assessment of flood hazard and flood risk maps information...

12 December 2014

1 of 29

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: FI – Finland

Date that the assessment was completed: 12 December 2014

Information reported and assessed

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

with a wealth of information. Finland made available links to its national flood risk and flood hazard

maps. Detailed summaries were also provided on the methods used to prepare the maps. 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.

Main outcomes of the assessment

a) Good / current practices adopted:

- The maps are easy to navigate and links to additional information are clearly displayed,

the purpose and intended use of the maps is clear; it is appreciated that a feedback

button is made visible directly on the map.

- The floods hazard and flood risk maps display different scenarios - the probability is

displayed either as a percentage (from 0.1% to 50%), as text (very rare flooding to yearly

flooding) and occurrence rate 1/1,000 years to 1 every 2 years. This approach might

increase the understanding of the relative hazards and risks from flooding for the general

public.

b) Weaknesses:

- The preparation date of the maps should be made visible. The Finnish authorities have

commented that the preparation date is available as an attribute using a “Find data on the

map” tool, and they accept that making the date more visible is something to consider in

future.

12 December 2014

2 of 29

- Some of the links to additional information do not work properly and should be fixed to

ensure the credibility of the website. The Finnish authorities have explained that this was

caused by changes to the website, but it should be corrected by now.

c) Lessons to be learnt:

- It would add clarity to the maps if the flooding sources were better explained and

differentiated – does flooding from river systems also cover pluvial flooding / failures in

sewerage systems / Artificial Water Bearing Infrastructure (AWBI)? The Finnish

authorities subsequently stated that a more detailed explanation will be added to the

webpage.

d) Questions seeking clarification from Member State:

- It is indicated on the Environment Administration website that separate layers depicting the

impacts of climate change on floods are expected to become available. Which data will be

used for this and for when is that foreseen?

o The FI authorities have provided a response to this question: Some layers taking

climate change into account are already available in the “special scenario” dataset in

the Finnish version of the service (e.g. Savonlinna and Uusimaa). The latter, for

example, is based on the estimation of the sea level rise on the Finnish coast

because of climate change. This estimation is made by the Finnish Meteorological

Institute and it was published 2014. Several discharges and water levels for fluvial

floods under different future climate scenarios have been simulated by SYKE using

the Watershed Simulation and Forecasting System. The most important of those

results will be presented as flood maps during the second cycle of the implementation

of the Floods Directive.

- Is it foreseen to add a layer to the map depicting risks to human health (including fatalities)

arising from pollution or interruption of services related to water supply and treatment?

o The FI authorities have provided a response to this question: These types of severe

consequences are exceptional in Finland and thus, existing information on possible

polluting sources and number of inhabitants are considered to be sufficient

information in this regard and there are no plans to include this information on public

flood maps.

- On the Environment Administration website it is indicated that “vesistötulvat” refers to the

flooding from rivers and lakes. It should be made clear what is included under the “river

system flooding” (vesistötulvat), i.e. is it fluvial floods only or does it also include pluvial /

groundwater / artificial water bearing infrastructure flood sources? Is it foreseen to add layers

to the map depicting floods from storm water (snowmelt and pluvial)?

o The FI authorities have provided a response to this question: “Vesistötulvat” includes

fluvial floods. Groundwater floods are not relevant in Finland: if there are any, they do

not pose significant flood risks. Flood hazard maps for dam breaches are presented

as a separate layer but other artificial water bearing infrastructure flood sources are

not presented. The development of pluvial flood maps is ongoing and the maps will

be available later (date unspecified).

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?

12 December 2014

3 of 29

Flood hazards and flood risks maps have been prepared for the 21 areas identified in the preliminary

flood risk assessment in 2012; these maps became available in January 2014 with the launch of the

map-service. Methodology used for the automatic identification of flood risk areas is described here:

http://www.environment.fi/floodmaps (in English).

According to the Environment Administration website, pluvial floods caused by storm water or

snowmelt shortly become identifiable on the map next to floods due to rivers and lakes (vesistötulvat)

and sea water. In addition, the FI authorities have confirmed that joint maps displaying flooding both

from river systems (vesistötulva) and sea water are now available in the “special scenario” dataset in

the Finnish version of the flood map service.

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

FIVHA1 No flood risk areas No flood risk areas

FIVHA2 6 6 6 No No 0






FIWDA No flood risk areas No flood risk areas

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.

http://www.environment.fi/floodmaps

12 December 2014

4 of 29

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?

