1. The county commission may, when the same is necessary for the public health, convenience or welfare, cause to be constructed or enlarged any bridge or culvert made necessary by the crossing of any ditch constructed by a district organized under the provisions of this chapter; provided, however, that if such bridge or culvert shall belong to any corporation other than the county, the county clerk shall give such corporation notice by delivering to its agent the order of the commission declaring the necessity for constructing or enlarging such bridge or culvert. A failure to construct or enlarge such bridge or culvert within the time specified shall be taken as a refusal to do said work, and thereupon the county commission shall proceed to let the work of constructing or enlarging the same, and assess the corporation with the cost thereof, and the county clerk shall place such assessment on the tax book against said corporation, and it shall be a lien upon the property of the corporation, to be collected as taxes. But before the county commission shall let such work, they shall give to the agent of such corporation at least twenty days’ actual notice of the time and place of letting such work.

2. When a bridge has been constructed across a drainage ditch that crosses any public highway in this state, that shall be adjudged sufficiently by the county commission of the county in which said drainage district is organized, such bridge shall become a part of such highway and shall thereafterwards be maintained, repaired or replaced by the authority authorized by law to maintain the road of which it becomes a part.