Before the board may acquire storage facilities in any reservoir, the board shall find affirmatively that:
(1) it is reasonable to expect that the state will recover its investment in the facilities;
(2) the cost of the facilities exceeds the current financing capabilities of the area involved, and the facilities cannot be reasonably financed by local interests without state participation;
(3) the public interest will be served by acquisition of the facilities; and
(4) the facilities to be constructed or reconstructed contemplate the optimum development of the site which is reasonably reserved under all existing circumstances of the site.