Michigan Compiled Laws, Chapter 141. Municipal Financing § 141.132

Sec. 32. Nothing in this act shall be construed as authorizing any borrower to impair or commit a breach of the obligation of any valid lien or contract created or entered into by it, the intention hereof being to authorize the pledging, setting aside and segregation of gross revenues only where consistent with outstanding obligations of such borrower. The severance of any lands from the jurisdiction of the borrower subsequent to the issuance of bonds under this act, shall be subject to the obligations created by the issuance of such bonds.