(1) Since 1967, the segment of the Columbia basin groundwater system centered around the community of Odessa has experienced a steady decline in groundwater levels.

(2) Spurred by local concern and foreseeable management problems, the department of water resources (now department of ecology) closed an area of approximately 1,100 square miles to the drilling of large producing water wells and initiated a detailed investigation of groundwater conditions in the Odessa basin.

(3) As a result of this investigation, a digital groundwater model of the Odessa basin was developed and used in 1974 and 1975 to predict the effect of additional groundwater withdrawals on existing water level declines.

(4) In 1975, the department expanded its groundwater monitoring program and discontinued use of the predictive model.

(5) The expanded monitoring program, with additional data on the actual effects of pumping, included wells south of the subarea which showed groundwater declines similar in magnitude to those inside the subarea.