River sinuosity measured by the Mansikkaniemi method: a critical evaluation

Abstract

Mansikkaniemi's method of studying river sinuosity (first presented in Annales Universitatis Turkuensis A II: 43, 1970) has been assessed through some simple geometrical tests. A fundamental critical comment applies to the vague definition of the river which forms the basis for all measure­ments. Several inconsistent solutions have led to weaknesses in the subsequent statistical evaluation and regional conclusions. In the tests it has also been found that the location of the sinuosity being measured and the length of the river both have an effect on the sinuosity index. The small sinuosity index (Sis) for distance zones varies dramatically depending on the method of subdivision applied to the river channel. Thus, with exactly the same sinuosity, but in different positions on equally long rivers, completely different sinuosity index values are obtained for the distance zones using Mansikkaniemi's method.