The Board of Supervisors may call a special meeting of the District when it deems it necessary or prudent to do so and shall call a special meeting of the District when action by the voters of the District is necessary under this agreement or under any applicable law. In addition, the Board of Supervisors shall call a special meeting of the District if petitioned to do so by not less than five percent of the legal voters of the District. The Board of Supervisors may rescind the call of a special meeting called by them but not a special meeting called on application of five percent of the legal voters of the District. The Board of Supervisors shall endeavor to have the time of such special meetings coincide with the time of annual municipal meetings, primary elections, general elections, or similar meetings when the electorate within the member municipalities will be voting on other matters.