The board of supervisors shall investigate and determine:
(a) If the improvement or development work generally described in the petition is feasible.
(b) If, when completed it will result in the improvement or development of the harbor.
(c) If the estimated cost and incidental expenses are the reasonable and necessary costs of the improvement or development work and incidental expenses.
For the purpose of investigation and determination, it may submit the improvement or development work described in the petition to engineers for examination and report.