Sediment plumes arising from marine aggregate and contract dredging are perceived by many stakeholders in the marine and coastal environment to lead to environmental impacts requiring investigation, monitoring or mitigation. However, while information on sediment plumes existed, it was disparate and difficult to use in a structured manner. The aim of this book is to address how plumes should be assessed, having considered the likely or possible effects of dredging operations. The report also outlines the necessary components of a structured framework for assessing the environmental effects arising from dredging plumes. It considers the steps required to inform the decision-making process, and details the data and tools required to inform the steps.