LIMNOLOGY OF A WARM HYPERTROPHIC WASTE-WATER RESERVOIR IN ISRAEL .2. CHANGES IN WATER-QUALITY

Factor analysis was used to identify the processes responsible for the changes in water quality in a stratified wastewater reservoir. These reservoirs are well suited to study hypertrophic conditions. In the ep ilimnion, the main source of variablility was the external loading due to variations in wastewater inputs and water level (volume) of the re servoir. The second source was the seasonal climatic changes affecting photosynthesis. The third source was differences between night and da y processes affecting REDOX potential. In the hypolimnion, the main so urce of variability was organic loading but due to both external loadi ng (wastewater inputs) and internal loading (compounds released from t he sediments). The second source was related to the input of chrorophy ll into the hypolimnion, which were external (entry of chlorophyll ric h inflow from a waste stabilization pond) and/or internal (input of ch lorophyll from upper layers due to water column mixing).