4(1)The Secretary of State may carry out, in any manner and by any means appearing to him to be appropriate, such excavations, such dredging and dumping operations and such pumping operations as appear to him to be necessary or convenient for the purpose of—U.K.
(a)the principal works; or
(b)any works authorised by paragraph 1 or 2 above.
(2)The Secretary of State may carry out, in any manner and by any means appearing to him to be appropriate, such operations for the purpose of maintaining any channel or trench excavated or dredged in pursuance of this paragraph as appear to him to be necessary or convenient for that purpose.
(3)The Secretary of State may use, appropriate, store, deposit or dispose of any materials (including liquid) excavated, dredged or pumped in pursuance of this paragraph in any manner or by any means appearing to him to be appropriate.