In any proceeding to consolidate drainage districts pursuant to the provisions of this chapter, no special assessment district shall be established and no bonded or other indebtedness shall be incurred and no construction or other contracts shall be let in counties having a board of county auditors or a county comptroller without the written consent of the said board of county auditors or the said county comptroller: Provided, however, That the approval of said board of county auditors or said county comptroller shall not be required in proceedings relative to the establishment of an intercounty consolidated drainage district.