(2) The provisions of ORS 273.775, 308A.050 to 308A.128, 522.005, 522.015, 522.405 to 522.545, 522.815 and 522.990 shall not affect the ability of a ground water user to exercise a water right that existed before the initiation of a unit agreement. [1981 c.588 §18; 1999 c.314 §76]