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Background to the PFRA European Overview – UC10508

The individual Member State Reports reflect the situation as reported

by the Member States to the European Commission in 2014

The situation in the MSs may have altered since then

Assessment of Flood Hazard and Flood Risk Maps

Member State Report: SI - Slovenia

26 November 2014

Information reported and assessed

The schemas for electronically reporting/making information available to the Commission were filled in

with a detailed level of information. Slovenia made available links to its national flood risk and flood

hazard maps for its 2 units of management. Detailed summaries were provided on the methods used

to prepare the maps and specific details of national maps for visualisation at the European level were

also reported. No links to other relevant information on the preparation of the maps were provided.

This report is structured according to a questionnaire that was completed for all Member States that

reported on their flood hazard and risk maps. Questions 2 and 3 of the questionnaire were answered

on the basis of a qualitative check of a subset of the Member State’s flood hazard and flood risk maps

located on national servers and/or web pages. All other questions (question 1 and questions 4 to 11)

were answered on the basis of an assessment of numeric and summary information reported by the

Member State on the methods used in the preparation of their maps. The report does not include in-

depth assessment of national background methodological reports which may have been referenced in

the Member State’s reports and/or provided with their electronic reports.

This report includes information on what the Member State has included/considered or not

included/considered in its flood risk and hazard maps and their development. This is a presentation of

the facts on the electronic information reported to WISE by Member States and does not discuss

which elements are mandatory according to the Directive and which are optional.

Maps of flooding in Slovenia are available at two web portals: “Atlas okolja” and “Atlas voda”. This

assessment is based on the maps provided via the web portal “Atlas okolja”. The maps on “Atlas

voda” were also checked but, at the time, they were the same as those in the “Atlas okolja”.

Main outcomes of the assessment

a) Good practices adopted:

The maps that are provided via the web portal, “Atlas okolja”, the governmental official

database and an interactive map viewer, which is accessible to general public, is a great

tool. The database is downloadable in different formats. One can view data and prepare

maps of different kind and scale and print them directly from the application. It is intended

for professional (e.g. by local authorities, environmental assessment studies, flood risk

management planning) as well as general public use, as well as for public awareness.

The topic of floods is generally covered by five types of maps (information) on a state level:

Map of APSFRs (developed 2012, published 2013) with some numeric information on

potential adverse consequences associated to the APSFR areas (Flood Risk

elements).

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Flood hazard maps (last update 2013 or 2014)1; Flood hazard maps are very detailed

and presented in two forms: (1) probability of flood events (for Q10, Q100, Q500) and

(2) presenting classes of flood hazard (4 classes). Specific common methodology on

a state level is decreed in 2007 and since that time, these maps are produced

through different studies and placed on a common platform.

Warning map of floods (“Opozorilna karta poplav”) - last update 2007; old general

flood hazard map developed from information that was gathered from maps and

various other sources.

Flood event maps for floods from 1980 to 2010

Other maps: Infra-red aerial photo of floods in 2010 for Ljubljana

b) Weaknesses:

Flood hazard maps are prepared according to specific common methodology on a state

level that is decreed in 2007 and, since that time, these maps are produced through

different studies and placed on a common platform. Not all APSFRs are covered by these

studies. This is because they are produced when there is a need for planning something

in the flood area or close to it. So the level of accuracy differs from case to case, from

study to study, but in general it is very good (minimum required scale is 1:5,000 and up to

scale 1:1,000 or more). Besides that, each study has to be approved by the state office

and then it is integrated into the state database. However, one APSFR can be covered by

several such separate studies, or some parts of the APSFRs are not covered at all.

Through time, this weakness will be dealt with.

Numeric information on potential adverse consequences is associated with the APSFRs

as part of the APSFR map (the layer showing only the extent of APSFR). Some of the

required topics are missing.

The SI Authorities subsequently indicated that the statistics on the number of inhabitants

potentially affected were produced for the PFRA but not the mapping of flood risk.

However the number of potentially affected inhabitants by medium probability floods was

provided for some of maps reported to WISE for some but not all APSFR: for others the

number was reported as “yet to be measured”.

There is no distinction among different flood sources (fluvial, pluvial, sea-water,

groundwater, etc.). They are all presented as one integral flood layer (with different return

periods) in the maps. The SI authorities subsequently reported that the flood hazard

maps sometimes include information about flood extent of other flood sources.

c) Lessons to be learnt:

Implementing a specific common methodology on a state level for preparing flood hazard

maps (decreed in 2007), and making it mandatory for each development plan or project

that can have an impact on floods, is a good way of optimising the available resources.

1 Subsequent to the assessment, the SI authorities commented that the maps were updated in early

2015 and that the integrated maps would be updated in summer 2015. The maps that were subject to the assessment were last updated in 2013 or 2014.

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Subsequent to the assessment, the SI authorities stated that more detailed and more

accurate flood hazard maps and flood risk maps for certain APSFRs are under

construction.

d) Questions seeking clarification from Member State. Subsequent to the assessment, the SI

authorities responded to the questions, as shown below:

1. "Source: 3030, 3021, 3067 and 3129" or some other numbers are written on hazard

maps right after the title of a map. This seems to refer to the source of information. What

are these codes? Do they refer to the separate studies? Please explain.

SI response: These numbers refer to internal codes of individual hydrologic-hydraulic

studies, which were allocated at the Institute for Water of the Republic of Slovenian

Environment Agency (SEA/ARSO) in the process of reviewing the compliance of studies

with methodological rules (in the process of obtaining the water consent). Studies

represent a data source for preparing data layers with flood extent lines, depths classes,

hazard classes and the area covered by the validated results. If any individual APSFR is

overlapped by the areas covered by more than one study, the results for each study are

combined according to uniform rules to derive the combined flood extent lines, depths

and hazard classes. The hazard map also lists codes of individual studies, as through

them it is possible to trace the emergence of individual lines of hazard classes.

