Flood-CBA#2 Training Seminars

Proforma B

Amadora Case Study

Amadora Case Study

A B C D E F

Collecting information regarding

the site that is to be assessed.

Collecting details about

(a) the current flood risk situation and (b) the key features at risk today and in the future from flooding at

the site.

Overview of the impacts

that are expected under the do-nothing

or the baseline scenario.

An assessment

of the possible future

changes and/or

interventions that may affect the

site

the potential of a range of

flood risk prevention measures and assess

their efficacy based on

CBA and/or MCA

methods

To be determined

1-4 5-11 12-15 16-18 19-23 24-27

5% 20% 25% 25% 10% 20%

Proforma

The rationale

Approx. % of the total

effort

Number of steps/tasks

Amadora Case Study

B

Collecting details about

(a) the current flood risk situation and (b) the key features at risk today and in the future from flooding at

the site.

5-11

20%

Proforma

The rationale

Approx. % of the total

effort

Number of steps/tasks

Task 5: For the site (in the past): Collect information on flood extent/history in the past (maps of flooding; numbers of properties

affected, and their types [e.g. residential; non-residential etc]; photos; etc)

Task 6: For the site (in the past): Collect information on any flood

damages and/or disruption to economic activities (i.e. traffic; railways; agriculture) in the past

Task 7: For the site (in the past): Collect details any injuries and loss

of life in floods in the past here.

Task 8: For the site (now and in the future): Collect data on Flood hydrology (flows; flood return periods; flood extents, etc) for the site.

Task 9: For the site (now and in the future): Collect data on modelled

or estimated future flood extents (geographical areas) by return period (e.g. for the 2; 5; 20; 50; 100 year floods).

Task 10: For the site (now and in the future): Collect data on property

numbers and types [e.g. residential; non-residential etc] in each of those areas identified above.

Task 11: For the site (now and in the future): Collect data on population numbers (estimated) in each of those areas.

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and (b) the key features at risk today and in the future from flooding at the site.

Task 5 For the site (in the past): Collect information on flood extent/history in the past (maps of flooding; numbers of properties affected, and their types [e.g. residential; non-residential etc]; photos; etc)

It will be useful to know the extent to which the study location has a history of flooding, to inform both our assessment of damages and our elaboration of potential risk reducing measures. For example, it will be useful to know whether the area is affected very rarely by major events or

regularly by minor floods.

Tasks 5-11

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Task 5 For the site (in the past): Collect information on flood extent/history in the past (maps of flooding; numbers of properties affected, and their types [e.g. residential; non-residential etc]; photos; etc)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Difficulty in outflow

Flooded area

Land slide

Street in bad conservation

sediments and garbage flows with the water

Flooded area

2 meters acumulated

in shirts factory FLOOD PAST

EVENT Damaia de Baixo (1983)

Amadora Case Study

Task 5 For the site (in the past): Collect information on flood extent/history in the past (maps of flooding; numbers of properties affected, and their types [e.g. residential; non-residential etc]; photos; etc)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

FLOOD PAST EVENT

Damaia de Baixo (2005)

Flooded streets by emergency calls

Yellow = between 1 to 3 emergency calls Orange = between 3 to 5 emergency calls Purple = more than 5 emergency calls

Amadora Case Study

Task 5 For the site (in the past): Collect information on flood extent/history in the past (maps of flooding; numbers of properties affected, and their types [e.g. residential; non-residential etc]; photos; etc)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Damaia de Baixo Floods

18th February / 29th April / 28th May 2011

6,2

1,4

4,4

7,7

17

6,4

13,9

31,2

3

8,8

3,5

10,1

1,7 0,7 0 0 0 0 0 0 0 0,1 0 0

0

10

20

30

40

(mm

)

Hourly Rainfall – 18th February 2008

Weather Station SNIRH - Cacém

Rainfall/hour

0 0 0 0 0 0 0 0 0 0,1 0 0 0 0 0

8

1,2

3,4

0,5 0 0 0 0 0

0

2

4

6

8

10

(mm

)

Hourly Rainfall – 28th May 2011

Weather Station SNIRH - Cacém

Rainfall/hour

Airmass from Meteosat at 12 am on 29th April

Atmospheric pressure field on 29th April

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and (b) the key features at risk today and in the future from flooding at the site.

Task 6 For the site (in the past): Collect information on any flood damages and/or disruption to economic activities (i.e. traffic; railways; agriculture) in the past

It will be useful to have an idea of the kind of damages that are caused in this location, not least so we can concentrate on those areas where damage is greatest.

