(a) If a person is uncertain whether a proposed activity is subject to the provisions of this Part, he may request the regional permit administrator to make a determination as to whether the permit provisions of this Part apply to such activity.

(b) If a person desires the determination requested in subdivision (a) of this section to be made in writing, such request shall be made in writing and shall contain all information deemed necessary and appropriate by the regional permit administrator to make such determination. Within 15 days after receipt by said administrator of such written request and all such information, he shall notify such person by letter whether his activity is subject to the permit provisions of this Part.