Effective site selection is a key component of maximizing litter removal during coastal clean-up actions, particularly along complex and remote coastlines, such as we have in the Arctic. SALT is therefore developing a GIS-based predictive model to identify marine litter hotspots in collaboration with GRID-Arendal; mostly in Lofoten, but we are also working to generalize the model nationally and internationally.
The model is based on identifying the characteristics of the coastline affecting the potential for litter accumulation. Work with beach gradient, for example, has revealed a clear threshold value where high densities of litter are extremely unlikely along shores steeper than approximately 20 degrees. Other factors being investigated include coastline shape, fetch and orientation of the coastline relative to prevailing winds, and substrate. In addition, we are also investigating correlations between litter densities and proximity to local sources of litter, such as population density in the surrounding area, distance to nearest road, river and port, and the amount of nearby fishing activity.
The model is quantitative in nature, and based on rigorous field work, followed by independent validation in the field. Consequently, the model stands apart from most other beach litter hotspots modeling efforts as being underpinned by actual registrations of beach litter.
A preliminary study was completed in Lofoten in 2017. Extensive field work has been carried out in 2018, and a completed model for Lofoten and Vesterålen will be ready in the first half of 2019. Field work and further model development nationally will also be carried out in Finnmark and an area in southern Norway in 2019. International model development and testing will take place in 2020.