The Board of Supervisors expressly reserves the right to amend or repeal this Article, provided that rights which may have vested hereunder prior to said repeal or amendment through the actual installation of pipes, wires and conduits shall not be affected by such repeal or amendment. Provided, further, however, that the Board of Supervisors may, by general ordinance, compel the removal of all pipes and conduits used for any of the purposes herein set forth, from the roadways of the streets, and their replacement beneath sidewalk areas.