Evaluation and Analysis of Drought on the Quantity and Quality Water Resources in Lorestan Province (Case study of Khorram River)

In recent decades following a lot of droughts many changes have been made in the quantity and quality of the country water resources. This factor has caused many uncertainties in the management of the country water resources. The purpose of this study is to improve the understanding of drought effects on the quantity and quality of water resources in Lorestan province during the years 2008 to 2018 by coherence and cross wavelet method. To achieve this goal, first to drought assessment according to precipitation data has been examined using (SPI) index and then the effect of drought on Khorram river runoff is analyzed. Then, the global index of water and the drought impact on this index in the Khorram River were evaluated. Also the global index of water quality (WQI) and the impact of drought on this index in the Khorram River are evaluated. The results of coherence and cross wavelet indicated the relative effect of precipitation with a wavelet coherence coefficient of 0.6 on changes in water runoff in the Khorram River is of degree first importance. Also, the relative impact of drought with a wavelet coherence coefficient of 0.4 changes in water quality of Khorram River has been more than other factors. Therefore, climatic factors in reducing the water runoff of Khorram River from factors other are more important. Also, the results showed human factors as the most important one in water quality changes of Khorramabad River.