The SMA applies to major water bodies and their adjacent shorelands throughout Washington State. Within the State, there are approximately 28,204 miles of shorelines including:
- All associated wetlands
- Marine waters
- Streams over 20 cubic feet per second mean annual flow
- Upland areas called shorelands that are 200 feet landward of the Ordinary High Water Mark
- Water areas and reservoirs 20 acres and greater
Within the City of West Richland, the SMP applies to land within 200 feet of the Yakima River and any associated wetlands.