Streams

These natural aqueducts, which generally run along the beds of deep, narrow valleys, are very numerous on this island and carry abundant water in the winter season. They rise on the slopes of the central mountain range and flow into the ocean, and some of them have tributaries that increase their volume and the speed of their course. ‘All of them, in winter,’ says the illustrious annotator of the Saudades, ‘carry abundant water, often torrential: they then fill up and at times overflow, carrying down from the mountains thousands of tonnes of boulders of varying size, many so large that they can afterwards be removed only in pieces; and all of them, tumbling in the torrent against one another, make a sinister noise as they collide, until, blocking the beds of these streams, they raise them above the land along the banks; and this land, when it is not buried, is carried off by the stray waters far out to sea, dissolved into mud. In summer, however, their flow of water becomes scant, and some streams even run dry, because of the diversions made both for irrigating the land along their banks and for the levadas (irrigation channels), which take up the running water there and carry it to fertilise distant crops across the whole coastal area of the island.’ From time to time these streams turn into raging torrents which, leaving their beds and invading the banks on either side, violently sweep away large stretches of cultivated land, animal pens and even dwelling houses, at times causing considerable loss of life and property to those living nearby. The principal streams of Madeira are the following: