The IALA Waterway Risk Assessment Program (IWRAP) is a desktop risk assessment program which is aimed at the calculation of probabilities of ship collisions, allisions and groundings.
The program is a part of the overall IALA Risk Management Toolbox as referenced in IALA Guideline G1018 Risk Management. IWRAP is a quantitative tool intended to work in conjunction with other tools in the Toolbox. The tool involves developing a model of the waterways to be analysed, including the geometry of the relevant routes, the traffic volume and composition, as well as the bathymetry of the waterways in question.
Once the model has been defined, IWRAP calculates the expected average annual number of collisions and groundings likely to occur. This calculation is based on the above-mentioned model and a set of so-called Causation Factors which can be thought of as the probability that the vessel fails to make an evasive action to avoid the grounding or collision.
IWRAP only addresses the probability of collisions and groundings, it does not consider the consequences associated with these incidents. It is left to the analyst and the authority performing the analysis to assess the possible consequences of the incidents. The output of IWRAP tool is well suited for performing such an analysis.
More information can be found from G1123 on the use of the IALA Waterway Risk Assessment Program (IWRAP) and the IWRAP Wiki