Tenn. Code Ann. § 64-1-208

Any one (1) county, individually, or in combination with one (1) or more counties, may undertake works of improvements as provided for in this part with the authority and the state, if such works are not in conflict with the basin-wide plans for control of water. A majority of the members of the board of directors representing such county wanting to act individually, together with the member at large, as provided for in § 64-1-203(a)(2)(A)(iii), are sufficient to make all decisions and take action for the board with regard to works of improvements for such county.