Tenn. Code § 68-221-1103
The governing body of any municipality may authorize the construction, extension, enlargement, or acquisition of necessary storm water facilities or flood control improvements within its corporate boundaries. The improvements may include, but are not limited to, the extension, enlargement, construction, or acquisition of storm water facilities or flood control improvements; the widening, straightening, or relocating of streams, surface waters, or water courses; and the acquisition, extension, enlargement, or construction of any works necessary to regulate the quantity or quality of water for the protection of streams, water courses, surface waters, life, and property; provided, that the municipality obtains all applicable permits and complies with all applicable state and federal laws.
T.C.A. § 68-221-1103