Water quality - Guidance standard for assessing the hydromorphological features of rivers

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].

Wasserbeschaffenheit - Anleitung zur Beurteilung hydromorphologischer Eigenschaften von Fließgewässern

Der Schwerpunkt dieses Dokuments liegt auf den strukturellen Eigenschaften von Flüssen, auf geomorpholo¬gischen und hydrologischen Prozessen sowie der Durchgängigkeit von Flüssen. Dieses Dokument gibt eine Anleitung zu den bei der Charakterisierung und Beurteilung der Hydromorphologie von Fließgewässern zu berücksichtigenden Merkmalen und Prozessen. Das Wort „Fluss“ wird als Oberbegriff für fließende Wasserläufe aller Größen verwendet, mit Ausnahme künstlicher Gewässer wie Kanäle. Das Dokument beruht auf Verfahren, die in Europa entwickelt, geprüft und verglichen worden sind, einschließlich des europaweiten REFORM-Projekts (https://reformrivers.eu/). Das Hauptziel dieser Norm ist es, die Vergleichbarkeit der hydromorphologischen Beurteilungsmethoden, der Datenverarbeitung und der Interpretation zu verbessern. Es enthält umfassende Empfehlungen für die Arten von Parametern, die bewertet werden sollten, und die Methoden dafür in einem Rahmen, der die Flexibilität bietet, erschwingliche Arbeitsprogramme zu planen. Obwohl dieses Dokument keine CIS-Leitlinien für die WRRL darstellt, wurden relevante Referenzen der CIS-Expertengruppe für Hydromorphologie in die Bibliographie aufgenommen.
Obwohl es von besonderer Bedeutung für die WRRL ist, indem eine Anleitung zur Beurteilung der hydromorphologischen Beschaffenheit bereitgestellt wird, hat dieses Dokument einen erheblich größeren Geltungsbereich für andere Anwendungen. Es wird weder versucht, Methoden zur Definition eines hohen Status für die Hydromorphologie im Rahmen der WRRL zu beschreiben, noch eine breit angelegte hydromorphologische Klassifizierung mit Bewertungen des ökologischen Status zu verknüpfen. Obwohl der bedeutende Einfluss der Hydromorphologie auf die Pflanzen- und Tierökologie anerkannt wird, wurde darüber hinaus kein Versuch unternommen, in diesem Bereich eine Anleitung zur Verfügung zu stellen; die wichtigen Einflüsse der Biota auf die Hydromorphologie wurden jedoch einbezogen.
ANMERKUNG Eine Fallstudie, die die Anwendung dieses Dokuments veranschaulicht, ist in GURNELL and GRABOWSKI [1] enthalten.

Qualité de l'eau - Guide pour l'évaluation des caractéristiques hydromorphologiques des rivières

Le présent document se concentre sur les caractéristiques structurelles des rivières, les processus physiques et géomorphologiques, ainsi que sur la continuité de la rivière. Il fournit des recommandations relatives aux caractéristiques et processus à prendre en considération lors d’une caractérisation et d’une évaluation de l’hydromorphologie d’une rivière. Le mot « rivière » est utilisé en tant que terme générique pour décrire les cours d’eau de toutes tailles, à l’exception des plans d’eau artificiels, tels que les canaux. Le présent document se fonde sur les méthodes développées, testées et comparées en Europe, y compris le projet REFORM paneuropéen (https://reformrivers.eu/). Il a pour objectif d’améliorer la comparabilité des méthodes d’évaluation hydromorphologique, du traitement et de l’interprétation des données. Il fournit des recommandations relatives aux types de paramètres qu’il convient d’évaluer ainsi qu’aux méthodes d’évaluation, dans un cadre qui propose suffisamment de flexibilité pour prévoir des programmes de travail qui sont abordables. Bien que le présent document ne constitue pas des recommandations CIS pour la WFD, les références pertinentes fournies par le groupe d’experts CIS concernant l’hydromorphologie ont été incluses dans la Bibliographie.
Bien qu’il soit d’une importance toute particulière pour la WFD du fait qu’il fournisse des recommandations relatives à l’évaluation de la qualité hydromorphologique, le présent document peut également s’appliquer à de nombreux autres domaines. Il n’a pas pour objectif de décrire des méthodes permettant de définir un très bon état pour l’hydromorphologie selon la WFD ni de faire le lien entre la classification hydromorphologique à grande échelle et les évaluations de l’état écologique. En outre, malgré l’influence importante de l’hydromorphologie sur l’écologie végétale et animale, aucune recommandation n’est faite dans le présent document. Cependant, ces influences sont mentionnées dans les cas où les biotes exercent une influence cruciale sur l’hydromorphologie.
NOTE   Une étude de cas illustrant l’application du présent document est fournie par Gurnell et Grabowski[1].

