drainage icon Drainage
Reduce impervious surfaces by narrowing the road; create more space for plants and soil to absorb rain water; control flooding and move stormwater away from the roadway.


Making the Most of the Right-of-Way

Before it was transformed into SEA Street, this stretch of 2nd Avenue NW was covered in pavement and compacted gravel. When water flows over these hard surfaces, it picks up pollution and speed, often causing damage to creeks and lakes. The project designers have applied a Natural Drainage Systems (NDS) approach to managing the stormwater from the neighborhood. The NDS approach mimics nature by increasing the ability of the landscape to absorb rainwater with shallow depressions, amended soils, and plants - improving water quality and quantity, and reducing pollution and runoff speed.

The drainage goals for this project include conveyance, flood control, and minimizing the flow of stormwater off-site. The project team sculpted the project area to move water away from the roadway and homes and into planted swales along both sides of the road.

By retrofitting the street using an NDS approach, the project team supported the transportation needs of the neighborhood while simultaneously providing space for rainwater to return to the earth, rather than flowing rapidly across the paved landscape toward Pipers Creek.