SIST EN 16870:2017

SLOVENSKI STANDARD
oSIST prEN 16870:2015
01-julij-2015
.DNRYRVWYRGH1DYRGLOR]DGRORþDQMHKLGURPRUIRORãNLKSRJRMHYYMH]HULK
Water quality - Guidance standard on determining the hydromorphological conditions of
lakes
Wasserbeschaffenheit - Anleitung zur Bestimmung der hydromorphologischen
Eigenschaften von Seen
Qualité de l'eau - Guide pour la détermination des conditions hydromorphologiques des
lacs
Ta slovenski standard je istoveten z: prEN 16870
ICS:
07.060 Geologija. Meteorologija. Geology. Meteorology.
Hidrologija Hydrology
13.060.10 Voda iz naravnih virov Water of natural resources
oSIST prEN 16870:2015 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 16870:2015

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oSIST prEN 16870:2015

EUROPEAN STANDARD
DRAFT
prEN 16870
NORME EUROPÉENNE

EUROPÄISCHE NORM

May 2015
ICS 07.060; 13.060.45
English Version
Water quality - Guidance standard on determining the
hydromorphological conditions of lakes
 Wasserbeschaffenheit - Anleitung zur Bestimmung der
hydromorphologischen Eigenschaften von Seen
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16870:2015 E
worldwide for CEN national Members.

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Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .6
3 Terms and definitions .6
4 Principle .9
5 Determining the hydromorphological condition of lakes . 10
5.1 Feature categories . 10
5.2 Procedure for scoring . 10
6 Interpreting and reporting hydromorphological modifications . 11
6.1 Modification scores . 11
6.2 Assigning classification terms . 12
Annex A (normative) Characterization of lake modification based on hydromorphological
features . 14
Annex B (normative) Alterations to mean annual water level range . 25
Annex C (normative) Land cover in the lake catchment . 27
Annex D (informative) Case study examples . 28
D.1 Lake Maggiore (Italy) . 28
D.1.1 Summary description . 28
D.1.2 Morphometric characteristics . 29
D.1.3 Degree of modification using Annex A. 30
D.1.4 Conclusions . 31
D.2 Lake Bidighinzu (ITALY) . 31
D.2.1 Summary description . 31
D.2.2 Morphometric characteristics . 32
D.2.3 Degree of modification using Annex A. 33
D.2.4 Conclusions . 34
D.3 Lake Lidzbarskie (Poland) . 34
D.3.1 Summary description . 34
D.3.2 Morphometric characteristics . 35
D.3.3 Degree of modification using Annex A. 36
D.3.4 Conclusions . 37
D.4 Lake Velenje (Slovenia) . 37
D.4.1 Summary description . 37
D.4.2 Morphometric characteristics . 38
D.4.3 Degree of modification using Annex A. 39
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D.4.4 Conclusions . 40
D.5 Arkanj Lake (Serbia) . 40
D.5.1 Summary description . 40
D.5.2 Morphometric characteristics . 41
D.5.3 Degree of modification using Annex A . 42
D.5.4 Conclusions . 42