Table 2.1

Unit of Management FIVHA2 FIVHA2 FIVHA3 FIVHA3 FIVHA3

APSFR code FITulvaTietoId141AlueId1 FITulvaTietoId29AlueId8 FITulvaTietoId31AlueId5

FITulvaTietoId130AlueId9 FITulvaTietoId133AlueId11 FITulvaTietoId53AlueId22

The provided link went straight to the APSFR

Yes Yes Yes Yes Yes

Map located by searching for name of APSFR

Source(s) of flooding mapped Sea water Fluvial Fluvial Fluvial Fluvial

Mechanism(s) of flooding mapped) (1) None None None None None

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

Linked map available to public Yes Yes Yes Yes Yes

12 December 2014

5 of 29




Mapped scenarios

Floods with a low probability mapped Yes Yes Yes Yes Yes

Floods with a medium probability mapped

Yes Yes Yes Yes Yes

Floods with a high probability mapped Yes Yes Yes Yes Yes

Separate maps or layers for each probability scenario

Yes Yes Yes Yes Yes

Separate maps or layers for each flood type

Yes Yes Yes Yes Yes

More than one scenario shown on the same Map

Yes Yes Yes Yes Yes

More than one source of flooding shown on the same Map (2)

No No No No No

Hazard Elements shown on map

Flood extents Yes Yes Yes Yes Yes

Water depth Yes Yes Yes Yes Yes

Water levels Yes Yes Yes Yes Yes

Flow velocities No No No No No

Relevant water flow No No No No No

Flood Hazard and Flood Risk on the same map

Yes Yes Yes Yes Yes

Separate maps of Flood Hazard and Flood Risk

No No No No No

Potential adverse consequences shown on:

Number of Inhabitants potentially affected

Yes Yes Yes Yes Yes

Human health No No No No No

The community Yes

Yes

Yes

Yes

Yes

Type and sectors of economic activity Yes Yes Yes Yes Yes

Land use Yes Yes Yes Yes Yes

Point locations for storage of chemicals, vital networks and services

Yes Yes Yes Yes Yes

12 December 2014

6 of 29




Property Yes Yes Yes Yes Yes

Infrastructure Yes Yes Yes Yes Yes

Location of Industrial Emissions Directive installations

Yes Yes Yes Yes Yes

WFD Protected Areas Yes Yes Yes Yes Yes

Status of water bodies (3) No No No No No

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

No No No No No

Other significant sources of pollution Yes

Yes

Yes

Yes

Yes

Cultural Heritage Yes Yes Yes Yes Yes

Other useful information No No No No No

Impacts of Climate Change No No No No No

Coastal protection defences in place Yes No No No No

(1) The Finland authorities subsequently indicated that some scenarios caused by ice are available in a “special scenario” dataset in the Finnish version of the flood map service. However, these are not included in the maps assessed for this report: they are only relevant in certain areas.

(2) The Finland authorities subsequently indicated that some combinations e.g. coastal and fluvial flood at the same time, are available in the “special scenario” dataset in the Finnish version of the flood map service. However, these are not included in the maps assessed for this report.

(3) The Finland authorities subsequently indicated that water bodies are presented in the map if there’s a negative influence due to flood.to the status of the water body. However, it is not clear in the maps that the “water body” symbol only appears when flooding has a negative effect on the water body. When clicking on the symbol, the information does not provide details on the change that would take place due to floods.

Table 2.2 Unit of Management FIVHA3 FIVHA4 FIVHA5 FIVHA6 FIVHA7

APSFR code FITulvaTietoId53AlueId22 FITulvaTietoId21AlueId15 FITulvaTietoId90AlueId20 FITulvaTietoId32AlueId21 FITulvaTietoId95AlueId17

The provided link went straight to the APSFR

Yes Yes Yes Yes Yes

Map located by searching for name of APSFR

Source(s) of flooding mapped Sea water Fluvial Fluvial Fluvial Fluvial

Mechanism(s) of flooding mapped

None None None None None

12 December 2014

7 of 29



Characteristic(s) of flooding mapped

None None None None None

Linked map available to public Yes Yes Yes Yes Yes

Mapped scenarios

Floods with a low probability mapped

Yes Yes Yes Yes Yes

Floods with a medium probability mapped

Yes Yes Yes Yes Yes

Floods with a high probability mapped

Yes Yes Yes Yes Yes

Separate maps or layers for each probability scenario

Yes Yes Yes Yes Yes

Separate maps or layers for each flood type

Yes Yes Yes Yes Yes

More than one scenario shown on the same Map

Yes Yes Yes Yes Yes

More than one source of flooding shown on the same Map

No No No No No

Hazard Elements shown on map

Flood extents Yes Yes Yes Yes Yes

Water depth Yes Yes Yes Yes Yes

Water levels Yes Yes Yes No Yes

Flow velocities No No No No No

Relevant water flow No No No No No

Flood Hazard and Flood Risk on the same map

Yes Yes Yes Yes Yes

Separate maps of Flood Hazard and Flood Risk

No No No No No

Potential adverse consequences shown on:

