Snohomish County Public Utility District No. 1

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Customer Service (M-F 8a-5:30p): 425-783-1000

Jackson Hydro Project

 Jackson powerhouse

The Henry M. Jackson Hydroelectric Project, which began operating in 1984, is located in the Sultan River Basin. The 112-megawatt hydroelectric generating facility produces about 7 percent of the PUD’s power needs. In addition to generating enough power for 53,200 homes using a clean renewable resource, the project also provides recreation, enhances fish and wildlife habitats, provides an element of flood control and assures an abundance of clean drinking water. A new 45-year license was issued by the Federal Energy Regulatory Commission (FERC) in 2011 (click for details).

How does water get from Spada Lake reservoir to our water supply?

Water from the lake flows through a tunnel/ pipeline before reaching the powerhouse on the Sultan River, downstream from the dam.

After traveling through the turbine-generators at the powerhouse, most of the water goes back into the river. Some of it flows to Lake Chaplain where it becomes part of the water supply. Water from Lake Chaplain is distributed to 75 percent of Snohomish County’s population or is used to maintain proper water flows for fish populations in the Sultan River.

The Henry M Jackson Hydroelectric Project was built in two phases. Phase I, which was completed in 1965, involved the building of Culmback Dam and the creation of the Spada Lake reservoir to increase the water supply. Phase II, completed in 1984, involved raising Culmback Dam 62 feet, which quadrupled water storage capacity of Spada Lake. The Spada Lake reservoir covers 1,870 acres (1,970 acres at maximum flood) with 17.3 miles of shoreline. Its maximum normal elevation is 1,450 feet.

We go to great lengths to ensure that the wildlife and aquatic resources affected by the Jackson Project survive and thrive. This effort is part of our agreement with the Federal Energy Regulatory Commission (FERC) and is also part of our own commitment to improve the community in which we live, work and play. Our biologists endeavor to maintain and improve the wildlife and fish habitats in the Sultan Basin area.

In addition, day-use recreation sites around the perimeter of Spada Lake reservoir are available for public use. The facilities provide access for fishing and boat launching at two locations, picnic areas, trails, viewpoints, interpretive signs, and public restrooms. Because Spada Lake reservoir provides drinking water, swimming, board sports and overnight camping are not allowed in the area. Only row boats and electric-powered boats are permitted on the lake.

The Jackson Project was dedicated in 1984 to the memory of Senator Henry M. Jackson, Snohomish County native who became one of the most influential senators in U.S. history.

Spada Lake Reservoir & Sultan River Access

Updated 1/21/20

The South Shore Road is now closed for the winter season. The road is currently unsafe for public vehicle travel. No vehicular access to the South Fork, South Shore, Nighthawk, and Bear Creek recreation sites or DNR Greider Trail during this time.

Diversion Dam Road will be closed for maintenance until March 1, 2020 (see notice below). Heavy truck traffic is expected during rock removal work, the road will be closed to all public access for safety. Signs have been placed in the area to alert visitors.

Culmback Dam Road is open. Non-vehicular public access through the Gateway site and across Culmback Dam is permitted.  

PUD property and Recreation Sites are day-use only.  


For more details:

(click to view map)

Important Notice

The City of Everett, in conjunction with Snohomish County PUD, is conducting a road repair and culvert construction project on the Diversion Dam Road. To ensure public safety, this project requires temporary closure of certain recreational access points through March 1, 2020, or until further notice.

Due to construction activities including rock work, hazardous conditions for boating and fishing may occur along the river in the reach (Reach 2) between the Diversion Dam [River Mile (RM) 9.7] and the Powerhouse (RM 4.5). Public access will be closed for kayak put-in/take out locations at the Sultan River Canyon Trail and the Diversion Dam. The river will be accessible downstream at the Powerhouse.

The entire Diversion Dam Road system will be closed to all public access including foot traffic due to heavy truck traffic during construction.


Keith Binkley

Dawn Presler