Estimating Evaporation from Lakes and Reservoirs under Limited Data Condition in a Semi-Arid Region

The Bowen ration energy balance (BREB) is considered as a standard method for estimating lake evaporation. The BREB method however requires numerous input data which may not be readily available especially in developing countries. This limitation could be solved by using methods with fewer data requirements. Evaporation from lakes and reservoirs in Iran is commonly estimated using pan evaporation because there have not been a consensus on which methods are most applicable under the limited data condition and arid climate. Therefore, the objective of this research was to determine the most appropriate evaporation methods over Doosti dam reservoir in Iran. Eighteen existing methods were tested and ranked based on the BREB method. The Jensen-Haise, Makkink, Penman and deBruin methods were among the most consistent methods with BREB in which the RMSD values were obtained 1.2, 1.34, 1.62 and 1.65 mm d(-1), respectively. Finally, we concluded that methods which rely only on air temperature, or air temperature combined with sunshine data (e.g., Jensen-Haise and Makkink), were relatively cost-effective options for estimating evaporation at the study area due to their simplicity, least sensitivity and high accuracy.