At the time that a proposal to incur debt is first submitted to the qualified electors, the qualified electors of the authority shall elect five qualified directors, two to serve a term ending January 1, 1969, two to serve a term ending January 1, 1971 and one to serve a term ending January 1, 1973. At the first election, the five candidates receiving the highest number of votes shall be elected as directors. The terms of the directors shall be determined by lot at their organizational meeting. At each election thereafter, the qualified electors of the authority shall elect similarly one or two qualified electors as directors to serve six-year terms as directors and as successors to the directors whose terms end following each election. Nothing in this section may be construed as preventing qualified electors of the authority from being elected or reelected as directors to succeed themselves.