In the event that a new senior high school is constructed in such unified school district, the board of education of the unified school district shall provide for a sixth member district to be numbered “six,” and one member of the board of education shall be elected from such member district at each succeeding regular election. Thereupon only one member shall be elected at large from the entire unified school district and such board member shall have in lieu of a position number the designation position-at-large. In the event that this section becomes operative, other provisions of this act shall be construed accordingly.