Geology and landforms
The Morbihan is part of the Armorican Massif, an ancient mountain range including Brittany, the Channel Islands, western Normandy, western Pays de la Loire and the Deux-Sèvres department. This massif has been greatly affected by erosion, creating low relief, vast plains and plateaus and undulating landscapes. The Montagnes Noires are one of the two ridge lines in Brittany. Of these granitic mountains forming a separation with the neighboring departments, Morbihan sees only the southern slope, with a peak at the border of Finistère, north of the town of Gourin, at 301 meters altitude. But the highest peak of the department is the Calotte Saint-Joseph, at 292 meters of altitude, not far from there. If the north of Morbihan, up to the Lanvaux moors, offers appreciable reliefs, the rest of the territory is very flat, in particular near the coast.
The characteristic rock of the Morbihan is granite, in which the prehistoric megaliths were carved. Other rocks can be observed, among which the blue schist and the green schist, on the island of Groix. This island also has the rare geological characteristic of hosting a convex and mobile beach. Not only paradisiacal with its white sand and its surprising shape, this beach is a real witness of the evolution of our landscapes, since it has moved several hundred meters in less than a century!
The islands
The Gulf of Morbihan, the "Little Sea" which gave its Breton name to the department, extends over a width of 20 kilometers and is dotted with about forty islands and islets (their exact number remains a subject of dispute). Gradually formed, this mixture of fresh water from rivers and salt water from the Atlantic Ocean, whose level has gradually risen, forms a unique setting. Several millennia ago, inhabitants lived in the parts that are now submerged, as evidenced by the presence of menhirs under the water. The current islands of the gulf would thus be the parts always emerged of old hills. The marshes and mudflats of this ever-changing landscape, subject to the tides of the Atlantic Ocean, are ideal for oyster farming, bird watching and fishing. Île aux Moines and Île d'Arz are the largest and most populated islands in the Gulf of Morbihan. Many of the small islands are now privatized, the others belong to the Public Maritime Domain or to communities. Finally, the gulf is bounded by two peninsulas: Quiberon to the west, and Rhuys to the east.
But Morbihan has four other islands of great size, all inhabited. The largest of the Breton islands is Belle-Île-en-Mer, with its 8,560 hectares and its population growing from 5,000 souls in winter to 40,000 when the tourist season is in full swing! It must be said that Belle-Île-en-Mer lives up to its name, with its preserved nature, its dozens of kilometers of coastal paths and bike paths, its 58 beaches... A dozen kilometers south of Quiberon, it has two smaller but no less charming neighbors to the east: Houat and Hoëdic. Finally, the island of Groix, very popular, stands off Lorient.
The land
The total area of the department is 682,300 hectares, with forests occupying 16% of it, mainly in the north and center. Although they have been largely reduced since medieval times, Morbihan remains the most wooded department in Brittany. The forest of Paimpont is located between the north-east of Morbihan, Ille-et-Vilaine and Côtes-d'Armor. There is also the forest of Lanouée, the second largest forest in Brittany, north of the village of Josselin, and the forest of Quénécan, shared with the Côtes-d'Armor, a preserved natural site, home to dozens of bird species. As for the Lanvaux moors, they form a pretty green setting in the heart of the Morbihan territory, and even allow you to get a little height (175 meters at the most) to enjoy beautiful views of the gulf!
57% of the land in Morbihan is used for agriculture, a lower proportion than in other Breton departments. Morbihan is the first French producer of poultry, the second for eggs, the third for beef and the sixth for milk.
Watercourses
Morbihan has three main rivers, the Scorff, the Oust and the Blavet, and many streams. One can also observe this geographical particularity formed by the tides which empty then fill the estuaries of the rivers: the ria. The most famous is the Ria of Étel and its small house of Nichtarguér. But you can also discover the Ria de Pénerf, south of the Rhuys peninsula.
Let's take a closer look at the Blavet, whose Breton name, ar Blavezh, means "gushing water, running water". 148,9 km long, if its mouth is in Lorient, it takes its source much higher, in the Côtes-d'Armor. It arrives in Morbihan at the artificial lake of Guerlédan, which it feeds thanks to a dam. Then, it passes through 28 locks between Pontivy and Hennebont. This part of the waterway was built on the decision of Napoleon I in the 19th century. The Blavet canal has since played a major role in the life of the locals, as a source of drinking water, electricity production, and as a waterway of nearly 60 km.
The climate
A word about the climate, of which the Morbihan people are so proud! The territory benefits from the phenomenon of microclimates, and the inhabitants are not mistaken, concentrating in the mildest (and least rainy!) areas, near the coast. This temperate oceanic climate, relatively preserved from the cold in winter and the heat in summer, can make other Breton departments jealous. Rainfall falls mainly on the land, from the Lanvaux moors to the Black Mountains in the northwest, exceeding 1,300 mm per year, while Belle-Île-en-Mer just approaches 700 mm. Belle-Île-en-Mer, like the peninsulas of Quiberon and Rhuys, enjoys an exceptional microclimate. The sunshine is at its maximum from May to October, and Lorient enjoys more than 2,000 hours of sunshine per year, a rare record in the northern half of France!
