The contract creating the joint institution shall provide:
(1) the total proposed expenditure for the construction, purchase, or lease of the joint institution and the proposed cost of equipping and operating the joint institution;
(2) for the management of the joint institution by a method which will provide that each contracting county shall be represented and have an active part in the management of the joint institution;
(3) that the management of the joint institution shall have such powers as will be necessary to accomplish the purpose of this part.