| Coordinates | 48°59′14″N 117°20′51″W |
|---|---|
| Country | United States |
| Location | Pend Oreille County, Washington |
| Purpose | P |
| Status | O |
| Opening | 1967 |
| Owner | City of Seattle |
| Dam height | 338 ft (103 m) |
| Dam length | 740 ft (225.6 m) |
| Dam width crest | 8.0 ft (2.44 m) |
| Dam width base | 32.0 ft (9.75 m) |
| Dam crosses | Pend Oreille River |
| Spillway count | 2 |
| Res capacity total | 95,000 acre.ft |
| Res catchment | 25,200 sq mi (65,000 km2) |
| Res surface | 1,668 acres (675 ha) |
| Plant name | Boundary Dam Hydro Power Plant |
| Plant coordinates | 48.98722°N 117.3475°W |
| Plant operator | Seattle City Light |
| Plant commission |
|
| C | Boundary Dam Hydro Power Plant |
| Plant turbines |
|
| Plant capacity | 1,159.7 MW |
| Plant annual gen | 3,020 GWh (10,900 TJ) (2024) |
| Extra | [1][2][3][4] |
The Boundary Dam is a concrete arch-gravity dam across the Pend Oreille River, located in the U.S. state of Washington, in the northeast corner of the state. Completed in 1967 for the conventional generation of hydroelectricity, the dam is operated by Seattle City Light[5] and generates a significant portion of the City of Seattle's energy portfolio. On average, it provides between 46 and 60 percent of the power generated by Seattle City Light.[6]
The dam wall is 338 ft (103 metres) high and 738 ft (225 metres) long.[4]
The underground powerhouse, called the Boundary Dam Hydro Power Plant, is completely built inside of the rock that makes up the left abutment of the dam wall. It has a nameplate capacity of just over 1 gigawatt (1,300,000 hp) of generation. The hydroelectric project was listed on the National Register of Historic Places in 2018.
The 1997 film The Postman was partially filmed at the dam. A facade of the town (Bridge City in the film) appeared on the face of the dam for a period of time that year.[7]
Hydroelectric power capacity
| Generator (all Francis-type) | Nameplate capacity[2] | Brand[4] | Commissioned[8] | |
|---|---|---|---|---|
| MW | hp | |||
| 51 | 180.5 megawatts | 242,100 hp | General Electric | October 1967 |
| 52 | 161.5 megawatts | 216,600 hp | General Electric | August 1967 |
| 53 | 158.4 megawatts | 212,400 hp | General Electric | September 1967 |
| 54 | 180.5 megawatts | 242,100 hp | General Electric | August 1967 |
| 55 | 239.4 megawatts | 321,000 hp | Toshiba | November 1985 |
| 56 | 239.4 megawatts | 321,000 hp | Toshiba | May 1986 |
| Total[a] | 1,159.7 megawatts | 1,555,200 hp | ||
See also
References
- ^ "Boundary Dam". NPDP Dam Directory. Stanford University. Archived 2011-07-16 at the Wayback Machine.
- ^ "Generator 2026". EIA 860M. January 2026.
- ^ "Generator 2024". EIA-923. 2024.
- ^ "Projects: Boundary Hydroelectric Power Plant, Washington". NS Energy. 2018-07-16. Retrieved 2026-04-11.
- ^ "Seattle City Light: Boundary Project". Archived from the original on 2011-11-25. Retrieved 2011-09-26.
- ^ "Projects: Boundary Dam". Schnabel Engineering. 2026. Retrieved 2026-04-11.
- ^ "Boundary Dam". Seattle Municipal Archives
- ^ "Boundary Dam Hydro Power Plant WA USA". Global Energy Observatory. 2015-09-18. Retrieved 2026-04-11.