Fish Passage
The federal dams on the Columbia River were designed for balanced use of the basin's water resources. Fish ladders planned by Corps engineers, environmental specialists and fisheries experts simulate the waterfalls and pools found in natural streams. These fish ways allow migrating fish to continue their accustomed paths from the sea to tributaries of the Columbia and Snake rivers.
Bypass facilities at each project divert ocean-bound juvenile fish around the turbines. The Corps' Walla Walla District transports millions of fingerlings downstream in barges and tanker trucks each year under its juvenile salmonid transportation program. Raising fingerlings at hatcheries also helps to compensate for the spawning areas lost when the lakes filled behind the dams cutting off access to upstream spawning grounds.
The federal hydropower dams on the Columbia River were designed and constructed for multi-purpose use. The US Army Corps of Engineers (USACE) considers fish passage as a primary operational function. Migration between the up-river spawning grounds and ocean environment is essential for survival for many fish species found living in the Columbia/Snake River Basin. That group includes some of the more economically and ecologically important fish in North America: four Pacific Salmon species, steelhead, lampreys and American shad.
Issues of fish passage around hydropower dams are complex and technically challenging. They can be divided into the two distinct components, upstream migration of adults and downstream movement of juveniles. The life cycle of Salmon starts as juvenile fish that are hatched throughout the Columbia River/Snake River Basin and their tributaries. After a short period of rearing they follow the river current down to the ocean. After living in the ocean for one to five years (This time varies with different species.), adult Salmon return to the stream where they were born. The fish have to pass around the dams twice by two different routes; 1) juveniles guided downstream away from the working turbines and 2) adults ascending the fish ladders. This requires creative methods for directing and attracting fish into specific areas for the safest possible passage.
The USACE employs professional fish biologists to study and provide safe passage around its hydropower dams. Fish ladders and bypass systems planned by engineers, environmental specialist and fisheries experts simulate the waterfalls and pools found in natural streams. These fish-ways allow migrating fish to continue their accustomed path from the sea to spawning areas of the Columbia and Snake rivers. The work has been intensifying in recent years due to the drastic decline in fish numbers leading to the Endangered Species Act (ESA) listings of many migratory fish populations. Below, you will find a brief description of the typical fish passage installations and fish monitoring methods currently deployed at The Dalles and John Day Dams. Detailed information about the entire Portland District Fish Program can be obtained at these web sites: Portland District Environmental Resources and Northwestern Division Fish Management.
Fish Ladders
Fish ladders were designed and exist at all hydropower dams on the Columbia and Snake Rivers within the United States, except for Grand Coulee and Chief Joseph Dams. A fish ladder's main purpose is to provide an up-stream passageway for the migratory adults of four Pacific Salmon species (Chinook, Coho, Sockeye, Pink) and steelhead. Fish ladders are also used by lamprey, shad as well as other species of fish.
Two fish ladders per dam are currently located at The Dalles and John Day Dams, one on the Oregon shore and another on the Washington shore. A single ladder slopes upward from downstream of a dam (known as tail-water) to its top (known as fore-bay.) Adult migrants are attracted to a ladder entrance at tail-water by the water flow. Once the fish enters the ladder system it swims the entire length of the ladder and then exits into the fore-bay (see diagram).
Pools in the fish ladders are formed by cross barriers called weirs, which slow down the water flow between them allowing resting opportunities for migrating fish. The weirs also have submerged openings at the bottom and the majority of fish pass through the weirs by this route. Chinook (king), Coho (silver) and Sockeye (blueback) salmon, steelhead, shad and other fish use the ladders in their upstream migration. Proper fish passage system operation requires frequent adjustments performed by the dams’ operators.
The Dalles Dam's fish ladders, one on each shore, slope upward from below the project to Lake Celilo upstream. 
John Day Dam's fish ladders, also one on each shore, slope upward from below the project to Lake Umatilla upstream. The ladders are each nearly one-third mile long, serving as passageways for fish that seasonally migrate upstream to spawn.
Fish Bypass System
A juvenile fish bypass system was installed at John Day Dam to increase survival rates of downstream migrant fish. The system is designed to collect fish before they enter turbine intake areas and to transport them around the powerhouse for release downstream with minimum amount of injury or disorientation. The system was completed in February 1987 at a cost of $23 million and was operational in time for the spring downstream fingerling migration.
The Smolt Monitoring Facility (SMF) was constructed at John Day Dam as a part of the juvenile bypass system at a cost of $27 million and started its first season of operation in 1998. Its main objective is to monitor the timing and magnitude of juvenile salmonid out-migration so the dam managers can make flow and spill recommendations designed to facilitate optimal downstream passage. A new fish marking technology, Passive Integrated Transponder (PIT) tag, is providing improved estimates of the juvenile passage. All juvenile fish collected in the bypass channel are diverted through the dewatering structures and flumes to the PIT tag detectors. A small percentage, less than 3%, are sub-sampled to access their growth rate and physical condition.
Fish Counters
At each fish way, a person tabulates the various species of salmon, steelhead and shad moving up the fish ladder. Fish are counted as they pass underwater viewing windows. The daily count of fish for the dams on the Columbia and Snake Rivers is posted and this important information helps management make decisions to sustain fish runs. Fish counts have been recorded at The Dalles Dam since 1957 and has been recorded at John Day Dam since 1968.
About 450,000 adult salmon and steelhead migrate upstream, and from 30 - 50 million salmon and steelhead fingerlings move downstream past The Dalles Dam in an average year. Shad, sturgeon, lamprey and other species also are observed.