13.—(1) The Company, as may appear to them to be necessary or desirable for the purposes of the harbour undertaking, may deepen, dredge, scour, cleanse, alter and improve so much of the bed, shores and channels of the harbour and the approaches thereto, and may blast any rock in that area, and they may use, appropriate or dispose of the materials (other than wreck within the meaning of Part IX of the Merchant Shipping Act 1995) from time to time dredged by them.
(2) No materials so dredged shall be deposited below the level of high water except in such places and in accordance with such conditions and restrictions as may be approved or prescribed by the Secretary of State.