As soon as practicable, following each federal census, and again ten (10) years later, the City Council shall review the wards and ward boundaries of the City. Any change in the boundaries of wards shall be made by ordinance with due regard to the convenience and contiguity of the wards. The effective date of a change in the names or boundaries of wards shall be the effective date of the City Council ordinance making such change, unless the City Council provides otherwise. Election of Councilmembers for wards which have no representation due to such change shall take place at the next regular City election, and their terms of office shall be as provided by the Charter.