2. One APSFR is covered by several separate areas where the calculated data is correct.

(map provided in the LinkToMS schema). These areas refer to the results of different

studies. Why isn’t one APSFR entirely covered by one such study?

SI response: Individual hydrologic-hydraulic (flood) studies are prepared in accordance

with the provisions of the methodological rules (2007) and, since 2008, have been used in

the procedures for obtaining the water consent as a basis for the conditions and limits for

the implementation of activities and interventions in flood areas. The whole area of

APSFR is therefore covered by the results of several studies that have been merged and

coordinated in a joint map for each APSFR.

3. What are the differences among the layers (event scenarios with return period 10, 100,

500 years) that are used in the Flood Hazard maps presented through the LinkToMS

schemas and the Flood Hazard maps presented through "Atlas okolja" via web portal

http://gis.arso.gov.si/atlasokolja/profile.aspx?id=Atlas_Okolja_AXL@Arso, which is

available to general public?

SI response: In principle, the difference is only in the digital format (charts (PDF format)

and data layers (SHP format)). Data on Flood Hazard maps in PDF format are consistent

with the data layers on Integrated Flood Hazard maps in SHP format, published on the

Environmental Atlas and Water Management Atlas, of course taking into account the

timing of producing the maps and updating the layers.

4. Are there any differences in numeric information between the Flood Risk maps in the

LinkToMS schema and the numeric information on potential adverse consequences

associated to the APSFR areas in the "Atlas okolja"?

SI response: Statistics of people at risk of flooding in APSFRs obtained in the Preliminary

flood risk assessment is made on the basis of methodological guidelines and data layers

other than the ones used for preparing Flood Hazard maps for the years 2011-2013, so

there are some differences in numerical information. Statistics in APSFRs were prepared

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within a non-generalised polygon of network cell size of 75 m, where certain types of at-

risk people were selected on the basis of data layers used in the preparation of

classification of flood-risk areas maps. For flood risk maps a set of potential at-risk people

was slightly modified, as shown in the legend on the map. In particular, the statistics of at-

risk people refer to the whole area covered by the validated results of all studies that are

at least partially located in the area of potentially significant flood risk, i.e. the area of

flood risk is significantly expanded.

5. For Piran (APSFR SI5_42) and Dravograd (APSFR SI3_08) there is no other

information available except for the Areas of Potentially Significant Flood Risk and

associated numeric information on potential adverse consequences. Is that true and why?

SI response: For APSFR SI5_42 Piran Flood Hazard maps and Flood Risk maps are

prepared and available on the Water Management Atlas and on the Environmental Atlas

(with a click to APSFR/OPVP, links to individual maps in a PDF file are opened). They are

also available through an Excel spreadsheet on MESP’s web site:

http://www.mop.gov.si/fileadmin/mop.gov.si/pageuploads/podrocja/voda/opvp/OPOPO.xls

A detailed Flood Hazard map Q100 for APSFR Piran is available on:

http://www.mop.gov.si/fileadmin/mop.gov.si/pageuploads/podrocja/voda/opvp/OPVP_Si_

KPO/ogrozenost_Q500_Piran.pdf

In addition, links to maps for APSFR Piran are included in the updated reporting forms.

For APSFR SI3_08 Dravograd, the estimated potential consequences of flooding

(number of inhabitants, number of employees, number of cultural monuments, number of

IPPC and SEVESO facilities, etc.) are within the layer APSFR/OPVP. Within the Flood

Indication Map Flood Hazard is mapped with less precision.

In the area of Dravograd construction and implementation work of EU cohesion project

Drava is ongoing (for period 2007-2023), which significantly alters the hydrologic and

hydraulic situation in the area.

6. It seems that there is no distinction amongst the sources of floods (fluvial, pluvial,

groundwater, sea water, etc.). Are there or will there be separate layers prepared for each

relevant source of floods?

SI response: Preparing separate data layers depending on the source of flooding is not

foreseen; there are currently only divisions between the flooding of watercourses and

flooding of the sea and lakes. In the case of overlapping of the flood extents from the two

sources, a common area with validated results and combined flood extent lines, depths

and hazard classes is prepared by the uniform rules (e.g. APSFR Izola and APSFR

Koper).

7. How and when are the separate layers of information updated (in "Atlas okolja")?

SI response: Integral maps on the Water Management Atlas and the Environmental Atlas

(Integral flood hazard map, Integral flood hazard classes map and Integral map of water

depth at Q100) are updated approximately every 6 months. Flood risk maps and Flood

events maps are updated every 6 years; the same goes for Areas of potentially significant

flood risk and Flood Risk maps.

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8. The classes of Flood hazard are not explained in the "Atlas okolja". There is just a

reference to the methodology that was decreed. Should there be an explanation of

classes in terms of depth of water, etc.?

SI response: Flood hazard classes are explained in more detail in the metadata of each

layer (flood hazard class) under iKRPN Si (integrated flood hazard classes maps), so is,

for example class of high flood hazard explained in metadata at the web address:

http://gis.arso.gov.si/geoportal/catalog/search/resource/details.page?uuid={9C5CAEE4-

42FA-48E9-A79A-E98A186CAA29}

where it is written in the abstract:

On the basis of criteria which classify the strength of the flood flow at the same probability

of occurrence of the event, flood hazard areas are graded into flood hazard classes, with

the decisive criterion of one, which shows the greatest hazard class. The planar spatial

objects represent volume of significant flood hazard areas class (Pv), where the water

depth is same or greater than 1.5 m at the flow of Q100 or surface G100 or the product of

depth and speed of water is same or greater than 1.5m2/s.

In addition, flood hazard classes and the methodology of their determination are clearly

defined in Rules on the methodology for determination of flood risk areas and, with them,

associated erosion of inland and marine waters, and the method of classifying land into

the risk classes (Official Journal of the Republic of Slovenia, No. 60/07):

https://www.uradni-list.si/1/content?id=81148.

