The Effects of dam construction on temperature, pH, salinity, alkalinity and hardness of water along Hanna river continuum

The variations of pH, alkalinity, salinity and hardness were measured and compared in different sampling sites in headwaters of Hanna river and Hanna reservoir and its outflow. The results showed that the headwaters were saline and hard and had relative higher alkalinity with stable pH. But due to extended biological activities exerted by lentic condition, the salinity, hardness and alkalinity were modified in the reservoir. The pH of the water column of reservoir were not constant and showed significant daily and annual changes and reached to a high mean value of 9.7 in mid summer. The magnitude values of above mentioned chemical parameters in the Hanna river, or in the other hand, in outflow of reservoir were usually lower than reservoir and higher than headwaters. Apart from existence of hot summer and very cold winter days, there were no observed thermal stratification in the water column of the reservoir. In summer, the stratification was eliminated by the blowing of severe wind.....