This document provides guidance on the features to be recorded when characterising and assessing the hydromorphology of rivers. It is based on methods developed, tested, and compared in Europe. Its main aim is to improve the comparability of hydromorphological survey methods, data processing, interpretation and presentation of results. Whilst it has particular importance in relation to the reporting requirements of the WFD, it also has considerably wider scope for other applications. Although hydromorphology is dependent on hydrology and underlying geology, this standard is focused on the structural features of rivers and on river continuity. In addition, whilst recognising the important influence of hydromorphology on plant and animal ecology and, conversely, the influence of plants and animals on hydromorphology, no attempt is made to provide guidance in this area.