Author(s): Areeya Rittima; Krittaya Samarnwongrak; Punthipa Sritamma; Ittiphol Cheeranoravanich
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Keywords: Reservoir evaporation losses
Abstract: Hydrological data plays a crucial role for reservoir planning and management especially the reservoir evaporation loss which is regarded as the major data to reflect the amount of water supply of the reservoir system. This paper aimed to present the pattern and tendency of evaporation data from large, medium, and small size reservoirs in Thailand due to the climate change effects. Four large reservoirs; (1) Ubolratana, (2) Rajjaprabha, (3) Srinakarind, and (4) Sirikit reservoirs, four medium reservoirs; (1) Tubsalao, (2) Pasakchonlasith, (3) Nongplalai, (4) Maekuang Udomthara reservoirs, and one small reservoir; (1) Yangchoom reservoir located in the different regions of Thailand were selected as a case study. The observed evaporation data together with four estimation methods; water budget, empirical, mass transfer, and combination methods were used to estimate the reservoir evaporation loss. For large reservoirs, the results apparently showed the upward trend of evaporation loss at Ubolratana reservoir subject to the increase in mean temperature significantly. It was estimated that the evaporation loss at Ubolratana reservoir was up to 19. 68% of the active storage at the average water level. However, it showed the lower values of evaporation loss for Rajjaprabha, Srinagarind, and Sirikit reservoirs which ranged between 3. 92% -7. 38% of the active storage. It was found that evaporation loss for these large reservoirs fluctuated around the long-term average data and it also showed the tendency effect indistinctly. For the medium and small reservoirs, the results showed higher percentage in evaporation loss especially at Pasakchonlasith, Nongplalai, Yangchoom reservoirs which ranged between 14. 97% -21. 01% of the active storage. Moreover, the evaporation loss tended to be increased due to the high variation in meteorological data and physical characteristics of each reservoir. Additionally, using the empirical method for evaporation loss estimation also gave the lower percentage error than others.
Year: 2013