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Foreword
This document (prEN 16870:2015) 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.
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Introduction
This European Standard will enable broad comparisons to be made of the hydromorphological condition of
lakes throughout Europe (e.g. for reporting by the European Environment Agency). In this document the word
‘lake’ is used as a generic term for standing waters including natural lakes, reservoirs, excavated pits and
other artificial water bodies.
The Guidance standard for assessing the hydromorphological features of lakes (EN 16039) describes a
protocol for survey (field and remote sensing methods) and feature recording, whereas this standard gives
guidance on assessing the condition of those features, and focuses especially on human pressures that affect
lakes. This standard has applications for nature conservation, environmental impact assessment, lake
management, and guiding lake restoration work.
The assessment of lake ‘quality’ in Europe has evolved over the past decades from its focus on chemical
conditions to a more comprehensive ecological approach. The EC Water Framework Directive (WFD) has
reinforced the need for this broader view of lake ‘quality’ through its requirement for determining ‘ecological
status’ based on phytoplankton, phytobenthos, macrophytes, invertebrates and fish. The Directive also
requires hydromorphological and physico-chemical conditions to be suitable for supporting biological
communities. This standard, therefore, may be helpful for implementing the WFD when indicating the extent to
which pressures might have caused a departure from natural hydromorphological conditions. In doing so it
complements methods that have been developed within particular countries for assessment and reporting
under the WFD. However, this standard makes no links between hydromorphology and biology, nor does it set
any hydromorphological condition targets that should be achieved. Whereas decisions on management for
individual lakes require expert local knowledge and vary according to lake type, this standard provides a
framework to help those decisions to be made consistently.
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1 Scope
This European Standard provides guidance on determining the degree of modification of lake
hydromorphological features described in EN 16039. It enables consistent comparisons of hydromorphology
between lakes within a country and between different countries in Europe, providing a method for broad based
characterization across a wide spectrum of hydromorphological modification. Its primary aim is to assess
‘departure from naturalness’ for a given type of lake as a result of human pressures, and it suggests suitable
sources of information that may contribute to characterizing the degree of modification of hydromorphological
features. For wholly artificial lakes or reservoirs formed by damming rivers the aim is to assess the extent to
which processes approximate to those in comparable natural water bodies. However, this standard does not
replace methods that have been developed within particular countries for local assessment and reporting.
Decisions on management for individual lakes require expert local knowledge and vary according to lake type.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 15843, Water quality - Guidance standard on determining the degree of modification of river
hydromorphology
EN 16039, Water quality - Guidance standard on assessing the hydromorphological features of lakes
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bank
physical edge of the lake shore, or of the island(s) within, generally defined by a wave-cut break in slope at or
near the water’s edge of the lake, but can also be defined as the line along which riparian (terrestrial or land)
conditions change to littoral in-lake conditions
[SOURCE: EN 16039:2011, definition 3.3]
3.2
bar
discrete, natural, depositional feature with shallow slope into water composed of unconsolidated material
3.3
bathymetry
systematic survey of size, shape and water depth distribution in a lake
Note 1 to entry: Bathymetry is the basis of deriving morphometric parameters and to predict thermal stratification,
residence time and sediment redistribution processes.
[SOURCE: EN 16039:2011, definition 3.5]
3.4
catchment
drainage basin contributing water and sediment into a lake (also recognised as drainage area)
[SOURCE: EN 16039:2011, definition 3.10]
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3.5
connectivity
continuity
uninterrupted movement of water, sediment and organisms into, out of and within a lake system
[SOURCE: EN 16039:2011, definition 3.11]
3.6
drawdown
lowering of lake levels caused by deliberate water release
3.7
dune
underwater ridge formed by wave or current action on the lake bed
3.8
ecological status
expression of the quality of the structure and functioning of aquatic ecosystems, by comparing the prevailing
conditions with reference conditions
Note 1 to entry: As classified in accordance with Annex V of the EC Water Framework Directive.
3.9
embeddedness
extent to which fine sediment infiltrates littoral gravels
3.10
gauging board
staff gauge
graduated scale, fixed to a lake outlet or inflow structure, or directly into the substrate, used to measure the
water level in a lake
3.11
geotextile
permeable fabric often used to reinforce or protect banks
3.12
groundwater table
surface of a body of underground water below which the soil or rocks are permanently saturated with water
3.13
hard engineering
stabilization of the shoreline using ‘hard’ materials including concrete walls, gabion baskets and sheet piling
3.14
hydromorphology
physical and hydrological characteristics of lakes including the underlying physical processes from which they
result
[SOURCE: EN 16039:2011, definition 3.22]
3.15
island
landform protruding from the surface of a lake
[SOURCE: EN 16039:2011, definition 3.26]
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3.16
lake stratification
variations in water column structure with respect to temperature and density
[SOURCE: EN 16039:2011, 3.30]
3.17
littoral zone
habitat extending from the water’s edge to the lakeward limit of rooted macrophytes or algae on the lake bed
[SOURCE: EN 16039:2011, definition 3.33]
3.18
pelagic zone
open water zone extending from the littoral zone towards the centre of a lake
[SOURCE: EN 16039:2011, definition 3.41]
3.19
planform
view of lake shape from above, e.g. elongate, circular, etc., and also relevant in relation to the shoreline
development index which expresses the degree of irregularity of a lake compared with a circular form of the
same area
[SOURCE: EN 16039:2011, definition 3.42]
3.20
profundal zone
deeper parts of the lake where light does not penetrate and there is no photosynthetic activity
3.21
ramping rate
rate of rise and fall of water levels often associated with hydropower generation
3.22
remote sensing
group of techniques for acquiring data on land forms and land cover (e.g. aerial photographs, satellite
imagery, radar, sonar)
3.23
residence time
retention time
time for water in a lake to be replaced, which can be calculated in a range of ways (e.g. instantaneous,
seasonal, annual) and may be applied to the entire lake, to individual lake basins or to strata within the lake
3.24
riparian zone
area of land adjoining the lake capable of directly influencing the condition of the aquatic ecosystem (e.g. by
shading and leaf litter input)
[SOURCE: EN 16039:2011, definition 3.45]
3.25
scour hole
depression in the lake bed created by wave or current action
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3.26
shore zone
littoral zones around the perimeter of a lake, including the bank
3.27
sidescan sonar
