Seattle City Light Biologist’s Co-Author Research Paper on Chinook Salmon in Skagit River

Seattle City Light Biologists Ed Connor and Dave Pflug co-authored a research paper on Chinook Salmon in the Skagit River that was recently published by the scientific journal Transactions of the American Fisheries Society.


“The paper, titled “Abundance, survival, and life history strategies of Juvenile Chinook Salmon in the Skagit River, Washington,” investigated the influence of river flows in the survival of juvenile Chinook salmon. It found that fish management flows from City Light’s Skagit River Hydroelectric Project, particularly reductions in peak flows, have improved juvenile Chinook survival in the river downstream of the project.”

The paper identifies “potential actions for conserving Chinook Salmon Oncorhynchus tshawytscha in the Skagit River.” Seattle City Light contributed to the funding of this research that observed river flows as well as freshwater rearing patterns, spawning and more regarding the six recognized populations of Chinook salmon. The research demonstrated the importance for Chinook salmon survival of managing river flows to avoid peak flow events.  Furthermore, Chinook juveniles exhibiting extended freshwater rearing periods would benefit from additional restoration of freshwater rearing habitats.

Another conclusion derived from the research is that Chinook salmon juveniles with extended freshwater requirements could be enhanced with additional increases in the quality and quantity of rearing habitat, especially backwater areas, natural banks and off-channel habitat in the middle and lower portions of the Skagit River.

Seattle City Light is actively engaged in promoting healthy salmon runs on the Skagit River as part of its operations of the Skagit Hydroelectric Project. City Light’s three dams were built above natural barriers to fish passage and the utility operates them to manage river flows to support spawning runs and juvenile fish. Staff biologists monitor river conditions and research opportunities to enhance fish populations on the river.



Seattle City Light Lowering Diablo Lake for Boat Landing Repairs

Seattle City Light is making repairs to boat landings near the Ross Powerhouse at the utility’s Skagit Hydroelectric Project that will require lowering Diablo Lake.

A 2010 rockslide destroyed a landing for heavy-haul barges that carry heavy equipment to and from the Ross Powerhouse.  Six transformers now in use at the powerhouse are due for replacement, starting in 2016. A light duty landing survived and has been in use since the rockslide, however, it requires a sharp turn that the semi-tractor trailers that will transport the 80-ton replacement transformers cannot make.

A pickup parked near the National Park Service boat landing was hit by the 2010 rockslide.

The $1.5 million project will install a new barge landing and swap locations for two docks used by the National Park Service and a ferry that carries visitors to Ross Lake.

To avoid environmental impacts on the lake, construction needs to be done above the water line. City Light plans to lower the lake level either May 21 or 26. Construction will continue through June 15, when the utility will return the lake to its regular operating level.

A similar draw down will be done, starting Sept. 15 through Nov. 1 to complete the work.  If needed, another draw down may be scheduled in spring 2016.

Draw downs will limit boat movement and recreation. Among the impacts, Colonial Creek Boat Ramp, Colonial Creek canoe launch, boat-in camping at Buster Brown and Thunder Point, the National Park Service dock and the ferry dock will be unusable during some or all of the construction.

Last year, City Light improved the road from the landing and docks to enhance safety.

The access road for the docks in 2013.

The access road after safety improvements.

City Light Biologist Co-Authors Baseline Report for Steelhead Recovery Effort

Steelhead – photo by Oregon State University

The National Oceanographic and Atmospheric Administration (NOAA) published a report on the historic populations of steelhead in the Puget Sound co-authored by Ed Connor, a senior fish biologist at City Light.

Ed Connor

The report identifies and describes fish based on genetics, life history, and geographical, hydrological and habitat characteristics. It will be used to develop a steelhead recovery plan for Puget Sound, which is expected in 2018.

Two of the most important steelhead populations in this region are downstream of City Light’s Skagit and Tolt hydroelectric projects, which generate about 21 percent of the electricity City Light delivers to its customers.

Planning, Quick Thinking Limit Storm’s Impact on Skagit Salmon


Summer Chinook salmon spawn in the Skagit river from August through October each year. Managing river flows during heavy November rains protected the eggs those fish laid from being washed away. — Photo by Dave Bickford, courtesty of U.S. Forest Service

Careful planning, quick thinking and coordination with the U.S. Army Corps of Engineers prevented major flooding and salmon egg losses on the Skagit River after a massive Thanksgiving week storm dumped nearly 11 inches of rain near City Light’s dams.

On Nov. 24, the National Weather Service forecasted a significant rain storm for the Skagit basin, similar in scope to storms in 1990 and 1995 that caused major floods downstream. In preparation, City Light power marketing and operations lowered the levels at Gorge and Diablo lakes to make room and reduce spill, and stopped generation at the Ross Powerhouse.

On Nov. 27, a day after the rains started, river flows at Concrete exceeded 90,000 cubic feet per second – about six times the average flow at that location. At that point, the Army Corps of Engineers took control of the City Light dams.

From Nov. 24 to 29, 10.87 inches of rain fell at the Diablo Powerhouse, raising Ross Lake 6.71 feet.  On Nov. 29, the Army Corp of Engineers released control of the Skagit project back to Seattle, as Concrete flows decreased below 80,000 cfs.

Despite the heavy rain and spills into the lower river, we were able to minimize flooding downstream, with only a 48-hour period when high river flows could scour Chinook and chum salmon redds. This was the direct result of lowering of lake levels ahead of the storm, an action that was planned early in the season in cooperation with the Skagit Flow Plan Coordinating Committee, a review board comprised of state, tribal, and federal fisheries resource agencies.

Seattle City Light Funds Study of the American Pika in North Cascades

Photograph by Matthew Waterhouse

Seattle City Light’s Wildlife Research Grants Program began in 1995 as one of the requirements of the federal license to operate the Skagit River Hydroelectric Project.  The main goal of the program is to “facilitate the development of improved methods for the understanding, management and protection of wildlife resources in the North Cascades ecosystem, with an emphasis on the Skagit River Watershed.”

Each year, the program funds a number of qualified projects selected through a competitive application process. Priority is given to projects that address topics of interest to the agencies in the Skagit River Hydroelectric Project Area, the Skagit River Watershed and the North Cascades/ Western Okanagan ecoregions.

One ongoing project in the North Cascades National Park Complex is studying the American pika (Ochotona princeps).  The project is addressing the research question: “How is climate change affecting high elevation mammal populations such as pika?”

The American pika is a very outgoing herbivore that is a tiny relative of rabbits and hares.  These critters can be found at high altitudes in North American mountain ranges.  In order to test the effect climate has on these mammals, this research project will be retrieving DNA samples through hair snares.  Samples will be taken at multiple different location sites at multiple levels of elevation.

This research project is still underway and is expected to be completed within the next year.  Check out the University of British Columbia researchers’ Pika blog at