Number of Inhabitants potentially affected

Yes Yes Yes Yes Yes

Human health No No No No No

The community Yes

Yes

Yes

Yes

Yes

12 December 2014

8 of 29



Type and sectors of economic activity

Yes Yes Yes Yes Yes

Land use Yes Yes Yes Yes Yes

Point locations for storage of chemicals, vital networks and services

Yes Yes Yes Yes Yes

Property Yes Yes Yes Yes Yes

Infrastructure Yes Yes Yes Yes Yes

Location of Industrial Emissions Directive installations

Yes Yes Yes Yes Yes

WFD Protected Areas Yes Yes Yes Yes Yes

Status of water bodies No No No No No

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

No No No No No

Other significant sources of pollution

Yes Yes Yes Yes Yes

Cultural Heritage Yes Yes Yes Yes Yes

Other useful information No No No No No

Impacts of Climate Change No No No No No

Coastal protection defences in place

No Yes No No Yes

Link to national maps: http://www.ymparisto.fi/tulvakartat

http://www.ymparisto.fi/tulvakartat

12 December 2014

9 of 29

Contextual information provided with maps

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

Table 3.1




Title: brief description of the map

Yes Yes Yes Yes Yes

Explanation to the public on how to understand and interpret the flood maps

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes Yes

Date of preparation / publication

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes Yes

Purpose of development and intended use

Yes Yes Yes Yes Yes

Method of development Yes Yes Yes Yes Yes

Limitations of map and / or assessment of uncertainty

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes

12 December 2014

10 of 29

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

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

Table 3.2



Title: brief description of the map

Yes Yes Yes Yes Yes

Explanation to the public on how to understand and interpret the flood maps

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes Yes

Date of preparation / publication

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes Yes

Purpose of development and intended use

Yes Yes Yes Yes Yes

Method of development Yes Yes Yes Yes Yes

Limitations of map and / or assessment of uncertainty

Yes Yes Yes Yes Yes

12 December 2014

11 of 29

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

Yes Yes Yes Yes Yes

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

Yes Yes Yes Yes Yes

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

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

12 December 2014

12 of 29

Summary of findings from questions 2 and 3.

At the welcome page contextual information on the purpose of the map and its intended use

is provided. In addition a short textual explanation on the recurrence intervals and how to

navigate the website is available. Navigation to more specific information is clear and

comprehensive. Links are made visible to websites with more background information;

however, sometimes these links did not work properly. It has been explained by the FI

authorities that this was due to ongoing changes to the website; the authorities have

confirmed that the links have now been corrected. The date of publication of the map exists

but is not visible enough. The authorities responsible are displayed. A ‘’feedback’’ button is

made available on the panel above the map.

The sources of flooding displayed on the map are not entirely clear, as on the map users can

choose between flood risk maps for floods due to river systems (vesistötulvat, including lakes

and rivers) or sea water, but no further explanation is provided on what sources of flooding

the former covers. After the assessment was carried out, the FI authorities clarified that

groundwater floods are not considered relevant in FI and so are not included in the maps.

Failures in sewerage systems are not included in the maps either. The authorities revealed

that a separate layer about the hazard area caused by dam breach is available in the Finnish

version of the flood map service.

The probability rate for all maps is displayed either as a percentage (0.1%, 0.4%, 1%, 2%,

5%, 10%, 20% or 50%), in a text (ranging from very rare flooding until very frequent flooding)

and occurrence rate (probability is shown for 1/1,000, 1/250, 1/100, 1/50, 1/20, 1/10, 1/5 and

1/2 years). The highest probability rate for which a map has been prepared is 1/2years (in

FIVHA2 and FIVHA3), however in most ASPFRs the highest probability scenario seems to be

1/20 years or 5%.

The legend of the map is clear and easy to follow. Point locations displayed include hospitals,

fire stations, colleges, telecommunication enterprises, energy production and transmission

facilities, storage of chemicals, wastewater treatment facility, manufacturing site (industry),

waste treatment, harbour, airport, railway, main roads, etc.

The indicative number of people affected is displayed under all different flood scenarios. Point

locations displayed include a wide variety of activities and services - including fishery,

telecommunication, industry, energy production etc. These activities have not been

categorized into economic sectors (the FI authorities have commented that damages for

economic sectors are not highlighted in the Finnish flood risk legislation). The point locations

displayed include beaches, protected areas, water bodies. However, no link with the WFD is

made.

12 December 2014

13 of 29

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 Hazard assessed but not published

Neither published nor assessed

Not relevant

Fluvial FIVHA2, FIVHA3, FIVHA4, FIVHA5, FIVHA6, FIVHA7

FIVHA1

Pluvial FIVHA1, FIVHA2, FIVHA3, FIVHA4, FIVHA5, FIVHA6, FIVHA7

Coastal FIVHA2, FIVHA3, FIVHA4

FIVHA1 FIVHA5, FIVHA6, FIVHA7

Groundwater FIVHA1, FIVHA2, FIVHA3, FIVHA4, FIVHA5, FIVHA6, FIVHA7

Artificial water bearing infrastructure (1)

FIVHA1, FIVHA2, FIVHA3, FIVHA4, FIVHA5, FIVHA6, FIVHA7

Sewerage systems


Other (described below if applicable)


(1) The FI authorities subsequently commented that a separate layer about the hazard area caused by dam breach is available in the Finnish version of the flood map service (“Patojen vahingonvaara-alueet”). However, when checked by the MS assessor, the layer was found to show no new or different features to distinguish it as showing the hazards associated with dam breach, as opposed to other flood sources.

