roadstead
A roadstead or road is a sheltered body of water where ships can lie reasonably safely at anchor without dragging or snatching.United States Army technical manual, TM 5-360. Port Construction and Rehabilitation'. Washington: United States. Gove ...
Finistère
Finistère (, ; ) is a Departments of France, department of France in the extreme west of Brittany. Its prefecture is Quimper and its largest city is Brest, France, Brest. In 2019, it had a population of 915,090.department in
Brittany
Brittany ( ) is a peninsula, historical country and cultural area in the north-west of modern France, covering the western part of what was known as Armorica in Roman Gaul. It became an Kingdom of Brittany, independent kingdom and then a Duch ...
in northwestern
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
. The surface area is about 180 km² (70 sq mi). The port of Brest and one of the two French naval bases, Brest Arsenal, are located on its northern edge. It is linked to the
Atlantic Ocean
The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...
strait
A strait is a water body connecting two seas or water basins. The surface water is, for the most part, at the same elevation on both sides and flows through the strait in both directions, even though the topography generally constricts the ...
about 1.8 km wide. Three main rivers drain into the roadstead: the Penfeld (the town of Brest and the first buildings of the naval base were built on
its banks), the
Aulne
The Aulne (; ) is a long river of Brittany in north-western France, flowing down the hills and emptying into the roadstead of Brest, one of the many fjord-like bays just south of Brest. The river is part of the Canal de Nantes à Brest, the na ...
For a number of centuries, Brest has been an important military port. The easily defensible roadstead of Brest therefore has a number of military installations, for example:
* Fort du Mengant, and Brest Arsenal, on the north of the bay;
*the submarine base of the ÃŽle Longue, to the south-west;
*the
paused at ''Roche Mengant'' (a rock in the middle of the entry into the roadstead) whilst on his way from Brest to Siam, and had the following to say about the defences:
"This is a rock at the entry to the roads; it is right in the middle of the channel; they want to build a fort there and construct a good battery on it. Already a lot of stones have been cast down, but the sea undoes more in a quarter of an hour what it takes ( sic) six months to lay down. Work is being done on gun emplacements on either side of the passage; the canons will crossfire, but if there were a battery on the rock in the middle, it would be impossible for enemy vessels to enter the roadstead, where more than 10,000 ships would be safe".
Aulne
The Aulne (; ) is a long river of Brittany in north-western France, flowing down the hills and emptying into the roadstead of Brest, one of the many fjord-like bays just south of Brest. The river is part of the Canal de Nantes à Brest, the na ...
Thanks to its layout, the roadstead harbours a wide diversity of natural habitats and a high level of biodiversity. It also includes many sites of importance for birds, several networks of habitats and underwater corridors and coastal areas of importance. These areas have been greatly affected by the human activities in the north-west, but have justified the classification of around half of the roadstead as a zone in
Natura 2000
Natura 2000 is a network of nature protection areas in the territory of the European Union. It is made up of Special Areas of Conservation and Special Protection Areas designated under the Habitats Directive and the Birds Directive, respectiv ...
.
Pollution
The rich ecology of the roadstead has been diminished by the past exploitation of certain resources, and by the presence of a number of pollutants including
heavy metals
upright=1.2, Crystals of lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead
Heavy metals is a controversial and ambiguous term for metallic elements with relatively h ...
and
tributyltin
Tributyltin (TBT) is an umbrella term for a class of organotin compounds which contain the group, with a prominent example being tributyltin oxide. For 40 years TBT was used as a biocide in anti-fouling paint, commonly known as bottom paint, ...
which were used as
biocide
A biocide is defined in the European legislation as a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. The US Environmental Protection Agency (EPA) uses a sli ...
s in
anti-fouling
Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...
bottom paints. These products are now illegal, but they remain present in sediments and certain organisms. The products which have replaced them for small boats (e.g. Diuron and Irgarol) pose similar problems and have been measured in non-negligible quantities in the roadstead by
Ifremer
The or Ifremer is an oceanographic institution in Brest, France. A state-run and funded scientific organization, it is France’s national integrated marine science research institute.
Scope of works
Ifremer focuses its research activities in ...
Second World War
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
s. Pollutants trapped in submerged or unexploded
munitions
Ammunition, also known as ammo, is the material fired, scattered, dropped, or detonated from any weapon or weapon system. The term includes both expendable weapons (e.g., bombs, missiles, grenades, land mines), and the component parts of ...
are expected to aggravate existing pollution with the first large leaks predicted by experts to occur in the years 2000-2010.