IDENTIFICATION AND ASSESSMENT OF MARINE DEBRIS USING SATELLITE AND AERIAL IMAGERY IN COASTAL WATERS OF KARACHI: IMPACTS ON MARINE AND COASTAL ENVIRONMENT

Abstract

In recent years, more and more attention has been paid to the major environmental issue of marine debris. Due to the vastness of the marine environment and the limited access, it is frequently challenging to monitor the extent and distribution of marine debris in coastal areas. This research aims to identify and evaluate the effects of marine debris in the Karachi, Pakistan, coastal waters using unmanned aerial vehicle (UAV) and MAXAR satellite imagery.

Three locations of Lyari River, mouth, Gizri Creek, and aerial imagery of Beach View Park along the Karachi coast were identified, and debris was classified using high resolution satellite imagery. The marine debris and gathered litter were noticed after processing imagery using machine learning algorithms. Field surveys and ground truth data was used for validation.

According to the study findings, plastics were found to be the most common debris type in the coastal waters of Karachi with around 65% including polythene bags and plastic bottles. 15% of glass and metal, and 20% of fishing gear and other debris were also existing, although in smaller quantities. It was discovered that untreated sewage directly dumped into the main estuarine flows had a significant impact on the diffusion of marine debris. Aquatic environments are shown to be seriously affected by the consequences of marine debris on the marine and coastal environment, including the entangling of marine creatures and the swallowing of plastics. The presence of marine debris on beaches and coastal areas also has negative impacts on tourism and local economies.