EXPLANATORY STATEMENT
Issued by the authority of the Attorney‑General
Seas and Submerged Lands Act 1973
Seas and Submerged Lands (Territorial Sea Baseline) Proclamation 2006
Section 7 of the Seas and Submerged Lands Act 1973 (the Act) provides that the Governor‑General may, from time to time, by Proclamation, declare, not inconsistently with section 2 of Part II of the United Nations Convention on the Law of the Sea [Australian Treaty Series 1994 No 31] (the Convention), either or both of the breadth of the territorial sea, and the baselines from which the breadth of the territorial sea, or any part of it, is to be measured.
The Seas and Submerged Lands (Territorial Sea Baseline) Proclamation 2006 (the Proclamation) revokes a previous Proclamation made in 1983 and amended in 1987, which defined Australia’s territorial sea baselines. The Proclamation declares Australia’s territorial sea baselines using revised and updated geographic coordinates of the baselines to reflect information obtained from a survey of all territorial sea basepoints and baselines recently completed by Geoscience Australia in cooperation with the Australian Hydrographic Office and State and Territory mapping authorities. The Proclamation uses the Geocentric Datum of Australia, which is a coordinate reference system being progressively implemented throughout Australia as the preferred datum for all spatial information. The previous Proclamation used a different coordinate reference system called the Australian Geodetic Datum.
A map depicting the straight baselines drawn pursuant to the Proclamation and to the Seas and Submerged Lands (Historic Bays) Proclamation 2006, so far as scale permits, is at Attachment A.
The Proclamation defines the territorial sea baseline as the low-water line along the coast except where the Convention enables straight baselines to be drawn sea‑ward of the coast so as to enclose bays or the mouths of rivers, and in cases where there is a fringe of islands along the coast, or the coast line is deeply indented and cut into.
Sections 5 to 11 of the Proclamation set out rules for determining the baselines, consistent with section 2 of Part II of the Convention. Schedule 1 defines the Geocentric Datum of Australia which is the basis for determining positions on the surface of the earth used in the Proclamation, subject to an exception relating to Macquarie Island. In relation to Macquarie Island, the Proclamation provides for positions to be determined in accordance with the International Terrestrial Reference Frame 2000 as defined by the International Earth Rotation Service at epoch 1 January 2000. The Proclamation uses Geocentric Datum of Australia, which is a coordinate reference system being progressively implemented throughout Australia as the preferred datum for all spatial information. Schedule 2 sets out the geographic coordinates along the coast between which straight baselines may be drawn.
The Proclamation does not apply to certain islands forming part of the State of Queensland as the baselines and territorial seas for them are the subject of the Treaty between Australia and the Independent State of Papua New Guinea concerning Sovereignty and Maritime Boundaries in the area between the two Countries, including the area known as Torres Strait, and Related Matters [Australian Treaty Series 1985 No 4].
Details of the Proclamation are set out in Attachment B.
The Proclamation is a legislative instrument for the purposes of the Legislative Instruments Act 2003.
No public consultation was undertaken in relation to the Proclamation, as it merely makes minor changes to a previous Proclamation.
The Proclamation commences the day after it is registered in the Federal Register of Legislative Instruments.
Attachment A
Attachment B
Details of the Seas and Submerged Lands (Territorial Sea Baseline) Proclamation 2006
Section 1 – Name of Proclamation
Section 1 gives the name of the Proclamation as the Seas and Submerged Lands (Territorial Sea Baseline) Proclamation 2006.
Section 2 - Commencement
Section 2 provides that the Proclamation commences the day after it is registered on the Federal Register of Legislative Instruments.
Section 3 – Revocation of previous Proclamation
Section 3 revokes the Proclamation of 4 February 1983 made under section 7 of the Seas and Submerged Lands Act 1973 (the Act) and an amending Proclamation made on 19 March 1987.
