Tag Archives: Salmon habitat

Are we winning or losing the ongoing battle for salmon habitat?

It has been said that the Puget Sound ecosystem would be far worse off today were it not for the millions of dollars spent on restoration projects over the past 25 years.

Undoubtedly, that’s true, but I think most of us are hoping that these costly efforts will eventually restore salmon populations while improving conditions for other creatures as well. Shouldn’t we be able to measure the progress?

Juvenile chinook salmon
Photo: John McMillan, NOAA

This basic question became the essence of my latest story published in the Encyclopedia of Puget Sound: “Are we making progress on salmon revovery?”

As I describe in the story, what seems like a simple question becomes tangled in the difficulties of measuring population and ecological changes. It turns out that you can’t just count the fish to see if restoration is working. That’s because natural variabilities of weather, ocean conditions and predator/prey populations cause salmon populations to swing wildly from year to year no matter what you do.

While researching this story, I learned a good deal about freshwater habitat conditions needed to help various species of salmon to thrive. Habitat improvements resulting from restoration projects are no doubt helping salmon in significant ways. On the other hand, one cannot ignore human development that continues to degrade habitat — despite improved regulations designed to reduce the damage.

I’ve heard some people say that wild salmon would come back in larger numbers if everyone would just stop fishing for them. This may be true to some extent, especially for high-quality streams that may not be getting enough salmon to spawn. But the key to the problem is understanding the “bottlenecks” that limit salmon survival through their entire lives.

A stream may have plenty of adult spawners, but that does not mean the salmon runs will increase if the eggs are buried in silt or if food supplies limit the number of fry that survive. There may be multiple limiting factors that need to be addressed to ensure healthy ongoing salmon populations.

Small improvements in habitat may actually boost the productivity of salmon in a stream, meaning that more salmon will survive. But the benefits of small projects on large streams may be difficult to distinguish from natural variation. Statistical analysis is used to determine whether increases or decreases in salmon populations are more related to habitat changes or natural variation. It takes a fairly dramatic change to link cause to effect in a statistically significant way.

One ongoing experiment is measuring changes in fry populations in several streams within the same watersheds. One stream is left alone — the “control” stream — while habitat improvements are made in others. Because the streams are closely related, biologists hope to attribute population increases to habitat improvements with a high level of certainty. See Intensively Monitored Watersheds on the website of the Washington Department of Fish and Wildlife.

The same issue of statistics applies to the aquatic insects that salmon eat. It appears that food supplies are improving in many salmon streams as a result of restoration, but not all benthic invertebrates are responding in the same way. For many streams, it will take more time to get enough data to determine whether the increased bug populations are statistically significant. This happens to be one issue that I side-stepped in the latest story, but I will be returning to it in the future. For background, check out an earlier story I wrote for the Encyclopedia of Puget Sound, “Healthy Streams, Healthy Bugs.”

While habitat restoration is ongoing, so too is human development, which continues unabated at what appears to be an accelerating pace. New regulations are designed to result in “no net loss” of important habitats, including shorelines, streams and wetlands. But questions remain about whether local regulations themselves and/or enforcement of the regulations are adequate.

Biologists at NOAA’s Northwest Fisheries Science Center are conducting research to determine whether habitat changes are for better or worse, especially with regard to chinook. We should see some results within the next few years, as the agency prepares to draft the next five-year status report for Puget Sound’s threatened chinook population.

Extensive floodplain restoration brings new hope to Clear Creek

A giant piece of a cedar log stands erect in a barren landscape north of Silverdale, where a new channel for Clear Creek stands ready to receive water.

An old cedar log was recovered during excavation for a new channel for Clear Creek. Photo: Dunagan
An old cedar log was recovered during excavation for a new channel for Clear Creek.
Photo: Christopher Dunagan

Well, maybe this channel won’t be entirely new. Designers working to restore this portion of Clear Creek studied old maps. They tried to align the new man-made channel to the meandering stream that existed 150 years ago, before farmers diverted the creek around their fields.

During excavation, workers uncovered buried gravel — remnants of the old streambed — along with chunks of cedar that had lain along the edge of the stream. Buried and cut off from oxygen, these pieces of wood survived for decades underground, while cattle grazed in the fields above.

Workers excavating for the new channel used their heavy equipment to pull out what remained of a great cedar log. They stood the log vertical and buried one end in the ground — a monument to the past and future of Clear Creek.

