Mich. Comp. Laws § 280.447

Sec. 447. After any drainage districts have consolidated as provided for in this chapter, the consolidated district shall, except as otherwise provided in this chapter, have all the rights and powers and be subject to all laws applicable to county or intercounty drainage districts, as the case may be. The provisions of sections 441 through 447 of this act shall not be construed to validate and shall not validate any bonds or other obligations issued prior to May 5, 1954, nor shall said sections be construed to revive or validate any obligations of an old existing or established drain which has heretofore been determined in a court of competent jurisdiction to be invalid.