Abstract
This paper presents a review on analysis methods for eutrophication phenomenon or growth of phytoplankton, which is one of typical water quality problems in dam reservoirs. Methods and models on predictions of phytoplankton growth in dam reservoirs have long been studied and basic methodologies seem to have been confirmed for practical uses. However, there are issues for improvement of prediction models requested from the needs of the public, as well as from mere problems of technique. The prediction methods applied in practical business are categorized into two types: simple analysis methods and ecosystem simulation models. Simple analysis methods are mainly based on statistical data analysis collected from many dam reservoirs. A representative example is the phosphorus load model by Vollenweider. Ecosystem simulation models have also long been studied and various types of the model have been proposed. A basic structure of an ecosystem model is consisted of a hydraulic model and water quality — ecosystem model. Issues to be tackled on phytoplankton prediction in dam reservoirs are also discussed. More precise predictions on occurrence of water bloom and water quality disorder and on effects of water quality preservation facilities are needed. On the other hand, simple analysis methods are needed to be improved. These issues are expected from a view point of accountabilities as well as mere technical viewpoint.
