Observation of currents in Karun River

This paper represents the results of Karun river field measurements during one month in spring, 2013. This measurement was conducted on the currents in a location with an average depth of 5 meters and a distance of approximately 120 km from the northern end of the Persian Gulf, in order to better understanding the currents’ hydrodynamics. Spectral analysis of the currents showed a high magnitude of energy in tidal frequencies that expresses the effect of tides on these measurements. The results indicated that the maximum measured current by a current-meter was 70.6 cm/s, in a seaward direction, and unexpectedly corresponded with the neap tide. The high river discharge concurrently with the neap tide, cause this maximum velocity. In the observation period, the most important factors for determination of river flow direction were tides along with the river discharge variations. Moreover, it is noticeable that harmonic analysis of the sea surface level data, showed that M2, K1, O1 were the most important tidal frequencies with relative predominance of semidiurnal tides at the time and place of the measurement.