The Risk Assessment of Water Pollution in the Gorgan Bay Catchment Using the WRASTIC Index

Abstract The WRASTIC model is one of the most practical methods to assess the risk and an advanced method to evaluate the potential for the pollution in a catchment basin. In order to assess the risk of pollution in the Gorgan Bay catchment, six sub-basins of the study area were extracted using the elevation map in QGIS and TerrSet software. The risks have been detected by field visits, library studies, and asking experts and related organizations. Finally, the WRASTIC index was provided as seven informational layers and the index number for each sub-basin was calculated by weighting, ranking, and integrating the layers. The results showed that three sub-basins have a high risk and three others have a medium risk. According to the level of risk, this catchment is exposed to pollution and has vulnerability mainly due to human activities including a high volume of sewage discharged into the catchment, a high amount of agricultural and entertainment activities in the region, transport pathways and railways, as well as the vastness of the catchment. Therefore, supervising and controlling human activities in the catchment is necessary to improve the ecological conditions of water resources in the area.