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Mapping of areas of potential significant flood risk

Question 1: What are the reasons reported in the FHRM schema for the non-inclusion of some

APSFRs, elements or aspects in the flood hazard and flood risk maps?

SI reported links to maps of each of the APSFRs identified according to Article 5, and also

details of the maps in the FHRM schema. The links were to maps that were at the time of the

assessment (November 2014) not publicly available. However, there were flood hazard maps

that were available to the public on a government web portal, and the content is basically the

same (very small differences). They are presented as interactive maps where one can zoom

in from the state level to the property.

Areas of Potential Significant Flood Risk (APSFR) and other risk areas identified by the assessment of flood risk and those for which maps were prepared

Unit of Management

Number of Areas of Potential Significant Flood Risk (1)

FHRM information reported at Unit of

Management scale (2)

Number of other areas with available

national FHRM (3)

a) Identified according

to Article 5

b) with links to national

maps

c) with details of

maps provided to

WISE

b) with links to national

maps

c) with details of

maps provided to

WISE

b) with links to national maps

SI_RBD_1 51 51 51 No No 0

SI_RBD_2 10 10 10 No No 0

Key: a) Article 5 requires the identification of areas of potential significant flood risk (APSFR) based

on a new Preliminary Flood Risk Assessment or an existing one. b) Member States were asked to provide links to national web pages or viewers where maps of

the flood hazard and flood risk associated with APSFRs could be viewed (column 1). Alternatively or additionally maps could be made available and reported at the level of the Unit of Management (column 2) or at other geographical scales (column 3),

c) Member States were asked to provide numeric details (such as source of flooding, numbers of potentially affected inhabitants and types of potential adverse consequences) of the maps associated with the APSFR so that they could be depicted on a European map of flooding. The maps could be reported with the relevant APSFR code (column 1) and/or at the level of the Unit of Management (column 2). In some circumstances, (c) may be greater than (a), for example if additional APSFRs were

identified after 2012.

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Content of flood hazard and flood risk maps

Note: Not all of the maps prepared by Member States have been examined. Instead a subset was selected and reviewed by designated assessors.

The maps for checking were selected on the basis of information provided by Member States with their Preliminary Flood Risk Assessments (PFRAs) in 2012 (where available) and the screening of the maps made available in the “LinkToMS” schema. The aim was to select a sufficient number of maps to reflect:

Potential differences in methodologies, presentation and visualisation of maps between the Units of Management (UoM) within a Member State. Some Member States have a strong national approach, in others there are differences between administrative regions;

Differences in sources of floods included in hazard and risk maps. Some APSFRs and UoM are associated with more than one source of flooding whereas others are not. The aim was to check maps associated with all possible types of flood associated with a Member State. For those Member States applying Article 4 and Article 13.1.a the selection of relevant flood types can be informed from the reporting of APSFR in March 2012;

Differences in the Articles applied across a Member State and within UoMs. Whilst some Member States have applied only one Article across their whole territory and for all flood types, others have applied different Articles within a UoM and also according to flood types.

The application of Article 13.1.b and Article 13.2 by some Member States in at least some of their UoMs. In these cases Member States may have provided UoM codes, other area codes or both: in these cases it was the flood maps associated with the areas that were checked. The objective was to check examples of maps within the linked areas in relation to all potential and relevant sources of flooding and that may have been mapped.”

Links to national web pages where examples of national maps can be viewed are given below.

Question 2 Which types of flood, scenarios, hazard elements and potential adverse consequences have been mapped and visualised?

Unit of Management SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_2 SI_RBD_2 SI_RBD_2

APSFR code SI1_01 SI1_01 SI1_12 SI1_12 SI3_08 SI15_03 SI15_03 SI5_42

The provided link went straight to the APSFR Yes No Yes No No Yes No No

Map located by searching for name of APSFR N/A Yes N/A Yes Yes N/A Yes Yes

Source(s) of flooding mapped Not clear Not clear Not clear Not clear None Not clear Not clear None

Mechanism(s) of flooding mapped None Not clear None Not clear None None Not clear None

Characteristic(s) of flooding mapped None None None None None None None None

Linked map available to public (1) No / Yes Yes No / Yes Yes Yes No / Yes Yes Yes

Mapped scenarios

Floods with a low probability mapped Yes Yes Yes Yes Yes Yes Yes No

Floods with a medium probability mapped Yes Yes Yes Yes Yes Yes Yes No

Floods with a high probability mapped Yes Yes Yes Yes Yes Yes Yes No

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Unit of Management SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_2 SI_RBD_2 SI_RBD_2

APSFR code SI1_01 SI1_01 SI1_12 SI1_12 SI3_08 SI15_03 SI15_03 SI5_42

Separate maps or layers for each probability scenario

Yes Yes Yes Yes Yes Yes Yes No

Separate maps or layers for each flood type No No No No No No No No

More than one scenario shown on the same Map No Yes No Yes Yes No Yes No

More than one source of flooding shown on the same Map

Yes Yes Yes Yes Yes Yes Yes No

Hazard Elements shown on map

Flood extents Yes Yes Yes Yes Yes Yes Yes No

Water depth (2) No No No No No No No No

Water levels No No No No No No No No

Flow velocities (3) No No No No No No No No

Relevant water flow No No No No No No No No

Flood Hazard and Flood Risk on the same map No No No No No No No No

Separate maps of Flood Hazard and Flood Risk Yes Yes Yes Yes No Yes Yes No

Potential adverse consequences shown on:

Number of Inhabitants potentially affected Yes Yes Yes Yes Yes Yes Yes Yes

Human health Yes Yes Yes Yes Yes Yes Yes Yes

The community Yes Yes Yes Yes Yes Yes Yes Yes

Type and sectors of economic activity No Yes No Yes Yes No Yes Yes

Land use Yes No Yes No No Yes No No

Point locations for storage of chemicals, vital networks and services

Yes No Yes No No Yes No No

Property Yes Yes Yes Yes Yes Yes Yes Yes

Infrastructure Yes No Yes No No Yes No No

Location of Industrial Emissions Directive installations

Yes Yes Yes Yes Yes Yes Yes Yes

WFD Protected Areas Yes No Yes No No Yes No No

Status of water bodies No No No No No No No No

Areas vulnerable to floods with high content of transported sediment and debris flow

