The board of supervisors of the various counties are hereby authorized, in their discretion, to join on behalf of their respective counties the rivers and harbors association of Mississippi, and to pay from the general fund of the county membership dues of the association. The payment of membership dues shall entitle the county to all of the rights and privileges of membership and the county shall not be liable for any additional dues or assessments. After a county has joined the association, it may terminate its membership by formal resolution or failure to pay membership dues.