Other: Not relevant

Comments

Based on the information on the Environment Administration website, the Centre for

Economic Development, Transport and the Environment (ELY-keskus) assessed riverine

flood risks (vesistötulvat, including rivers and lakes) and sea water flood risk. The

methodology applied is similar across the RBDs with some regional differences due to natural

circumstances. It is stated that municipalities were responsible for flood risks caused by

pluvial and snowmelt water in built-up urban areas. The methodology, reporting and Excel

data sheets to be filled in for pluvial/snow melt water were prepared by the Finnish

Environment Institute SYKE. Separate maps for pluvial flooding sources have not yet become

available on the map viewer. The FI authorities have clarified that this is because no APSFRs

12 December 2014

14 of 29

were named for pluvial floods; however, developing work is ongoing. Generic information on

the GIS-based approach of flood risk mapping used in Finland is available here:

http://www.ymparisto.fi/en-

US/Waters/Floods/Flood_risk_management/Flood_risk_management_planning/Flood_mappi

ng/Flood_mapping(8888) (in English)

On the maps the flooding sources can be differentiated for riverine floods (vesistötulvat) and

for sea water floods. There is no information as to what exactly the former contains, but the FI

authorities have since clarified that it covers only fluvial sources because groundwater and

pluvial floods are not relevant or designated as APSFRs. Based on the information reported

to WISE fluvial, coastal and pluvial floods were assessed (although no APSFRs for pluvial

floods were identified). However, based on the information available on the Environment

Administration website, flood risk maps will be made available for storm water (pluvial floods

including floods caused by snowmelt and rainfall): these have not yet become available on

the published maps. There was no information found on whether the impact of groundwater or

sewage system failures was assessed, but these sources seem not to be / are not relevant in

Finland. One APSFR was reported to be associated with flooding from artificial water bearing

infrastructure in 2012 and the Finnish authorities have subsequently clarified that a separate

layer on the hazard area caused by dam breach is available in the Finnish version of the flood

map service.

Flood risk maps have been prepared for the probabilities 1/20 years, 1/50 years, 1/100 years,

1/250 years, 1/1,000 years. In addition, the flood risk maps also higher probabilities are

considered for certain areas - 1/10 years, 1/5 years and approximately 1/2 years (the

maximum probability scenarios differ according to RBDs and APSFRs, in FIVHA2 and

FIVHA3 maps have been prepared for all probability scenarios until the highest 1/2 years

(50%) probability, whereas in the rest of the FIVHAs the maximum probability shown seems

to be 1/20 years). The extent of floods is clearly visible and maps are easily navigable.

http://www.ymparisto.fi/en-US/Waters/Floods/Flood_risk_management/Flood_risk_management_planning/Flood_mapping/Flood_mapping(8888)



12 December 2014

15 of 29

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 1 x 250;1 x 1,000

0.1%;0.4% very rare flooding

Medium probability

1 x 50;1 x 100 1%;2% occasional flooding

High probability 1 x 20;1 x 10;1 x 5;1 x 2

5%;10%;20%;50% frequent flooding

Summary of the information found and in particular any differences between the UoMs in the Member State. The probability rate for all maps is displayed either as a percentage, in a text (ranging from very rare flooding until frequent/yearly flooding) and occurrence rate (probability is shown for 1/1,000, 1/250, 1/100, 1/50, 1/20, 1/10, 1/5 and 1/2 years). This approach applies across the RBDs. Elements mapped or assessed

Scenario Flood extent Water depth/level

Water/flow velocities

Other

Low probability Yes Yes No

Medium probability

Yes Yes No

High probability Yes Yes No

Summary of the information found and in particular any differences between the UoMs in the Member State. Water depth during the floods is shown visually, explanation is provided in the legend (scale from below 0.5m until above 3m from the ground), the scale used is the same for riverine floods and for sea water floods. Water levels are shown when selecting a specific area on the map. The reference base of the water levels is not immediately apparent. The FI authorities have clarified that it can be found using the “find data on the map” tool. Water levels are shown for each probability scenario. No information was found concerning flow velocities. This applies to all of the RBDs. Methods used

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

Fluvial floods cover floods due to river systems (vesistötulvat, includes rivers and lakes) and apply to open water bodies (without ice coverage).Flood risk maps have been prepared for the probabilities 1/20 years, 1/50 years, 1/100 years, 1/250 years, 1/1000 years. In addition, the flood risk maps also higher probabilities are considered for certain areas - 1/10 years, 1/5 years and approximately 1/2 years (the maximum probability scenarios differ according to RBDs and APSFRs, in FIVHA2 and FIVHA3 maps have been prepared for all probability scenarios until the highest ½ years (50%) probability, whereas in the rest of the FIVHAs the maximum probability shown seems to be 1/20 years). There is no information available

12 December 2014

16 of 29

as to whether other probability scenarios were considered and tested in the development of maps. River water discharges and water levels in lakes are determined using either observation data and the statistical method, or if the data has not been available, the hydrological model (Hydrological Model System, SYKE-WSFS). Statistical method is based on the data extracted from the observation station: longest observation period for each year and the largest one-day average flow estimate. Overflow rate is adapted according to the Gumbel probability distribution, which provides the estimates for the return periods. Hydrological model system for a given return period flood is obtained when applying an average rainfall data and calculating e.g. 40-year period average for water overflows. The method applied is said to be very reliable also in case of used waterways. In case of rivers one-dimensional hydraulic HEC-RAS flow model has been used to define the water level (http://www.hec.usace.army.mil/software/hec-ras). The calculation is performed using the data of stationary flow. The necessary input data for cross-sections are measured in mm. depth soundings and GPS-based line data. The model is calibrated to the observed water levels.

