Associated Press
JUNEAU — City officials and the Juneau Watershed Partnership hope a recently completed project will alleviate flooding and improve fish spawning habitat in Jordan Creek near Jennifer Drive.
The three-mile creek supports coho, pink and chum salmon, Dolly Varden char and cutthroat trout. It was placed on the Alaska Clean Water Action’s “impaired waterbody” list in 1998 because of excess debris, sediment and low oxygen levels.
After the watershed partnership, the Alaska Department of Environmental Conservation, U.S. Fish and Wildlife and the city’s Water Utility spent $600,000 and a summer restoring it and a tributary causing much of the problem, “We can see immediate impacts in terms of removal of sediment and flood mitigation, and the water level has gone way down,” said watershed partnership Executive Director Beverly Schoonover.
Water quality sampling will take longer to judge, she said, adding that the Alaska Department of Fish and Game will be doing fish trapping and monitoring to track the numbers of fish.
Before, the area where the east valley tributary joined Jordan Creek was “just a bare, silty area,” said Schoonover, adding that plants will also help filter sediment.
“It’s a huge project,” Schoonover said. “It’s such a big change. It’s unbelievable, really.”
Much of the creek’s problem was due to debris from a tributary that runs alongside an access road leading to the East Valley Reservoir, a 2 million-gallon water tank that supplies the Mendenhall Valley with water.
City engineering department project manager Michele Elfers said when the access road was built, the tributary’s movement was restricted, and it didn’t distribute sediment across as wide an area as before.
Then in 1996, a big storm washed out the basins built on each side of the tributary’s culverts to filter out sediment. Gravel, silt and sand started ending up in the creek, causing a dam-like buildup of rock and debris that caused flooding.
Silt and sediment also prevented oxygen from circulating to fish eggs laid in the stream’s gravel beds.
To address that problem, the city and watershed partnership built basins above and below the culverts over the summer. Water flows into the basins, silt drops to the bottom, and silt-free water spills over the top.
“It’s a man-made solution to a man-made problem,” Schoonover said.
Schoonover said some sediment is natural in the creek, and increasing because glacial rebound is making the slope of creek less steep.
“So some is natural, but it’s also a man-made issue,” she said. “We’re hoping those two sediment pools will help filter out some of the finer sediment.”
Project organizers also removed the piled-up debris and regraded the tributary so that it followed its natural contours, planted willow trees, dogwood trees and native grasses, put in stream and bed gravel the right size for salmon spawning and put in two log jams that serve as fish habitat and to steer the water away from private property.
