8. For article 16 (scientific instruments etc) substitute—
16.—(1) Article 4 applies—
(a)to the deposit of any scientific instrument or associated equipment in connection with any scientific experiment or survey;
(b)to a removal activity carried on for the purpose of removing any scientific instrument or associated equipment referred to in sub-paragraph (a);
(c)to the deposit of any reagent;
(d)to the deposit of any tracer.
(2) Sub-paragraph (a) of paragraph (1) is subject to condition 1.
(3) Sub-paragraph (b) of paragraph (1) is subject to condition 2.
(4) Sub-paragraphs (c) and (d) of paragraph (1) are subject to conditions 3 and 4.
(5) Condition 1 is that details of any scientific instrument or associated equipment to be deposited must be notified to the UK Hydrographic Office at least 5 days before the day on which any deposit is made.
(6) Condition 2 is that notification is given to the UK Hydrographic Office of any removal of any scientific instrument or associated equipment within 5 days of the removal.
(7) Condition 3 is that the reagent or tracer must be one the use of which is for the time being approved for the purposes of this Order by the licensing authority.
(8) Condition 4 is that the reagent or tracer must be used in accordance with any conditions to which the approval is subject.
(9) But article 4 does not apply to—
(a)any such deposit made for the purpose of disposal;
(b)any such deposit that causes or is likely to cause obstruction or danger to navigation, in particular where such a deposit is tethered to the seabed or reduces navigational clearance by more than 5% by reference to Chart Datum(1);
(c)any such deposit or removal activity that is likely to have a significant effect on a marine protected area.”
Chart Datum is the plane below which all depths are published on a navigational chart. It is also the plane to which all tidal heights are referred, so by adding the tidal height to the charted depth, the true depth of water is determined. By international agreement, Chart Datum is defined as a level so low that the tide will not frequently fall below it. In the United Kingdom, this level is normally approximately the level of the Lowest Astronomical Tide.