SIST EN 16870:2017

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Wasserbeschaffenheit - Anleitung zur Bestimmung der hydromorphologischen Eigenschaften von SeenQualité de l'eau - Préconisations pour la détermination du degré de modification des caractéristiques hydromorphologiques des lacsWater quality - Guidance standard on determining the degree of modification of lake hydromorphology13.060.10Voda iz naravnih virovWater of natural resources07.060Geologija. Meteorologija. HidrologijaGeology. Meteorology. HydrologyICS:Ta slovenski standard je istoveten z:EN 16870:2017SIST EN 16870:2017en,fr,de01-junij-2017SIST EN 16870:2017SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16870
February
t r s y ICS
r yä r x râ
s uä r x rä v w English Version
Water quality æ Guidance standard on determining the degree of modification of lake hydromorphology Qualité de l 5eau æ Guide pour la détermination des conditions hydromorphologiques des lacs
Wasserbeschaffenheit æ Anleitung zur Bestimmung der hydromorphologischen Eigenschaften von Seen This European Standard was approved by CEN on
v December
t r s xä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
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s x z y rã t r s y ESIST EN 16870:2017

Classification terms for 5 classes (Score band A) . 14 Table 5 — Classification terms for 3 classes (Score band B) . 14 Annex A (normative)
Characterization of lake modification based on hydromorphological features . 15 Table A.1 — Characterization of lake modification based on hydromorphological features . 16 Annex B (normative)
Alterations to mean annual water level range. 29 Table B.1 — Alterations to mean annual water level range . 29 Annex C (normative)
Land cover in the lake catchment . 31 Table C.1 — Land cover in the lake catchment . 31 Annex D (informative)
Case study examples . 32 D.1 Lago Maggiore (Italy) . 32 D.1.1 Summary description . 32 Figure D.1 — Location of Lago Maggiore . 32 D.1.2 Morphometric characteristics . 33 Table D.1 — Morphometric characteristics of Lago Maggiore . 33 D.1.3 Degree of modification using Annex A. 33 Table D.2 — Modification scores for Lago Maggiore, using reporting option 1 . 33 Table D.3 — Modification scores for Lago Maggiore using reporting options 2, 3 and 4 . 34 SIST EN 16870:2017

4: Produce a single score for the lake assessed Reporting overall hydromorphological modification of a lake without the detail. Take the mean of the 16 scores (see no. 1 in table). Round up or down to the nearest integer. Scores ending in ‘0,5’ 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. SIST EN 16870:2017

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 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. SIST EN 16870:2017

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.
Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use
Riparian zone N/A N/A N/A N/A N/A
Shore zone (see Annex B) (see Annex B) (see Annex B) (see Annex B) (see Annex B) 1. HYDRAULICS Open water zone Lake volume (includes residence time, stratification and mixing)
Feature not scored
1 = Near-natural. Very little or no change to lake volume 3 = Lake volume moderately altered 5 = Lake volume severely altered This attribute captures changes in three related phenomena: i) water volumes and throughflow, e.g. change to residence times; ii) water volume and depth relations that influence stratification behaviour and stability of thermal or density layering; iii) mixing behaviour within the water column. If stratification or mixing is substantially different from a suitable natural analogue, a score of 5 should be allocated. If there is any abstraction or augmentation from the lake or the catchment (e.g. for hydropower production) a score of 1 cannot be assigned. Water level time series; use of historical maps to show changes in planform, e.g. smaller equates to drawdown and reduced volume; modelling linked to catchment-scale water balance; Lake Habitat Survey (LHS) database; regular physico-chemical measurements at the deepest part of the lake; temperature and oxygen profiles; remote sensing data to indicate shoreline exposure; discussion with lake managers on whether there are water-mixing measures (e.g. aeration systems) 2. MORPHOMETRY Riparian zone N/A N/A N/A N/A N/A SIST EN 16870:2017

