Proposed pebble bed modular reactor



Download 3.96 Mb.
Page11/17
Date conversion31.03.2018
Size3.96 Mb.
1   ...   7   8   9   10   11   12   13   14   ...   17

u = observers who will be aware of the new development

If the context theory is applied, tourists will clearly note the proposed structure from these roads. The awareness of regular viewers, who travel on the above roads regularly and at a speed, will become accustomed to the structure with time, until the element blends into the overall picture. The same principle would be applicable for people who work or stay in Duynefontyn, Van Riebeeckstrand, Melkbosstrand and Atlantis, where observation fades with time.

According to Bentley (1996: p. 42) users, rather than designers, form images of layout, the designer merely arranges the physical layout itself to achieve legibility. Legibility can be defined as the quality that makes a place graspable, and that enables people to form clear, accurate images of a city/ structure or new entity. Table Mountain and Robbeneiland are of natural-, historical- and cultural significance. These landmarks contribute to the legibility of Cape Town.

Researchers have explored the contents of these images, using techniques such as interviews, asking directions to places, and getting people to draw maps from memory. Certain types of physical features play a key role in the content of these shared images. Kevin Lynch, an American planner, grouped these features into five key elements, namely nodes, edges, paths, districts and landmarks. These key physical elements are illustrated below.

 

THE KEY PHYSICAL ELEMENTS, WHICH CONSTITUTE THE SKELETON OF THE URBAN IMAGE – BENTLEY (1996: p. 43)



The most significant viewing points would be the Koeberg Private Nature Reserve, Table Mountain and Robbeneiland, due to the awareness and category of users, which mainly entails tourists. Table Mountain and Robbeneiland, however, are located at distances of 31 and 15km respectively from the proposed structures, which implies that the proposed reactor will not be seen as an individual element, but becomes part of its surroundings and speaks mainly through its silhouette.

The character of the respective viewing points is rated in Table 17-29.



Table 17‑29: CHARACTER OF VIEWING POINTS

VIEWING POINTS

VISUAL EXPOSURE

IMPORTANT VISTAS/ VIEWPOINTS

43CHARACTER

FEATURE/ 44LANDMARK

West Coast Road

High

No

rural, agricultural

no

The National N7 Road

High

No

rural, agricultural

no

Otto du Plessis Drive

Low

No

rural, agricultural

no

Mamre-Darling Road

Low

No

rural, agricultural

no

Dassenberg Road

Low

No

rural, agricultural

no

Philadelphia Road

Low

No

rural, agricultural

no

Brakfontein road

Low

No

rural, agricultural

no

Melkbosstrand road

Low

No

rural, agricultural

no

Duynefontyn

High

No

suburban

no

Van Riebeeckstrand

High

No

suburban

no

Melkbosstrand

High

No

suburban

no

Table Mountain

Low

yes (tourism)

natural

yes

The Atlantic Ocean

Low

No

natural

yes

Koeberg Nature Reserve & visitors centre

High

yes (tourism)

natural

yes

Atlantis residential area

Low

No

suburban

no

Atlantis industrial area

Low

No

suburban

no

Robbeneiland

Low

yes (tourism)

natural, suburban

yes

 

17.8. ASSESSMENT OF VISUAL IMPACTS

17.8.1. DESCRIPTION OF METHODOLOGY FOR ASSESSMENT OF SIGNIFICANCE

The Department of Environmental Affairs and Tourism has published a guideline document on the implementation of sections 21, 22 and 26 of the Environment Conservation Act, 1989. The mentioned document states that the significance of impacts can be determined through a synthesis of the aspects produced in terms of the nature, duration, intensity, extent and probability of identified impacts.

Poltech (Pty) Ltd has developed a Significance Assessment Methodology in accordance with the above guidelines. In terms of the above methodology the significance of an impact is the product of a probability rating and a severity rating. This methodology has been adapted by ILA (Pty) Ltd for the purposes of visual impact assessments. A detailed description of the mentioned methodology is as follows.

The Probability Rating is determined from the following, namely:

Improbable - Low possibility of visual impact to occur

- Rating:2

Probable - Distinct possibility that visual impact will occur.

- Rating: 3

Highly probable - Most likely that visual impact will occur.

- Rating: 4

Definite - Visual impact will occur, in the case of adverse impacts regardless of any prevention measures.

- Rating: 5

The Extent factor is awarded to each impact according to the following method:

Low extent - visual perception not affected to a measurable extent or local impact

- Factor 1

 

Medium extent - regional impact



-          Factor 2

High extent - national impact

- Factor 4

The duration of the visual impact is assessed and a factor awarded in accordance with the following:

Short term - <1 to 5 years - Factor 2

Medium term - 5 to 15 years - Factor 3

Long term - visual impact will only cease after the operational life of the activity, either because of natural process or by human intervention

- Factor 4.

Permanent - mitigation, either by natural process or by human intervention, will not occur in such a way or in such a time span that the visual impact can be considered transient

- Factor 4.

The severity rating is obtained from calculating a severity factor by multiplication of the Extent and Duration Factors. The Severity factor is used to determine the Severity Rating from Table 17-31.

The Severity factor = Extent factor X Duration factor

= 2 x 3

= 6


A Severity factor of six (6) equals a Severity Rating of Medium severity (Rating 3) as per table below:

Table 17‑30: SEVERITY RATINGS



RATING

FACTOR

Low Severity (Rating 2)

Calculated values 2 to 4

Medium Severity (Rating 3)

Calculated values 5 to 8

High Severity (Rating 4)

Calculated values 9 to 12

Very High severity (Rating 5)

Calculated values 13 to 16

Severity factors below 3 indicate no impact

 

The Severity Rating and Probability Rating determined by the methodology described above are multiplied to calculate the Significance Rating of the specific environmental impact. The Significance Rating is used to determine the level of mitigation (adverse impacts) required or enhancement (beneficial impacts), as per the following classification, namely:



Low significance (calculated Significance Rating 4 to 6)

Positive impact and negative impacts of low significance should have no influence on the proposed development project.



