Okla. Stat. tit. 82 § 105.7
In any suit for the determination of rights to the use of the waters of any stream, brought pursuant to Section 6, any person who is using or who has used water from the stream or who claims the right or who might claim the right to use water from the stream may be made a party to the suit. Any person who is using or who has used or who claims the right to use water from the stream may intervene. No person not a party to the suit shall be bound by the decree therein, but the rights determined between the parties thereto and their privities shall be bound in all subsequent litigation. When any such suit has been filed, the court may by its order, duly entered, direct the Board to furnish data necessary for the determination of the rights involved.
Okla. Stat. tit. 82, § 105.7