120 



Prepared Statement of Col. Bartholomew B. Bohn, Deputy Command, North 

 Pacific Division, U.S. Army Corps of Engineers 



introduction 



Mr. Chairman and Members of the Subcommittee, I am pleased to be here today 

 to provide information on the U. S. Army Corps of Engineers efforts related the de- 

 velopment of the spill policy for the Columbia River hvdropower dams. I am Colonel 

 Bartholomew Bohn, Depuh' Division Engineer of the North Pacific Division. Accom- 

 panying me today is Mr. Doug Amdt, Senior Fish Program Planner with the North 

 Pacific Division. 



Northwest salmon stocks are in serious trouble. Three species of Snake River 

 salmon are listed under the Endangered Species Act. In 1994, only one Snake River 

 Sockeye Salmon returned to the Redfish Lake spawning grounds in Idaho. Returns 

 of listed spring/summer and fall chinook salmon runs were very disappointing last 

 year, and are even more dismal this year so far. 



The Corps of Engineers has been working with other Federal and State agencies, j 

 Tribes, Northwest Power Planning CouncU, and other interested parties in the re- i 



f'.on for years to determine the causes of salmon run declines and to find solutions. \ 

 ut the listing of these three salmon species and their precipitous declines over the 

 past few years have focused our programs and directed us to more intensified efforts 

 to improve conditions for this important resource. 



A number of factors have contributed to the cvurent state of the salmon stocks 

 in the Colvmibia and Snake River Basin. These include: adverse effects of logging, 

 mining, cattle grazing and pollution on spawning and rearing habitat: increased 

 competition for food and spread of disease fi'om hatchery stocks; dams that impede 

 the migration of juvenile salmon from their upriver rearing areas to the ocean and 

 as they return as adults to spawn; and, over harvesting — historically in the 1800s 

 and since then by ocean take and sport and commercial fisherv in the Basin. The 

 situation is further compounded by poor ocean conditions which have also brought 

 coastal salmon and steelnead stocks along the Pacific Northwest coast to similar lev- 

 els of decline. All of these have combined to lessen survival chances of the wUd 

 salmon stocks. 



OPERATION of HYDROPOWER DAMS TO MINIMIZE IMPACTS ON SALMON 



The Corps' eight hydroelectric dams on the lower Columbia and Snake Rivers are 

 widely believed to be a major factor in the decline in numbers of wild Snake River 

 salmon stocks. Besides physically impeding fish migration, the dams create res- 

 ervoirs that alter water velocities and temperatures, interfering with juvenile migra- 

 tion patterns and improving conditions for predators. 



We have sought and continue to seek solutions for the impacts of the Federal 

 dams. Adult fisn ladders have been built into each of the ei^t lower Snake and 

 Columbia River dams. These allow adult fish to follow a series of graduated steps 

 and pools to scale the 100-foot rise in elevation from the tailrace to the forebay of 

 the aams. The ladders work very well. 



In the years since the dams have been in operation, many improvements have 

 been made to juvenile fish passage routes at the dams. There are a number of ways 

 for juvenile fish to pass the dams: through the turbines, over tJie spillways, through 

 the juvenile bypass systems, and in specially designed tanks for transport around 

 the dams by barge and truck. Based upon juvenile passage studies, projects are op- 

 erated to provide optimum passage conditions. 



The survival rate for turbine passage ranges fi'om about 85 percent to 95 percent, 

 depending on the hydraulic ana hydrologic conditions at the dam, tvpe of turbine, 

 efficiency range of turbine operation, and other factors. The survival rate for spill- 

 way passage is considered to be about 98 or 99 percent. Survival rate through the 

 bypass systems is about 97 or 98 percent. The svuvival rate for barged fish is about 

 98 percent to the release point. Jish collected at the bypass systems for transport 

 at four dams are conveyed past all remaining dams. 



Survival numbers depend upon how many of the juvenile fish use each passage 

 route and upon conditions they encounter. Turbine passage may disorient some fisn, 

 making them easy prev for squawfish and gulls in the tailrace downstream of the 

 dam. High levels of spill result in gas supersaturation levels that can cause gas bub- 

 ble disease in fish. 



Another factor is the percentage of fish using each different passage route. Juve- 

 nile bjrpass systems deflect 80 to 90 percent of steelhead, 60 to 70 percent of spring/ 

 summer chinook and as few as 30 percent of fall chinook salmon away fi'om the tur- 

 bine intakes and through the bypass channel. Recent improvements in deflector 

 screens — especially the extended length screens — are expected to improve this sig- 



