Before the FERC Application for New License for the Annex Creek ...

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the crown of the arch, the dam measures 6 feet thick at the crest and 47.5 feet
at the foundation contact.
Releases can be made directly into Salmon Creek through the reservoir
outlet. The outlet consists of a 36-inch pipe through the dam with a
36-inch gate valve used to maintain the reservoir level at E1 1140 (USCD).
The spi 11 way is an uncontrolled crest wi th ten 5-foot-wi de bays
separated by 1-foot-thi ck concrete pi ers. A concrete-1 i ned chute downstream
of the spillway directs water into the creekbed below the right abutment. The
hydraulic capacity of the spillway at Salmon Creek Dam is approximately
810 cfs with no freeboard on the dam crest. The spillway does not function
due to the limitation imposed by the FERC of the maximum pool level as
described below in paragraph 3.3.
Salmon Creek Upper Power Conduit. The intake structure measures 10 feet
wide by 11 feet high and is equipped with trashracks. Water is conveyed from
the intake structure to the va1vehouse immediately downstream of the dam
through a 36-inch-diameter concrete conduit. Flow into the Upper Penstock is
contro 11 ed there by a 36-inch, hand-operated gate va 1 ve. The Upper Pens tock
is 4,475 feet in length and varies ;n diameter from 30 to 40 inches. The penstock
is made of riveted steel varying in thickness from 0.25 to 0.47 inches.
The Upper Penstock bifurcates immediately upstream of the powerhouse. Downstream
of the bifurcation a butterfly valve has been installed on each
branch. One condui t goes to the Upper Powerhouse and the other goes to the
Lower Powerhouse via the Lower Penstock.
Sa 1 mon Creek Upper Powerhouse. The Upper Powerhouse is a ti mber frame
structure 63 feet long, 34 feet wide and 27 feet high with a concrete substructure.
A 15-ton overhead crane serv ice s the fac i 1 i ty. Two 2, 500-horsepower
impu1 se type turbi ne-generator un; ts are housed ; n the structure wi th
six transformers in an attached 48-foot-10ng by 15-foot-wi de by 27-foot-hi gh
re i nforced concrete bu i 1 d; ng . The 30-i nch-d i ameter pen stock b i furca tes jus t
upstream of the units. The nozzle jet of the turbines is at E1 449.3 (USCD)'
Discharge from the plant flows into the South Fork of Salmon Creek. Nearby
detached structures serve as workshop, storage, and living accommodations.
Salmon Creek Lower Penstock. The Salmon Creek Lower Penstock is a buried
42-inch-diameter welded steel pipe varying in wall thickness from 0.375 to
0.507 inches. It is approximately 11,030 feet long and is buried for its
entire length except for the 346-foot section from the bifurcation to a pOint
downstream of the Salmon Creek Bridge and for 225 feet at the lower bridge.
The 42-inch-diameter penstock reduces to 30 inches in diameter just prior to
entering the new Lower Powerhouse.
Salmon Creek Lower Powerhouse. The new Lower Powerhouse structure is an
insulated prefabricated metal building approximately 57 feet long by 44 feet
wide by 22 feet high. It houses a single impulse turbine-generator unit with
the turbine jet at E1 34 (LSCD). Equipment is serviced by a 30-ton capacity
overhead bridge crane.