GREEN STORMWATER IN CAPITOL HILL
Green Stormwater Infrastructure (GSI) is an important part of building environmental resilience – a critical element of public life – for the Capitol Hill community. As Seattle’s population has grown, the built environment has continually hardened, and tree canopies, native soils, and vegetation have declined. Rainfall now flows too quickly over streetscapes, parking lots, and sidewalks on the way to the sewer system and waterways. As the water flows downhill, it picks up whatever is in its path, such as trash, dirt, oil, metals, fertilizers, bacteria, animal waste, and other impurities. These polluted waters are toxic to all living things.
Fortunately, there's a lot we can do reduce this form of pollution! Methods known as Green Stormwater Infrastructure can slow, detain, and clean stormwater before it enters our sewers and waterways. Scroll down to learn more.
Join us for a Capitol Hill stormwater walking tour
Tours were held October 16, 2021. If you missed them and are interested in future tours, sign up for our mailing list.
Join the Capitol Hill EcoDistrict and Seattle 2030 District to explore the impact of stormwater in Capitol Hill. We are hosting mile-long guided walking tours of Capitol Hill that highlight the impacts of climate change, permeable infrastructure, trees, and rain gardens on Capitol Hill. We'll also view future rain paint mural locations.
Come with us on a journey through our historically rich neighborhood to learn about how “Seattle Showers” impact our own backyard.
Stormwater in Capitol Hill and beyond
Seattle’s reputation for being rainy is misleading, as New York City receives an average of 46 inches of rainfall annually, whereas Seattle only receives 38 inches of rain annually. Most rainfall occurs in the winter, and the summer months here are typically very dry. Seattle does, however, have an exceptionally high number of days with cloud cover, at 226 days per year.
Below are several GSI methods and tools:
This hardscape, intended to break the flow of surface run-off, is designed to allow for percolation. Permeable concrete or asphalt and pavers with extra-wide gaps between them are all examples of permeable paving. The sub-base for these types of paving is specially prepared to create a stable base while providing voids for water to collect and pass through on its way to native soils. These surfaces require regular cleaning or vacuuming to maintain their porosity.