|Madeira undoubtedly appeared at the quaternary era, at the time of an volcanic eruption or a gigantic earthquake. Underwater raisings and several convulsions accentuated the geological evolution of the island. The crater of Curral das Freiras (where the principal accidents of the central relief of the island would have been formed), several lakes and chimneys of craters, the prismatic basalt piles bordering the valleys and the coasts attest this origin.|
The island is consisted an alternation of immense benches of lava and slags, visible often on the roadside new which notched the mountain.
The relief was then modified by erosion: the waterways dug steepsided valleys, the waves shredded the cliffs which they output out of rollers. The torrents, born from precipitations, extinguish the gigantic blazing inferno, erode the sides of rock porous and streaming, dig during millenia the narrow ones and deep valleys towards north or the south to cut through a path to the sea, leaving the watershed in the middle of the island.
Until the 14th century of our era, the man will be absent from this hostile world covered with an immense forest populated with reptiles and birds.
|One distinguishes two quite distinct slopes, the watershed extending from the point of Tristão, towards Oporto Moniz, to the forefront of São Lourenço, at the end is, dropping only in his center to the collar of Encumeada (boca da Encumeada). The northern slope is wetter than the southern slope.|
This central chain lengthens of is in west and separates the Madeira in two slopes north and south, quite distinct, making obstacle with the oceanic winds (the light blowing one of the east, will terrai it coming from the mountains and moving north in the south, and the embate newcomer of the south).
If the rainwater, mainly, modelled the interior relief of Madeira, it is the sea especially which worked the coasts of them. The powerful swell of the Atlantic tackled the slopes, even not very stiff, to transform them into cliffs which constitute nearly 80% of the littoral; a third of them exceeds the 100 Mr.
Madeira presents a tormented and wild landscape. Proud peaks are neighborly with deep chasms, covers of a dense vegetation, at the bottom of which torrents (will ribeiras) dug their way towards the sea. The only plane part is the plate of Paúl da Serra, deserted and inhospitable, which extends on 20 km² in the North-West from the island, to 1,400 m of altitude, and which is used as pasture with the sheep.
The coasts, very steep, by places are intersected with estuaries where small fishing ports were established. The beaches rare and are generally covered with large rollers. The near total of the north-eastern coast plunges right in the ocean, sometimes in a spectacular way. The accesses to the sea are generally the outlets of the valleys.
|Colonization ran up against the geography, and the fertility of the ground has of equal only the difficulty of exploiting it. Without making a main effort of imagination, one carries out the extent of completed work to transform whole slopes into cultivable terraces.|
The first colonists employed fire to take, on the thick primitive forest, the grounds which they coveted. The fire was propagated, one says, during seven years, of 1420 to 1427, saver however certain places where the forest of origin remains. Cleared by this large fire of the 15th century, the mountain had to be then domesticated. It was the beginning of an obstinate labor: with obstinacy, black peasants and slaves raised thousands of terraces, sometimes tiny, the poios, which overflow now of vines or banana trees. The arable land was non-existent on the tops: it was thus necessary to seek it with the bottom of the slopes and to transport it on the back of man in hoods, because no draft animal had been able to acclimatize itself to the island. All these walls give today to the island its characteristic aspect and force our admiration today, but one will not forget that it was necessary to fill these terraces with ground, brought on the back of man.
Only some farms of State, installed on the most favourable grounds, use tractors. Each one, that he is or not owner of his ground, plows, sows, harrows and collects using two or three very rudimentary tools.
|The island is an enormous natural basin: the rainwater infiltrates in the mass of the volcanic ash and is stopped only by the impervious layer of laterite and basalt. It then constitutes underground reserves which spout out in sources. The intensive culture all the year must be freed from the dry periods. To exploit this sufficiently rich ground as well as possible to give several intensive annual harvests, and to mitigate the whims of irregular rains, one began the digging of irrigation canals, the levadas or drains, to convey the water heights and to bring it on each terrace… Prowess of ingeniousness and civil engineering, this network of levadas, undertaken at the beginning of colonization was sometimes the work of convicts or slaves, but more often of workmen who put their life in danger to bring the water heights towards the gardens located low, sometimes above vertiginous cliffs.|
The southern part is cultivated, but less sprinkled than its neighbor. To lead invaluable water towards destinations distant or on the other pouring from the island, these levadas often borrows tunnels dug from the pickaxe and aqueducts which enable them to follow contours imperturbably. Sometimes, they cling to the wall and overhang vertiginous cliffs, and it is necessary to imagine the men who carried them out, installed in wicker baskets suspended above vacuum.
At the beginning of the century, one counted approximately 200 levadas. The gigantic task only finished rather recently, in 1950, with the completion of the levada do Furado, long 80 km.
Today, a thousand of kilometers of levadas cross the processions between the vertical walls, slip under the tunnels (furados), span the chasms, run to the side of the abysses to transport the water of the mountains until the smallest piece. Narrow and not very deep, the levadas are often doubled by the paths bordered of trees and flowers which the hikers will borrow.
The network is nationalized today when it is not with the load of the communes, but control is entrusted by it to agents sharpened by the owner of the ground. In 1939, the Portuguese government undertook a vast program of irrigation thus. This one includes the routing of the water, collected around 1,000 m of altitude, to an hydroelectric station then the redistribution on the cultivable grounds.
The use of water is very strictly codified: a law of the middle of the 19th century regulates the use of the water of the levadas. Rotations of irrigation are fixed in advance. Each farmer is entitled to evaluated a water share, paid in hour, and not in quantity. It would be indeed complicated to evaluate volume, variable over the year, according to the flow of the levada; when the flow drops, the whole of the users is affected, nobody is not thus injured. After having irrigated his small holding, each peasant thus closes the valve at the hour envisaged so that its neighbor can then sprinkle his ground. This system allows fields located close to the coasts, in more disadvantaged zones, to benefit from the water of the summits.
Two networks are distinguished: the primary distributers, which drain water towards a sector (the levada is inclined soft, broad 40 cm to 60 cm), and the district distributers, which distribute more or less stiff slopes according to the ground. The levada is not reduced then until not being any more but one drain with the last terraces.
This single network requires a constant maintenance because dead leaves or falling rocks would early have done all to block. For this purpose, each channel is skirted by a small way, regularly traversed by the levadeiros, generally easy to follow, and which transforms the least walk into an enchantment. Always with mountainside, accompanied by the light lapping of water, one discovers unsuspected funds of valley, the sumptuous points of view. These paths are a marvellous opportunity, for the amateurs of walking, to discover splendid landscapes without never knowing of uneven truth.
Among the most important levadas, the levada do Norte, the levada back Tornos and the levada do Furado appear.