Encuentro meteo 92 : memoria, segunda parte

Cette communication fait le point des travaux sur la rosée et le brouillard dans les zones arides entrepris au XXème siècle. Le brouillard a permis l'existence de forêts à croissance très lente mises gravement en danger par la désertification anthropique. (Résumé d'auteur

L'eau et l'argent à Potosi (ancien Haut-Pérou puis Bolivie)

The mining city of Potosi in the arid zone of the Andes range has an exceptional heritage of industrial archeology with a factory of silver mineral trituration, its mill and other hydraulic installations. However, the Potosi particularity is to keep efficient the water network built by the Spaniards between the 16th and the 17th centuries and especially a complicated tank system of twenty lakes. The Viceroy Francisco de Toledo ordered in 1572 these pharaonic works - the tanks are located between 4300 m and 4800 m above sea level - to adapt the production of silver to the diminution of the quality of the veins and so Toledo pushed to adopt an advanced technology coming from Mexico which needed important and permanent quantities of water : the "patio". So, all trituration factories - more than eighty in 1633 - were located close to the artificial channel, the so-called Ribera de la Very Cruz, which has been crossing the city since 1575. The Ribera became the economical center of the richest city in the World and the most populated town of America at the beginning of the 17th century (160 000 inhabitants in 1611). This hydraulic masterpiece was completely restored by the North-American engineer William E. Rudolph in the thirties to provide huge quantities of water to the factories during the tin mining boom. Actually, the Ribera still crosses Potosi and its water is used by thirty small factories of lead, silver, zinc, and tin. (Résumé d'auteur