Quality of water in reservoirs is very important for managing dam to supply water in a city. Therefore the quality has correlation with the water treatment cost. Stratification in a dam reduces the quality of water, algal bloom in particular. By using an artificial surface mixers as destratifiers, the algal bloom in reservoir can be reduced or prevented. The variation of water quality through water column can be assessed and monitored by DYRESM-CAEDYM model to select the water layer for best water quality to withdraw raw water for water treatment plant. The quality of water in reservoirs can...