Flood control district elections shall be held pursuant to the Local Election Act. At each local election after organization of the district, there shall be elected by the qualified electors of the district one or two members of the board to serve for a term of six years. Except for the initial board of directors and except for any director chosen to fill an unexpired term, the term of each director runs for six years. Each director shall serve until a successor has been duly chosen and qualified.