During the progress of construction work on an approved subdivision in Classes S-2 and S-3, the applicant, for himself and his assigns, on detecting any unusual or unanticipated condition or any condition which would make the work contrary to this chapter, shall immediately report such condition to the Borough Engineer, to the Planning Board and to the Board of Health or other agencies involved. All construction work in that area shall be suspended until all agencies have agreed in writing to the necessary changes.