sonar scanning obliquely onto the lake bed used to characterize lake-bottom features
3.28
soft engineering
stabilization of the shoreline using ‘soft’ materials including basket-work, planted saplings and live willow,
dumped natural debris (to re-nourish sediment supply) and degradable synthetic materials. Also includes
earth-moving where re-sectioning and re-profiling takes place
3.29
step
feature of erosion where a lake bank or an old depositional bar has been eroded to create distinct edges
(steps) into water. Several steps can develop down the shore to reflect different periods of erosion at times of
different water level
3.30
substrate (substratum)
natural sediment or engineered surfaces comprising the shore and bed of a lake. Natural sediments are
generally characterised by texture and organic matter content, while artificial substrates are described by their
construction materials
[SOURCE: EN 16039:2011, definition 3.49]
3.31
tracer experiment
one of a group of hydrogeological field techniques used to quantify groundwater flow
3.32
water balance
flow of water into and out of a lake (e.g. groundwater, rain water, evaporation)
3.33
wetland
transitional zone between permanently inundated, and generally dry, environments, e.g. marshes (wet ground
without peat), fens (groundwater fed peats) and bogs (rain-fed peat systems)
[SOURCE: EN 16039:2011, definition 3.52]
3.34
willow spiling
method of soft engineering used to strengthen lake shores using retaining walls constructed of woven willow
stems from which trees will sprout
4 Principle
A standard protocol is described for assessing the degree of modification of the hydromorphological features
of different lake zones. Both this European Standard and EN 16039 focus attention on lake features as
surrogates for lake processes. Those making assessments, therefore, do not need to be trained
geomorphologists although some geomorphological input may be useful. To ensure consistency in approach,
the main feature categories are in general the same as those in EN 16039. However, some minor adjustments
have been made to the details to help facilitate scoring.
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5 Determining the hydromorphological condition of lakes
5.1 Feature categories
Assessments are made for the feature categories listed in EN 16039, with subdivisions into specific features
where appropriate (Table 1).
Table 1 — Features to be assessed when determining the hydromorphological condition of lakes
Feature category Feature
1. Hydraulics Water level variability
Lake volume
2. Morphometry Slope profile of shore zone
Planform
Depth distribution
3. Bedforms/Landforms and Landform and substrate characteristics
Substrate
Bank structure and modifications
Littoral substrate
Lake bottom bedforms
Extent of artificial material/imported natural substrate
4. Connectivity and Natural exchange with groundwater
Continuity
Connectivity of lake with adjacent riparian wetlands
Natural erosion/deposition patterns
Natural exchange between groundwater and surface water
Migratory movement
Sediment transport
5. Aquatic Vegetation Human disturbance or active management of aquatic vegetation (shore zone)
Human disturbance or active management of aquatic vegetation (open water
zone)
6. Land Cover Land cover in riparian zone
5.2 Procedure for scoring
5.2.1 Users should note whether the lake being assessed is natural (N), heavily modified (H) or artificial
(Ar). Annex A sets out guidance on how to allocate scores for each feature category. It contains two separate
procedures for scoring – using score band A with quantitative data, or score band B with qualitative data.
Score band A is a 5 point scale (1 = lowest degree of modification, 5 = highest degree of modification). Score
band B is a 3 point scale (1, 3, 5; following the same general approach as for score band A). Quantitative data
should always be used where available; where there are quantitative data for some of the features but not for
all, a mix of quantitative and qualitative data may be used. Users should state which scores have been
assigned based on quantitative data and which on qualitative descriptions, as this determines the degree of
confidence in the assessment. This note should also be added to any maps produced that show the results of
lake hydromorphological assessment.
5.2.2 Where the majority of scores have been derived from 5 band scales users may wish to retain the five
bands. Where the majority have been derived from 3 band scales users may wish to change the 5 band
scores to 3 band scores as follows, making clear in the results which scores have been changed in the way
given in Table 2.
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Table 2 — Conversion table
5-band score 3-band score
1 1
2 1
3 3
4 5
5 5
5.2.3 For those features where scoring 1 = 0 % to 5 % change, an asterisk should be added (i.e. 1*) where
the recorded change is only 0 % to 1 %. This is to highlight lakes with extremely low levels of modification. A
☠ symbol should be added (i.e. 5☠) to indicate extreme levels of modification.
5.2.4 The importance of each of the features in Annex A for hydromorphological and ecological functioning
will not be the same. However, at present there is insufficient scientific evidence to justify differential weighting
of the scores allocated.
5.2.5 Three additional annexes are included in this document. Annex B provides information to support
interpretation of the scoring system for the ‘water level variability’ feature. Land cover in the wider catchment
(Annex C) is included so that this information can be collated in order to provide context for the scored
assessment of a lake. (This is undertaken as a separate assessment and does not form part of the
hydromorphological assessment of the lake itself.) Annex D provides case studies to help in understanding
and interpreting the overall scoring system. These examples include a description of the lake, a map or
photograph(s), a summary of the scores with some interpretation, and a short conclusion.
6 Interpreting and reporting hydromorphological modifications
6.1 Modification scores
6.1.1 Scores should be reported as shown in Table 4. This process provides a range of options for different
purposes, but shows clearly how each of the three combined scores (options 2, 3 and 4 in Table 4) has been
derived.
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Table 3 — Options, applications and procedures for reporting hydromorphological modification
scores
Reporting option Examples of applications Procedure
1: Tabulate 16 scores Providing maximum amount of Score as in Annex A for all
separately information for lake management. features; do not combine.
2: Create a 2-digit code Reporting lake modification within the Combine the scores for category 1
two main hydromorphological quality to create a single mean score for
elements given in the WFD hydrological regime (the first of the
(hydrological regime, morphological two digits). Scores should be
conditions) but with no attempt to link rounded up or down to the nearest
hydromorphology with biology. integer (rounding up any that end
in .5).
Combine the scores for categories
2–6 to create a single mean score
for morphological conditions (the
second of the two digits). Scores
should be rounded up or down to
the nearest integer (rounding up
any that end in .5).
[For example, a code of 1,1 would
indicate a lake with near-natural
hydrology and with the lowest
degree of morphological
modification.]
3: Group features according to Reporting on the three main lake Feature categories should be
zone zones: open water pelagic/ profundal grouped and mean scores
zone, shore zone and riparian zone, calculated for the three zones.
as recommended in EN 16039. Scores should be rounded up or
down to the nearest integer
(rounding up any that end in .5).