Kakovost vode - Navodilo za ocenjevanje hidromorfoloških značilnosti vodotokov

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6060 - Definitive text made available (DAV) - Publishing
Due Date
09-Sep-2020
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SLOVENSKI STANDARD
SIST EN 14614:2021
01-januar-2021
Nadomešča:
SIST EN 14614:2005
Kakovost vode - Navodilo za ocenjevanje hidromorfoloških značilnosti vodotokov

Water quality - Guidance standard for assessing the hydromorphological features of

rivers

Wasserbeschaffenheit - Anleitung zur Beurteilung hydromorphologischer Eigenschaften

von Fließgewässern

Qualité de l'eau - Guide pour l'évaluation des caractéristiques hydromorphologiques des

rivières
Ta slovenski standard je istoveten z: EN 14614:2020
ICS:
07.060 Geologija. Meteorologija. Geology. Meteorology.
Hidrologija Hydrology
13.060.10 Voda iz naravnih virov Water of natural resources
13.060.70 Preiskava bioloških lastnosti Examination of biological
vode properties of water
SIST EN 14614:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14614:2021
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SIST EN 14614:2021
EN 14614
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2020
EUROPÄISCHE NORM
ICS 07.060; 13.060.70 Supersedes EN 14614:2004
English Version
Water quality - Guidance standard for assessing the
hydromorphological features of rivers

Qualité de l'eau - Guide pour l'évaluation des Wasserbeschaffenheit - Anleitung zur Beurteilung

caractéristiques hydromorphologiques des rivières hydromorphologischer Eigenschaften von

Fließgewässern
This European Standard was approved by CEN on 17 May 2020.

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. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists 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, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14614:2020 E

worldwide for CEN national Members.
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SIST EN 14614:2021
EN 14614:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 4

Introduction .................................................................................................................................................................... 5

1 Scope .................................................................................................................................................................... 6

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 6

4 Principle .......................................................................................................................................................... 14

5 Study context and requirements ............................................................................................................ 14

5.1 Investigating hydromorphology across both space and time ...................................................... 14

5.2 Desk study ....................................................................................................................................................... 15

5.3 Field survey .................................................................................................................................................... 16

5.4 Analysis and interpretation ..................................................................................................................... 16

6 Delineation ..................................................................................................................................................... 16

6.1 General ............................................................................................................................................................. 16

6.2 Extent of delineation ................................................................................................................................... 17

6.3 Catchments ..................................................................................................................................................... 17

6.4 Landscape units ............................................................................................................................................ 17

6.5 Valley segments ............................................................................................................................................ 18

6.6 River reach units .......................................................................................................................................... 18

7 Characterization ........................................................................................................................................... 20

7.1 General ............................................................................................................................................................. 20

7.2 Catchment to valley segment units ........................................................................................................ 20

7.3 River reach units .......................................................................................................................................... 22

8 Reference conditions .................................................................................................................................. 31

8.1 Pristine reference conditions .................................................................................................................. 31

8.2 Near-natural reference conditions and processes ........................................................................... 32

9 Quality assurance in obtaining and analysing data ......................................................................... 33

9.1 Qualifications and experience ................................................................................................................. 33

9.2 Training ........................................................................................................................................................... 33

9.3 Certification, data entry and validation ............................................................................................... 34

Annex A (informative) Overview of some freely available pan-European data sets ........................ 35

Annex B (informative) Explanations of the relevance of elements in this document ...................... 38

B.1 Introduction ................................................................................................................................................... 38

B.2 Hydromorphological characteristics indicative of processes and human pressures at

spatial scales from catchment to valley segment (Table 1) .......................................................... 38

B.3 Hydromorphological characteristics indicative of flow and sediment transport

processes (Table 2) ..................................................................................................................................... 39

B.4 Hydromorphological characteristics indicative of river channel size and type

(Table 3) .......................................................................................................................................................... 40

B.5 Hydromorphological characteristics of the river bed (Table 4) ................................................. 41

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B.6 Hydromorphological characteristics of the river channel (and large island) margins

(Table 5) ........................................................................................................................................................... 42

B.7 Hydromorphological characteristics of floodplains (Table 6) ..................................................... 43

Annex C (informative) River and related floodplain styles ........................................................................ 45

Bibliography ................................................................................................................................................................. 50

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SIST EN 14614:2021
EN 14614:2020 (E)
European foreword

This document (EN 14614:2020) has been prepared by Technical Committee CEN/TC 230 “Water

analysis”, the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by March 2021, and conflicting national standards shall

be withdrawn at the latest by March 2021.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

This document supersedes EN 14614:2004.

