In addition to comprehensive growth planning, there are other planning provisions in Tennessee statutes.  The Department of Economic and Community Development has created and defined the boundaries of other planning regions, which are drawn without regard to county lines or other existing boundaries. T.C.A. § 4-3-701 et seq.  For each planning region the department also creates a regional planning commission, or a municipal planning commission may direct regional planning under certain circumstances.  T.C.A. §§ 13-3-101, 13-3-102. In actual practice, most planning regions consist of a single county.