Dead salmonOne salmon skitters across the water doing the “Jesus walk” before succumbing to a premature death. Another swims in dazed circles near the water’s surface then limply drifts downstream. Still another lies on its side, no longer swimming, mouth gaping open and shut and fins splayed out. All are the likely victims of stormwater pollution.

The coho were captured in videos collected by the Northwest Fisheries Science Center, a Seattle office of NOAA Fisheries. Scientists there are studying what’s called pre-spawn mortality in coho that return to urban waterways to lay eggs. The fish are killed off with bellies full of roe before they have the chance to spawn, and pollution running off the urban landscape is the prime suspect in their demise. Those that aren’t killed outright can have their noses deadened by the chemicals, eliminating a key sense for survival.

And that’s only one way in which stormwater is taking its toll across the Northwest. The runoff that streams across pavement and buildings carries with it a wallop of toxic chemicals that harm everything from tiny herring to the region’s iconic orcas. Economically, the polluted rainwater is a burden on budgets from the local to the national levels. It threatens to make drinking water undrinkable, and shellfish unsafe to eat from BC’s Georgia Basin (including urban locations well north of Victoria’s notorious sewage outfalls) to the Puget Sound’s southern reaches.

Just how big is the problem in dollars and salmon senses?

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  • Cities and counties across Washington alone spent more than $270 million last year trying to control and clean stormwater, according to the Association of Washington Cities. That figure will likely rise as local governments work to meet the state’s updated, more stringent regulations.

    A force of man and nature

    Stormwater is created when rain falling on roofs, pavement, and developed landscapes runs off these surfaces and into roadside gutters, creeks and rivers, and ultimately into the sea. The pollution it carries is harmful, but so is the sheer volume of water cascading off these impervious surfaces. The torrent scours creeks, washing away small gravel, insects, and salmon eggs. It erodes stream banks. It triggers landslides.

    Seattle landslideIn a natural landscape, trees, plants, and a healthy layer of soil helps the water soak deeply into the ground where it can replenish groundwater that’s drained by wells. When the rain races off in stormwater, that groundwater recharge doesn’t happen and wells risk running dry.

    In urban settings, a deluge of runoff can even prove deadly. On Dec. 14, 2006, Seattle resident Kate Fleming was drowned in the basement of her Madison Valley home when it suddenly filled with stormwater.

    In identifying its flood-prone areas, maps from Seattle Public Utilities show swollen streams all across the city sending water over roadways and on to private property. More than 600 properties were identified by the city this fall as at risk for flooding from runoff.

    Statewide, damage from floods—some of which is tied to urban stormwater—resulted in $28.9 million in federal relief to Washington residents and $4.8 million to folks in Oregon in 2007, according to the most recent numbers available from the Federal Emergency Management Agency.

    Officials from Bellingham and Eugene point to stormwater as the primary source of toxic chemicals that contaminate their cities’ drinking water.

    The McKenzie River, which is the only source of drinking water for more than 200,000 people in the Eugene area, contains pesticides, metals, and other pollutants that come from stormwater.

    Bellingham is struggling to stay one step ahead of the development surrounding Lake Whatcom that’s sending increasing amounts of dirty water into the lake. From 1992 through 2008, the city planned to spend more than $2 million on projects to catch and clean stormwater. The region developed a comprehensive stormwater plan for the lake, which contains levels of mercury and phosphorus (which can cause algal blooms) that exceed state standards.

    OystersFlows tainted with fecal waste

    Another measure of the economic and social impact of stormwater is taken by looking at the shellfish industry. Washington state’s Department of Health monitors the water quality in shellfish areas, closing it to harvest when pollutants—namely fecal coliform that comes from the waste of warm-blooded animals including people—become too high.

    In an analysis of the 95 spots around Puget Sound where oysters, clams, and other shellfish are commercially harvested, more than one-third of the locations had elevated levels of fecal waste in 2007.

    Over the past 10 years, the amount of gross revenue earned by Washington’s shellfish industry plummeted 66 percent to $55 million last year. While the reasons for the decline are manifold, research from the University of Washington suggests that harvest closures due to pollution are a significant factor.

    The problem extends beyond commercial interests to the people who live in this region and simply would like to enjoy some of the sea’s bounty. But the entire stretch of shoreline from north of Everett to south of Tacoma is unsafe for the recreational harvest of shellfish due to pollution from stormwater and sewage plants, said officials at the Health Department.

    Over the years, some sites have been reclaimed as the pollution is cleaned up and controlled, including a spot near Des Moines that will be opened for geoduck harvesting by scuba divers. But as development around Puget Sound expands, the battle to protect shellfish from stormwater will grow more urgent.

    “It’s like the guy with the finger in the dike,” said Bob Woolrich, a manager with Health’s Office of Shellfish and Water Protection. “They keep improving the dike, but there keeps being more water to stop.”

    Stormwater’s toxic cocktail

    While stormwater contamination of shellfish is a concern mostly for humans who want to eat them, other wildlife are themselves harmed by it. As we already mentioned, urban runoff injures or kills salmon. At the base of the food chain, herring eggs undergo mutations when exposed to certain polycyclic aromatic hydroc
    arbons—also called PAHs. The family of chemicals is created when petroleum or wood is burned and 14.6 tons of the pollutants are washed into Puget Sound annually. The PAHs can cause serious abnormalities in herrings’ hearts during development, according to NOAA researchers. They expect that PAHs can harm a wide range of fish species.

    Stormwater recently was identified as the No. 1 source for the PCBs that get into Puget Sound. A study by the Washington Department of Ecology reported PCB contamination in herring, Chinook salmon, and different kinds of sole at levels that would warrant human consumption warnings from the EPA.

    Orca Moving to the peak of the food chain, the orcas found in Washington and British Columbia’s waters “are among the most PCB-contaminated marine mammals in the world,” say Canadian scientists. The chemicals were banned in the 1970s, but are long-lasting in the environment and can accumulate in organisms. They can harm the endangered orcas by suppressing their immune function, reducing their ability to successfully reproduce, and damaging their brain development. That’s no small matter for a population struggling to survive.

    And that’s just what’s happening with PCBs. Countless other toxic chemicals are carried by stormwater into the Sound and its wildlife.

    Josh Baldi, Ecology’s special assistant for Puget Sound, made a call for action in an April press release tied to the PCB research, saying: “This new science and the advances of the last several years show us how enormous and complex the stormwater problem is, and that we are going to need a lot of help to fix it.”


    This post is part of a series on stormwater. Please also see “Smart, Cheap Stormwater Fixes” and “Water Pollution Enemy is Us.”

    Photos are from Flickr and used under the Creative Commons license. Dead—possibly pre-spawn—salmon photo is courtesy of “Soggydan” Dan Bennett. Seattle landslide post-rainstorm photo is courtesy of Looney1 Photography. And oyster harvest photo is courtesy of willapalens. Orca photo is courtesy of Alanna@VanIsle.