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

From the maps once a specific area from the APSFR is chosen, the water level is shown for all probability scenarios. In case a very high probability flood indicates as a result a minor flooded area, a map has not been prepared.

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

The measurement series used are in most cases based on 40 years periods.

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 FI authorities have clarified that the scale is 1:20 000 and it is possible to zoom in and out.

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

For the topography of the maps the National Land Survey (Maanmittauslaitos) digital terrain models produced by precise laser scanning (2 m x 2 m screen size) were used. The maps terrain model is produced in laser scanner that has a pixel density of at least 0.5 points per square metre. Terrain level of the flood maps is accurate to an average of 0.3

http://www.hec.usace.army.mil/software/hec-ras

http://www.hec.usace.army.mil/software/hec-ras

12 December 2014

17 of 29

metres.

How were existing flood defences taken into account?

From the reported information, it is unclear how flood defences were taken into account. Finland does not provide a direct answer to this question. The presented methodology and reported information provides arguments for both considering and not considering flood defences in the flood risk calculation. Firstly, the use of the HEC-RAS model could imply the consideration of the flood defence structures through the cross-sections (input data for HEC-RAS). By contrast, it is not common practice to cover flood defences in hydrological modelling. It is unclear whether the hydrological model that was used (SYKE- WSFS) is able to integrate flood defences. Finally, the Finnish statement that “On flood protected areas, the same water level is applied on both sides of the flood protection defence”, raises questions on how flood defences have been considered.

How were existing infrastructure or buildings taken into account?

For existing infrastructure the data from the national Building and Dwelling Register is used. The data for infrastructure is updated for all the flood scenarios to wherever the flood hazard maps are updated. Flood risk areas are calculated and show in addition to the water depth the number of inhabitants (permanent and temporary separately) and floor areas according to their sector of activity. Building heights are set according to ground level using the digital terrain model, the data from the construction and buildings registry does not contain information on plinth or lowest floor surface height. Using flood risk areas exploitation is necessary to take into account the impact of the situation according to the height of the buildings, their vulnerability and instability.

What other data sets were used? According to the information reported to WISE several other data sets were used, including the Construction and Building Registry, information from the national statistics office. For the specific data sets used please see questions 5a-d

What are the key assumptions of the method?

River water discharges and water levels in lakes are determined using either observation data or the statistical method, or if the data has not been available, the hydrological model (Hydrological Model System, SYKE-WSFS). Hydrological model system for a given return period flood is obtained when applying an average rainfall data and calculating e.g. 40-year period average for water overflows.

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

Terrain level of the flood maps is accurate to an average of 0.3 metres. It is reported to WISE that the flood probability of 1/250 years might have a confidence level of 95% of 1/100

12 December 2014

18 of 29

years...1/1,000 years, additional effects by the varying climate change scenarios. Such uncertainties are said to affect the possibility to use the flood maps for land use planning.

What were the shortcomings of the method? No information found.

What were the advantages of the method? No information found.

12 December 2014

19 of 29

B) Pluvial floods

The FI authorities have clarified that flood maps for pluvial floods were not produced in Finland. No APSFRs were identified for pluvial floods.

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 1 x 250; 1 x 1000

0.1%;0.4% very rare flooding

Medium probability

1 x 50; 1 x 100 1%;2% occasional flooding

High probability 1 x 20; 1 x 10; 1 x 5; 1 x 2

5%;10%;20%;50% frequent flooding

Summary of the information found and in particular any differences between the UoMs in the Member State. The probability rate for all maps is displayed either as a percentage, in a text (ranging from very rare flooding until frequent/yearly flooding) and occurrence rate (probability is shown for 1/1000, 1/250, 1/100, 1/50, 1/20, 1/10, 1/5 and 1/2 year). This approach applies across the RBDs. Elements mapped or assessed

Scenario Flood extent Water depth/level

Water/flow velocities

Other

Low probability Yes Yes No

Medium probability

Yes Yes No

High probability Yes Yes No

Summary of the information found and in particular any differences between the UoMs in the Member State. On the maps, the flooding sources can be differentiated for river system floods (vesistötulvat) and for sea water floods. Methods used

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

Flood risk maps have been prepared for the probabilities 1/20 years, 1/50 years, 1/100 years, 1/250 years, 1/1000 years. In addition, the flood risk maps also higher probabilities are considered - 1/10 years,1/5 years and approximately 1/2 years (the maximum probability scenarios differ according to RBDs and APSFRs, in FIVHA2 and FIVHA3 maps have been prepared for all probability scenarios until the highest 1/2years (50%) probability, whereas in the rest of the FIVHAs the maximum probability shown seems to be 1/20 years). There is no information available as to whether other probability scenarios were considered and tested in the development of

12 December 2014

20 of 29

maps. The Finnish Meteorological Institute has identified flood mapping for each flood scenario (probability / return period) based on sea water levels (N2000-level system) using marigraphs or the data from water level measuring stations (13 station, period 1982-2011). The calculations based on this data take into account, inter alia. short-term water level fluctuations, the theoretical mean of water, changes in land elevation due to ocean height variations.

