In Muir Woods National Monument, Redwood Creek meanders past giant redwood trees — its banks carefully manicured of twigs and logs giving it a tidy, pristine look.
Todd Steiner and his salmon advocacy group SPAWN want to reverse that.
Steiner’s group, along with the National Park Service just completed a project creating small thickets of logs, branches and debris at spots along the waterway, with the aim of giving endangered coho salmon places to hide from predators and ride-out storms.
“It’s a really simple method, low-tech,” Steiner said on a recent rainy day in the park. “We literally collect woody debris and it’s all woven together so it’ll stay together.”
Steiner said over the years, the thinking by park managers was to clean the creek of debris creating an uncluttered setting. But that thinking has morphed with the realization adult fish need woody habitat to survive. Adults returning to the river to create their nests and spawn need places to hide from predators. The same for juvenile salmon which will spend the first year-and-a-half of their lives in the creek, where they also need shelter from storm-fueled currents that would prematurely whisk them out to the ocean.
“These structures allow the fish to find places to hide in the summertime,” Steiner said, “when they have to spend the whole summer here.”
Because of the sensitive habitat of Muir Woods and the crowds of visitors, all the work had to be done by hand. Over six weeks, volunteers and staff from SPAWN collected twigs, branches, and logs — some weighing 500 pounds — from parts of the park and hauled them to twenty-one spots along a mile-long stretch of the creek.
The debris was woven together, each held in place by four posts covered with mud to help camouflage them. Their structure informed their official title — “post-assisted log structure.”
“We don’t want it to look like a human-made structure,” Steiner said, “we want it to look natural.”
The aim of the project is the restoration of the creek’s critically endangered coho salmon population, which has dwindled precipitously from historical records when thousands of fish would return to the creek to spawn. Last year, biologists counted only a couple dozen coho adults that returned to the creek.
In recent years to help spark their population, the National Park Service has released thousands of hatchery-raised fish in the creek. Steiner hopes the newly created debris piles will help support that effort.
“People from other National Parks came to see what we’re doing,” Steiner said. “This technique is a new technique and we were really eager to have it in our conservation tool box.”
Not far from Muir Woods, Steiner’s group recently performed a large-scale version of the project in the Lagunitas Watershed with the same aim of helping the fish. The group used heavy machinery to place massive logs in creek beds, while re-shaping the creek to create pullouts for the fish to hide from raging wintertime currents.
The new pro-salmon ethos echoes the massive project further North where four hydroelectric dams were removed on the Klamath River, leading to the rapid return of salmon to the upper river for the first time in over a century.
“Everyone is committed to restoring and recovering these species because they’re so critical,” Seiner said.
The price tag for the Muir Woods’ project ran $100 thousand, paid with a donation from the Woodard and Curran Foundation. Steiner believes the twenty-one piles will last several years before they naturally deteriorate. Spawn and the National Park Service will carefully monitor their impact.
“We were really happy to have an opportunity to test it out right here in Muir Woods,” Steiner said as rain pelted the hood of his jacket. “We’re doing everything we can to recover the salmon.”
Source: NBC Bay Area