Indiana Code Title 36. Local Government § 36-9-29-20

Sec. 20. (a) All contracts of the flood control district for the construction of flood control works shall be let by the flood control board under the statutes concerning the letting of contracts for public improvements by the works board of the city.  The flood control board may let one (1) contract for the entire works or separate contracts for parts of the works.

(b) All contracts shall be awarded to the lowest and best bidder.  However, a contract may not be let at a bid higher than the cost of the work, as shown by the estimates previously adopted and filed, unless approved by the circuit court on petition of the flood control board.

(c) All contracts must be in writing and signed by the flood control board's president or vice president and by its executive secretary.

(d) The validity of a contract may be questioned only in an action to enjoin the execution of the contract, filed within ten (10) days after the date of its execution.