In the event an emergency should arise, in which it would be impossible for the commission to employ an engineer, as hereinabove provided for, then, in that event, the commission shall employ a competent road supervisor who need not be an engineer, but, when so employed, he or she shall have all the duties and authority of the engineer, and be subject to this article; but an emergency shall not exist longer than necessary to employ a qualified engineer who shall accept employment by the commission under the terms of this article, it being the intention of this article to provide that, when county roads, bridges, and ferries are to be maintained or constructed in the county, the supervision thereof shall be under a qualified engineer.