No No No No No No No No

Other significant sources of pollution Yes No Yes No No Yes No No

Cultural Heritage Yes Yes Yes Yes Yes Yes Yes Yes

Other useful information No Yes No Yes Yes No No No

Impacts of Climate Change No No No No No No No No

Coastal protection defences in place No No No

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(1) Areas marked “No/Yes” had links to maps reported in the schemas but those links were not publicly available at the time of the assessment. However, there were flood hazard maps that were available to the public on a government web portal, and the content is basically the same (very small differences). Subsequent to the assessment, the SI authorities clarified that the maps are available in an Excel spreadsheet on the MESP’s web site or through the Water Management Atlas or the Environmental Atlas. (2) water depths were not found on the maps during the assessment. However, subsequent to the assessment, the SI authorities stated that Classes of water depths (0-0.5 m; 0.5-1.5m; above 1.5 m) are publicly available in an Excel spreadsheet on MESP’s web site or through the Water Management Atlas or the Environmental Atlas. (3) Subsequent to the assessment, the SI authorities stated that, for some areas (where applicable), the speed of water (less than 1m/s and greater than 1m/s) are shown, for example, for APSFR Litija depths and speed for Q500 are shown on the map on the link: http://www.mop.gov.si/fileadmin/mop.gov.si/pageuploads/podrocja/voda/opvp/OPVP_Si_KPN/35_Litija_IHR/Globine_pri_Q500.pdf. Links to national maps: Links provided via the LinkToMS schema (available to the public via an Excel spreadsheet on the website of the Ministry: http://www.mop.gov.si/fileadmin/mop.gov.si/pageuploads/podrocja/voda/opvp/OPOPO.xls):

SI1_01 http://www.mko.gov.si/fileadmin/mko.gov.si/pageuploads/podrocja/voda/opvp/OPVP_Si_KPN/01_Ljubljana_jug_3030_3129_3021_3067/Poplavna_linija_Q500.pdf

SI1_12 http://www.mko.gov.si/fileadmin/mko.gov.si/pageuploads/podrocja/voda/opvp/OPVP_Si_KPN/12_Zalog_Podgrad_Videm_3065_3067_3081_3029/Poplavna_linija_Q10.pdf

SI5_42 http://www.mko.gov.si/si/delovna_podrocja/voda/poplavna_direktiva/ Atlas Okolja: http://gis.arso.gov.si/atlasokolja/profile.aspx?id=Atlas_Okolja_AXL@Arso

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Contextual information provided with maps

Question 3 What contextual information was generally provided with the maps?

Unit of Management SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_1 SI_RBD_2 SI_RBD_2 SI_RBD_2

APSFR code SI1_01 SI1_01 SI1_12 SI1_12 SI3_08 SI15_03 SI15_03 SI5_42

Title: brief description of the map Yes Yes Yes Yes Yes Yes Yes Yes

Explanation to the public on how to understand and interpret the flood maps No Yes No Yes Yes No Yes Yes

Responsible authority (organisation responsible for the development and publishing of the maps, with contact details)

Yes Yes Yes Yes Yes Yes Yes Yes

Date of preparation / publication Yes Yes Yes Yes Yes Yes Yes Yes

Legend (textual description of symbols, colours, line features, etc.) Yes Yes Yes Yes Yes Yes Yes Yes

Purpose of development and intended use No Yes No Yes Yes No Yes Yes

Method of development No Yes No Yes Yes No Yes Yes

Limitations of map and / or assessment of uncertainty No Yes No Yes Yes No Yes No

Disclaimer (to enforce explanatory information and limitations, and provide legal protection to the responsible authority against adverse consequences of misuse)

No Yes No Yes Yes No Yes Yes

North and scale: preferably using scale bar as this allows for changes in page size Yes Yes Yes Yes Yes Yes Yes Yes

Scope and detail of the explanatory information: should be appropriate to the intended audience

Yes Yes Yes Yes Yes Yes Yes Yes

Intended audience & complexity: Maps intended for public use should be simple and self-explanatory and include a clear legend, such that as little supporting or explanatory information as possible is required for correct interpretation.

Yes Yes Yes Yes Yes Yes Yes Yes

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Summary of findings from questions 2 and 3.

The same approach was used in both sub-units. There is a national approach with uniform

methodology described in the Rules on methodology to define flood endangered areas and

associated erosion of continental and sea waters, and classification of lands in classes of

endangerment (Pravilnik o metodologiji za določanje območij, ogroženih zaradi poplav in z

njimi povezane erozije celinskih voda in morja, ter o načinu razvrščanja zemljišč v razrede

ogroženosti, Uradni list RS, št. 60/07).

The maps provided with direct links in the LinkToMS schema are all in PDF form and were

not publicly accessible at the time of the assessment, although the SI authorities have

subsequently stated that the maps are available through an Excel spreadsheet on the

MESP’s website, on the Water management Atlas and on the Environmental Atlas (layer

APSFR/OPVP). At the time of the assessment, maps were publicly available via a web viewer

only for certain APSFRs; of those assessed, the following APSFRs were available in the web

viewer: SI1_01; SI1_12; SI15_03. They are all prepared for each APSFR separately. For the

other APSFRs that were assessed (SI3_08 and SI5_42), the LinkToMS schema provides a

link to the official governmental Flood Directive web site. There is a link provided to “Atlas

okolja” (Atlas of Environment)

http://gis.arso.gov.si/atlasokolja/profile.aspx?id=Atlas_Okolja_AXL@Arso. “Atlas okolja” is a

governmental official database and an interactive map viewer which is accessible to the

general public without any restrictions or limitations. The database is downloadable in

different formats. One can prepare maps of different kind and scale and print them directly

from the application. It is intended for professional as well as general public use, as well as for

public awareness.