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

From the maps once a specific area from the APSFR is chosen, the water level is shown for all probability scenarios. In case a very high probability flood indicates as a result a minor flooded area, a map has not been prepared.

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

The Finnish Meteorological Institute has calculated return periods / probabilities for coastal flooding based on sea water levels (N2000-level system) using marigraphs or the data from water level measuring stations. It is reported that the measurement series used for sea level were from years 1982-2011 and were taken from 13 monitoring stations.

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 FI authorities have clarified that the scale is 1:20 000 and it is possible to zoom in and out.

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

For the topography of the maps, the National Land Survey (Maanmittauslaitos) digital terrain models produced by precise laser scanning (2 m x 2 m screen size) were used. The digital terrain model is produced in laser scanner that has a pixel density of at least 0.5 points per square metre. Terrain level of the flood maps is accurate to an average of 0.3 metres.

How were existing flood defences taken into account?

The information on existing flood defences was taken from the data from national construction and building register. In case of flood protection the same water level is applied as on the other side of the flood protection. In this way a general picture of the flood protection benefit to the area appears – for example the area can have a flood risk due to sewage failure. On the maps in areas where one or more of the flood scenarios exceeds the flood protection level, embankment failure/overrun is reported.

How were existing infrastructure or buildings taken into account?

For existing infrastructure the data from the national construction and building registry is

12 December 2014

21 of 29

used. The data for infrastructure is updated for all the flood scenarios to wherever the flood hazard maps are updated. Flood risk boxes are calculated to show in addition to the water depth rating the number of inhabitants (permanent and temporary separately), building volume and floor areas according to their sector of activity, as well as land-use categories. Building heights are set according to ground level using the digital terrain model, the data from the construction and buildings registry does not contain information on plinth or lowest floor surface height. Using flood risk boxes exploitation is necessary to take into account the impact of the situation according to the height of the buildings, their vulnerability and instability.

What other data sets were used? According to the information reported to WISE several other data sets were used, including the Construction and Building Registry, information from the national statistics office. For the specific data sets used please see questions 5a-d

What are the key assumptions of the method?

The Finnish Meteorological Institute has identified flood mapping for each flood scenario (probability / return period) based on sea water levels (N2000-level system) using marigraphs or the data from water level measuring stations (13 station, period 1982-2011). The calculations based on this data take into account, inter alia. short-term water level fluctuations, the theoretical mean of water, changes in land elevation due to ocean height variations.

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

Terrain level of the flood maps is accurate to an average of 0.3 metres. Confidence levels of floods probabilities are not indicated for coastal floods.

What were the shortcomings of the method? No information found.

What were the advantages of the method? No information found.

12 December 2014

22 of 29

D) Groundwater floods

Groundwater floods are not considered relevant in Finland and so are not included in the maps. E) Floods from Artificial Water Bearing Infrastructure Based on the information reported to WISE it is not clear whether and to what extent the floods caused by failures in the AWBI have been assessed. The FI authorities have since clarified that flood hazard maps for dam breaches are presented as a separate layer but other artificial water bearing infrastructure flood sources are not presented.

F) Floods from sewerage systems

Based on the information reported to WISE it is not clear whether and to what extent floods caused by failures in the sewerage systems have been assessed. The FI authorities have clarified that failures in sewerage systems are not included in the maps. G). Other types of floods

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

been mapped.

12 December 2014

23 of 29

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 data for the indicative number of inhabitants affected was drawn from the national and local authorities and most importantly from the National Building and Dwelling Register. The Register was the source of information detecting the number of inhabitants on the APSFR. The population affected is shown for each grid cell that is associated to particular APSFRs, following three categories: less than 10; 10-60; greater than 60. The total population affected is also available for each grid cell. The scale used is 1:20,000. Risk categories are calculated based on the Ministry of Interior operational reaction instruction A:71 (available here: http://www.finlex.fi/pdf/normit/15851-toimintavalmiusohje.pdf) A risk class is created when the class prescribed in terms of population or the floor area on the screen threshold values is satisfied. Boxes in which there is the highest risk are categorized as 1, boxes with the lowest risk are categorized as 5. Risk area is formed when at least ten risk classes are connected to each other. It is unclear from the reported information how the three population classes were allocated to five risk classes. The FI authorities have commented that information can be found on the webpage: http://www.ymparisto.fi/download/noname/%7B5AC94477-00B4-43DE-BE92-CFC5045149F7%7D/56979 (Table 1).

