Empowering Citizen Science: A Multi‐Scale Framework for Understanding the Physical Condition of River Systems

ABSTRACT Citizen scientists have long made important contributions to the monitoring and appraisal of environmental features and processes. However, they have tended to focus more on biological and water quality than on physical aspects of rivers. Nevertheless, in the last two decades, a variety of survey methods have emerged for recording physical processes, forms and human pressures and interventions. This has created a need for guidance on selecting appropriate methods and combining them effectively. Reflecting the many professional multi‐scale physical frameworks that have been proposed since the 1980s, we present a simple, cost‐effective framework for appraising the physical condition of river networks that can be applied by citizen scientists. The framework includes the range of spatial scales where citizen scientists can make significant additional contributions to information already routinely collected by river management agencies. We indicate the types of physical information that can be incorporated at the different spatial scales, and we provide examples of relevant survey techniques that are currently in use within the United Kingdom. We apply the framework to the River Crane, Greater London, to illustrate how it can be applied, using selected citizen science survey approaches, to enhance understanding of system functioning, answer specific questions and support river restoration site selection and monitoring. This case study illustrates the scale of work undertaken, the number of citizen scientists involved, the evolution of the survey programme, lessons learned and future intentions. We conclude by providing some broader perspectives on citizen river science and the physical framework approach.