The content of Flood Hazard maps (probability of flood events for return periods 10, 100 and

500 years) seems to be more or less the same in both the LinkToMS and the national portal

(LinkToMS schema seems to provide a bit newer information). At the national portal “Atlas

okolja”, there is another set of flood hazard maps available, which presents the content in four

categories (please see below) of flood hazard that take into account not only the extent of

flood at different return periods, but also water speed, water depth and water flow. With higher

speed of water flow, the flood hazard category can be higher. Flood hazard maps are very

detailed (minimum required scale 1:5,000 and up to scale 1:1,000 or more).

At the time of the assessment, the Flood Risks maps were not available via the national portal

“Atlas okolja”. However, numeric information on potential adverse consequences was

associated with the Areas of Potentially Significant Flood Risk (APSFR) as part of the APSFR

map (the layer showing only the extent of APSFR).

The Flood risk information presented in the maps provided through the LinkToMS schema

does not cover the following required topics:

(1) Type and sectors of economic activity in potentially affected area such as manufacturing,

construction, retail, services and other sources of employment;

(2) Consequences on the status of water bodies;

(3) Areas vulnerable to floods with a high content of transported sediment and debris flows.

The Flood risk information presented at the national portal “Atlas okolja” associated to the

APSFR does not present the following required topics:

(4) Human health such as might arise from pollution or interruption of services related to

water supply and treatment, and would include fatalities;

(5) Land use (e.g. agricultural land);

(6) Point locations for storage of chemicals, vital networks and services (highways, railways,

airport, lifeline services like electricity, sewerage and drinking water, hospitals, etc);

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(7) Infrastructure such as utilities, power generation, transport, storage and communication;

(8) Location of potentially affected WFD protected areas;

(9) Consequences on the status of water bodies;

(10) Areas vulnerable to floods with a high content of transported sediment and debris flows;

There is no distinction among different flood sources (fluvial, sea-water, groundwater etc) –

they are all presented as one integral layer in the maps. All the contextual information is

provided in the web application.

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Methodologies used to prepare flood hazard maps

Question 4 What methods and relevant information have been used to identify, assess or

calculate flooding hazards for the relevant scenarios, and are these compliant with the

requirements of the Floods Directive?

The sources of flood for which flood hazard maps have been published, or which have been assessed but flood hazard maps have not been published, were:

Source of flooding

Published Assessed but not published

Neither published nor assessed

Not relevant

Fluvial SI_RBD_1, SI_RBD_2

Pluvial SI_RBD_1, SI_RBD_2

Coastal SI_RBD_2 SI_RBD_1

Groundwater SI_RBD_1, SI_RBD_2

Artificial water bearing infrastructure

SI_RBD_1, SI_RBD_2

Sewerage systems

SI_RBD_1, SI_RBD_2

Other (described below if applicable)

Other: Not relevant

Comments

There are no differences between both UoMs in the Member State. There is no

differentiation among different flood sources at presentation of flood hazard maps. All

considered flood sources (namely fluvial and sea-water) are integrated into one flood map

(presented in three scenarios for 10, 100 and 500 year return period). However, WISE

Floods summery report (FD.9.0 FHRM A) provides the information on different methodology

used to analyze floods from different sources (rivers, lakes and seawater). The sources of

flooding that were included as fluvial are also lakes, artificial water bearing infrastructure,

groundwater and pluvial.

A) Fluvial floods

Scenarios mapped or assessed

Scenario Return period e.g. 100 years

Percentage e.g. 1%

Decimal e.g. 0.01

Other expression

Low probability 500 four classes of flood hazard

Medium probability

100 four classes of flood hazard

High probability 10 four classes of

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flood hazard

Summary of the information found and in particular any differences between the UoMs in the Member State. The probability scenarios have been expressed in two different ways (two different sets of maps): (1) In terms of return period (10, 100 and 500 years), and

(2) In terms of four classes of flood hazard at water flows at rivers and water levels at lakes

corresponding to 100 year return period taking into account water depth and water speed.

There are no differences between the UoMs in the MS because one common methodology is

mandatory for the whole country. The sources of flooding that were included as fluvial are

also lakes, artificial water bearings and pluvial.

Elements mapped or assessed

Scenario Flood extent Water depth/level*

Water/flow velocities*

Other

Low probability Yes No No combination of water depth and speed at specific water flow

Medium probability

Yes No No combination of water depth and speed at specific water flow

High probability Yes No No combination of water depth and speed at specific water flow

* Subsequent to the assessment, the SI authorities stated that water depth classes for scenarios Q10, Q100 and Q500 are displayed on the maps and the same goes for velocity, where appropriate. Summary of the information found and in particular any differences between the UoMs in the Member State. The flood hazard maps are prepared according to decreed methodology, therefore, there are

no differences between the UoMs in the MS.

Flooding hazard maps are prepared in two different ways (two sets of maps). The first set of

maps presents flood hazard as flood extent for return periods 10, 100 and 500 years. The

second set of maps presents flood hazard in an integral way as four classes of flood hazard.

Flood hazard classes where defined as combination of water depth and water speed (greater

than 1 m/s) at water flows at rivers and water levels at lakes corresponding to 100 year return

period is taking into account:

(1) The class of high hazard: water depth ≥1,5 m or product of water depth and speed is ≥1,5

m2/s;

(2) The class of medium hazard: water depth less than 1,5 m and ≥ 0,5 m or product of water

depth and speed is less than 1,5 m2/s and ≥ 0,5m

2/s;

(3) The class of low hazard: water depth less than 0,5 m or product of water depth and speed

is less than 0,5 m2/s;

(4) The class of very low hazard: when flood is caused by exceptional natural or man-made

causes (heavy rain, malfunction or destruction of flood defence and other water structures

etc.);

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Methods used

What scenarios were considered and tested in the development of the published maps?

