16. Every person constructing or improving a road other than a winter road shall respect the natural drainage of the soil by installing a culvert to maintain the normal flow of water. The diameter or span of the pipe of such culvert shall be at least 30 cm. The end of the culvert shall extend at least 30 cm beyond the base of the fill supporting the road and the fill in that location shall be stabilized at the same time. If the culvert is made of wood, its span may not exceed 1 m.