A guide to the assessment of vessel wash within sheltered waterways

Sheltered waterways are being subjected to increasing pressure from recreational activities, including recreational boating, as well as public transport and marine tourism. The characteristics of the waves generated by such craft can be very complex and their effect on shoreline environments is poorly understood. To date the development of vessel operating criteria for mitigating foreshore impacts has been largely vessel and site-specific, making transposition of operating criteria between different sites very difficult. In order to develop a rational means of assessing and regulating vessel wash, the relevant scientific, environmental and social issues should be understood and embraced. The basics of vessel wash generation are summarised to introduce the potential difficulties when attempting to measure and parameterise wash components. The likely impacts on the natural and manmade environment are discussed, as well as a range of wash criteria that are currently in use. Lastly, an overview is provided of commonly measured wash parameters and how they may be incorporated into operating requirements.