Scenarios for high (10), medium (100) and low probability (500 year return period) were considered and tested in the development of the published maps.

What were the reasons for the exclusion or inclusion of certain scenarios for the final published maps?

All included. No further explanation provided. (Not prepared for all the APSFRs.)

How were return periods and/or probabilities of flooding calculated, for example what was the length of measurement series used in the calculations?

The decreed methodology defines probabilities of certain flood risk with standard probabilities of the appearance of flows with return periods 10, 100 and 500 years. For defining the quantity of water flow with probability of 500 year return period the methodology allows also simplified calculation: - for river catchments larger than 1000 km

2

the equation Q500 = 1,2 * Q100 is used; - for catchments greater than 100 km

2 and

smaller than 1000 km2 the equation Q500 =

1,3 * Q100 is used; - for catchments smaller than 100 km

2 the

equation Q500 = 1,4 * Q100 is used. In the case of lakes, the maximal measured water level is used. The methodology does not define the length of measurement series used in the calculations. This depends on best available information for each separate case.

How was the most appropriate scale of the map determined? For example, flood maps intended to raise public awareness should enable anyone to find out where there are risks of flooding. Maps for this purpose may have a relatively larger scale e.g. 1: 10,000 to 1: 25,000 compared to those used for national or regional planning purposes (1:100,000 to 1: 500,000). Also the mapping of some hazard features such as flow velocity may require a more detailed scale such as 1:1,000 or 1:5,000.

The minimal accuracy of the flood hazard maps is decreed and it is 1:5,000. The flood hazard maps presented in the PDF form via direct links in the LinkToMS are prepared in scale 1:5,000. The maps provided through governmental official database in the interactive map viewer “Atlas okolja” (Atlas of Environment) can be enlarged up to the scale 1:1,000. http://gis.arso.gov.si/atlasokolja/profile.aspx?id=Atlas_Okolja_AXL@Arso

What was the resolution of digital terrain models used to calculate flood hazards?

The resolution of digital terrain models used to calculate flood hazards was minimum 1:5,000 or larger (basic topographic maps). Besides that, data gathered with the use of LiDAR technique of capturing geodetic data have 7,5 cm accuracy for height and density of 10 points per m

2. For the river beds of the main rivers,

bridges and other hydraulically important structures field geodetic measurements were prepared.

How were existing flood defences taken into account?

Data gathered with the use of LiDAR technique captured existing flood defences. No further information is provided.

How were existing infrastructure or buildings taken into account?

In modelling, buildings are taken into account as high walls. Data gathered with the use of LiDAR technique captured existing infrastructure or buildings. No further information is provided. Subsequent to the

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assessment, the SI authorities stated that the buildings cadastre is taken into account in the modelling.

What other data sets were used? For the modelling of pluvial runoff, all available pluvial data series were used.

What are the key assumptions of the method?

Key assumptions of the method are: (1) Climatic variability was considered with the analysis of all recorded pluvial and water flow values. (2)The low probability scenario (500 year return period) equals the extent of flooding in the case of malfunction of flood defence structures (as that they were not build). (3) The potential effects on flood risk of spatial planning policies such as those on land use and infrastructure development have not been considered in Slovenia, because protective measures are being carried out with the help of the Decree on conditions and limitations for constructions and activities on flood risk areas, which ensures that the mass of damaging potential from human activity is not increasing due to re-directing new developments outside of flooding areas. In the case of foreseen enlargements of existing infrastructure in the areas already endangered by floods, mitigation measures have to be implemented to reduce existent endangerment.

What were the identified uncertainties in the methods and resultant maps and assessments?

There is no information on identified uncertainties in the methods and resultant maps and assessments except the observation,that calculated extents of floods does not necessarily match the observed extents of floods because of possible changes of water bed, obstructions of water flow, etc.

What were the shortcomings of the method?

There is no information on the shortcomings of the method.

What were the advantages of the method? There is no information on the advantages of the method.

B) Pluvial floods

Note: Pluvial flooding was combined/mapped with fluvial flooding.

C) Coastal floods

Scenarios mapped or assessed

Scenario Return period e.g. 100 years

Percentage e.g. 1%

Decimal e.g. 0.01

Other expression

Low probability 500 four classes of flood hazard

Medium probability

100 four classes of flood hazard

High probability 10 four classes of flood hazard

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Summary of the information found and in particular any differences between the UoMs in the Member State. The probability scenarios have been expressed in two different ways:

(1) In terms of return period (10, 100 and 500 years), and

(2) In terms of four classes of flood hazard at water levels of sea corresponding to 100 year

return period taking into account water wave with return period 50 years.

The methodology is relevant only in one UoM. Pluvial sources of flooding were also included

as well as sea water flooding. There is no separate layer for sea water sources of flooding.

Sea water flooding is integrated within fluvial flooding.

Elements mapped or assessed

Scenario Flood extent Water depth/level*

Water/flow velocities*

Other

Low probability Yes No No combination of water level and water wave

Medium probability

Yes No No combination of water level and water wave

High probability Yes No No combination of water level and water wave

* Subsequent to the assessment, the SI authorities stated that water depth classes for scenarios Q10, Q100 and Q500 are displayed on the maps and the same goes for velocity, where appropriate. Summary of the information found and in particular any differences between the UoMs in the Member State. The flood hazard maps are prepared according to decreed methodology, therefore, there are

no differences between the UoMs in the MS. Flooding hazard is presented in first set of maps

as flood extent for each scenario (for return periods 10, 100 and 500 years). In the second set

of maps, it is presented as four classes of flood hazard where combination of water levels at

sea corresponding to 100 year return period and water wave with 50 year return period is

considered:

(1) The class of high risk: water depth ≥1,5 m;

(2) The class of medium risk: water depth less than 1,5 m and ≥ 0,5 m;

(3) The class of low risk: water depth less than 0,5 m;

(4) The class of very low risk: when flood is caused by exceptional natural or man-made

causes (heavy rain, malfunction or destruction of flood defence and other water structures

etc.);

Methods used

What scenarios were considered and tested in the development of the published maps?

