Tenn. Code Ann. § 64-3-102

There is hereby created the Mill Creek watershed flood control authority, referred to as authority in this chapter, to exercise the powers granted in this chapter in and with respect to the portions of Davidson, Williamson and Rutherford counties making up the watershed of Mill Creek and for the purpose of cooperating with the United States corps of engineers and other federal agencies, including the Tennessee Valley authority, and state and local agencies for the construction and maintenance of flood control and drainage.