Section 4 - Definitions
Subsection 4(1) defines particular terms that are used in the Proclamation as follows:
“Act” means the Seas and Submerged Lands Act 1973;
“bay” means a coastal indentation as defined by section 5 of the proposed Proclamation;
“Convention” refers to the United Nations Convention on the Law of the Sea [Australian Treaty Series 1994 31];
“Geocentric Datum of Australia” refers to the matters specified in proposed Schedule 1;
“historic bay” refers to a bay that is declared by Proclamation under section 8 of the Act to be an historic bay. Historic bays are those claimed by coastal nations by reason of historical usage, rather than because they fit the description of juridical bays set out in article 10 of the Convention;
“low-tide elevation” is defined to have the same meaning as in the Convention. Article 13 of the Convention specifies that a low-tide elevation is a naturally formed area of land which is surrounded by and above water at low tide but submerged at high tide;
“low-water” refers to Lowest Astronomical Tide. Lowest Astronomical Tide is the lowest level to which the sea can be predicted to fall under normal meteorological conditions, and is usually estimated by reference to charts, geospatial imagery and other sources;
“mile” refers to the international nautical mile, being 1,852 metres;
“straight line” refers to a geodesic line, being the shortest possible line between two points on a curved surface; and
“territorial sea” refers to the territorial sea of Australia, the band of water in relation to which the Governor-General may make Proclamations declaring its breadth, and specifying the baselines from which that breadth may be measured, consistently with the Convention.
Article 11 of the Convention specifies that the outermost permanent harbour works which form an integral part of a harbour system are to be regarded as forming part of the coast. Proposed subsection 4(2) reflects this position.
Paragraph 4 of article 7 of the Convention specifies that straight baselines cannot be drawn from a low-tide elevation unless there is a lighthouse or other structure erected on it that is permanently above water. Subsection 4(3) of the Proclamation makes this rule applicable to straight baselines determined under the proposed Proclamation.
Paragraph 4(4)(a) provides that, for the purposes of the Proclamation, the position on the surface of the Earth of a point, line or area is to be determined by reference to the Geocentric Datum of Australia. Paragraph 4(4)(b) relates to the determination of spatial positions on Macquarie Island. In accordance with surveying practice, the datum for determining spatial positions on the Island is the International Terrestrial Reference Frame 2000 as defined by the International Earth Rotation Service at epoch 1 January 2000.
Section 5 – Bays
Section 5 describes indentations that are juridical bays for the purposes of article 10 of the Convention. Subsection 5(1) provides that an indentation is a bay if the distance between the low-water marks of the natural entrance points of the indentation do not exceed 24 nautical miles.
Subsection 5(2) provides than an indentation is not a bay if its area is less than that of a semi-circle the diameter of which is a line drawn across the mouth of the indentation. In the case of an indentation that, because of the presence of islands has more than one mouth, it is not to be regarded as a bay if its area does not exceed that of a semicircle drawn on a line as long as the sum total of the lengths of the lines across the different mouths.
Subsection 5(3) defines the term “area of the indentation” as the area lying between low-water mark around the shore and a line joining the low-water marks at the natural entrance points of the indentation. The area is also taken to include any islands within the indentation as if they were part of the water.
Section 6 – Baseline – mainland of Australia
Section 6 describes the baseline around the mainland from which the breadth of the adjacent territorial sea is to be measured. The baseline is the low-water mark on the coast except where, because of the regime of straight baselines, a baseline may enclose waters beyond the low-water mark. Where a river flows into the sea, the baseline would be a line drawn across the mouth of the river. In the case of a bay, the baseline is a line drawn between the low-water marks of the mouth. In both cases, if a straight baseline may be drawn beyond the mouth of the river or bay, then the outermost line is the baseline.
Paragraph 6(d) specifies that straight lines drawn between the two geographic coordinates mentioned in each item in Part 1 of Schedule 2 constitute the baselines. There are 300 straight baselines along the coast of the mainland. The regime of straight baselines set out in article 7 of the Convention permits them to be drawn in localities where the coastline is deeply indented and cut into, or where there is a fringe of islands along the coast in its immediate vicinity. Examples include an area around the Whitsunday Islands off the central coast of Queensland and the Archipelago of the Recherche, near Esperance off the south coast of Western Australia.