Scenarios for high (10), medium (100) and low probability (500 year return period) were considered and tested in the development of the published maps.

What were the reasons for the exclusion or inclusion of certain scenarios for the final

All included. No further explanation provided. (Not prepared for all the APSFRs.)

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published maps?

How were return periods and/or probabilities of flooding calculated, for example what was the length of measurement series used in the calculations?

The decreed methodology defines probabilities of certain flood risk with standard probabilities of the appearance of water level with return ages 10, 100 and 500 years. The methodology does not define the length of measurement series used in the calculations. This depends on best available information for each separate case.

How was the most appropriate scale of the map determined? For example, flood maps intended to raise public awareness should enable anyone to find out where there are risks of flooding. Maps for this purpose may have a relatively larger scale e.g. 1: 10,000 to 1: 25,000 compared to those used for national or regional planning purposes (1:100,000 to 1: 500,000). Also the mapping of some hazard features such as flow velocity may require a more detailed scale such as 1:1,000 or 1:5,000.

The minimal accuracy of the flood hazard maps is decreed and it is 1:5,000. The flood hazard maps presented in the PDF form via direct links in the LinkToMS (not publically accessible) are prepared in scale 1:5,000. Public accessible maps provided through governmental official database in the interactive map viewer “Atlas okolja” (Atlas of Environment) can be enlarged up to the scale 1:1000. http://gis.arso.gov.si/atlasokolja/profile.aspx?id=Atlas_Okolja_AXL@Arso

What was the resolution of digital terrain models used to calculate flood hazards?

The resolution of digital terrain models used to calculate flood hazards was minimum 1:5,000 or larger (basic topographic maps). Besides that, data gathered with the use of LiDAR technique of capturing geodetic data have 7,5 cm accuracy for height and density of 10 points per m

2. For hydraulically

important structures field geodetic measurements were prepared.

How were existing flood defences taken into account?

Data gathered with the use of LiDAR technique captured existing flood defences. No further information is provided.

How were existing infrastructure or buildings taken into account?

In modelling buildings are taken into account as high walls. Data gathered with the use of LiDAR technique captured existing infrastructure or buildings. No further information is provided. Subsequent to the assessment, the SI authorities stated that the buildings cadastre is taken into account in the modelling.

What other data sets were used? For the modelling of pluvial runoff, all available pluvial data series were used.

What are the key assumptions of the method?

Key assumptions of the method are: (1) Climatic variability was considered with the analysis of all recorded pluvial and water flow values.

What were the identified uncertainties in the methods and resultant maps and assessments?

There is no information on identified uncertainties in the methods and resultant maps.

What were the shortcomings of the method? There is no information on the shortcomings of the method.

What were the advantages of the method? There is no information on the advantages of the method.

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D) Groundwater floods

Note: Groundwater flooding is not specifically mapped and there is no explicit mention that groundwater flooding was considered to be a part of fluvial flooding. However, the recorded historic data that was taken into consideration did not make any distinction between groundwater and fluvial flooding. Slovenia also has large areas of karst where it is especially hard to distinguish between groundwater floods and fluvial floods. E) Floods from Artificial Water Bearing Infrastructure

Note: Flooding from artificial water bearing infrastructure was combined/mapped with fluvial flooding.

F) Floods from sewerage systems

Note: No information was found on whether the hazard and risk of flooding from this source

has been mapped.

G) Other types of floods

Note: No information was found on whether the hazard and risk of flooding from other sources

have been mapped.

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Methodologies used to prepare flood risk maps

Question 5 What methods and relevant information have been used to prepare flood risk

maps? Which potential adverse consequences are reported and how have they been identified

and presented in flood risk maps?

a) Risk to human health

The indicative number of inhabitants potentially affected by each flooding scenario is

determined by spatial data analyses of the central register of population (Ministry of

the Interior of Republic of Slovenia, 2014) and data of register of spatial units –

records of house numbers (Geodesy Administration of the Republic of Slovenia,

2014). Permanent and temporary inhabitants are considered. The number of people

at potential risk in each APSFR have then been rounded into a number of categories

(e.g. 1-50, 51-100, 101-500, 501-1000 and more than 1000 inhabitants per km2) and

symbolically presented on Flood risk maps. There are no differences in the methods

and criteria used within the Member State.

b) Risk to economic activity

Risk assessment to determine economic activity affected, for each flood scenario the

location of economic activity was analyzed. Spatial data of actual land use using

nomenclature of Corine Land Cover (European Environment Agency, 2006) was used

since the national data layer of actual land use does not give a separate category for

industrial, retail and transportation areas. The Corine Land Cover categories were

reclassified into five categories (industrial, retail and transportation area, residential

area, agricultural area, park area, water area) that are presented on flood risk maps.

To increase the accuracy, for each of the categories, the number of businesses

affected by floods was defined by spatial analysis of data from national business

registry and national registry of house numbers.

To present the influence of floods on transportation, spatial data on roads and

railroads from national registry of economic infrastructure was used. There are no

differences in the methods and criteria used within the Member State.

The risk to economic activity is visualized on the maps (maps included into the

LinkToMS shema) with five categories of land use (industrial, retail and transportation

area, residential area, agricultural area, park area, water area) or as location of roads

and railroads that area at risk.