b) Risk to economic activity

The text below is based on the information reported to WISE. This information is valid for all the Finnish RBDs, except for FIVHA1 for which there has been no information reported to WISE. According to the Government Act on Flood Risk Management (659/2010) §3 the flood maps must display: -Infrastructure such as roads, energy grids, telecommunication networks, water supply and sewage facilities; -Community vital services All these different elements are displayed on the map as point locations and explained in the legend. Economic activity is displayed on the flood maps in the land cover background map (CLC 2006 25m). However, no explanation of the colours used is provided in the legend. It is stated that when reporting the risks to the economic activity the overall negative impact and injurious consequences were taken into account, considering the overall logic of the law 659/2010 and are therefore not differentiated in terms of damage to property / forestry / agricultural land. When assessing the flood risk and properties affected the impacts from floods such as water depth, blockage caused to vital infrastructures (e.g. rescue centres or hospitals), existing permanent and temporary flood protection structures, climate change, sewage flooding / basement floods etc. was taken into account. In addition the external impacts of floods, such as cut off in the electricity supply affecting hospitals or the power plant's cooling system no longer being operational was considered.

http://www.finlex.fi/pdf/normit/15851-toimintavalmiusohje.pdf

http://www.ymparisto.fi/download/noname/%7B5AC94477-00B4-43DE-BE92-CFC5045149F7%7D/56979

http://www.ymparisto.fi/download/noname/%7B5AC94477-00B4-43DE-BE92-CFC5045149F7%7D/56979

12 December 2014

24 of 29

In order to assess the risk for communication services base stations, communication centres and fibre optic cables have been identified according to the information from the register of construction and buildings; in addition the data from telecommunications’ operators and local telephone companies has been used. Information about energy generation and transmission sites (power plants, substations, transmission stations and power lines) has been compiled based on the information from the following sources: RHR, Environmental Monitoring and Pressures Information Systems (Vahti), National Land Survey of Finland (MML), terrain database management network, local electrical and transmission companies and the national power system administrator Fingrid.

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

Directive (IED) or previously under the IPPC Directive

The text below is based on the information reported to WISE. This information is valid for all the Finnish RBDs, except for FIVHA1 for which there has been no information reported to WISE. According to the Government Act on Flood Risk Management (659/2010) the flood risk maps must display installations covered by the requirements of the Industrial Emissions Directive. Information for this has mainly been obtained from the Environmental Monitoring and Pressures Information Systems (Vahti). According to the memo accompanying the Government Act on Flood Risk Management also other information relevant and likely to cause environmental damage should be included. The installations potentially causing environmental damage have been categorised into following risk type properties: - Fuel/chemical storage facilities - Sewage/waste water treatment plants - Waste treatment facilities - Stables - Fish farming facilities. If the installation is subject to an environmental permit requirement the information is available from the Vahti information system. To identify the hazardous chemicals and explosive production sites the information is retrieved from the registry of the Finnish Safety and Chemicals Agency (Tukes). The level of risk is classified in this planning cycle for all flood risk areas into two main categories: significant and non-significant. Significant sites have been reported to the EU. Non-significant items (representing a slight risk to the target), however, are used nationally, even if they do not fulfil the criteria set by the Act (659/2010). The practice is the same as for the preliminary flood risk assessments and the reporting on the APSFRs.

d) Risk to WFD protected areas

The text below is based on the information reported to WISE. This information is valid for all the Finnish RBDs, except for FIVHA1 for which there has been no information reported to WISE. According to the Government Act on Flood Risk Management (659/2010) the flood risk maps must display the following areas: - Zone from which a daily average of 10m

3 of drinking water are is taken/zone

providing drinking water to more than 50 people (source: statistical system VELVET and ground water information system POVET) - Bathing zones - Natura 2000 areas.

12 December 2014

25 of 29

The abovementioned areas are displayed as points on the map (icons explained in the legend). The exposure of these areas is visualised on the map, however the impact of floods on the protected areas and the criteria used to assess the impact and risk to WFD areas is not clear. Based on the information available, the criteria to determine the risk to a water body seems to be whether the flooding potentially causes deterioration to its environmental status or whether the floods through the impact on the water body/WFD protected area cause a direct threat to human health. The general criteria to assess risk as defined by the directive have been applied.

e) Other consequences considered

According to information reported to WISE, Finland has provided information on the floods map for the following point installations: - Health-care facilities (hospitals, health centres); - Buildings difficult to evacuate (retirement homes, mental care centres) - Kindergartens; - Fire stations; - Schools. This information is valid for all the Finnish RBDs, except for FIVHA1 for which there has been no information reported. The information for this has been retrieved from the Construction and Building Register. The additional information displayed on the maps related to cultural heritage sites and includes: - Libraries, archives, collections, and museums as well as art galleries (Source: Construction and Building Register) - Fixed antiquities (Source: National Registry for Archaeological Sites) - Protected buildings (Source: National Board of spatial data: special buildings protected by law; municipalities) - Cultural Environment (Source: Register of Nationally important cultural environments (RKY)) - World Heritage (Source: National Board of spatial data: World Heritage Sites) No other information is reported as to the criteria used to select and assess the potential risk to cultural heritage and the reasons for their selection. More information concerning flooding and cultural heritage in Finland is available here: http://www.ymparisto.fi/fi-FI/Vesi/Tulviin_varautuminen/Tulvariskien_hallinta/Tulvariskien_hallinnan_suunnittelu/Tulvakartoitus (in English).

http://www.ymparisto.fi/fi-FI/Vesi/Tulviin_varautuminen/Tulvariskien_hallinta/Tulvariskien_hallinnan_suunnittelu/Tulvakartoitus



12 December 2014

26 of 29

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 for FIVHA2, 3, 4, 5, 6, 7.

