An inventarisation is made of a bog-region, influenced by eutrophic water, which enters into the area by way of a system of canals. 50 samples are analysed. A division into 8 groups is made, based upon the structure of the landscape and the vegetation. The distribution of planktonic species is analysed and the results are discussed. The canals have a fine gradient from eutrophic to mesotrophic conditions; the uninfluenced peat-pits are oligo-dystrophic. Of particular interest are the places of contact between the canal water and the peat-water. Two stages are distinguished: enrichment of the originally oligotrophic water, with disturbance and without disturbance. The greater the difference between the two waters that form contact with each other, the greater the disturbance. The disturbed type is called “metatrophic” after Leentvaar (1961). Theoretical backgrounds of these features are discussed and a comparison is made with the existing saprobic system. All these forms are to be seen in one system. The two main factors, controlling the difference within the category of stagnant fresh water, are trophy and stability. Together they will make a typology possible, a typology which may be of interest for those who are entrusted with the management of surface waters.