Whenever the boundaries of a senatorial or representative district coincide with the boundaries of a county or municipality, and said county or municipal boundaries are changed by annexation or detachment, the boundaries of the senatorial or representative district shall remain the same until such time as a new redistricting is made following a national census as provided in sections 46 to 48.4 of article V of the state constitution.
C.R.S. § 2-2-508