Table A.1 (Continued)
Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use
Slope profile of shore zone 1 = 0 % to 5 % of lake with non-natural slope profile. 2 =
> 5 % to 15 % of lake with non-natural slope profile 3 =
> 15 % to 35 % of lake with non-natural slope profile 1 = Near-natural slope profile. 3 = Slope profile near-natural throughout part of the lake. 5 = Slope profile non-natural in majority of lake; or lake completely or almost completely
Assessment of the change in slope profile is very difficult to do accurately without repeat survey. There is some scope to estimate change by using a section of the shoreline that is unmodified. Alternatively, a change in slope profile might be indirectly inferred from: If using LHS, the following sections of the survey form will help to infer changes: (i) ‘Bank face erosion’ and ‘Signs of erosional or depositional imbalance’ from section 2.2 – Hab-Plot Attributes, Exposed Shore. (Use the median value of the range, e.g. for a score of 2
Shore zone
4 =
> 35 % to 75 % of lake with non-natural slope profile 5 =
> 75 % of lake with non-natural slope profile modified. (i) imbalances in shore erosion or deposition; (ii) historical changes to water level elevation and planform (because the shore zone is located in a different section of the landscape); (iii) presence of hard bank engineering (because of increased reflection of waves and associated scour and deposition). In the case of artificially dug lakes the natural slope is taken to be that of similar-sized lakes, once geomorphological processes
(>10 %–40 %), assume 25 % of the bank length is eroding); (ii) ‘Bank erosion’ from section 3.1 – Whole Lake Assessment, Lake Perimeter Characteristics. (Use the median value of the range); (iii) ‘Height water level raised or lowered’ from section 4 – Hydrology; (iv) ‘Predominant bank material’, ‘Bank face modification(s)’and ‘Predominant shore forming material’ from section 2.2 – Hab-Plot Attributes, Exposed Shore.
Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use
have been formative. Historical changes to water level elevation and planform may also be inferred from field evidence of historically higher lake levels or comparison of historical and contemporary maps or aerial photographs.
Planform
1 = 0 % to 5 % of lake with non-natural planform. 2 =
> 5 % to 15 % of lake with non-natural planform 3 =
> 15 % to 35 % of lake with non-natural planform 4 =
> 35 % to 75 % of lake with non-natural planform 5 =
> 75 % of lake with non-natural planform 1 = Near-natural planform. 3 = Planform near-natural throughout part of the lake. 5 = Planform non-natural in majority of lake; or lake completely or almost completely modified. The comparison of lake areas shall be based on a consistent datum, such as mean maximum water level within the historical observation period, or the mean minimum water level, combined with information on bathymetry. Potential data sources are listed in EN 16039:2011, 6.3.
Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use Open water zone Depth distribution
Feature not scored 1 = Depth distribution reflects near-natural condition. 3 = Depth distribution reflects moderate departure from near-natural condition. 5 = Depth distribution is artificial
Need information on the mean surface area of the lake and the depth per % of the area. Need information on mode of formation. Accurate assessment of the degree of modification of depth distribution is very difficult without repeat surveys of bathymetry. It is anticipated that assessments will become easier in future when new methods of measurement are developed. Alternatively, modifications might be indirectly inferred from historical changes to water level elevations and planform. Direct assessments of change might be made using hydro-acoustic data, remote sensing, profile data, interpolation program, bathymetric data or GIS applications. Indirect assessments may be made using LHS data from section 4 – Hydrology, ‘Height water level raised or lowered’, or by comparison of historical and contemporary maps or aerial photographs.
Riparian zone N/A N/A N/A N/A N/A SIST EN 16870:2017

Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use 3. BEDFORMS/ LANDFORMS AND SUBSTRATE Shore zone Landform and substrate characteristics (erosion/deposition character) 1 = 0 % to 5 % of lake with evidence of non-natural erosion or deposition 2 =
> 5 % to 15 % of lake with evidence of non-natural erosion or deposition 3 =
> 15 % to 35 % of lake with evidence of non-natural erosion or deposition 4 =
> 35 % to 75 % of lake with evidence of non-natural erosion or deposition 5 =
> 75 % of lake with evidence of non-natural erosion or deposition
1 = Erosion/deposition features reflect near-natural conditions 3 = Erosion/deposition features reflect moderate departure from near-natural conditions 5 = Erosion/deposition features conspicuously different from those expected under near-natural conditions
In-lake features comprise depositional features (e.g. steps, bars, islands), and erosional features (e.g. cliffs) and also features such as cushions of aquatic plants, large wood, etc. The significance of these features depends on the characteristics of the shoreline (e.g. slope, substrate, inflows). Where significant amounts of erosion and/or deposition are recorded it is important to distinguish one from the other, so that appropriate management can be put in place. Sediment core samples could be taken if further investigation is required to better understand the sedimentation regime. In some cases extensive non-natural deposition can cause embeddedness of substrate material. Hydromorphological surveys; databases; aerial photos. When using LHS survey data recorded erosion on the whole lake survey section will give % of shoreline affected. This information can be checked using records in Hab-Plots section 2.2 – Shorezone; Bankface which has a line where any erosion is recorded. This is indicated on the form as ‘ER’ and can be used as an indicator of erosion.
Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use
Bank structure and modifications – extent of artificial bank material (% of shore perimeter) 1 = Banks affected by 0 % to 5 % hard or 0 % to 10 % soft engineering. 2 = Banks affected by > 5 % to 15 % hard, or > 10 % to 30 % soft engineering. 3 = Banks affected by > 15 % to 25 % hard or > 30 % soft engineering. 4 = Banks affected by > 25 % to 50 % hard engineering. 5 = Banks affected by > 50 % hard engineering. 1 = Near-natural. No, or minimal, presence of artificial material 3 = Small to moderate presence of artificial material 5 = Extensive presence of artificial material
If modified bank materials are ‘natural’ (e.g. willow spiling) maximum score is 3. Assessment of extent of bank affected is based on predominant material present (may be a mix of two types) Hydromorphological surveys (e.g. LHS); databases; aerial photos If using LHS, key Hab-Plot data include Section 2.2 – Bank Face: ‘predominant bank material’ and ‘bank face modifications’; Beach: ‘predominant shore forming material’ SIST EN 16870:2017

Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use
Littoral substrate – extent of artificial material/ imported natural substrate 1 = 0 % to 1 % artificial material/imported natural substrate 2 =
> 1 % to 5 % artificial material/imported natural substrate 3 =
> 5 % to 15 % artificial material/imported natural substrate 4 =
> 15 % to 30 % artificial material/imported natural substrate 5 =
> 30 % artificial material/imported natural substrate 1 = Near-natural. No, or minimal, presence of artificial material 3 = Small to moderate presence of artificial material 5 = Extensive presence of artificial material
Artificial materials include brick-laid stone, concrete, geotextiles, etc. The percentage assessed is expressed as a proportion of the perimeter length and not as a proportion of the overall area of the littoral zone. Imported natural substrate refers to natural substrate types (e.g. gravel, sand, boulders) deliberately placed in areas of a lake where they would not naturally occur (e.g. large stone slabs positioned around the lake shore to prevent bank erosion). Record only natural substrates: mud, silt, sand, pebbles, gravel, stones, rocks, organic substrates. NOTE: The natural range of substrates is lake type- and site-specific. Hydromorphological surveys (e.g. LHS); records made during biological sampling; databases; aerial photos If using LHS, key Hab-Plot data include Section 2.3 Littoral zone: ‘predominant littoral substrate’ and ‘recent sedimentation over natural substrate’
Open water zone Lake bottom bedforms Feature not scored 1 = Near-natural bedforms 3 = Bedform changes throughout part of the lake/basin 5 = Bedforms changed in majority of the lake/basin This includes assemblage of natural bedform features (e.g. dunes, scour holes) and their associated properties (texture, structure). Activities such as dredging for navigation may be expected to influence bedforms. In lakes undergoing eutrophication increased Bathymetric survey; sidescan sonar; grab samples, coring to provide information on changes to sedimentation rates; sedimentation traps; data from SCUBA surveys SIST EN 16870:2017

Features Score band A – Quantitative Score band B –
Qualitative Guidance Examples of methods/ data use sedimentation may also influence bedform structure. Extent of artificial material/imported natural substrate 1 = 0 % to 1 % artificial material/imported natural substrate 2 =
> 1 % to 5 % artificial material/imported natural substrate 3 =
> 5 % to 15 % artificial material/imported natural substrate 4 =
> 15 % to 30 % artificial material/imported natural substrate 5 =
> 30 % artificial material/imported natural substrate 1 = Near-natural. No, or minimal, presence of artificial material 3 = Small to moderate pr
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