Evaporation from the reservoir of the High Aswan Dam, Egypt: A new comparison of relevant methods with limited data

Previous estimates of average annual evaporation from the lake formed by the High Dam at Aswan, Egypt, fall in the range from 4.65 mm d−1 to 7.95 mm d−1. The difference between these limits, more than 7 billion m3 yr−1 at the highest storage level, is nearly one-eighth the share by treaty of Egypt, and more than one-third of the share of the Sudan. It is also more than the estimated increase of the annual water need for Egypt between 1990 and 2000. This state of affairs renders proper management of the river flow for the sake of Egypt and the Sudan quite difficult. This paper compares the relevant methods of estimating evaporation from the limited data available.