"NEW SECTION.  Sec. 1   A new section is added to chapter 47.01 RCW to read as follows:
     (1) For highway construction projects where the department considers agricultural lands of long-term commercial significance, as defined in RCW 36.70A.030, in reviewing and selecting sites to meet environmental mitigation requirements under the national environmental policy act (42 U.S.C. Sec. 4321 et seq.) and chapter 43.21C RCW, the department shall, to the greatest extent possible, consider using public land first.
     (2) If public lands are not available that meet the required environmental mitigation needs, the department may use other sites while making every effort to avoid any net loss of agricultural lands that have a designation of long-term commercial significance.
     (3) Nothing in this section shall be construed to restrict the department from meeting environmental mitigation requirements, described in subsection (1) of this section, by the purchase of credits from a wetland mitigation bank certified for the sale of such credits, including but not limited to credits for lands that were or are agricultural lands of long-term commercial significance."