objections.] Such county flood commissioners, their agents and employes [employees] shall have free and unobstructed ingress and egress to any and all lands and premises where such ingress and egress are necessary to the performance of the duties by this act N.M. Stat. Ann. § 4-50-1 to 4-50-9 imposed, and shall not be liable for damages because of any such entry, except for wanton and malicious injury, and any person or persons obstructing such ingress or egress shall, upon conviction thereof, be found guilty of a misdemeanor. Provided, however, that no such dikes, embankments, dams and ditches, or other structures or excavations shall be constructed, built or maintained where written objection to such construction, building and maintaining are filed by the state engineer with any commissioner in charge thereof, and except in the manner as, after such objection, shall be approved by said state engineer.