wilfully obstructs any officer or servant of the Ministry in the exercise of any functions of the Ministry under this Order, or any person engaged in the construction of any works in pursuance thereof; or

removes any works (whether constructed or in course of construction) which are vested in the Department for the purposes of this Order; or

removes, …F2 any pegs, poles or marks placed or made by any authorised person for the purpose of, or in connection with, the construction of any such works; or

places any solid matter in, or causes or permits any solid matter to fall or pass into, any watercourse in respect of which any works are about to be, or are in course of being, constructed by the MinistryF1. . . so as to cause any obstruction, hindrance or delay to such construction; or

obstructs the flow of water to, through or from any worksF1 vested in the Department for the purposes of this Order in such manner as to prevent or hinder the efficient operation of those works, or to cause flooding of such works or any land drained thereby;