The maps below show the different watersheds within the City and the storm pipe and stream network. Click the links below to view maps of the drainage system in Shoreline:

• Stormwater Master Grid Updated 06/30/09 (41 mgs)
• Stormwater Grid North Central (NC) (52 mgs)
• Stormwater Grid North East (NE) (54 mgs)
• Stormwater Grid North West (NW) (51 mgs)
• Stormwater Grid South Central (SC) (52 mgs)
• Stormwater Grid South East (SE) (53 mgs)
• Stormwater Grid South West (SW) (52 mgs)

There are six major watersheds are located within the City of Shoreline boundary: Boeing, McAleer, Lyon, Thornton, Puget Sound Drainages, and West Lake Washington. McAleer, Lyon, Thornton, and West Lake Washington watersheds all eventually flow into Lake Washington. Boeing and the Puget Sound Drainages flow directly into Puget Sound.

A watershed or drainage basin is an area of land where water from rain and melting snow or ice drains downhill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea, or ocean. Each drainage basin is separated topographically from adjacent basins by a geographical barrier, such as a ridge or hill, which is known as a water divide.