Texas Local Government Code - LOC GOV'T § 561.002. Joint Project

(a) The commissioners court of a county may contract with a governmental unit, including a county, municipality, or other political subdivision, to jointly acquire a right-of-way or to jointly construct or maintain a canal, drain, levee, or other improvement for the purpose of providing flood control or drainage as it relates to flood control or for the purpose of providing and maintaining necessary outlets.

(b) The contract may contain any provisions that the governing bodies of the contracting entities consider necessary.

(c) The contracting entities may provide by contract, on mutually agreeable terms, that they shall jointly maintain the project or that one of them shall maintain the project under its exclusive direction and control while the other entity contributes to the expense of maintenance.