In order to facilitate an orderly transition to resident voter elections in June of even-numbered years and to preserve staggered terms, the terms of office of directors serving on the effective date of this section shall be modified in accordance with this section. At the 1980 general district election, two directors shall be elected to fill the positions of the two directors who were elected by landowner vote. At the 1982 general district election three directors shall be elected to fill the positions of the other three directors. In order to coincide with these election dates the terms of office of directors shall be extended or shortened as follows: