Assessing the Physical Habitat Condition of Navigable Canals and Rivers in England

ABSTRACT Monitoring can identify environmental problems and help to set environmental objectives, design management interventions, and assess environmental responses. The need to monitor rivers for such purposes has long been emphasized, but canals have received less attention. We applied the River Condition Assessment (RCA) tool to navigable canals and rivers. The tool was designed to assess rivers in England as part of the UK Department for Food and Rural Affairs' Biodiversity Metric. This Metric is applied to development sites and aims to achieve Biodiversity Net Gain alongside planned land developments. The RCA focuses on the current condition of river reaches within development sites and the potential uplifts in condition that could be achieved. Thirty‐three 250 m long reaches of English navigable canals and rivers were selected to represent a wide range of conditions. They were used (i) to investigate whether the RCA method and its field survey component could be applied without modification to canals and (ii) to identify the properties of canals that are key to differentiating condition and indicating opportunities for improvements. The field survey proved to be a powerful tool for identifying canal condition without modification, but the way the RCA interprets this field data required minor modification. The RCA assigned groups of the 33 investigated reaches to all five RCA condition classes (from Good to Poor). Furthermore, the reaches displayed diverse physical properties that can support ecosystem functioning, demonstrating many ways in which navigable canals in poorer condition could be improved.