Mich. Comp. Laws § 280.444
In case any drainage district which is included and merged in the consolidated district has any outstanding bonded or other indebtedness, any funds in the treasury of such debtor district shall be used to retire such indebtedness. If said funds are insufficient, the indebtedness shall be paid from any funds derived from any special assessments theretofore levied or extended against the lands in the debtor district, and if further funds are necessary the drain commissioner or drainage board of the consolidated district shall levy a special assessment against the lands in the debtor district sufficient to pay such indebtedness. The proceeds of such special assessment shall be used only for the purpose of paying such indebtedness, bonded or otherwise, and the interest thereon.
MCL 280.444