Selective Water Withdrawal facility
The Selective Water Withdrawal facility at the lower end of Lake Billy Chinook became operational in December 2009.


Closeup view of the Selective Water Withdrawal facility
This closeup view of the Selective Water Withdrawal facility shows the fish collection station.

 
Rendering of the Selective Water Withdrawal Tower
Rendering of the Selective
Water Withdrawal Tower
Click to enlarge
 
Rendering 2 of the Selective Water Withdrawal Tower
Rendering of the Selective
Water Withdrawal Tower
Click to enlarge
 
Tower dimensions
Bottom Section   70 ft. tall x 60 ft. wide
1.4 million lbs.
Pipe   40 ft. diameter
135 ft. tall
Top section   60 ft.  tall x 90 ft.  wide x 150 ft.  long
5 million pounds
32 concrete floats - 45,000 lbs. each
Fish Collection Facility   2 V-screens
two 40 ft.  tall x 30 ft. wide openings

 

Underwater Tower

This massive structure is truly unique—its one-of-a-kind design combines fish collection and water flows for power generation. The design that makes Pelton Round Butte an important source of green energy for Oregon. Referred to as a "Selective Water Withdrawal Tower," the structure draws water both from the surface and from the bottom of Lake Billy Chinook. This accomplishes several things:

  • Changes the currents to attract fish into the fish collection facility.
  • Lowers the temperature of Lake Billy Chinook, providing healthier conditions for the fish.
  • Modifies the temperature of the lower Deschutes River to more closely match what it was before the dams were constructed.
  • Improves the water quality both in the reservoirs and in the river.

In addition, 100 percent of all powerhouse flows are screened to protect the fish.

How it works
The tower draws water both from the warmer surface layer and from the colder bottom layer of Lake Billy Chinook. This will be enough to change the currents in the lake to draw fish toward the tower and into the fish collection facility. The fish are collected in the two V-screens and sorted by size. Larger fish (bull trout and kokanee) are returned to the lake. The smaller fish are further sorted and tagged on an adjacent floating Fish Transfer Facility. The juvenile Chinook salmon and steelhead are then trucked and released downstream to continue their migration to the sea.

Why this design
PGE and the Tribes spent many years researching different options for restoring fish passage above Pelton Round Butte. Of all the proposals they reviewed, this was the most effective in attracting fish into the facility and maintaining the current level of power output. It was also the most cost effective design. Other options would have either decreased the power output of the facility, cost more or both.

View rendering of the new structure with major sections labeled