New ideas | Project meets challenge of runoff

Not much about Shamrock Heights says "revolutionary."

The Craftsman-inspired architecture, the cul-de-sac and the neat rows of new homes with closely cropped lawns could be a slice of suburbia anywhere.

But subtle features signal this isn't just a typical development on the outskirts of Renton.

Sidewalks run along only one side of narrow streets, all built on what was formerly a plant nursery. Instead of big backyards, a shallow, landscaped, artificial creek bed splits two rows of homes with smaller yards. "Your Rain Channel," declares a nearby sign.

The 117-home project is one of a few housing developments built around Puget Sound using unconventional strategies to reduce damage from stormwater.

Known collectively as low-impact development, it's an effort to get water to soak into the ground before it flows into nearby creeks.

Narrow streets and fewer sidewalks mean less runoff-creating pavement. The rain channels soak up rain and slow the rush of stormwater. Kirkland-based developer CamWest still used a man-made pond to catch water from big storms. But a rebuilt wetland acts as a final stormwater sponge.

Eric Campbell, CamWest's founder, said there were extra costs because it took more work from consultants and longer to get the permits, even though King County encouraged it as a guinea pig for such approaches.

But, he said, "low-impact, if embraced, could really become cost-effective."