4: Produce a single score for Reporting overall hydromorphological Take the mean of the 16 scores
the lake assessed modification of a lake without the (see no. 1 in table). Round up or
detail. down to the nearest integer.
Scores ending in ‘.5’ should be
rounded up.
6.2 Assigning classification terms
6.2.1 Where five classes are used, the terms in Table 4 should be assigned to descriptions of
hydromorphological modification, and represented (if required) on a map using the colour codings
recommended in EN 16039:
Table 4 — Classification terms for 5 classes (Score band A)
Score Class Description Map colour
1 to < 1,5 1 Near-natural Blue
1,5 to < 2,5 2 Slightly modified Green
2,5 to < 3,5 3 Moderately modified Yellow
3,5 to < 4,5 4 Extensively modified Orange
4,5 to 5,0 5 Severely modified Red
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6.2.2 Where three classes are used, the terms in Table 5 should be assigned to descriptions of
hydromorphological modification, and represented (if required) on a map using the following colour codings:
Table 5 — Classification terms for 3 classes (Score band B)
Score Class Description Map colour
1 to < 2,5 1 Near-natural to slightly modified Blue
2,5 to < 3,5 3 Slightly to moderately modified Yellow
3,5 to 5,0 5 Extensively to severely modified Red
6.2.3 The names used to describe each class (e.g. ‘near-natural’) have been deliberately chosen to be
different from terms used in the WFD (e.g. ‘high’, ‘good’) to emphasize that classifications using this standard
are unrelated to classifications of ecological status for the WFD. Although the five colours listed in 6.2.1 for
reporting hydromorphological modification are the same as those in the WFD, they are also used routinely for
reporting other (non-WFD) aspects of environmental quality.
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Annex A
(normative)

Characterization of lake modification based on hydromorphological
features
When assessing artificial water bodies it may be possible to make a comparison with natural water bodies of a
similar size and in a similar landscape setting, either in the same area or in areas remote from the artificial
water body, but where a similar set of natural lake processes are operating. Alternatively, it may be possible to
assess whether lake processes in the artificial water body have become naturalized by looking for evidence of
historical water levels and depositional or erosional imbalances. Such evidence might also be obtained from
modelling lake volumes, inflows and outflows, or by modelling lake landform evolution in response to the
prevailing energy regime.
Land cover in the wider catchment should also be assessed, using the guidance in Annex C, in order to
provide context for the scored assessment of a lake. This should be undertaken as a separate assessment
and should not be part of the hydromorphological assessment of the water body itself.

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Table A.1 — Characterization of lake modification based on hydromorphological features
Features assessed Score band A – Score band B – Guidance Examples of methods/

Quantitative Qualitative data use
N/A N/A N/A N/A N/A
(see Annex B) (see Annex B) (see Annex B) (see Annex B) (see Annex B)
Lake volume (includes Feature not scored 1 = Near-natural. Very little This attribute captures Water level time series;
reside
...