Estimating evaporation from reservoirs using energy budget and empirical methods: Alavian Dam reservoir, NW Iran

Authors

  • Elahe Hojjati Department of Water Engineering, University of Zanjan, 45371-38791, Zanjan, Iran
  • Ghorban Mahtabi Department of Water Engineering, University of Zanjan, 45371-38791, Zanjan, Iran
  • Farshid Taran Department of Water Engineering, University of Tabriz, 51666-16471, Tabriz, Iran
  • Ozgur Kisi Faculty of Natural Sciences and Engineering, Ilia State University, Tbilisi, Georgia

DOI:

https://doi.org/10.13128/ijam-1033

Keywords:

Alavian reservoir, evaporation, energy budget, empirical methods, temperature simulation

Abstract

Accurate measurement of evaporation from open water resources like lakes and dam reservoirs is necessary to proper water balance management, especially in arid and semi-arid regions. A detailed daily evaporation study was conducted on Alavian Dam reservoir, located in the northwest of Iran. A two-dimensional hydrodynamic model was used to obtain the distribution of daily water temperature of the reservoir. The water temperature model was calibrated and validated using a three-year observed data set (2013-2016). The Bowen ratio energy budget (BREB) is accepted as a standard approach in estimating evaporation from lakes. To select the best evaporation method (s) over the lake, evaporation rates were determined using 30 empirical methods. These methods were evaluated and ranked with respect to the BREB values. The estimated evaporation values by the BREB approach showed that the monthly mean and the annual evaporation from the Alavian Reservoir during the year 2015-2016 were equal to 4.08 mm.d-1 and 1508 mm.year-1, respectively. The Rohwer (Dalton) and the deBruin (combination) methods with the RMSEs of 0.71 and 0.79 mm.d-1, respectively, provided the highest accuracy. To summarize, the methods depended only on measurement of vapor pressure deficit and wind speed (e.g., Rohwer, deBruin and McMillan) were relatively found to be more cost-effective and more practical alternatives for determining evaporation at the studied area, owing to their high efficiency and simplicity.

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Published

2021-01-25

How to Cite

Hojjati, E. ., Mahtabi, G., Taran, F. ., & Kisi, O. . (2021). Estimating evaporation from reservoirs using energy budget and empirical methods: Alavian Dam reservoir, NW Iran. Italian Journal of Agrometeorology, (2), 19-34. https://doi.org/10.13128/ijam-1033

Issue

Section

RESEARCH ARTICLES