CEN/TC 230/WG 25 - Water body characteristics

This document is focused on the structural features of rivers, on geomorphological and hydrological processes, and on river continuity. This document is focused on the structural features of rivers, on geomorphological and hydrological processes, and on river continuity. It provides guidance on the features and processes to be taken into account when characterizing and assessing the hydromorphology of rivers. The word ‘river’ is used as a generic term to describe flowing watercourses of all sizes, with the exception of artificial water bodies such as canals. The document is based on methods developed, tested, and compared in Europe, including the pan-European REFORM project (https://reformrivers.eu/). Its main aim is to improve the comparability of hydromorphological assessment methods, data processing and interpretation. It provides broad recommendations for the types of parameters that should be assessed, and the methods for doing this, within a framework that offers the flexibility to plan programmes of work that are affordable. Although this document does not constitute CIS guidance for the WFD, relevant references provided by the CIS expert group on hydromorphology have been included in the Bibliography.
Although it has particular importance for the WFD by providing guidance on assessing hydromorphological quality, this document has considerably wider scope for other applications. It does not attempt either to describe methods for defining high status for hydromorphology under the WFD, or to link broadscale hydromorphological classification to assessments of ecological status. In addition, while recognizing the important influence of hydromorphology on plant and animal ecology, no attempt is made to provide guidance in this area, but where the biota have an important influence on hydromorphology, these influences are included.
NOTE   A case study illustrating the application of this document is given in Gurnell and Grabowski[1].

This European Standard provides guidance on characterizing the modifications of the hydromorphological features of TraC waters described in EN 16503, enabling consistent comparisons of hydromorphological modification between TraC waters within a country and between different countries in Europe. Its primary aim is to assess ‘departure from naturalness’ as a result of human pressures on TraC hydromorphology, and it suggests suitable sources of information that may contribute to describing the modification of hydromorphological features. The procedures set out in this standard will encourage the objective assessment and reporting of the variability in transitional and coastal waters, and contribute to the work needed to implement the WFD and the MSFD; however, it does not replace methods that have been developed for local assessment and reporting.

This document provides guidance on characterizing the modifications of river hydromorphological features described in EN 14614:2020. Both standards focus more on morphology than on hydrology and continuity, and include a consideration of sediment and vegetation. This document will enable consistent comparisons of hydromorphological forms and processes between rivers within a country and between different countries in Europe, providing guidance for broad-based characterization across a wide spectrum of hydromorphological modification of river channels, banks, riparian zones and floodplains. Although of lesser focus, it considers the indirect effects of catchment-wide modifications to these river and floodplain environments. Its primary aim is to assess ‘departure from naturalness’ as a result of historical and modern human pressures on river hydromorphology, and it suggests suitable sources of information (see EN 14614:2020, Table A.1) which may contribute to characterizing the modification of hydromorphological properties. In doing so, it does not replace methods that have been developed for local assessment and reporting.
Decisions on river management for individual reaches or catchments require expert local knowledge and vary according to river type.

This document concerns the restoration of rivers, including their channels, riparian zones, and floodplains. The word ‘river’ is used as a generic term to describe permanently flowing and intermittent watercourses of all sizes, with the exception of artificial water bodies such as canals. Some aspects of landscape restoration beyond the boundaries of what are often considered typical river processes are also considered. This document focuses on ‘nature-based solutions’, which are ‘actions to protect, sustainably manage and restore natural or modified ecosystems that address societal challenges effectively and adaptively, simultaneously providing human well-being and biodiversity benefits’ (https://portals.iucn.org/library/sites/library/files/documents/2016-036.pdf).
A clear framework of guiding principles to help inform the planning and implementation of river restoration work is provided. These principles are aimed both at individuals and organizations wishing to restore rivers, and stress the importance of monitoring and appraisal. This document makes reference to existing techniques and guidance, where these are appropriate and within the scope of this document.
This document provides guidance on:
—   the core principles of restoration
—   the aims and overall outcomes of river restoration
—   the spectrum of typical approaches to river restoration (the ‘restoration mode’) with a focus on those that are nature-based and restore both physical and ecological aspects
—   identifying opportunities for restoration and possible constraints, with a focus on physical and natural rather than socio-economic aspects
—   the different scales of restoration and how restoration works across different catchments and landscapes
—   the importance of monitoring and appraising restoration work across the range of approaches and scales.