Arboretum creek undergoing repair
Garden Springs Creek, once a bubbling brook through the heart of Finch Arboretum, is returning to a more natural state.
A contracting crew has set up temporary fencing and diverted the water into a flexible pipe while it excavates the creek bed in the first step of restoration.
The result is the piling up of sediment that was trapped behind a low dam near the Woodland Center.
Work began on Monday even as visitors strolled through the arboretum to check out the fall leaves.
“It’s been silting up over years and years,” said Tye McGee, who was overseeing the project by A.M. Landshaper Inc., of Spokane County.
The project involves 900 feet of the creek and includes removal of a small dam and two culverts. The barriers resulted in erosion along the creek bank, officials said.
Some 200 cubic yards of sediment will be hauled away for reuse on a piece of private property.
Then, a new channel will be lined with rock so that the creek bed will stay within its banks. New native plantings will anchor the banks as well.
Turf grass will be moved back away from the creek, and the new plantings will increase shade on the water to help reduce summertime water temperatures. The turf setback also reduces the chances of fertilizer runoff getting into the creek.
Part of the idea is to create more favorable habitat for the small populations of fish that occupy parts of the stream. Removing the dam and culverts will allow the fish to move up and down the stream.
“It is going to improve the aesthetics,” said Marlene Feist, city utilities spokeswoman.
Brook Beeler, spokeswoman for the state Department of Ecology, said she hopes that people who own creekside property will check out the project as an example of how to manage a shoreline.
“It’s a good demonstration of what streamside landowners can do on their property,” she said.
Feist said a natural creek becomes a better educational example for class visits to the arboretum.
The creek restoration is just one part of the face-lift at the arboretum.
In a second project, a portion of the parking lot on the south side of the Woodland Center has been repaved with porous asphalt to divert contaminated runoff from reaching the creek.
Underneath the asphalt, workers installed a water collection system that will allow excess water to be diverted into a grass-lined basin, or swale. The turf is capable of removing pollutants and sediment from the water before any overflow reaches the creek, Feist said.
That will not only keep Garden Springs Creek cleaner, but it will also help reduce downstream pollution.
Garden Springs Creek flows into Latah Creek, which flows into the Spokane River.
Interpretive signs explaining the small stormwater facility are going up near the parking lot project.
Cost of creek restoration is $166,000. The parking lot project is $190,000.
The work is being supported with a $154,000 grant from the state Clean Water Fund, Beeler said.
Although small in size, the projects are part of a wider effort to prevent storm runoff from carrying pollution and sediment into Latah Creek and the Spokane River.
Latah Creek is under a state water quality improvement plan to reduce sedimentation, water temperature and bacterial contamination, Beeler said.