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Public Radio's Environmental News Magazine (follow us on Google News)

Salmon Lose to Sprawl

Air Date: Week of

Urban sprawl is a major factor in the decline of the salmon since nature's waterway systems are altered by loss of wetlands and forest. Christine Arrasmith has the details on how development changes the water flows salmon need to live.


ARRASMITH: I'm Christine Arrasmith. In the rural areas of the Northwest, the biggest threats to salmon are hydroelectric dams and logging and cattle grazing in sensitive watersheds. But here in urban Seattle, the biggest problems are the places where people live, work, shop, and play. Researchers are finding that when spongy forest floor and a natural canopy of trees are replaced by pavement, roofs, and grass, runoff into streams increases dramatically. And that can make the waterways almost uninhabitable for salmon.

(Birds chirp; a dog barks)

GRIFFIN: This is where our community has the Easter egg hunt for the kids, every year.

ARRASMITH: This stretch of Maplewood Creek near Ray Griffin's home outside Seattle used to be home to salmon. Coho, sockeye, steelhead, and maybe a few of the biggest, Chinook. But no salmon have made it up the stream to spawn for at least a decade. The banks of the creek are raw and shaved. On the far side is a bald, almost vertical slope.

GRIFFIN: If you look over here to your right, you'll see the whole hillside on that side there is all sliding down. It's all getting washed away at the base, and from now on you're going to see trees laying all over, in all directions, from losing their footing and sliding into the canyon.

ARRASMITH: Ray Griffin says that when it rains here, and this means Seattle, it rains a lot, the uplands become saturated almost immediately and the water runs off in sheets toward the creek. He blames this erosion on the parking lots and roof tops of strip malls and apartment complexes nearly a mile away. At first blush it seems far-fetched, but scientists think Mr. Griffin is right. Geologist Derek Booth, director of the Center for Urban Water Resources Management at the University of Washington, says that development concentrates the flow of rainwater and speeds up its movement through nearby open ground.

BOOTH: With the increase in pavement and rooftops, that water now moves very efficiently into the stream channel. And every time it rains just a little bit, there is more water in the stream channel. And when it rains a lot, there's a lot more water in the stream channel.

ARRASMITH: Dr. Booth says development can increase runoff by 20 to 50 times, and as it surges into streams like Maplewood Creek, all this water strips out the gravel and woody debris that salmon need.

(A golf ball is hit, followed by voices talking)

ARRASMITH: Just beyond the ravine by Ray Griffin's house, Maplewood Creek runs through a municipal golf course in a channel dug years ago when this land was a farm. With its smooth, closely-mowed banks, a golfer here might easily see the creek as merely an ornamental feature or a water hazard.

MAN: A real stream, huh?

ARRASMITH: Yeah. You don't think it's a real stream?

MAN: Oh yeah, I believe it. (Laughs) Just never really paid it any attention...[trails off]

(Flowing water; crows and other birds)

ARRASMITH: Long ago, the creek probably meandered in S-curves here, with lots of eddies, downed wood, plants, and slow-moving ponds. But forced into an arrow-straight trench, the water sluices through too fast for salmon. The artificial flows are especially high in the winter, when the Puget Sound region gets most of its rainfall. Geno Lucceti, an ecologist with King County, says that's especially bad for salmon.

LUCCETI: A species of fish like Coho salmon, which tend to spawn in the mid to late fall, early winter time period, are laying their eggs at a time when in this environment around here, those eggs are going to be very susceptible to flooding.

ARRASMITH: Scientists say the key to restoring healthy salmon runs to Seattle and other urban areas is to reduce runoff and slow streams down. For years, developers have built ponds to catch runoff from big storms, but scientists now are finding the ponds have never been big enough. They believe even more land would have to be set aside at each development to capture all the runoff. But builders say the ponds are already too expensive and take up too much land. King County developer Bill Finkbeiner says individual developers shouldn't have to shoulder the burden of a regional problem.

FINKBEINER: I think the regional solution is simply that all of the municipalities, together with King County, need to get together and cooperatively determine where regional detention is going to take place. Where regional water quality is going to take place. And where regionally you have the best opportunity to restore salmon habitat.

ARRASMITH: But the salmon are in trouble throughout the region because of the cumulative effect of thousands of individual developments. And researchers say individual watersheds can't be repaired with one size fits all solutions. Some argue that virtually every structure or parking lot should have its own holding pond, cistern, or trench. And everyone agrees that wherever possible, the best thing for salmon is undisturbed open space.

(Panting dogs)

BURLINGAME: What we're doing is nothing.

ARRASMITH: Joan Burlingame's dogs navigate her tangled underbrush of bramble, logs, and trees, far better than people. She and her husband have left 3 of their 5 acres wild in exchange for a big tax break from King County. Ferns, dead leaves, and water-loving cedars cover the hillsides, which can soak up 6 inches of rain.

BURLINGAME: We've been, worked really hard not to disturb any of the soil. In fact, we even hand-dug our septic field. We didn't allow a bulldozer down here.

ARRASMITH: The Burlingames' woodland is a natural sponge and filter for water headed for Rock Creek, a still healthy salmon stream nearby. But their efforts alone can't save the stream. The region's housing boom is spreading out to these quiet forested areas, so Joan Burlingame also serves on a local council charged with making tough development decisions. The council recently approved a much denser housing development than has usually been allowed in the area, in exchange for a key piece of land being left undeveloped.

BURLINGAME: It's a tough compromise. Do we want to have that connecting piece to be able to connect all those greenbelts along Rock Creek and that drain into Rock Creek and the Cedar River, in exchange for all the traffic and the noise we're going to get with the 600 homes?

ARRASMITH: But for salmon to have any chance to survive in the Seattle area, this kind of compromise will have to happen a lot more often. Higher-density development in some areas in exchange for less or even no development in others. And in a region where nearly every neighborhood has a salmon stream, King County ecologist Geno Lucceti says that means some will be saved and some might have to be sacrificed.

LUCCETI: Our approach to trying to protect and restore salmon is to shut the barn doors, if you will, and keep the horses that we have. So that relates back to going out and identifying your good quality habitats that are still here.

ARRASMITH: But reducing the impact of new development won't be enough. Many existing neighborhoods and shopping centers in the Puget Sound region will have to be retrofitted at a cost of more than $200 million in King County alone. But officials here believe that's far cheaper than Federal controls that could be imposed if they don't reinvent a place for wild salmon in the urban northwest. For Living on Earth, I'm Christine Arrasmith in Seattle.



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