Whenever it shall be necessary for the public health, safety or welfare to establish a water management district to undertake a project in all or part of 3 or more contiguous counties in this state for purposes of flood control or drainage, a petition therefor may be filed with the director of agriculture, signed by 3 or more public corporations, and, if a district with 8 or more counties, by 3 or more counties, which will be subject to assessments to pay the cost of such project. Such petition shall state that it is filed pursuant to the provisions of this chapter, shall set forth the proposed name of the district and the necessity for the project in the interest of the public health, safety or welfare; and shall contain a general description of the type, purpose and location of the proposed project, which description need be only sufficiently accurate as to determine with reasonable certainty the waters, works and territory involved in the project and the public corporations to be benefited thereby. A map showing the boundaries of the proposed district and a certified copy of the resolution of the governing body of each public corporation, authorizing its signature thereto, shall be attached to the petition. Such petition may be filed in more than 1 counterpart.