Justification for applying Article 6.7

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

applied?


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 for FIVHA2, 3, 4, 5, 6, 7.

Compliance of the use of Article 13.2 with the requirements of

Article 6

Question 9 Has the use of Article 13.2 provided a level of information in flood hazard and

flood risk maps equivalent to the requirements of Article 6?


12 December 2014

27 of 29

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

2 (FIVHA6, FIVHA7) Summary of the information reported and in particular any differences between UoMs

in the Member State.

According to the information reported to WISE in FIVHA6 cooperation with Sweden on the assessment and preparation of flood maps took place under the Interreg IV A North Programme during 2009-2012. During this project flood maps for the probability scenarios 1 x 100, 1 x 250 and according to the scenarios used in Sweden qualified as the lowest possible (BHF, corresponding to 1 x 10,000 years scenario) were prepared. More information on the project is available at http://www.smhi.se/2.153/professionella-tjanster/bygg-och-anlaggning/detaljerad-oversvamningskartering-i-nedre-delen-av-tornealven-1.18195 Finland wanted flood maps to be prepared also for more common probability scenarios; therefore Finland updated the flood risk maps for FIVHA6 in 2013. In the updated version, maps for probability scenarios for 1 x 20,1 x 50, 1 x 100, 1 x 250 and 1 x 1,000 years were prepared. The update included the area for which previously a common map had been prepared. Finland has since decided to use completely updated flood hazard maps, Sweden has instead opted for a common flood mapping showing 1 x 100 years and low probability scenarios and updated flood mapping for 1 x 50 year scenario (different modelling has been applied in the two countries). This divergence is known to both parties and has been discussed during the various stages of planning. After the update of the maps in 2013, it has been noted that the water levels shown do not coincide with the water levels identified in the joint Interreg project. Efforts are ongoing between the two authorities to harmonise the results. For the current period different maps have been published by the respective map services. In order to overcome the above-mentioned problems in the next planning cycle discussions are ongoing how to best make cross-country maps operational. In the FIVHA7 there are no APSFRs shared with Norway. The initial flood risk assessment was performed in close cooperation with Norwegian authorities. The management of joint planning and exchange of information with Russia is taking place under the Finnish-Russian Trans-boundary Water Commission (information exchange also concerning FIVHA5). In FIVHA7 the APSFRs shared with Russia are marginal, therefore the joint-flood mapping with Russia was estimated not to be necessary.

http://www.smhi.se/2.153/professionella-tjanster/bygg-och-anlaggning/detaljerad-oversvamningskartering-i-nedre-delen-av-tornealven-1.18195

http://www.smhi.se/2.153/professionella-tjanster/bygg-och-anlaggning/detaljerad-oversvamningskartering-i-nedre-delen-av-tornealven-1.18195

12 December 2014

28 of 29

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 Yes

For which sources of flooding Climate change impacts have only been calculated for a medium probability scenario (1x100 years); it can be concluded based on the reported information that climate change impacts have been considered for coastal/pluvial and fluvial flood sources. The FI authorities have clarified that although the climate change impacts have been calculated, they have not been mapped.

For low probability scenario N/A. Climate Change impacts were calculated for the medium probability scenario only.

For medium probability scenario Specific information on how climate change was taken into account when preparing the flood maps and how the impacts of climate change to floods has been calculated for the APSFs is provided below.

For high probability scenario N/A. Climate Change impacts were calculated for the medium probability scenario only.

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

Yes

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

Yes

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

Yes

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

Yes

Flood hazard scenarios included a statistical assessment of historical climate data

Yes

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

According to the information reported to WISE in order to take into account the effects of climate the Finnish Hydrological and Meteorological Institute has calculated, using tide gauges, the estimated water levels for years 2050 and 2100. In the calculations in addition to short term climate change impacts also long-term impacts were taken into account. These long-term impacts include ocean level rise and its unequal regional distribution (based on IPCC 2013 report), as well as the impact on the water levels from the rising of land and changes in wind direction. Finnish Environment Institute (SYKE) has estimated climate change impacts on 67 river basins across Finland, the results are made available for flood risk mapping. According to the Environment administration web site, separate maps showing the impacts of climate change are foreseen to become available. For the hydrological modelling the model SYKE-WSFS has

12 December 2014

29 of 29

been used. This model simulates daily average discharges for 30 year periods for 2010-2039 and 2070-2099 using 20 global and regional climate models. On the chosen time-series the Gumbel distribution has been used and an approximate average change in 1/100 years flooding has been calculated for both time periods.

assessment of flood hazard and flood risk maps information...

Documents