Collateral Improvements: Spokane Stormwater Project Means Upgrades to Downriver Disc Golf Course
At 9:30 a.m. on a sweltering Tuesday, golfers were playing 18 holes at the Downriver Disc Golf Course, trying to thread their discs between shrubs or loop them around towering ponderosas.
It’s no surprise that people are willing to sweat and get up early to access the links here. The northwestern Spokane route is scenic, wrapped in a meander of the blue-green Spokane River and full of blooming flowers and birdsong.
If the course is beautiful, it is also a little disheveled. That is expected to change soon, when the course undergoes a renovation and redesign this summer as part of a major stormwater management project.
Improvements to the disc golf course are a side benefit. The route is being redeveloped so that the city can install infiltration basins that will filter pollutants from the rainwater of the Cochran basin. The disc golf makeover is tangential.
“We are dealing with a concern that we have, but at the same time, we are providing a better recreational outcome for the community,” said Marlene Feist, public works manager for Spokane.
Stormwater management is probably not at the forefront of the minds of many Spokanites, but the city has been struggling to upgrade its system for decades. The Cochran Basin represents a large part of the city’s stormwater management area.
The basin covers 5,328 acres of northern Spokane and represents about 60% of the city’s segregated stormwater system. It runs east to west from Alberta Street to Market Street and north to south from Francis Avenue to Montgomery Avenue.
All the rainwater in the Cochran Basin that doesn’t flow into the ground has to go somewhere. Each year, the city dumps between 350 and 500 million gallons of stormwater from the Cochran Basin into the Spokane River. When it rains, a large pipe near the TJ Meenach Drive bridge spurts out of the water.
It may sound benign. After all, stormwater is just rain and snowmelt, at least initially. But as it runs through the streets, it picks up a multitude of contaminants: motor oil, bits of rubber, metal shavings, and landscaping chemicals, to name a few. .
These contaminants pollute the Spokane River and can have negative impacts on wildlife. There is no immediate need for Spokane to clean up the Cochran Basin stormwater system – there are no urgent government mandates, at least – but the estimated investment of $ 20-30 million. of Spokane into pipes, storage tanks and seepage ponds for the Cochran Basin The project will help the city comply with possible future regulatory changes.
Disc golf course seepage ponds are the key to keeping toxins out of the river.
There will be six ponds, costing $ 2.5 million, that will hold and filter stormwater. Plants at the edges of ponds will suck up contaminated water. Sand, compost, and fine material will filter out more pollutants as the water seeps through the soil.
“The point here is to treat it like nature would,” Feist said.
Kyle Twohig, director of engineering services at Spokane, said the infiltration ponds may seem rudimentary, but they do a great job cleaning up stormwater before it returns to the river.
“By the time it’s 10 feet under, it’s really, really clean,” Twohig said.
The ponds will be able to handle most of the rain and snowmelt events in the Cochran Basin on their own. Twohig said they would be built to hold 240,000 cubic feet of stormwater. This is the amount of water it takes to fill 2.7 Olympic swimming pools.
The system won’t be able to handle the biggest storms and snowmelt, but Twohig said the ponds are designed to handle everything except the six-month rains. This means that about twice a year, the storm water will either go untreated into the river or into additional storage capacity that will be built next year along the TJ Meenach road.
Twohig said the water in the pond would be safe for people playing disc golf. Dumping huge amounts of stormwater into the Spokane River can cause ecological damage, but the stormwater won’t hurt someone’s hand if they have to search for a lost disc.
Asymmetrical ponds will cover a large part of the disc golf course. They will be integrated into the new layout of the course – golfers will have to hit the water on several holes.
The seepage pond project has yet to be tendered out, but Feist said construction will begin this summer and end in the fall.