Bemerkung zur Typologie amazonischer Flüsse

Abstract

In the first part, the three classic types of rivers and streams in the Amazon are deduced from physical (relief) and chemical (soil) factors in the headwaters. These factors must combine with each other in certain ways to result in certain types of rivers. Some problems that arise when entering into details of the typology of Amazonian rivers are discussed, problems that still cannot be solved. The typology of the Amazonian rivers is based only on easily verifiable phenomena, but it does not have, at the same time, as content, a causal explanation of the same. On the contrary, the more the unknowns contained in the concepts of types of rivers are recognized by meticulous study, the more the types dissolve into individualities that differ from one another until the different "types" are linked together by a series continuum of intermediate transitions. Added to this situation is the fact that many rivers can change their type temporarily - in annual or even non-periodic cycles, within days or even hours - so that a grouping in one or another type becomes illusory. Examples are cited for such facts and the alterations, even extreme ones, are explained by influences of the environment of the river mainly of climatic phenomena, sometimes in combination with certain pedological conditions. It follows from these circumstances that a river is determined, in its particularities, much less by its own, internal laws, than is the case with a lake. Unlike this, a river is, in each of its states, a product of its environment, reacting to alterations in the environment with alterations of its physical and chemical qualities, and with that even of its type. The "types" of rivers, therefore, do not represent abstractions, "ideas" of rivers, but only rough descriptions of them as integral sectors of the "system of actions and effects" that is the landscape.