RELATIONSHIPS BETWEEN DRAINAGE AREA CHARACTERISTICS AND LAKE WATER-QUALITY

The aim of this work is to quantify some of the complex relationships between drainage area characteristics (such as bedrocks and quaternary deposits) and lake water quality (pH alkalinity, conductivity, and hardness) Seventy-six drainage lakes, mainly oligotrophic, are described with respect to drainage area characteristics, morphometry, and water chemistry. The DAZ (drainage area zonation) method has been used to describe the drainage areas The method utilizes a weighting system to reduce the impact of land types with increasing distance from the lake. The most significant parameter governing the water chemistry parameters seems to be the percentage of open land (cultivated and and/or meadows) in the drainage areas High percentage leads to high pH, alkalinity, conductivity, and hardness. The correlations concerning alkalinity and pH are improved using the DAZ method. No significant relationships between bed-rock geology of the drainage areas and lake water chemistry have been recorded.