Whenever any such earthen dam or embankment shall be so placed and situated as that it may be made a part of some public roadway, and afford to public travel a means of crossing the valley, ravine or draw wherein such dam may be located, the township wherein the same is situate may aid in the construction and maintenance thereof, and shall have the right to constitute such dam or embankment a public highway, and to lay out and construct approaches thereto: Provided, That in every such case the authorities having charge of such highway shall keep that part used for the benefit and convenience of public travel in thorough repair at all times, so that such embankment shall be in nowise injured by such use, and shall properly and safely bridge the waste-way to such dam or embankment belonging, and provide such railings or other safeguards as may be necessary for the protection and safety of public travel.