DISPERSAL OF PLASTIC WASTE IN KHLONG U-TAPAO SUBBASIN TOWARDS THE LOWER SONGKHLA LAKE, SOUTHERN THAILAND: A GIS-AHP APPROACH

Plastic waste that is not properly managed and leaks into the sea is becoming a serious problem of marine debris.The aim of this study is to analyze the distribution of plastic waste in the Khlong U-Tapao Sub-basin, which flows into the lower Songkhla Lake, Thailand, by using a geographic information system (GIS) and the Analytic Hierarchy Process (AHP), a multi-criteria decision analysis process (MCDA).Physical factors and different geographic environmental characteristics, for a total of 16 data layers representing the origin of plastic waste, rainfall, wind speed and wind direction, slope, past flood events areas, land use, distance from stream, the flow characteristics of the river and distance from the ocean, were collected from field survey and analyzed using GIS.The results showed that towns and cities are where most plastic waste leaks occurred.The majority of this waste enters the Khlong U-Tapao River.The rate of plastic waste leakage is higher during the monsoon and when there are floods.The output of this GIS-AHP method offers incredibly precise spatial data.This study effectively demonstrates how plastic waste from the land flows into the Khlong U-Tapao River and other streams that are connected to the lower Songkhla Lake.The findings can be used to develop guidelines for sustainable management of marine debris in the future.