Prioritization of shipwrecks
The Swedish Agency for Marine and Water Management (SwAM) receives funding to recover environmentally hazardous substances and ghost nets from shipwrecks. Recovery operations are costly and it is important that the funding is used for the benefit of the environment. This is accomplished by removing environmental hazardous substances from those shipwrecks that pose the greatest risk.
As of 2018, SwAM receives SEK 25 million annually for ten years, from the Swedish Environmental Protection Agency’s budget for contaminated areas, for investigations and to perform oil and ghost net recovery operations on environmentally hazardous shipwrecks.
There are currently about 30 shipwrecks in Swedish waters that pose an acute environmental risk, however, oil recovery operations are expensive. It is therefore necessary to make qualified assessments of which wrecks that are to be prioritized for the operations. By removing environmental hazardous substances from the shipwrecks that pose the greatest risk we use the funding for the greatest environmental benefits.
SwAM uses a risk-assessment support tool to be able to assess and prioritize, in an objective and systematic approach, which shipwrecks that constitute the greatest risk and should therefore be emptied of hazardous substances. We take into account a number of factors when we decide which wreck to remediate. For example, the probability that a shipwreck will discharge oil, the volume of oil in the wreck and where in the marine environment the oil will end up.
To carry out these assessments, we use a decision-support tool developed for environmentally hazardous shipwrecks, VRAKA.
The tool is a probabilistic risk assessment tool for handling environmentally hazardous shipwrecks. It is developed by Chalmers University of Technology and is based on a well-established framework for risk management.
The tool is divided into two parts:
Part 1 - estimates the probability of an oil spill,
Part 2 - estimates consequences of a spill, by combining the probability of a discharge with the environmental effects (Figure 1).