During the early years of Clyde Hill’s development the City’s drainage facilities were designed to handle only the water collected from the public streets. In addition, these systems were designed only to handle a 10-year storm event. Because there was still plenty of room in the community, stormwater management was not a major concern.
In the mid to late 1980s Clyde Hill experienced flooding on its streets throughout the lower portion of the City. At the same time residents complained of springs appearing on their property or that their neighbor was discharging stormwater, causing them problems and property damage.
In 1989 the City installed an extensive upgrade and installed a new storm drain system on 84th Avenue NE, including a connection to the detention ponds on the Overlake Golf Course. Those improvements helped alleviate the flooding problems neighbors were experiencing within some of the lower areas of the City.
In the early 1990s the City conducted an analysis of its stormwater system. A conclusion was that some of the "newer" system improvements would manage the previous flooding, but only if the City was able to prevent a future increase in the flow rates throughout the entire system. Armed with this understanding the City revised its stormwater requirements for all new development that includes a requirement for detaining stormwater on newly developed property.
Maps of the City's stormwater system are available on this website for review. You should always rely on assistance from the City Engineer (and not these maps) when designing a stormwater system.
Given Clyde Hill's history of stormwater challenges, it is important for developers to understand their responsibility for stormwater. Click here for details.