(a) Each member shall be entitled to one vote plus one vote for each 1,500 people or any portion thereof of its population. The number of votes entitled to be cast on behalf of any member entitled to more than one supervisor shall be divided equally among its supervisors. Fractional votes, if any, shall be taken into account. No supervisor(s) may split votes. No proxies shall be allowed. Population shall be determined as follows until the results of the 1990 U.S. census are available for the members:

 (b) When the results of the 1990 census are available, and decennially thereafter when new U.S. decennial census data are available, the number of votes granted to each member shall be determined at the next organizational meeting. Any action adopted by a majority of the votes cast at a meeting of the Board at which a quorum is present shall be the action of the Board. Approval of the siting of any District facility or of the condemnation by eminent domain of any property by the District shall require approval by supervisors representing at least two-thirds of all votes entitled to be cast on behalf of all members and comprising at least two-thirds of the supervisors present.