*3.4. Analysis of Water Demand under Climate Scenario*

The results showed that the average temperature was increased in the long-term climate scenario from the baseline scenario. It was increased from 22.08 ◦C (1980–2016) to 24.04 ◦C (2017–2030) and 26.49 ◦C for the long-term future development (2030–2050) scenario. The increased average temperature was mainly observed in the month of May.

The average temperature was increased by 1.96 ◦C and 4.41 ◦C in 2017–2030 and 2030–2050 from the reference scenario, respectively. Thus, the change in average temperature would cause a change in the reservoir surface temperature and significant evaporation loss.

The average precipitation in the basin also showed a fluctuation from the reference scenario. The average precipitation was 1733.33, 2433.33, and 2525.00 mm under the reference, medium-term development, and medium-term development future scenario, respectively. The precipitation would be increasing in the long-term development future scenario (2030–2050) as compared to the other two scenarios.

As far as the trends of evaporation in the reservoir are concerned, the modeled results showed decreasing and increasing trends in some months. The maximum and minimum evaporation was observed as 53.8 and 16.5 Mm<sup>3</sup> in October and August, respectively. The evaporation under each scenario was also 33.73, 35.21, and 35.71 Mm3 in the 1980–2016, 2017–2030, and 2030–2050 scenarios, respectively. The simulation results of annual evaporation in each scenario was 404.80, 422.50, and 428.50 Mm3, respectively. The increase of evaporation in the reservoir was due to the increase of temperature under the climate change scenario. The climate change scenario with respect to temperature, precipitation, and evaporation is shown in (Figure 6).

**Figure 6.** Average monthly temperature, precipitation, and evaporation under the three scenarios. (**a**) Average temperature, (**b**) average precipitation, and (**c**) mean monthly evaporation.
