(2) When the Willamette River serves as the boundary between Linn and Polk Counties in subsection (1) of this section, a reference to the river refers to the center of the main channel of the Willamette River as it existed on January 8, 2003, and may be further identified using coordinates and other location information determined by the affected county surveyors and filed by the appropriate counties with the appropriate county assessors and the Department of Revenue under ORS 308.225. [Amended by 1981 c.332 §2; 1983 c.780 §1; 2003 c.97 §1; 2003 c.622 §5a]