Wash. Rev. Code § 89.12.150
From and after the date that the consent of the United States shall be given thereto by act of congress, the department of natural resources is authorized, upon request from the secretary of the interior, to cause an appraisal to be made by the board of natural resources of state lands in any division of any federal reclamation project which the secretary of the interior shall advise the department that he or she desires to have subdivided into farm units of class referred to in RCW 89.12.140, and also to cause to be appraised by the board of natural resources such public lands of the United States on the same project, or elsewhere in the state of Washington, as the secretary of the interior may propose to exchange for such state land, and when the secretary of the interior shall have secured from congress authority to make such exchange the department is authorized to exchange such state lands in any federal reclamation project for public lands of the United States on the same project or elsewhere in the state of Washington of approximately equal appraised valuation, and in making such exchange is authorized to execute suitable instruments in writing conveying or relinquishing to the United States such state lands and accepting in lieu thereof such public land of approximately equal appraised valuation.
RCW 89.12.150