The territory has suffered to alterations and continuous, increasing pressures and without precedents, that, in the reality, meet for backwards of the sensible malaise daily for citizen attributed the problems of sectorial and ambient character, particularly express in the form of climatic changes. The case of the city of So Paulo, for example, is typical. Without speaking of other regions, in the part most central of the city, in the Valley of the Anhangaba it passes a river, that until the end of century nineteen ran the open sky and serves of supplying source, at least, for the animals. At the beginning of century twenty, it was canalized, and from there, the urbanization if intensified each time more in what they would be the edges and the riverbed. The river Tamanduate is following the same destination, having good part of its canalized course.
As much the river Pines, how much the river Tiet, whose courses cross the city, has its edges each time more espremidas by the avenues Delinquents. This means that the natural escoadouros of waters of rains had started to have its respective capacities of outflow limited by the dimensions imposed for the Man. Such limitations of capacity form imposed through the canalization (in the case of river Anhangaba and of the river Tamanduate) and the dispute between stream bed and avenue (in the case of the river Pines and the river Tiet), with the trend to the victory for the last one. Reversion of changes climatic, by itself not will assure that the population of the city is uninjured the natural disasters as floods, that had always occurred, occur and will occur. is attempted against that the reference is made only the one of the item that promote upheavals to the inhabitants of urban centers? the problems caused for rains? the one has only left of the territory? the center of the city of So Paulo.