Seite - 639 - in Book of Full Papers - Symposium Hydro Engineering

6. SUMMARY The effect of climate change on precipitation, evaporation, and transpiration, surface runoff and extreme hydrological events on the local and regional scale, especially in arid and semi-arid regions of the country, is still a controversial subject. In the present research, the effect of climate change on annual and monthly discharge of Taleghan basin was investigated at the entrance to Taleghan reservoir. To this aim, firstly, the existence of the trend and occurrence of mutation in the meteorological-hydrologic variables was studied on climate change studies using statistical tests. The results of the trend test, while no trends were observed in precipitation, showed an increase in temperature (at a probability level of 99%) and water (at a probability level of 95%) during the winter, especially in the months of February and March. Also, the results of the mutation test showed that the temperature in 1963 was positive at a probability level of 99%. The mountainous state of the basin discusses the theory of increase in the temperature in the winter, snow melting, early runoff, and in other words, early melting of the snow from the spring to winter season. Then, using the remote sensing technique and selecting the Terra satellite, the snow coverage of Taleghan basin during 2000-2014 throughout the winter was investigated. The results indicated a decrease in snow covering level at the probability level of 99% in February. Hence, the effect of climate change on water resources of Taleghan basin, considering all factors such as a significant positive trend in temperature, reducing snow covering, decreasing spring flow and increase of winter flow to the dam were confirmed, although the volume and depth of annual runoff were stabilized. Consequently, it can be argued that climate change in this basin is a change in the precipitation pattern, i.e the change in the type of snowflake to rain as well as seasonal displacement. These studies have shown that according to the existing trend in the amount of annual discharge to the dam reservoir, the effect of human factors on changing the pattern and runoff rate of the basin has not been affected. Keywords: Climate change, cold climate, flow, Taleghan dam 7. CLEARANCES AND COPYRIGHT The author(s) is (are) responsible for obtaining written permission to profile the project or subject matter in their papers from any and all clients, owners or others who commissioned the work. ICOLD assumes proper permission has been obtained by author(s) and accepts no liability for the author(s) failing to do so. 639