A restored Clear Creek floodplain (before plantings) north of Waaga Way in Central Kitsap. Photo: Kitsap County Public Works
A restored Clear Creek floodplain (before plantings) north of Waaga Way in Central Kitsap.
Photo: Kitsap County Public Works

Chris May, manager of Kitsap County’s stormwater program, showed me the new channel this week. He said it was rewarding to uncover some buried history and realize that the stream would be restored in roughly the same place.

“We found the old channel,” Chris told me, pointing to a deposit of gravel. “We are pretty confident that we got it right.”

This $3-million project has been conceived and designed as much more than a stream-restoration project. The elevations of the land around the stream have been carefully planned so that high flows will spill into side channels and backwater pools. That should reduce flooding in Silverdale and help stabilize the high and low flows seen in Clear Creek.

Before photo: This was the farmers field as it appeared before restoration. Photo: Kitsap County Public Works
Before photo: This was the farm field as it appeared before restoration. // Photo: Kitsap County Public Works

The engineers did not calculate the reduced frequency of flooding, but floodwater storage is calculated to be 18.4 acre-feet, the equivalent of a foot of water spread over 18.4 acres or 29,700 cubic yards or 6 million gallons.

In all, about 30,000 cubic yards of material have been removed across 21 acres, including the former Schold Farm on the west side of Silverdale Way and the Markwick property on the east side. Native wetland vegetation will be planted along the stream and in low areas throughout the property. Upland areas will be planted with natural forest vegetation.

The topsoil, which contained invasive plants such as reed canarygrass, was hauled away and buried beneath other excavated soils to form a big mound between the new floodplain and Highway 3. That area will be planted with a mixture of native trees.

Graphic showing area before restoration. Graphic: Kitsap County Public Works
Graphic showing area before restoration.
Graphic: Kitsap County Public Works

Plans call for removal of 1,500 feet of an existing road with upgrades to two aging culverts. Adding meanders to the straightened channel will create 500 feet of new streambed that should be suitable for salmon spawning.

Plans call for adding 334 pieces large woody debris, such as logs and root wads to the stream. Some of that wood will be formed into structures and engineered logjams to help form pools and gravel bars.

Graphic showing area after restoration. Graphic: Kitsap County Public Works
Graphic showing area after restoration. Notice stream meanders near beaver pond habitat
Graphic: Kitsap County Public Works

“This will be one of the first streams to meet the Fox and Bolton numbers,” Chris told me, referring to studies by Martin Fox and Susan Bolton of the University of Washington. The two researchers studied natural streams and calculated the amount of woody debris of various kinds needed to simulate natural conditions, all based on the size of a stream. (Review North American Journal of Fisheries Management.)

The elevations on the property were also designed so that high areas on opposite sides of the stream would be in close proximity in several locations.

“Beaver will pick that spot,” Chris said, pointing to one location where the stream channel was squeezed by elevated banks on each side. “We want to encourage beaver to come in here.”

Beaver ponds will increase the floodwater storage capacity of the new floodplain and provide important habitat for coho salmon, which spend a year in freshwater and need places to withstand both high and low flows. Because the county owns the flooded property, there won’t be any complaints about damage from beavers, Chris noted.

Aerial photo showing project area with Silverdale in the background, Silverdale Way to the left and Highway 3 to the right. Photo: Kitsap County Public Works
Aerial photo showing project area with Silverdale in the background, Silverdale Way to the left and Highway 3 to the right. // Photo: Kitsap County Public Works

Clear Creek Trail (PDF 390 kb), which begins on the shore of Dyes Inlet, will be routed along the higher elevations as the trail winds through the property. Three new bridges will provide vantage points to watch salmon after vegetation obscures other viewing areas from the trail. Viewing platforms, as seen along other parts of Clear Creek Trail, were not included in this project but could be subject to further discussions.

Count me among the many people — experts, volunteers and users of Clear Creek Trail — who are eager to see how nature responds when water (now diverted) returns to the new stream channel. For decades, the lack of good habitat has constrained the salmon population in Clear Creek. The stream still has problems related to its highly developed watershed. But now a series of restoration projects is providing hope for increased coho and chum salmon and possibly steelhead trout as well as numerous other aquatic species.

In a story in the Kitsap Sun, Reporter Tristan Baurick described work this week on the Markwick property, where fish were removed in preparation for final channel excavation.

Here are some details (including photos) of various Clear Creek projects, as described in the state’s Habitat Work Schedule for restoration projects:

Washington Department of Ecology provided $2 million for the project. Kitsap County’s stormwater and roads programs each provided $500,000.