(a) The State shall keep the Regional Administrator fully informed of any proposed or actual changes to the State's statutory or regulatory authority or any other modifications which are significant to administration of the program.

(b) Any approved program which requires revision because of a modification to this part or to any other applicable Federal statute or regulation shall be revised within one year of the date of promulgation of such regulation, except that if a State must amend or enact a statute in order to make the required revision, the revision shall take place within two years.

(c) States with approved programs shall notify the Regional Administrator whenever they propose to transfer all or part of any program from the approved State agency to any other State agency. The new agency is not authorized to administer the program until approved by the Regional Administrator under paragraph (d) of this section.

(d) Approval of revision of a State program shall be accomplished as follows:

(1) The Director shall submit a modified program description or other documents which the Regional Administrator determines to be necessary to evaluate whether the program complies with the requirements of the Act and this part.

(2) Notice of approval of program changes which the Regional Administrator determines are not substantial revisions may be given by letter from the Regional Administrator to the Governor or the Tribal leader and are effective upon the date in the approval letter. The Regional Administrator will notify the Secretary of the approval of any approved program modifications. The Regional Administrator will also notify other Federal agencies of approved program modifications as appropriate. The Regional Administrator shall post any such approval letters on the relevant pages of EPA's website.

(3) Whenever the Regional Administrator determines that the proposed revision is substantial, the Regional Administrator shall publish and circulate notice to those persons known to be interested in such matters, provide opportunity for a public hearing, and consult with the Corps, FWS, and NMFS. The Regional Administrator shall approve or disapprove program revisions based on whether the program fulfills the requirements of the Act and this part, and shall publish notice of the decision in the Federal Register. For purposes of this paragraph, substantial revisions include, but are not limited to, revisions that remove waters from the retained waters description (other than de minimis removals), as well as revisions that affect the scope of activities regulated, criteria for review of permits, public participation, or enforcement capability. Revisions to an Indian Tribe's assumed program that would add a new geographic area to the approved program require that the Regional Administrator determine that the Tribe meets the eligibility criteria in § 233.60 with regard to the new geographic area and constitute substantial revisions.

(4) Substantial program changes shall become effective upon approval by the Regional Administrator and publication of notice in the Federal Register.

(e) Whenever the Regional Administrator has reason to believe that circumstances have changed with respect to a State's program, the Regional Administrator may request and the State shall provide a supplemental Attorney General's statement, program description, or such other documents or information as are necessary to evaluate the program's compliance with the requirements of the Act and this part.