Project: Priest Rapids Total Dissolved Gas Exchange Study
PI: Mike Schneider
Project Description/Activities/Capabilities:
Intends to describe spatial and temporal dynamics in TDG both near Priest Rapids Dam and
downstream of the dam in the receiving waters under a variety of spillway operations. The
primary goal of the investigations was to provide a description of current dissolved gas conditions
and processes as related to Priest Rapids Dam operation.
Sponsor: Grant County Washington Public Utility District (GCPUD), POC Cliff Sears
Personnel: Mike Schneider (CHL), Calvin Buie (CHL), Joe Carroll (EL), Carolyn Schneider (EL),
Kathryn Barko (Dyntel Corp.), Cliff Sears (GCPUD), Darrell Pock (GCPUD), and Dana Jeske
(GCPUD)
Project Location and Description:
Priest Rapids Dam is located at river mile 397.1 on the Columbia River about 27
miles east of Yakima, Washington. Priest Rapids Dam impoundment extends 18.7
miles upstream to Wanapum Dam and typically contains 191 kacreft of storage. As a
run-of-the-river hydroelectric facility, the Priest Rapids Project has limited water
storage capacity with a forebay water surface elevation ranging from 481.5 to 486 ft.
The tailwater elevation normally ranges from 400.5 to 411.6 ft varying in response
to total river flows. Priest Rapids Dam is owned and operated by the Grant County
Public Utility District No. 2. The dam is a reinforced concrete structure 2,450 ft in
length consisting of one powerhouse and spillway. The powerhouse is 1,035 ft in
length and consists of 10 turbines with a rated output of 788 MW and a hydraulic
capacity of 187 kcfs. The turbines are numbered consecutively from right to left
bank with the lower numbered units closest to the spillway. The spillway has a total
length of 1,132 ft and consists of 22 bays. The nominal width of each bay is 40 ft
and the adjoining piers are 12 ft in width. The spillway crest is located at elevation
436.5 ft or about 50 ft below the water surface elevation during normal conditions.
The stilling basin extends 70 ft and spans the length of the spillway at 387 ft
elevation and has a sloped end sill at elevation 391 ft that bounds the downstream
end of the stilling basin. A training wall separating the stilling basin from the
powerhouse bounds the east end of the stilling basin.
Facilities: Field Study
Related Topic Areas: Hydrualic Structures, Environmental Studies, Spillway Flow Deflectors,
Total Dissolved Gas, Hydropower, reservoir
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