Help save salmon from the dangers of rainwater


In the fall, when rain tumbles from thick gray skies, pours down streets and tumbles down storm drains, my thoughts turn to the fish. During this time, coho salmon return from the Pacific Ocean to the gravel stream beds where they hatched from golden eggs.

For each of the 3,000 eggs their mothers lay, only one or two survive to adulthood and return to spawn 3-6 years later. Their lives are in danger as soon as they are born, from the birds that feed on eggs, the fish that eat young ones the size of a little finger, and the seals, whales and humans that hunt them when they are born are grown up.

The few salmon that do return fight their way up the fall rain-fed streams, dodging coyotes and otters and searching for the perfect spot for a nest (called a redd) before their bodies are washed aside to feed animals and trees .

For the kohos that survive these natural dangers, an unobtrusive force lurks in the water, carrying a poison that kills the kohos before they can complete their life cycle, their upturned bellies still filled with the next generation. This force is called rainwater, and while it may seem harmless, it carries oils and liquids seeping from vehicles, fertilizers and chemicals from lawns, sediment from construction sites, trash from overflowing trash cans, and raw sewage from overflow pipes of the combined sewer system beneath most of the City.

The deadliest toxin found in rainwater was only recently identified after decades of research. Known to scientists as 6PPD quinone, it is a chemical compound that prevents tires from cracking and failing. It seeps into the water from tire dust washed up from streets and parking lots and can render a coho salmon lifeless in just a few hours of exposure. When the rain cleans the streets, the returning fish perish. The next generation died out in less than 24 hours.

Stormwater also poses another threat: Flow. When it rains, water pours into sewers and streams at alarming rates, propelled by miles of cobbled surfaces and clapboard roofs. Water spurts out with such force that it has the power to alter a stream’s form and function, uprooting and washing away redds while burying others with sediment collected from construction sites and roads, and suffocating the young.

As the coho population begins to dwindle, a ripple effect occurs that affects all animals that feed on them, which is why this incredible species is called the Capstone. Without the coho, this tightly knit food web begins to break down. But there is hope for the coho, the species that feed their nutrient-rich bodies, and for us. If given a chance, nature will attempt to restore itself. We can help by investing in citywide Green Rainwater Infrastructure (GSI). This comes in many forms and addresses pollution and flow: turn a lawn into a rain garden, replace concrete with porous paving, plant trees, and install green roofs.

For homeowners willing to dive in, a program from the City of Seattle called RainWise offers income-based reimbursements or mini-grants to build rain gardens and connects you with a contractor who speaks your native language. GSI is not the only option. Reducing stormwater pollution also includes commuting by public transport or bicycle, and volunteering in community action groups. Equally important is sharing with others to raise awareness of problems and available solutions.

Carkeek Watershed Community Action Project, Duwamish River Cleanup Coalition, Puget Soundkeeper, marine potential, Stewardship Partner and Tilth Alliance are some of the incredible organizations working to give us and nature the opportunity to rebuild. Not only for the salmon and their children, but also for our own children and grandchildren.


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