The Arvand River plume Detection by Using Numerical Modelling

The river plume can be categorized into two general types surface-advected and bottom-trapped and also intermediate type. The river plume classification affects seawater's biological and non-biological characteristics in the river mouth. Given the importance of this issue, using numerical simulations, the plume type of the Arvand river was revealed in this study. The river plume has apparent effects on seawater characteristics of the northwest of the Persian Gulf. For this purpose, the FVCOM model is used for the temperature, salinity, and circulation modelling of the Persian Gulf's water. The model used a horizontal grid of variable triangular elements and a vertical network with 20 Sigma layers. Temperature and salinity at the open boundary were used from the outputs of the HYCOM model. Also, four main tidal components were applied to the model in the open border. After model stability, water column stratification and the shape and width of the river plume were investigated. Several different regional winds were applied to the model to study the wind effect on the plume structure. In no wind, the plume was inclined to the south. The shape and width of the plume change with wind; Thus, the difference between the area of the plume in the two wind modes of 4 meters per second north and south is 300 square kilometres. According to this apparent stratification and the powerful influence of the wind on the plume, the Arvand river has a surface-advected plume that is significant in the fishery, environment, and contamination aspects.