Paragraph 6(e) provides for straight baselines to be drawn in respect of the four historic bays of South Australia: Anxious Bay; Encounter Bay; Lacepede Bay; and Rivoli Bay. The relevant coordinates are specified in Part 2 of Schedule 2.
Section 7 - Baseline – mainland of Tasmania
Section 7 makes provision for baselines around Tasmania in the same manner as section 6 does for mainland Australia. Thus the baseline is the low-water line along the coast, bay closing lines and lines across river mouths, and in other cases straight baselines drawn between the geographic coordinates specified in each item of Part 3 of Schedule 2.
Section 8 - Baseline – islands off the coast of a State or the Northern Territory
Section 8 makes provision for baselines around the coast of islands forming part of a State or of the Northern Territory in the same manner as section 6 does for mainland Australia and section 7 does for Tasmania. However, the provision does not apply in relation to Pearce Cay, Turnagain Island and Turu Cay, nor to the following groups of islands:
- Aubusi, Boigu and Moimi;
- Dauan, Kaubag and Saibai;
- Anchor Cay and East Cay;
- Black Rocks and Bramble Cay; and
- Deliverance Island and Kerr Islet.
The territorial sea for these islands and groups of islands, which form part of the State of Queensland, are provided for in the Treaty between Australia and the Independent State of Papua New Guinea concerning Sovereignty and Maritime Boundaries in the area between the two Countries, including the area known as Torres Strait, and Related Matters [Australian Treaty Series 1985 No 4]. The inner limits and outer limits of parts of the territorial sea around certain islands in the Torres Strait are declared in a separate Proclamation made under section 7 of the Act on 4 February 1983 and published in Gazette No. S 29 of 9 February 1983, which was not revoked by the Proclamation.
Section 9 – Low-tide elevations
Section 9 provides that a baseline around a low-tide elevation that occurs at a distance not exceeding the breadth of the territorial sea from the coast is to be the low-water line on the low-tide elevation. This is in accordance with article 13 of the Convention.
Section 10 – Low-water line of naturally formed area
Section 10 makes provision for where a straight baseline would pass through an area of land that is not submerged at any time. In such a case, the baseline between the points where the straight baseline intersects the coast is taken to be the low-water mark along the coast of that land.
Section 11 – Low-water line of island
Section 11 makes the same provision with respect to islands as does section 10 with respect to naturally formed land areas, in relation to situations where straight baselines would pass over an area of land that is not submerged. In such a case, the low-water line of the sea-ward part of the coast of the island forms the baseline, as if the island were part of the mainland.
Schedule 1 – Geocentric Datum of Australia
The Geocentric Datum of Australia (GDA) is a coordinate reference system that best fits the shape of the earth as a whole. It has an origin that coincides with the centre of mass of the earth, hence the term 'geocentric'. Its purpose is to place the geographical coordinates specified in the proposed Proclamation on the surface of the Earth.
Following a resolution of the Intergovernmental Committee on Surveying and Mapping in 1988, GDA is being progressively implemented throughout Australia as the preferred datum for all spatial information.
It is considered to be the most effective datum as it provides:
- compatibility with satellite navigation systems, such as the Global Positioning System;
- compatibility with national mapping programmes already carried out on a geocentric datum; and
- a single standard for the collection, storage and dissemination of spatial information at global, national and local levels.
Item 1 – Reference ellipsoid
The reference ellipsoid is the Geodetic Reference System 1980 ellipsoid with a semi-major axis of 6,378,137 metres and an inverse flattening of 298.257222101.
Item 2 – Reference Frame
The item explains how the GDA is realised.
Schedule 2 – Straight baseline points under article 7 of the Convention
Schedule 2 consists of 4 parts describing the straight baseline points for mainland Australia (300 baselines between 600 points), the four historic bays of South Australia (7 straight baselines between 14 points), the coast of Tasmania, including Macquarie Island, (50 straight baselines between 100 points) and the islands off the coast of the States and the Northern Territory (47 straight baselines between 94 points).