Design of the tunnelling worksE+W+S
35.—(1) TfL must undertake the detailed design and construction of the tunnelling works to ensure that, as far as is reasonably foreseeable, the navigable channel of the river Thames can be maintained by the PLA to a depth of at least 5.80 metres below chart datum.
(2) When complying with sub-paragraph (1) TfL must allow for potential ‘over-dredge’ of 0.5 metres attributable to standard dredging methodology.
(3) Prior to commencing construction of the tunnelling works and as soon as reasonably practicable after they each become available, TfL must provide to the PLA the following documents—
(a)an Approval in Principle, or similar, demonstrating that the design requirement has been incorporated into the detailed design of the tunnelling works;
(b)a Design Certificate demonstrating that the detailed design of the tunnelling works has satisfied the design requirement; and
(c)a Check Certificate, completed by an independent person, demonstrating that the detailed design of the tunnelling works has satisfied the design requirement.
(4) TfL must supply to the PLA—
(a)any of the drawings referred to in either of the certificates specified in sub-paragraphs (3)(b) and (3)(c); and
(b)such other information relating to any of the documents provided under sub-paragraph (2) or (3)(a) as the PLA may reasonable require,
upon request made by the PLA within 10 business days of the day on which the PLA receives the document that gives rise to the request.
(5) If, following receipt of any of the documents supplied under sub-paragraphs (3) and (4), the PLA is not reasonably satisfied that the design requirement will be met, it may within 20 business days of the paragraph 35 specified day, notify TfL that the PLA is in dispute with TfL and accordingly refer the matter to arbitration under paragraph 52 to review the proposed detailed design of the tunnelling works so far as it concerns the design requirement.
(6) In this paragraph—
(a)“Approval in Principle”, “Check Certificate” and “Design Certificate” have the same meaning as in the Design Manual for Roads and Bridges Volume 1 Section 1 Part 1 BD2/12;
(b)“the design requirement” means the detailed design requirement specified in sub-paragraphs (1) and (2);
(c)“” means Regions 2 and 4 as defined in article 52 (restrictions on other works in the river Thames);
(d)“the paragraph 35 specified day” means—
(i)the day on which the documents referred to in sub-paragraph (3) are provided to the PLA under that sub-paragraph; or
(ii)the day on which TfL provides the PLA with all drawings and further information that has been requested by the PLA under sub-paragraph (4),
whichever is the later.