Sub-watershed definition
Sub-watershed means the areas within a watershed draining to one or more major tributaries of the mainstem steam, such as the Deschutes or Nisqually River.
Sub-watershed or “subwatershed” shall mean a geographic area that drains, directly or indirectly, to a waterbody segment, including via man-made conveyances, but shall not include geographic areas that drain to an upstream segment of the same waterbody which has its own RI Integrated List of waterbodies identification number.