According to the CEN-CENELEC Internal Regulations, the national standards organisations of the

following countries are bound to implement this European Standard: 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, Turkey and the

United Kingdom.
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SIST EN 14614:2021
EN 14614:2020 (E)
Introduction

In the past, many countries in Europe assessed river ‘quality’ simply in terms of water chemistry or

pollution within river channels. A more comprehensive understanding of rivers is needed, however, in

view of global issues such as climate change, to answer pressing ecological questions such as those

arising from the EC Water Framework Directive (WFD), the EC Habitats Directive and EC Floods

Directive, to underpin the International Convention on Biodiversity, or to assess proposed river

engineering work and to evaluate the effectiveness of restoration schemes and other catchment

developments.

River habitats and physical processes have suffered historically from a wide range of human impacts,

especially changes in land use since World War II. In most European countries there is now widespread

agreement among environment and conservation agencies to see modified rivers returned to a more

natural condition. This implies a need to evaluate areas deserving protection and those requiring

restoration, and to encourage sustainable management of river systems throughout Europe.

NOTE In this document, ‘assessment’ is used as a broad term referring to the general description of features

and the pressures affecting them. It is not used to imply the judgement of particular levels of ‘quality’ or ‘value’,

whether related to status under the WFD or more generally.
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EN 14614:2020 (E)
1 Scope

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].

2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
aluvium
sediment deposited by rivers
3.2
anabranching river
river with more than one channel separated by vegetated islands
3.3
aquifer

underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials

(gravels, sands) from which groundwater can be extracted
3.4
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

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3.5
attribute
specific recorded element of a hydromorphological feature

EXAMPLE ‘Boulders’ and ‘silt’ are substrate attributes; ‘sheet piling’ and ‘gabions’ are attributes of

engineered banks.
3.6
backswamp

low-lying marshy area that lies between the valley margin and the natural levée of an alluvial channel

3.7
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

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.
3.8
bankfull
level at which water begins to spill out of the channel onto the floodplain
3.9
bar

in-channel, elevated sediment deposit exposed during periods of low flow, which could be a side bar

(including a point or counterpoint bar, located respectively along the convex or concave bank of a

meander bend) or a mid-channel bar
3.10
baseflow

sustained component of streamflow, usually resulting from drainage of groundwater, but also from

drainage of large lakes, swamps, soils, snow and ice packs
3.11
baseflow index

measurement of the ratio of the long-term baseflow to total stream flow, often representing the slow,

continuous contribution of groundwater to river flow
3.12
baseflow channel width, depth and slope

the width, depth and water surface slope of the part of the channel that conveys the baseflow

3.13
berm

natural or artificial, flat-topped shelf along the margin of a river channel that is exposed above water

level during low flows, but is submerged during high flows

Note 1 to entry: Natural berms are vegetated features composed of sediments deposited by the river to the

baseflow level.
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3.14
bench

natural flat-topped shelf along the margin of a river channel that evolves from a natural berm as further

deposited sediment raises its surface gradually to higher elevations within the river channel

3.15
boulder step

accumulation of boulders (> 256 mm) transverse to and crossing the river channel creating a step in the

river’s long profile
3.16
braiding

river whose bankfull channel is naturally divided by mid-channel bars into at least two separate flowing

threads at baseflow
Note 1 to entry: See also ‘bar’.
3.17
burial
accretion of fine sediment over coarser bed material
Note 1 to entry: Burial is the opposite of armouring.
3.18
cascade
stream bed covered with disorganized boulders in steep confined channels
3.19
characterization

selection of properties or special features of a spatial unit that are uniquely relevant to identifying its

hydromorphological processes, forms and pressures
3.20
coarse sediment

sediment of grain size at or larger than ‘very fine gravel’ (diameter ≥ 2 mm, ≤ −1 phi)

EXAMPLE Gravels, cobbles, boulders.

