The drainage goals for this project include moving stormwater off of roadways and property, controlling flooding, and minimizing the flow of stormwater off-site. This project was designed as a way to reduce roadway paving and create extra spaces for stormwater to be absorbed by soils and vegetation. This reduces heavy flows that cause flooding and erosion in the creek downstream.
The image at right shows Palatine Avenue NW, one of the three north-south oriented streets within the project. The streets that run north to south in this neighborhood generally have steep cross-slopes; the west side of the street is at a lower elevation than the east. Planted swales that store and convey water are located on both sides of the street. Seattle Public Utilities (SPU) engineers and landscape architects used the street slope to their advantage, maximizing swale size by building rock walls into the side slopes.