In the public viewer "Atlas okolja" the flood risk is provided as the number of working

places and businesses in a particular APSFR that are at risk because of flooding, as

well as a number of kilometers of roads and railroads that area at risk in a particular

APSFR. A table with numeric information is associated with each APSFR.

c) Risk to Installations covered by the requirements of the Industrial Emissions

Directive (IED) or previously under the IPPC Directive

Risk assessment to determine industrial installations affected, for each flood

scenario, the location of installations covered by the requirements of the Industrial

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Emissions Directive (IED) or previously under the IPPC Directive have been

assessed on the base of spatial distribution and size. To increase the level of

accuracy, communal wastewater purification plants, communal dumping sites and

companies liable under the Seveso Directive were also assessed on the base of

spatial distribution and size. Because these data layers are mostly given only by one

geodetic point, the actual risk was determined by visual assessment of digital

ortographic photographs in a scale 1:5,000 and data layers of flood risk categories.

There was no special focus on activities or installations with a high pollution potential

through the release of pollutants into water or land rather than those that potentially

only release pollutants into the air. All chosen industrial installations were treated

equally.

The risk to installations covered by the requirements of the Industrial Emissions

Directive (IED), communal wastewater purification plants, communal dumping sites

and companies liable under the Seveso Directive are visualised on the maps with

specific signs at the location (maps included into the LinkToMS schema).

In the public viewer "Atlas okolja" the flood risk is provided in as number of

installations (IED installations, communal wastewater purification plants, communal

dumping sites and companies liable under the Seveso directive) in a particular

APSFR that are at risk at flooding.

There are no differences in the methods and criteria used within the Member State.

d) Risk to WFD protected areas

Risk assessments used to determine, for each flood scenario, the risk to the types of

protected area in areas potentially at risk from flooding, were prepared using spatial

analyses of data layers of water-protection areas, of bathing waters, of Natura 2000

sites, of ecologically important areas, and of natural heritage protected areas. The

method that was used is simply the identification of such areas within the flooding

areas. There are no differences in the methods and criteria used within the Member

State.

e) Other consequences considered

The methodology defined in the Rules on methodology to define flood endangered

areas and associated erosion of continental and sea waters, and classification of land

in classes of endangerment (Pravilnik o metodologiji za določanje območij, ogroženih

zaradi poplav in z njimi povezane erozije celinskih voda in morja, ter o načinu

razvrščanja zemljišč v razrede ogroženosti, Uradni list RS, št. 60/07) considers also

potential risk to sensitive buildings:

(1) Where evacuation can be difficult (schools, kindergartens, hospitals, health

centres, homes of elderly people and health resorts);

(2) Where exceptional material, cultural or social damage can occur (libraries,

museums, archives);

(3) Where damages can cause large indirect economic loss (transport, supply);

(4) Location of emergency services (fire fighting, rescue and police stations);

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(5) A public utility water treatment plant and public utility dumps as potential sources

of water pollution in case of floods.

A very simple spatial analysis of mentioned data layers is used in defining risk. There

are no differences in the methods and criteria used within the Member State.

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Justification for applying Article 6.6

Question 6 What are the justifications for applying Article 6.6 (coastal areas), if applied,

and how has it been determined that an adequate level of protection is in place against coastal

floods?

Article 6(6) has not been applied in any UoM in Slovenia (source: WISE Flood report: FD.9.0 FHRM B - Application of Article 6.6).

Justification for applying Article 6.7

Question 7 What are the justifications for applying Article 6.7 (groundwater floods), if

applied?

Article 6(7) has not been applied in any UoM in Slovenia (source: WISE Flood report: FD.9.0 FHRM C - Application of Article 6.7). N.A. "The Article 6.7 has not been applied" is said in the Floods WISE report.

Application of Article 13.1.b in accordance with requirements of the

Floods Directive

Question 8 Have the flood hazard maps and flood risk maps been prepared in accordance

with the relevant provisions of the Floods Directive where Article 13.1.b has been applied?

Note: Article 13.1.b has not been applied in any UoM in Slovenia (source: WISE Flood report FD.1.1 Specific Areas to which each Article has been applied.)

Compliance of the use of Article 13.2 with the requirements of

Article 6

Article 13.2 has not been applied in any UoM in Slovenia (Source: WISE Floods summary reports: FD.9.0 FHRM G - Use of Article 13.2)

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Information exchanged between Member States and the

preparation of coherent maps in international RBDs or UoMs

Question 10 How has it been ensured that there was prior information exchange on the

production of maps between Member States sharing international RBDs or UoMs, and how

was it ensured that coherent maps were produced between the relevant Member States?

The number of cross border Units of Management with shared flood risk areas in this

Member State

Both Units of Management in Slovenia are cross border UoMs with shared flood risk areas. Summary of the information reported and in particular any differences between UoMs

in the Member State.

There was no further information provided in the Floods WISE summary report. Subsequent to the assessment, the SI authorities reported information formally to the Commission on their international coordination on the production of maps. This includes details of bilateral water management commissions through which information has been exchanged with Austria, Italy, Croatia and Hungary. In addition, SI is active within the Sava Commission (ISRBC) and the Danube Commission (ICPDR).

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Consideration of climate change impacts in the preparation of the

maps

Question 11 How has climate change been taken into account when the flood hazard

scenarios were identified?

Climate change has been taken into account No

For which sources of flooding -

For low probability scenario -

For medium probability scenario -

For high probability scenario -

Climate change trend scenarios have been obtained from the IPCC or other international sources

No

Climate change trend scenarios have been obtained from the national research programmes

No

Flood hazard scenarios are based on modelling of changes in flood hazard in relation to climate change

No

Flood hazard scenarios included trend analysis of historical data of hydrological and meteorological observations

No

Flood hazard scenarios included a statistical assessment of historical climate data

No

Summary of how climate change has been taken into account in the production of

flood hazard maps, and highlight any differences between UoMs in the Member State

Climate change has not been taken into account in the production of flood hazard maps. The

Flood WISE report provides the following information: “The influence of climate changes

and/or influence of prediction of changes of return periods of existing typical values of flows

was not considered within the hydrologic analyses. However, climatic variability was

considered with the analysis of all recorded pluvial and water flow values.”