oSIST prEN 15843:2024

SLOVENSKI STANDARD
01-oktober-2024
Kakovost vode - Navodilo za določanje stopnje spreminjanja hidromorfoloških
značilnosti vodotokov
Water quality - Guidance standard on determining the degree of modification of river
hydromorphology
Wasserbeschaffenheit - Anleitung zur Beurteilung von Veränderungen der
hydromorphologischen Eigenschaften von Fließgewässern
Qualité de l'eau - Guide pour la détermination du degré de modification de
l'hydromorphologie des rivières
Ta slovenski standard je istoveten z: prEN 15843
ICS:
13.060.10 Voda iz naravnih virov Water of natural resources
13.060.45 Preiskava vode na splošno Examination of water in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2024
ICS 13.060.45 Will supersede EN 15843:2010
English Version
Water quality - Guidance standard on determining the
degree of modification of river hydromorphology
Qualité de l'eau - Guide pour la détermination du degré Wasserbeschaffenheit - Anleitung zur Beurteilung von
de modification de l'hydromorphologie des rivières Veränderungen der hydromorphologischen
Eigenschaften von Fließgewässern
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 230.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15843:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Principle . 9
5 Approach . 10
5.1 Spatial scales and delineating spatial units . 10
5.2 River and floodplain hydromorphological type . 10
5.3 Hydromorphological reference conditions . 10
5.4 Modification bands . 12
6 River valley segments . 12
6.1 General. 12
6.2 River flow regime . 13
6.3 Sediment delivery . 13
6.4 Longitudinal connectivity . 14
6.5 Lateral connectivity . 15
7 River reaches . 16
7.1 Longitudinal connectivity . 16
7.2 Lateral connectivity . 17
7.3 River channel long and cross profile and planform (evidence of direct human
interventions) . 18
7.4 River channel long and cross profile and planform (evidence of channel dynamics in
response to human interventions) . 19
7.5 River bed and bank character . 20
7.6 Instream vegetation . 21
7.7 Geomorphological features . 22
8 Interpreting and reporting hydromorphological modifications . 23
8.1 General. 23
8.2 Using bands assigned to individual properties to describe the degree of modification
of river hydromorphology . 23
8.3 Combining bands assigned to several properties to summarize the degree of
modification of river hydromorphology . 24
9 Quality assurance in obtaining and analysing data . 24
9.1 Qualifications and experience . 24
9.2 Training . 24
9.3 Certification, data entry and validation . 25
Bibliography . 26

European foreword
This document (prEN 15843:2024) has been prepared by Technical Committee CEN/TC 230 “Water
analysis”, the secretariat of which is held by DIN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 15843:2010.
Introduction
This document will enable broad comparisons to be made of river hydromorphological modifications
throughout Europe (e.g. for reporting by the European Environment Agency). The assessment of river
‘quality’ in Europe has evolved over the past 30-40 years. From its original focus on organic pollution it
now relies on methods for analysing a range of chemical and biological attributes. More recently,
several European countries have developed systems for evaluating the hydromorphological features of
rivers. The EC Water Framework Directive (WFD) has reinforced the need for this broader view of river
‘quality’ through its requirement for determining ‘ecological status’ based on macrophytes,
phytobenthos, invertebrates and fish. The Directive also requires that hydromorphological and physico
chemical conditions should be suitable for supporting biological communities.
EN 14614:2020, Water Quality ― Guidance standard for assessing the hydromorphological features of
rivers describes a standard for field survey and feature recording, whereas this standard gives guidance
on assessing the modification of river hydromorphological features. It focuses especially on human
pressures that affect rivers; thus, it may be helpful for implementing the WFD by indicating the extent
to which these pressures might have caused a departure from hydromorphological reference
conditions. Although the procedure described in this standard enables the hydromorphological
characterization and assessment of rivers, 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. However, the content of this standard has the
potential to contribute to both of these.
In addition to its relevance to the WFD, this standard has applications also for nature conservation,
meeting the goals of the Biodiversity Strategy (e.g. re-instating connectivity), environmental impact
assessment, river basin management, flood risk management (e.g. the EC Floods Directive) and setting
targets for river restoration work.
1 Scope
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.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 14614:2020, Water quality - Guidance standard for assessing the hydromorphological features of
rivers
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
3.1
aquatic vegetation morphotype
morphological character of aquatic vegetation, which combines the shape of the leaves, whether the
leaves are emergent, floating or submerged, and whether or not the vegetation is rooted in the river bed
3.2
armouring
where the river bed surface comprises coarser particles than the underlying river bed layers as a result
of removal (mobilization and transport) of the finer particles from the bed surface layer
[SOURCE: EN 14614:2020, 3.4]
3.3
bank
side of a river channel or island which extends above the normal (e.g. mean) water level and is only
completely submerged during periods of high river flow
[SOURCE: EN 14614:2020, 3.7]
Note 1 to entry: In the context of this document, the bank top is marked by the first major break in slope, above
which cultivation or development is possible.
3.4
bar
in-channel, elevated sediment deposit exposed during periods of low flow, which may be a side bar
(including a point or
...