ABSTRACT
The idea of the drainage basin as a suitable framework for the study and organization of the facts of physical and human geography has a long tradition in the history of the subject. In 1752 Philippe Buache presented a memoir to the French Academy of Sciences in which he outlined the concept of the general topographical unity of the drainage basin. Changing technologies of transport have, of course, severely eroded such unity as ever attached to the smaller drainage basins of western Europe in terms of navigation and commerce. The closest and probably the most widespread association of past human activity with the hydrological balance, relief, slopes, and stream networks of the drainage basin has been achieved through the operation of irrigation systems. In coastal Peru, for example, early piecemeal irrigation was soon replaced by canal systems incorporating the whole of the irrigable area of a drainage basin below the Andean foothills.
