(1) The instream flows established in this chapter are based on the recommendations of the planning unit; consultation with the department of fish and wildlife, department of agriculture, and department of community, trade, and economic development; and public input received during the rule-making process. The planning unit recommended these instream flow levels by unanimous vote.

(2) Instream flows established in this chapter are water rights, which protect instream values and functions from future appropriations. The priority date of the instream flows is the effective date of this chapter. In accordance with RCW 90.82.080, this priority date received unanimous approval from the planning unit.

(3) Instream flow rights shall be protected from impairment by any new water rights commenced after the effective date of this chapter and by all future changes and transfers of senior and junior water rights, including both surface and groundwater rights. The following water rights are not subject to the instream flows:

(a) A water right put to beneficial use before the effective date of this chapter, unless otherwise stated in the conditions of the water right or change authorization.

(b) Water rights appropriated from the reservation of water established in WAC 173-527-110.

(c) Future withdrawals for environmental restoration purposes under WAC 173-527-140 unless included as a permit condition.

(4) Instream flows, expressed in cubic feet per second (cfs), are measured at the stream management control points in WAC 173-527-050. Instream flows apply to all stream reaches that contribute to flow at stream management control points, as shown in Table II of this section. For reaches that are downstream of all management points, the flows set for the nearest upstream management control point shall apply to those reaches. However, if a point of withdrawal is downstream of the confluence of two or more branches, each having a designated management point, the combined flows of the management points shall apply to that withdrawal.