Automated and manual mapping of solid waste characteristics on the foreshore of historical coastal landfill sites.

A large proportion of the world’s population lives near the coast; as a result, extensive anthropogenic modification, including historic coastal landfills, has affected large swathes of the global coastline. The acceleration of climate change is poised to increase erosion and inundation that already disturb these sites and mobilise stored solid waste into the marine environment. Before 1974, UK landfill operators had no legal requirement to keep records, and thus the composition and condition of the solid waste at risk of release is unknown. Field sampling campaigns of historic coastal landfills in the United Kingdom have identified hazardous heavy metals, asbestos and plastics, alongside inert geomaterials such as rubble, glass and ceramics being released into the marine environment

A gap remains in our understanding of this hazard, as it is unclear how geomorphological and hydrodynamic processes affect the spatial pattern of solid waste. This creates a need to map, classify and quantify the release of solid waste and its subsequent environmental impact. Three landfills in England have been selected for a mapping and monitoring campaign: East Tilbury, Essex; Shoebury East Beach, Essex; and Spittle Lane, Dorset. These sites are located near areas of high population density or on urban estuaries with a range of industrial developments.

Through the synthesis of existing sediment and grain-size mapping techniques, geomorphic mapping approaches and concepts from citizen science litter surveys, a new framework has been developed to characterise and quantify solid waste physical characteristics. This approach has been extended, using images taken via a phone and UAV, to develop a model to automate the detection and classification of solid waste in coastal settings. These different mapping approaches have been developed through repeat field visits, which have resulted in the creation of different solid waste datasets at different spatial scales with different levels of information.

Different spatial patterns of waste are explored, identifying hotspots of waste accumulation, their geomorphic behaviour and impact, as well as the effectiveness of the automated mapping approach. The refined anthropogenic geomaterial classification scheme will be able to be applied to a wider range of sites around the UK coast, alongside the development of automated mapping approaches, which will allow stakeholders to track the release of solid waste and their impacts.