(a) The board consists of seven directors.
(b) Directors serve staggered two-year terms and are appointed as follows:
(1) the Commissioners Court of Dallas County shall appoint one director to a term expiring each even-numbered year;
(2) the city council of the City of Carrollton shall appoint one director to a term expiring each even-numbered year and two directors to terms expiring each odd-numbered year; and
(3) the city council of the City of Farmers Branch shall appoint one director to a term expiring each even-numbered year and two directors to terms expiring each odd-numbered year.