Field study of sediment and current of Karoun and Arvandroud rivers, in flood conditions

In the March and April of 2019, a huge flood covered several provinces in the southwest of Iran and the route of these floods was finally Karun and Arvanroud rivers through Khuzestan province. The purpose of this study is to measure the current speed and direction, temperature, salinity, water level, suspended sediment concentration, sediment transportation, discharge of Karun and Arvanroud rivers in flood conditions. In tidal rivers such as Karun River in Khorramshahr and Arvanroud River at the Iran-Iraq border, the tidal wave causes severe changes in flow pattern, and water level, so that requires continuous measurement over a tidal cycle (about 24 hours) to estimate a net flux of water and suspended sediment. Field measurements were performed on 5th April 2019 in spring tide in two stations in Karun and Arvanroud rivers. Analysis of the data shows that in flood conditions, water level fluctuations reduced drastically, so that the tidal range in Khorramshahr has decreased from about 100 cm to 26 cm. The average of salinity and current speed in Karun and Arvanroud stations were 0.62psu and 2.1psu, and 1.6m/s and 1.9m/s respectively. The direction of the flow, against the usual, was continuously towards the sea. The maximum suspended sediment concentration were 380g/m3 and 67g/m3 at Karun and Arvanroud stations, respectively. According to the above data, the average water discharge in Karun and Arvanroud were 2153m3/s and 7883m3/s, and the average sediment flux were 142 kg/s and 454 kg/s, respectively.