What is a watercourse?
As defined in the Mercer Island municipal code, a watercourse is: "A course or route, formed by nature and generally consisting of a channel with a bed, banks, or sides throughout substantially all its length, along which surface waters, with some regularity (annually in the rainy season), naturally and normally flow in draining from higher to lower lands. This definition does not include irrigation and drainage ditches, grass-lined swales, canals, storm water runoff devices, or other courses unless they are used by fish or to convey waters that were naturally occurring prior to construction" (MICC 19.07.070).
What are the buffers for watercourses?
||Standard (Base) Buffer Width (feet)
||Minimum Buffer Width with Enhancement (feet)
|Restored or Piped
||Determined by the code official
This information is summarized from Title 19 of the Mercer Island City Code, "Unified Land Development Code" and is provided for quick reference only. To determine exact requirements, and for other development regulations affecting a parcel or lot, Title 19 should be consulted.