The District shall have the benefit of sovereign immunity to the fullest extent authorized by law, except to the extent that it shall have in force and effect liability or other insurance for itself and members of its Board of Supervisors. The District shall hold harmless and indemnify all members of the Board of Supervisors from all claims of every nature and kind arising out of or in connection with the exercise of a member's duties as a supervisor, with the exception of those actions which shall be deemed to be wilfully negligent or criminal in nature.