18.3. Where a provision of this Title prescribes that a water withdrawer is required to make a declaration on the basis of the withdrawal rated capacity of the works or facilities used for water withdrawals and it appears that the withdrawal capacity of those works or facilities exceeds the withdrawal volume that the withdrawer was authorized to withdraw, under the provisions of the Environment Quality Act (chapter Q-2) or a regulation thereunder, the authorized withdrawal volume must be considered to be the threshold beyond which declaration is required.