The following provisions of this chapter delimit the streams and rivers which constitute shorelines of the state as follows:

(1) Streams which constitute shorelines.

(a) Western Washington. Streams in Western Washington from the point at which the stream reaches a mean annual flow of twenty cubic feet per second down to the mouth of said stream or river: Provided, that the stream falls at said point, within the jurisdiction of chapter 90.58 RCW.

(b) Eastern Washington. Streams in Eastern Washington from the point at which the stream reaches a mean annual flow of twenty cubic feet per second down to the mouth of said stream or river: Provided, that the stream falls at said point, within the jurisdiction of chapter 90.58 RCW.

(2) Rivers which constitute shorelines of statewide significance.

(a) Western Washington. Any rivers west of the crest of the Cascade range downstream of a point where the mean annual flow is measured at one thousand cubic feet per second or more. Provided, that the river falls at said point within the jurisdiction of chapter 90.58 RCW.

(b) Eastern Washington. Either of the following points on rivers in Eastern Washington, whichever is farther upstream;

(i) The point at which the mean annual flow exceeds two hundred cubic feet per second; or

(ii) The lowest extremity of the first three hundred square miles of drainage area east of the crest of the Cascade Range; provided that either of said points which is utilized is within the jurisdiction of chapter 90.58 RCW.

(3) Until superseded as provided in WAC 173-18-044, rivers constituting shorelines of the state are listed in WAC 173-18-050 through 173-18-430. Other data related to these lists.

(a) Wherever a river of statewide significance falls within a county, it is followed by an asterisk.

(b) The following provisions set forth the name of the quadrangle maps where the stream or river is shown. The quadrangle in which the shoreline delimitation begins and the first quadrangle downstream from the county line is underlined. The quadrangle in which the shoreline of statewide significance begins is followed by an asterisk. The size, in minutes, of all quadrangle maps is designated.

(c) Where quadrangle maps are unavailable, photomaps have been used as indicated.