Soaking It Up In Seattle

Permeable surfaces in Seattle offer ideas on how cities can best deal with the environmental problems of urban runoff.

2 minute read

October 24, 2007, 8:00 AM PDT

By Nate Berg


"We used to think that we should get that water out of sight as quickly as possible; rather than flooding streets, send it off to the bay lickety-split. But now we know that the gunk in that runoff causes problems for everyone, especially fish. Take copper, leaching from worn brake pad linings, roofing materials, algaecides, and fungicides. Copper can cause salmon to lose their sense of smell, so they aren't as alert to the presence of predators or able to find their natal stream. Some pesticides have the same effect."

"So how do we deal with stormwater? Rechanneling it into our aging sewer systems is not an option. The problem only gets worse as we add impervious surfaces with parking lots and new housing. A recent visit to Seattle convinced me that there is a better way."

"Using a revolutionary series of "natural drainage systems," Seattle is attempting to detain and slow stormwater by trying to mimic the forest floor and pasture that once covered its landscape. Bit by bit, the city rips out pavement and pipes in suburban and urban neighborhoods, replacing concrete and asphalt with swales, rain gardens, and other soft surfaces."

"Seattle's first project, called SEA Street (for Street Edge Alternative Street) was put in the ground in 2000 in an older neighborhood northwest of downtown. The city's transportation and public utilities departments worked with neighbors to replace an old 'unimproved' gutter and ditch stormwater system with a series of connected, vegetated swales. The swales resemble the understory of a Pacific Northwest forest. 'We're trying to make an urbanized environment think like it's still forested,' says Bob Spencer, the city's Creek Steward. The ground is soft and covered with leaf litter; trees and shrubs glisten in the damp air. Most of the vegetation is native, but some drought-tolerant non-natives are included; neighbors were given a range of choices. Looking at other streets nearby, I can see that SEA Street (aka 2nd Avenue NW between 120th and 119th streets), was previously an 'anywhere USA' older suburb. SEA Street now has a vivid sense of place, and songbirds and butterflies flit among the shrubs and trees."

Tuesday, October 23, 2007 in Terrain

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 18, 2025 - Diana Ionescu

Rendering of Shirley Chisholm Village four-story housing development with person biking in front.

San Francisco's School District Spent $105M To Build Affordable Housing for Teachers — And That's Just the Beginning

SFUSD joins a growing list of school districts using their land holdings to address housing affordability challenges faced by their own employees.

June 8, 2025 - Fast Company

Two people walking away from camera through pedestrian plaza in street in Richmond, Virginia with purple and white city bus moving in background.

Vehicle-related Deaths Drop 29% in Richmond, VA

The seventh year of the city's Vision Zero strategy also cut the number of people killed in alcohol-related crashes by half.

June 17, 2025 - WRIC

Rendering of proposed 38-story tower in downtown Portland, Maine.

Downtown Portland Ready for Maine's Tallest Building

The city of Portland anticipates a major new urban development addition called the “Old Port Square” project.  

1 hour ago - News Center Maine

Map of EV charging ports in rural U.S. communities.

The EV “Charging Divide” Plaguing Rural America

With “the deck stacked” against rural areas, will the great electric American road trip ever be a reality?

June 20 - The Daily Yonder

Google street view of Bedford Avenue in Brooklyn with pedestrians crossing a crosswalk and cyclist in the bike lane.

Judge Halts Brooklyn Bike Lane Removal

Lawyers must prove the city was not acting “arbitrarily, capriciously, and illegally” in ordering the hasty removal.

June 20 - StreetsBlog NYC