The morphology of landscape elements as predictors of water quality in glacial/boreal lakes

In a statistical approach to the study of watershed-lake water quality interaction, information about geology, land cover and soils was digitized in the drainage area of 87 chemically monitored lakes. With standard 1:50000 scale maps as the source of information, 33 classes of landscape elements were identified. Using geographical information systems (GIS) facilitated the determination of morphological element characteristics such as basic area and dispersal measures. The variables thus derived are used to test whether or not the dispersal characteristics affect lake water quality. It is concluded that they significantly enhance the performance of regression models in explaining inter-lake variances of the characterizing chemical constituents, namely, hardness, colour, total phosphorus, pH, alkalinity, conductivity and Secchi depth. General conclusions regarding annual chemical variability and probability density functions of morphology variables are also made. As a result, landscape elements can be ranked according to their general influence on lake water quality. With variable ranges being quite broad, the results should be valid in many glacial/boreal lakes throughout the world. (C) 1998 Elsevier Science B.V. All rights reserved.