survey of rip current hazard in Base of Sefidroud River Delta

The rip currents are a strong and narrow stream that forms in the surf zone and is approximately perpendicular to the coast. The study area is the coastline of the southwestern part of the Caspian Sea in the Base of Sefidroud River Delta. The purpose of this study is to identify rip current and to investigate the causes of this phenomenon. The main tools and data of this research are Hydrographic map of kiashar sea chart to scale 1/10000 and GPS device with ArcGIS software. The method of this work is based on the recognition of rip current in field observations. In the next step, transferring the points to the software environment and adding it to the geomorphic parameters (sea bed topography, slope, coastline geometry, particle diameter and direction of the waves) to analyze the reasons for the occurrence of rip current in the base of the Sefidroud River Delta. The results show that the diameter of sand particles is smaller in the areas of rip current and the slope of these regions is less than adjacent regions. The coastline geometry also shows a large amount of curvature and indentation in the presence of rip currents that can be helpful in identifying this risk. In areas where there are small ridges between the sea stacks, conditions are created to create and strengthen these currents. Therefore, it can be concluded that because of the close connection between the occurrence of this phenomenon and the presence of stacks and troughs in the Wave Breakdown Zone, It is possible to identify the location of the currents and even assess the accuracy of the depth maps.