Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 540.060

The watermaster or an assistant appointed by the watermaster shall have power to arrest any person violating a provision of the Water Rights Act (as defined in ORS 537.010), ORS 537.120 to 537.360 or 537.505 to 537.795 and 537.992 and turn the person over to the sheriff or other competent police officer within the county. At the time the watermaster delivers the arrested person into the custody of the sheriff, the watermaster or assistant watermaster making the arrest shall file a complaint, as defined in ORS 131.005, against the person arrested.