Delta Life 9

MEXICO CITY Mexico City is 2,240 metres above sea level and, with 22 million inhabitants, it is the highest metropolis in the world. Surprisingly, part of this enormous city, which is surrounded by volcanoes, is built in a marsh. In obedience to Huitzilopochtli, their god of sun and war, the Aztecs once established strategic settlements on islands in Lake Texcoco. Or at least, so tradition would have it. Since then, the city has grown dramatically. The lowest-lying areas were reclaimed with dams and drainage systems. Rainfall is heavy here in the summer. The rainwater flows off the slopes of the volcanoes into the city at an almost uncontrollable speed. And in winter, there is actually a shortage of water. Water is then pumped up from below the city, accelerating land subsidence. Deltares is helping to devise solutions for the colourful Xochimilco area, the Venice of Mexico with its floating gardens and tourist gondolas. Specialists have also teamed up with the local government and partners to help develop a water management strategy for the entire city. Efforts have been made to find the best ways of storing water in every district so that the excess water in the summer can be used in the winter. More information: bas.vandepas@deltares.nl IMAGE HOLLANDSE HOOGTE