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 5/23/20

We are working to re-open recreation gradually and safely. Please check this website for regular updates. 

Currently, registration is NOT REQUIRED to use any of the recreation sites, in an effort to limit exposure and cross-contamination.

OPEN: The South Shore Road and associated recreation sites, including access to the DNR Greider Lakes Trail is OPEN.

OPEN: Culmback Dam Road is OPEN to pedestrians/bicycles only; the gate will remain closed. Park at Olney Pass and walk or ride in. Please maintain distance from those outside your party. 

CLOSED: Sultan River Canyon Trail is closed due to downed trees and debris slides. Anticipated opening is late June, 2020

CLOSED: To ensure safety of staff, Sultan River access from the Diversion Dam Road and Allen gate are closed. This closure also includes the gate at 116th Street accessing the recreation facilities near the Jackson Powerhouse. 

We will reassess the situation and update this website as applicable. 

For more details:

Spada Map (click to view)
(click to view map)


Keith Binkley

Dawn Presler