the authority shall be entitled in relation to any such pipes or apparatus to exercise the same powers as, for the purpose of carrying out its functions, are conferred on a water undertaker in relation to relevant pipes by section 158 of the Water Industry Act 1991 (street works); and
the provisions of that Act shall apply, with the necessary modifications, in relation to the power conferred by virtue of paragraph (a) above as they apply in relation to the power conferred by the said section 158; and in this section “street” has the same meaning as in that Act.