic resources. 
History

• During the mid-1800s, when early settlers arrived in the Northwest, Columbia River salmon and steelhead were abundant, with estimates of seven to 16 million fish returning each year.
• Rock Island Dam, built in 1932, was the first major hydroelectric dam built on the Columbia River, followed by Bonneville and Grand Coulee in 1938 and 1941.
• In 1938, adult salmon returns were about 264,000 compared to 846,000 in 2004; the average during these 67 years was slightly more than 350,000.
• Between 2001 and 2004, some of the highest salmon returns in recorded history occurred; in 2000 salmon returns were at almost 402,000 and in 2004 returns were at about 846,000.

Solutions
There are many solutions that are helping both juvenile and adult salmon safely pass the dams on the Columbia Snake River System.  The solutions vary from project to project since each hydroelectric project is configured differently and presents its own unique challenges and specific solutions. 

• Fish ladders were installed at all hydro dams on the Snake and Columbia Rivers below Hells Canyon and Grand Coulee, allowing adult fish to migrate upstream past the dams. 
• Mechanical bypass systems are often installed in front of the turbine intakes, and can divert 70 to 80 percent of the juveniles through or around a dam. At a few dams, the bypassed fish are loaded into barges and transported around the dams.
• Spilling water over dams when the fish are present is another way to move juvenile salmon downstream. Water that passes through the spillway cannot be used to generate electricity. Too much spill can be a problem, because when water plunges into the pool , too much air can be trapped in the water causing the fish to suffer from gas bubble disease.
• Surprisingly, many juvenile salmon safely pass the dams through the powerhouse, with some dams showing 90 percent juvenile survival through the turbine units. A new generation of turbine technology is being introduced.
• Hydro operators often change their operations to increase or reduce flows from the reservoirs in order to aid fish passage, or provide for spawning and rearing protection.

Hatcheries

• Fish hatcheries are one of the oldest ways to restore salmon populations.  Hatcheries were first constructed in the Columbia Basin in the 1870s to enhance fish runs that had been severely depleted by over fishing. 
• Since the mid-1980s, two to three hundred million salmon have been released into the Columbia River Basin each year.  Currently, hatcheries account for the majority of salmon in the Snake and Columbia rivers
• Funding for hatcheries is provided by hydro dam operators to mitigate for the impacts caused by dams. 

Habitat Enhancement

• All human activities affect the environment. Effects from hydroelectric projects largely stem from fluctuating reservoir levels and changes to river conditions and the land and vegetation bordering the river.
• Management of vegetation, including plant removal within a river, is also implemented to address issues related to nutrient loading and reduced oxygen levels; both which ultimately affect salmon.
• The condition of the streams and tributaries where salmon spawn are vitally important and hydro project owners often purchase lands and contribute to funds that help protect important fish and wildlife habitat.  Hydropower project owners have successfully worked with local property owners and government agencies to restore spawning areas by using such materials as logs and vegetation to restore in-stream habitat structures.

• Today, there are more fish in the Columbia River than at any time since the first dam was built at Bonneville in 1938. (Source:  US Army Corps of Engineers.)
• Salmon survival in the Columbia and Snake rivers is higher today than it was before the Snake River dams were built. (Source:  NOAA Fisheries.)
• During the past 20 years, juvenile salmon passage greatly improved at most dams in the Northwest, which now have a 90 percent or greater survival rate and many of the passage routes have as high as a 98 percent survival rate (Source:  Simpass Analysis/Assumptions)
• Between 2000 and 2004 the Northwest experienced near record salmon runs. According to NOAA, adult salmon passage at Bonneville Dam increased signifigantly for 12 out of 13 stocks.