Tasks 5-11

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Task 6 For the site (in the past): Collect information on any flood damages and/or disruption to economic activities (i.e. traffic; railways; agriculture) in the past

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Dom Pedro V Avenue, 2010

The situation in Damaia de Baixo:

4 buildings directly affected 12 businesses directly affected 125 residents directy affected

5 bus lines interrupted

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and(b) the key features at risk today and in the future from flooding at the site.

Task 7 For the site (in the past): Collect details any injuries and loss of life in floods in the past here.

It is important to stress within the case studies that economics using money values is not the whole story. Many intangible impacts from floods, and injury and loss of life are two of these.

Tasks 5-11

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Amadora Case Study

Task 7 For the site (in the past): Collect details any injuries and loss of life in floods in the past here.

Dom Pedro V Avenue, 2010

The situation in Damaia de Baixo:

No injuries or loss of life

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and(b) the key features at risk today and in the future from flooding at the site.

Task 8 For the site (now and in the future): Collect data on Flood hydrology (flows; flood return periods; flood extents, etc) for the site

Any assessment of the benefits of flood risk reduction requires the assessment of the impact in the future of a range of events of different return periods. Taking a single event is likely to lead to

gross errors. See Annex B4

Tasks 5-11

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and(b) the key features at risk today and in the future from flooding at the site.

Task 8 For the site (now and in the future): Collect data on Flood hydrology (flows; flood return periods; flood extents, etc) for the site

Any assessment of the benefits of flood risk reduction requires the assessment of the impact in the future of a range of events of different return periods. Taking a single event is likely to lead to

gross errors. See Annex B4

Tasks 5-11

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Task 8 For the site (now and in the future): Collect data on Flood hydrology (flows; flood return periods; flood extents, etc) for the site

Dom Pedro V Avenue, 2010

The situation in Damaia de Baixo:

No flood hydrology data Just flood extents

The return periods were drawned to this case study

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Task 8 For the site (now and in the future): Collect data on Flood hydrology (flows; flood return periods; flood extents, etc) for the site

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Return periods

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and(b) the key features at risk today and in the future from flooding at the site.

Task 9 For the site (now and in the future): Collect data on modelled or estimated future flood extents (geographical areas) by return period (e.g. for the 2; 5; 20; 50; 100 year floods)

Each of the floods of different severities in the future, the return periods of which are estimated, needs to have a map showing the properties affected. The rare floods (e.g. 1:100 years) will affect more properties than the more common floods (e.g. 1:10 years). If this is not the case, the data is

likely to be flawed.

Tasks 5-11

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Task 9 For the site (now and in the future): Collect data on modelled or estimated future flood extents (geographical areas) by return period (e.g. for the 2; 5; 20; 50; 100 year floods)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Return periods

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and(b) the key features at risk today and in the future from flooding at the site.

Task 10 For the site (now and in the future): Collect data on property numbers and types [e.g. residential; non-residential etc] in each of those areas identified above

This is a crucial ingredient, identifying properties and potential damage from events of different return periods. This is what will be used to calibrate the loss-probability curve (see Annex B4).

Tasks 5-11

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Amadora Case Study

Task 10 For the site (now and in the future): Collect data on property numbers and types [e.g. residential; non-residential etc] in each of those areas identified above

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Annual chance of flood (% AEP*)

Residential buildings *

Commercial property *

Total *

1 in 2 (50%) 4 12 16

1 in 10 (10%) 4 12 16

1 in 20 (5%) 6 16 22

1 in 50 (2%) 6 16 22

1 in 100 (1%) 6 16 22

*Figures include properties at risk of flooding above threshold for the Do Nothing option

* Annual Exceedance Probability sometimes shown as 0.20, 0.10, etc.

Amadora Case Study

Proforma B Collecting details about (a) the current flood risk situation and(b) the key features at risk today and in the future from flooding at the site.

Task 11 For the site (now and in the future): Collect data on population numbers (estimated) in each of those areas.

It may be possible to assess the number of properties in the area from the population that lives there, in the absence of better information (i.e. divide population by c. 2.3 to identify the number of households/houses). In any case this information may be useful for assessing the potential loss

of life or injury during floods, related to the population living there.

Tasks 5-11

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Amadora Case Study

Task 11 For the site (now and in the future): Collect data on population numbers (estimated) in each of those areas.

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Annual chance of flood (% AEP*)

Total Population (estimated)

1 in 2 (50%) 124

1 in 10 (10%) 208

1 in 20 (5%) 208

1 in 50 (2%) 208

1 in 100 (1%) 208

* Annual Exceedance Probability sometimes shown as 0.20, 0.10, etc.

Flood-CBA#2 Training Seminars

End of Proforma B

Amadora Case Study

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