Wash. Rev. Code § 87.80.220
An irrigation entity under contract with an agency of the federal government for the construction or operation of its irrigation system may not participate in a board of joint control under this chapter if this action is in conflict with provisions of the subject contract. If a responsible official of the federal agency notifies the board of county commissioners in writing on or before the day of hearing provided under RCW 87.80.060 of a conflict in contract provisions and evidences the conflict, the board of county commissioners must deny the irrigation entity's proposed participation. If subsequent to formation of a board of joint control, a judicial decision determines a conflict in contract conditions, the irrigation entity must not participate in a project or activity inconsistent with the court determination.
RCW 87.80.220