13. Subject to article 26 of this Order, and sections 19 and 21 of the Harwich Harbour Act 1974, the Company may, for the purposes of constructing and maintaining the works or otherwise for the purposes of the dock undertaking from time to time deepen, dredge, scour, cleanse, alter and improve so much of the harbour and foreshore as lies within their limits of jurisdiction and may use, appropriate or dispose of the materials (other than wreck within the meaning of Part IX of the Merchant Shipping Act 1894(1)) from time to time dredged by them–
Provided that no materials so dredged, other than those dredged for the purpose of constructing the works or filling in and reclaiming from the harbour and foreshore so much of the harbour and foreshore as is situated within the limits of deviation, 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.