(1) Within one hundred eighty days after the designation of a management area or the requiring of an action plan for a management area, a purpose of which is protection of water quality, the district or districts within whose boundaries the area is located shall prepare an action plan designed to stabilize or reduce the level and prevent the increase or spread of ground water contamination. Whenever a management area or the affected area of such a management area encompasses portions of two or more districts, the responsibilities and authorities delegated in this section shall be exercised jointly and uniformly by agreement of the respective boards of all districts so affected.

(2) Within thirty days after an action plan has been prepared, a public hearing on such plan shall be held by the district. Notice of the hearing shall be given as provided in section 46-743, and the hearing shall be conducted in accordance with such section.

(3) Within thirty days after the hearing, the district shall adopt and submit an action plan to the Department of Environment and Energy. Notice of the district's order adopting an action plan shall be published as required by section 46-744.