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Abstract
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There are many large dams scattered around the world that each of which, impounds a huge amount of water and prevents the natural movement of water flow downstream which can affect the climate of the local regions significantly. This study aimed to investigate the impact of the Three Gorges Dam (TGD) on slight local climate change. The monthly data (1980-2018) from 54 stations, which were classified into 3 altitude levels, were extracted. The analysis showed TGD had a minor effect on the variation of the precipitation data because similar variations have also been observed in the stations outside the study area. Also, due to the variation in dominant wind direction and speed, the spatial distribution of rainfall was altered significantly. The Standardized Precipitation Evapotranspiration Index (SPEI) analysis in 1, 3, and 12 months showed degradation in the positive drought index downstream of the dam after impounding. The data analysis showed that TGD had a strong impact on the increase in monthly temperature and relative humidity both upstream and downstream of the dam such that for the regions with altitudes of higher than 400 m.a.s.l., the month with the maximum monthly RH and temperature was shifted from December to June and from July to June, respectively. This shifting in lower altitude regions was not seen.
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