Power to deviate
4.—(1) Subject to paragraph (2), in constructing or maintaining any of the scheduled works the Agency may modify the design, as shown on the works plans and sections, of the scheduled works and deviate—
(a)laterally from the lines or situations shown on the works plans to any extent within the limits of deviation; and
(b)vertically from the levels shown on the sections to any extent upwards or downwards.
(2) The scheduled works must be so constructed that the unobstructed opening between the walls of the barrier, as shown on the works plans and sections, is not less than 20 metres wide.
(3) Nothing in paragraph (3) or paragraph (4) of article 3 (power to construct and maintain works) authorises the Agency to execute any works in contravention of the restrictions imposed by paragraph (2) of this article.