On the Relationship between Regional Geomorphology and Lake Morphometry—A Swedish Example

Abstract

The purpose of this work has been: (1) to collect data on certain lake morphometrical characteristics (area, volume and maximum depth) and geomorphological provenance from as many lakes as possible throughout Sweden, i.e., to establish a geomorphological lake register, and (2) to test a working hypothesis concerning a quantifiable relationship between lake morphometry and lake surroundings. Presently, the register includes 1060 lakes. The working hypothesis has been verified by means of a cluster analysis. The results include a new division of Sweden into five regions with lakes of similar morphometry. These results may, e.g., be used to statistically determine the most probable, 'normal', values of lake volume, mean and maximum depth, lake form and percentage area of lake bottom dominated by processes of erosion and transportation, from knowledge of lake area alone. Introduction Sweden has over 100 000 lakes. No one could give a precise figure because there are no exact definitions what is a lake, a pool, a pond or a river lake. Moreover, it could never be a definite figure because lakes undergo a characteristic lifespan: creation-youth-maturity-old age-extinction. This development is generally very slow and difficult to notice by individual standards in spite of the fact that lakes are often created both rapidly (in a geological sense) and drastically by endogenic and exogenic and, nowadays, anthropogenic forces. Lakes are unevenly distributed on the earth and are most abundant in areas affected by glacial activity (Hutchinson, 1957). Few parts of the world have more lakes than Scandinavia, which is demonstrated by Fig. 1 illustrating the distribution of lakes in Sweden. The morphometry largely determines the limnological, sedimentological and hydrological character of the lake, and lakes are often important integral parts of the ecosystem (cf. Wetzel, 1975). They are also sometimes the cause of conflicts, and different interest groups have different ideas and demands concerning the use of lakes and other bodies of freshwater as natural resources (cf. Franco and Wetzel, 1983). Presently, the prerequisites for aquaculture are under debate in many industrialised countries (Ackefors, 1982). Aquaculture. as agriculture, requires knowledge of natural functions and mechanisms so that adequate plans can be worked out and the possibilities for misuse minimized. Aim of the work The objective of this work is to test a working hypothesis whether there exists a quantifiable relationship between the lake surroundings, in this case the geomorphology, and the lake morphometry. To test this, data were collected from as many lakes as possible throughout Sweden on certain morphometric characteristics as well as on geom phological regions. This has been an arduous task which started in 1980. A more comprehensive report has been published in Swedish (Hakanson et al., 1983). This paper is intended to summarize some results and ideas of, hopefully, mo e general interest. Thus, we will only briefly discuss methods and possible future ways of utilizing these results in lake management and planni g. The focus here is on the working hypothesis and the general approach behind it. The ultimate idea underlying the work is to try to present a method that enables the determination of typical, characteristic lake morphometric features in different geomorphological regions; if the 'normal' morphometry can be determined objectively, then it would also be possible to quantify divergencies from the 'normal'. A comprehensive publication on Sweden's water resources has been presented by Falkenmark Geografiska Annaler * 66 A (1984) 1-2 103 This content downloaded from 157.55.39.163 on Wed, 21 Sep 2016 05:19:22 UTC All use subject to http://about.jstor.org/terms LARS HAKANSON AND BERT KARLSSON ATLAiS O£. stVEXtE _ SJ OAR LAKES Sant mman~,t~i[ av M6XGNUS LUI,NDQt:IST i .Al t xl{2: )00oo0i) ::o isO 14}E t.4i# ;