Boundary Dam

This article is about the dam in Washington. For the dam in Saskatchewan, see Boundary Dam Reservoir.

Boundary Dam is a concrete arch gravity-type hydroelectric dam, finished in 1967, on the Pend Oreille River, in the U.S. state of Washington. The dam is located in the northeast corner of Washington state. It is operated by Seattle City Light^[4] and makes up a significant portion of the City of Seattle's energy portfolio. On average, it provides upwards of 46% of the power generated by Seattle City Light. Boundary Powerhouse, located adjacent to the dam, is completely built inside of the rock that makes up the left abutment of the dam itself. It has a nameplate capacity of just over 1 gigawatt of generation. The component of the hydroelectric project were listed on the National Register of Historic Places in 2018.

Boundary Dam
Location of Boundary Dam in Washington (state)
Country	United States
Location	Pend Oreille County, Washington
Coordinates	48°59′14″N 117°20′51″W
Status	Operational
Opening date	1967[1]
Owner(s)	City of Seattle[1]
Dam and spillways
Type of dam	Arch-gravity
Impounds	Pend Oreille River
Height	340 ft (100 m)[1]
Length	740 ft (230 m)[1]
Reservoir
Total capacity	95,000 acre⋅ft (117,000,000 m3)[1]
Catchment area	25,200 sq mi (65,000 km2)[1]
Surface area	1,668 acres (6.75 km2)[1]
Power Station
Installed capacity	1,003.25 MW[2]
Annual generation	3,587 GWh[3]

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.^[5]

Climate

Climate data for Boundary Dam, Washington, 1991–2020 normals: 1837ft (560m)
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Mean daily maximum °F (°C)	32.6 (0.3)	38.3 (3.5)	47.5 (8.6)	58.0 (14.4)	67.2 (19.6)	72.4 (22.4)	83.6 (28.7)	84.6 (29.2)	72.9 (22.7)	55.7 (13.2)	40.3 (4.6)	32.2 (0.1)	57.1 (13.9)
Daily mean °F (°C)	26.7 (−2.9)	29.9 (−1.2)	37.1 (2.8)	45.3 (7.4)	54.0 (12.2)	60.1 (15.6)	67.8 (19.9)	67.2 (19.6)	57.8 (14.3)	45.2 (7.3)	34.2 (1.2)	26.8 (−2.9)	46.0 (7.8)
Mean daily minimum °F (°C)	20.9 (−6.2)	21.5 (−5.8)	26.8 (−2.9)	32.6 (0.3)	40.9 (4.9)	47.8 (8.8)	52.0 (11.1)	49.8 (9.9)	42.6 (5.9)	34.6 (1.4)	28.1 (−2.2)	21.4 (−5.9)	34.9 (1.6)
Average precipitation inches (mm)	3.10 (79)	1.98 (50)	2.35 (60)	2.21 (56)	2.60 (66)	3.18 (81)	1.42 (36)	0.81 (21)	1.32 (34)	2.40 (61)	3.23 (82)	3.60 (91)	28.2 (717)
Average snowfall inches (cm)	18.50 (47.0)	7.70 (19.6)	3.40 (8.6)	0.10 (0.25)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.10 (0.25)	6.80 (17.3)	18.20 (46.2)	54.8 (139.2)
Source: NOAA[6]

See also

• United States portal
• Water portal
• Renewable energy portal

• List of dams in the Columbia River watershed