(1) The policies and goals in this section are supplementary to existing authorities of the department.

(2) It is the policy of the department to avoid or mitigate adverse environmental impacts which may result from the department's decisions.

(3) The department shall ensure that presently unquantified environmental amenities and values will be given appropriate consideration in decision-making along with economic and technical considerations.

(4) When the environmental document for a proposal shows it will cause significant adverse impacts, the responsible official shall consider whether:

(a) The environmental document identified mitigation measures that are reasonable and capable of being accomplished;

(b) Other local, state, or federal requirements and enforcement would mitigate the significant adverse environmental impacts; and

(c) Reasonable mitigation measures are sufficient to mitigate the significant adverse impacts.

(5) When the environmental document for a proposal shows it will cause significant adverse impacts, the responsible official may:

(a) Condition the approval for a proposal if mitigation measures are reasonable and capable of being accomplished and the proposal is consistent with the policies in this section; or

(b) Deny the permit or approval for a proposal if reasonable mitigation measures are insufficient to mitigate significant adverse environmental impacts and the proposal is inconsistent with the policies in this section.

(6) The procedures in WAC 197-11-660 shall also be followed when conditioning or denying permits or other approvals.