Abstract:
The Akosombo dam is a major source of electric energy in Ghana. Considering the current increase in the
demand for electricity in the country, where such an increase in demand implies more pressure on the
dam, it is of key interest to study the tail behaviour of the water levels of the dam. Such a study is important
because the level of water in the dam determines the amount of electricity generated. The study employed
the Univariate Extreme Value Theory to model the monthly maximum and minimum water levels of the
dam. The Generalized Extreme Value Distribution was fitted to the data and the Maximum likelihood
estimation method was employed to estimate the model parameters. The study indicated that, the water
levels cannot fall below 226.00ft which is the critical water level of the Akosombo dam. It further showed
that, the lowest ever level of water the dam can attain is 226.69ft and the highest 279.07ft. The study also
found that, though the water cannot fall below the critical level, there was evidence of its falling below the
minimum operation head.
