The Shoreline Management Act (SMA) applies to major water bodies and their adjacent shorelands throughout Washington State. The approximate 28,204 miles of shorelines in the State include:
- Marine waters.
- Streams over 20 cubic feet per second mean annual flow
- Water areas and reservoirs 20 acres and greater
- Upland areas called shorelands that are 200 feet landward of the Ordinary High Water Mark
- All associated wetlands
Within the City of Milton, the SMP applies to Surprise Lake and the Hylebos Creek, along with land within 200 feet of these shorelines.