Note 1 to entry: The phi scale defines sediment grain size as the negative logarithm to the base 2 of the grain

diameter in millimetres.
3.21
confinement

degree to which the lateral movement of a river channel is confined by the presence of valley sides or

terraces
3.22
counterpoint bar

side bar type that develops in the flow separation zone along the concave bank of tight river bends

3.23
crevasse
breach in natural levée
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3.24
crevasse-splay

local accumulation of sand or gravel, deposited by water escaping from the river channel through a

crevasse
3.25
culvert

arched, enclosed or piped structure constructed to carry water under roads, railways and buildings

[SOURCE: EN 15843:2010, 3.8]
3.26
dune

usually fine sediment (sand–silt) river bed feature typical of low-gradient, alluvial sand-bed rivers that

is linear in plan, aligned perpendicular to the flow, with a gentle upstream and steep downstream cross

profile
−1 1

Note 1 to entry: Dunes can be distinguished from ripples by their larger height (10 m / 10 m) and wavelength

(proportional to the water depth).
3.27
embankment

artificial bank built to raise the natural bank level thereby reducing the frequency of flooding of

adjacent land
3.28
fine sediment

sediment of grain sizes equal to or smaller than ‘very coarse sand’ (≤ 2 mm diameter, ≥ 2 mm −1 phi),

i.e. sands, silt, clay

Note 1 to entry: The phi scale defines sediment grain size scale as the negative logarithm to the base 2 of the

grain diameter in millimetres.
3.29
floodplain

valley floor adjacent to a river that is (or was historically) inundated periodically by flood waters and is

formed of sediments deposited by the river
3.30
flow regime

typical magnitude, frequency, timing, and duration of river flows that drive physical and some

ecological processes and so, within the constraints of valley slope and confinement, influence the sizes

and types of river channel that could be present
3.31
fluvial geomorphology

scientific study of the physical processes, form and functioning of rivers and streams and their physical

interactions with the surrounding landscape
3.32
forced bar

non-mobile bar whose position is forced by the presence of natural (e.g. large wood) or artificial

structures
Note 1 to entry: See also ‘bar’.
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3.33
forced pool

non-mobile pool whose position is forced by the presence of natural (e.g. large wood) or artificial

structures
Note 1 to entry: See also ‘pool’.
3.34
gabion
wire basket containing stones, used for river-bed or bank protection
3.35
hyporheic zone

spatio-temporally dynamic ecotone between the surficial benthic substrate and the underlying aquifer

[SOURCE: EN 16772:2016, 2.13]
3.36
hydromorphology

morphological and hydrological characteristics of rivers including the underlying processes from which

they result
3.37
large wood
piece of wood that is more than 1 m long and 10 cm in diameter
3.38
landscape unit

area displaying distinctive combination of environmental attributes such as altitude, topography and

geology
3.39
lateral connectivity
lateral continuity

freedom for water, sediments and biota to move between the channel and the floodplain/hillslopes

3.40
lateral movement
freedom for a river channel to move across a floodplain
3.41
longitudinal connectivity
longitudinal continuity
freedom for water, sediments and biota to move along the river channel
3.42
meander
one of a series of regular, sinuous curves along the course of a stream
3.43
planform
the geometric form of a river channel viewed from above
EXAMPLE Sinuous, straight.
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3.44
pool

distinctly deeper part of a river bed that is usually no longer than one to three times the channel’s

bankfull width, and where the hollowed river bed profile is sustained by scouring

3.45
pseudo-meandering

river with a meandering, baseflow channel, defined by alternate side bars within a less sinuous bankfull

channel
3.46
rapid

area of steep confined river bed composed of boulders and large cobbles, often organized into irregular

lines approximately perpendicular to the channel and partially or completely crossing the channel

width that are only exposed at low flow
3.47
reach

section of river along which boundary conditions are sufficiently uniform that the river maintains a

near consistent internal set of process–form interactions

Note 1 to entry: In some situations, chemical changes along the length of a river, as well as physical and

hydrological ones, could also be important in defining river reaches.
3.48
reinforcement

strengthening of river beds and banks for various purposes (e.g. ford construction, erosion control)

using materials such as boulders, sheet piling, geotextiles, etc
[SOURCE: EN 15843:2010, 3.21]
3.49
ridge and swale

arcuate, alternating floodplain features, where the ridge is a rising, elongated deposit and the swale is a

depression, which develop from scrolls as they are incorporated into the floodplain

3.50
riffle

fast-flowing shallow water area of a river bed with a distinctly broken or disturbed water surface over a

gravel/pebble or cobble substrate
3.51
riparian zone

transitional, semi-terrestrial area of land adjoining a river channel (including the river bank) that is

regularly inundated and influenced by fresh water and can influence the condition of the aquatic

ecosystem (e.g. by shading and leaf litter input and through biogeochemical exchanges)

