(1) The department, having received a final environmental impact statement dated January 16, 1985, and having conducted an investigation of the surrounding impacts of the proposed reservation and having heard comments solicited through the notice of receipt of petition and having found groundwaters to be generally available for the purposes of the reservation and that the proposed use of the groundwaters will result in the maximum net benefit for the people of the state, does hereby reserve portions of those groundwaters for future public water supplies in Thurston County.

(2) The department finds that to provide peaking capacity on a daily basis the appropriate amount of the reservation shall be 40,589 gallons per minute, limited to a maximum annual withdrawal of 22,931 acre-feet/year, provided that the total annual withdrawal and diversion from all sources shall not exceed 48,225 acre-feet/year. This is intended to serve the estimated population of 288,092 in fifty years. The amount of this reservation shall be reviewed by the department whenever new information, changing conditions, or statutory modifications make it necessary to consider revisions.

(3) A map showing the reservation area boundary is shown in Figure II-1 of the coordinated water system plan for Thurston County, dated May 1982, as approved by the department of social and health services for the purposes of reserving water for future public water supply purposes, and shown as the reservation area boundary map in WAC 173-591-130, Illus. 1.

(4) Due to the nature of the geographic distribution of the groundwaters to be reserved and the development patterns that are anticipated in Thurston County, the reserved groundwaters are intended to be beneficially utilized from the unconsolidated materials overlying bedrock, and are prorated to the subareas designated in Figure V-1 of the coordinated water system plan for Thurston County, dated May 1982, as approved by the department of social and health services for the purpose of reserving water for future public water supply purposes, and shown as the reservation source of supply subareas map in WAC 173-591-130, Illus. 2. The reserved groundwaters are generally prorated to the reservation source of supply subareas as follows, with the totaled reserved quantity to be obtained from within the boundary area.

(5) The priority date of any permit issued pursuant to RCW 90.03.290 and 90.44.070 which authorizes withdrawal and use of public water for public water supply pursuant to the reservation provided in subsection (2) of this section shall be the effective date of this regulation.

(6) A record of all groundwater permits issued pursuant to the reservation provided in subsection (2) of this section shall be maintained by the department in a manner that will readily show the quantities that have been allocated from the reserved groundwaters for each subarea identified in subsection (4) of this section and the quantities of unappropriated groundwaters that may remain in the reserved status available for appropriation.

(7) No permit issued as described in subsection (5) of this section shall authorize a withdrawal that causes a lowering of the water levels below a reasonable or feasible pumping lift in any withdrawal facilities of a senior groundwater right holder.