Casad Dam | |
---|---|
Country | United States |
Location | Bremerton, Washington |
Coordinates | 47°32′17″N 122°46′47″W / 47.53806°N 122.77972°W |
Purpose | Municipal water supply[1] |
Status | Operational |
Construction began | 1955 |
Opening date | 1957 |
Construction cost | $1.4 million[2] |
Owner(s) | City of Bremerton |
Dam and spillways | |
Type of dam | Concrete arch |
Impounds | Union River |
Height | 190 ft (58 m) |
Length | 416 ft (127 m) |
Elevation at crest | 643.7 ft (196.2 m) |
Width (base) | 56 ft (17 m) |
Reservoir | |
Creates | Union River Reservoir |
Total capacity | 1,400,000,000 US gal (5,300,000 m3) |
Catchment area | 3,000 acres (1,200 ha) |
Surface area | 40 acres (16 ha) |
Normal elevation | 607 ft (185 m)[3] |
Coordinates from USGS,[4] specifications from factsheet[5] unless noted |
Casad Dam is a concrete arch dam in Bremerton, Kitsap County, Washington), built starting in 1955 and completed in 1957.[6][7]
The dam is Kitsap County's only major water diversion structure,[8] impounding Union River to form a reservoir that is the source of over half of Bremerton's municipal water supply.[5] The water is gravity fed from the reservoir at 607 feet (185 m) in the hills[3] to the city, most of which is at or near sea level.[9]
Bremerton owns 95% of the land in its 3,000-acre (1,200 ha) watershed, and the Union River reservoir behind Casad Dam holds 1,400,000,000 US gallons (5,300,000 m3) of water.[6] The city is unusual in drawing most of its water supply from an open air source, the reservoir, which can occasionally be affected by algal blooms.[10]
The dam's intake tower underwent seismic retrofit in 2012 to withstand a 0.78 g peak acceleration in a maximum credible earthquake from the Seattle Fault which runs about four miles (7 km) away, on the north side of Green Mountain.[11][12]