Note 1 to entry: ‘Riparian corridor’ is the linear extension of this concept along a channel or reach length; in this

document, the term ‘riparian zone’ does not include the wider floodplain.
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3.52
ripple

small fine sediment (sand-silt) river-bed features of a few centimetres high, linear in plan, with a long

crest perpendicular to the flow
Note 1 to entry: See also ‘dune’.
3.53
river bed incision
process where a river has cut vertically to lower its bed
3.54
river channel cross profile

two-dimensional representation of river channel morphology perpendicular to the flow

3.55
river hydromorphological type

group of river channels displaying similar morphological and hydrological characteristics and their

associated processes
3.56
river long profile

two-dimensional representation of river bed topography, where bed elevation is plotted against

longitudinal distance downstream along the channel
3.57
restoration

establishment of natural physical processes (e.g. variation of flow and sediment movement), features

(e.g. sediment sizes and river shape) and physical habitats of a river system (including submerged, bank

and floodplain areas)
3.58
runoff

net discharge of water into the stream from surface-water and groundwater sources with losses

occurring from evapotranspiration and other consumptive uses
3.59
scour hole
scour pool

local, often deep, scouring of the river bed, exploiting weakness in bedrock or downstream of roughness

elements such as rock, boulder or wood steps
3.60
scroll

linear ridge deposit formed on point and counterpoint bars of meandering rivers, which, when

incorporated into the floodplain develop into ridges and swales
3.61
sediment transport

movement of sediment particles of a range of sizes by flowing water, which could include mobilization

and deposition
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3.62
sheet piling
material used for vertical bank protection
EXAMPLE Corrugated metal sheets.
3.63
sinuosity

distance from upstream to downstream along the channel centre line between two point, divided by the

distance along the valley course between the same points

Note 1 to entry: The two points need to span a sufficient distance to differentiate river channel from valley

curvature.
3.64
spatial unit
subdivision of a catchment at various geographical scales
EXAMPLE Catchment, landscape unit, valley segment, reach
3.65
stream power

rate of energy dissipation against the bed and banks of a river per unit downstream length, which when

divided by channel width gives the specific stream power
3.66
substrate
material making up the bed of a river
3.67
valley segment

section of river subject to similar valley-scale influences and energy conditions

3.68
wandering

transitional river planform between single-thread and multi-thread (braiding, anabranching),

displaying a single flowing thread within the bankfull channel that splits locally into two or more

threads separated by bars, or channels separated by permanently vegetated areas (islands)

3.69
watershed
line delimiting the outer topographic boundary of a catchment or drainage basin
3.70
weir

artificial structure across a river for controlling flow and upstream surface level, or for measuring

discharge
3.71
wetland

habitat occupying the transitional zone between permanently inundated, and generally dry,

environments
EXAMPLE Marsh, fen, shallow temporary water.
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EN 14614:2020 (E)
4 Principle

A standard protocol is described for recording the physical features and assessing the processes of river

channels, banks, riparian zones and floodplains. The range of features and processes to be taken into

account, and the methods used for assessment, might vary according to river character and the

objectives of the study. This document provides a common framework for these different methods.

Guidance is given on the characteristics that should be used for defining river hydromorphological

‘types’ (see Clause 3) and for further assessment of hydromorphological integrity through comparisons

with reference conditions. The document recognizes that rivers are dynamic, and observing the way

that they have changed in the past helps in understanding their present condition, how they might look

in a less modified (reference) state, and how they could change in the future. The selection of features

and processes for survey and assessment will depend upon geographical scale and on the purpose of

the exercise, with some suitable for characterizing river hydromorphological types, some for

assessment, and some for both.
5 Study context and requirements
5.1 Investigating hydromorphology across both space and time

The hydromorphological features of particular lengths or ‘reaches’ of river reflect the biogeographical

region in which they are located. These features vary along a river and over time in response to local

gradient, river flows, sediment movements, and vegetation colonization and growth, as well as human

interventions and pressures that disrupt or alter processes in the channel and in the wider catchment.

A river could be responding to several factors operating over different timescales. Many of the features

observed today are strongly influenced by characteristics and processes beyond the river reach, notably

across the surface of the river’s catchment and its different landscape units and also within the valley

segment that contains the reach. Therefore, it is important not only to identify features and proce

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