Natural drainage systems slow stormwater and filter out pollutants before they can harm our creeks and other waterways. Keeping pollutants out of our water is important for fish, aquatic life, and people.

Building a natural drainage system in Longfellow Creek basin is part of the Plan to Protect Seattle's Waterways. SPU used to call these "roadside rain gardens" but now calls them "natural drainage systems" or "NDS."

Why Longfellow Creek? Longfellow Creek is a salmon-bearing urban creek with degraded water quality adjacent to where people live, work, and play. Stormwater picks up pollutants from streets-including oil, heavy metals, and fertilizers-every time it rains and flows into the creek through ditches or pipes. This project will remove pollutants from the stormwater before it reaches the creek.