The effect of climate change on flow regime in Bashar River using two meteorological and hydrological standards

ABSTRACT: An important and fundamental issue in the country is to utilize water and to avoid wasting it. Therefore, climate change can be considered as an effective factor on water resources. The most tangible climate change phenomenon is drought its which identification is much important. Actually, drought is a climatic natural feature and one of the most chronic and harmful natural disasters. Hydrological drought means water flow shortage compared to the normal value and is a natural and repeatable event. In this study, the effect of climate changes on flow rate in Bashar River, Shahmokhtar station of Yasouj city was evaluated usingStandard Index of Annual Precipitation (SIAP) and standard index flow occurrence probability using statistics of 39 years since 1350-1351 to 1388-1389. The best distribution is chosen using Smada software the amount of flow is estimated based on considered occurrences probability that in this study Log-Pearson type III distribution is the best distribution. The results of evaluating percentage of occurrence frequency of each meteorological and hydrological drought situations showed that, by decreasing the amount of precipitation of a certain value, flow rate would decrease and by increasing the amount of precipitation after drought, returning the amount of flow rate to be full of water and wet state, has been delayed. This reduction phenomenon is exacerbated by other factors such as degradation, overuse, etc. which necessitate the need for water resources management and it is feasible by improving water use in agriculture, industry, etc