Medium significance (calculated Significance Rating >6 to 15)

Positive impact:

Should weigh towards a decision to continue with the proposed development.

Negative impact:

Should be mitigated to a level where the impact would be of low significance before project can be approved.

High significance (calculated Significance Rating 16 and more)

Positive impact:

Should weigh towards a decision to continue, should be enhanced in final design.

Negative impact:

Should weigh towards a decision to terminate proposal, or mitigation should be performed to reduce significance to at least low significance rating.

17.8.2. ANTICIPATED VISUAL IMPACTS

Utilising the information reflected in Table 17-27 - Table 17-30, a significance assessment of each visual impact was performed according to the methodology described in section 17.8.1. The results of the significance assessment for the existing Koeberg structures, the additional visual impact of the PBMR (northern site) and the additional impact of the PBMR (southern site) are depicted in Table 17-31, Table 17-32and Table 17-33respectively.

From Table 17-32, it is clear that the most significant viewing points towards the existing Koeberg structures would be the N7, the West Coast road and the Koeberg Private Nature Reserve and the deck of the Visitors centre, due to the location there-of and the category of observers, namely tourists.

The visual impact of the northern site for the proposed PBMR, seen in relation to the existing Koeberg structures, would have a lower significance in comparison to the southern site, as indicated by Table 17-32 and Table 17-33. The visual impact of the northern site for the proposed PBMR, see as a stand-alone structure, would have a lower significance in comparison to the southern site, as indicated by   and  . From these tables it is clear that the anticipated visual impact of the proposed PBMR will be less significant than the impact of the existing Koeberg structures, due to the scale of the proposed structures (refer to Appendix H).

17.8.3.ASSESSMENT OF ALTERNATIVE SITES FOR MODULAR REACTOR IN TERMS OF ASSOCIATED ACTIVITIES

The anticipated visual impacts for the two alternatives, as described in paragraph 17.6.1.,based on a subjective visual evaluation of the study area in terms of the associated activities, are indicated in Table 17-36.

For the purposes of this assessment, the following assumptions were made:

Ü        that the existing intake water stilling basin will not be extended, and

Ü        that the existing residential facilities will not be extended with more that 20 houses for the purposes of the Proposed Pebble Bed Modular Reactor.

that the proposed structure would be viewed from the 3 viewing points with the highest significance rating according to Table 17-32, Table 17-33,   and  , namely the West Coast Road, the National N7 Road and the Koeberg Nature Reserve and deck of the Visitors Centre.

Table 17‑31: SIGNIFICANCE ASSESSMENT OF IDENTIFIED VISUAL IMPACTS OF THE EXISTING KOEBERG STRUCTURES



VIEWING POINTS

PROBABILITY RATING

EXTENT FACTOR

DURATION

¹SEVERITY FACTOR

²SEVERITY RATING

³SIGNIFICANCE RATING

West Coast Road

5

2

4

8

3 medium

15 medium

The National N7 Road

5

2

4

8

3 medium

15 medium

Otto du Plessis Drive

4

1

4

4

2 low

8 medium

Mamre-Darling Road

4

1

4

4

2 low

8 medium

Dassenberg Road

4

1

4

4

2 low

8 medium

Philadelphia Road

4

1

4

4

2 low

8 medium

Brakfontein road

4

1

4

4

2 low

8 medium

Melkbosstrand road

4

1

4

4

2 low

8 medium

Duynefontyn

5

1

4

4

2 low

10 medium

Van Riebeeckstrand

5

1

4

4

2 low

10 medium

Melkbosstrand

5

1

4

4

2 low

10 medium

Table Mountain

3

2

4

8

3 medium

9 medium

The Atlantic Ocean

3

1

4

4

2 low

6 medium

Koeberg Nature Reserve & visitors centre(deck)

5

2

4

8

3 medium

15medium

Atlantis residential area

4

1

4

4

2 low

8 medium

Atlantis industrial area

4

1

4

4

2 low

8 medium

Robben island

2

2

24

4

2 low

4 low

¹The Severity factor = Extent factor x Duration factor

 

³The Significance rating = Severity rating x Probability Rating




= 2 x 3

 

 

 

 




= 6

 

 

 

High (Calculated significance rating 16 and more)






 

 

 

Medium (Calculated significance rating 7 to 15)




²Low Severity (Rating 2): Calculated values 2 to 4

 

 

 

Low (Calculated significance rating 4 to 6)




Medium Severity (Rating 3): Calculated values 5 to 8

 

 

 

 




High Severity (Rating 4): Calculated values 9 to 12

 

 

 

 




Very High Severity (Rating 5): Calculated values 13 to 16

 

 

 

 




Severity factors below 3 indicated no impact

 

 

 

 




Table 17‑32: SIGNIFICANCE ASSESSMENT OF IDENTIFIED VISUAL IMPACTS OF THE PROPOSED PBMR (NORTHERN SITE), SEEN IN RELATION TO THE EXISTING KOEBERG STRUCTURES

VIEWING POINTS

PROBABILITY RATING

EXTENT FACTOR

DURATION

¹SEVERITY FACTOR

²SEVERITY RATING

³SIGNIFICANCE RATING

West Coast Road

5

2

4

8

3 medium

15 medium

The National N7 Road

5

2

4

8

3 medium

15 medium

Otto du Plessis Drive

3

1

4

4

2 low

6 low

Mamre-Darling Road

3

1

4

4

2 low

6 low

Dassenberg Road

4

1

4

4

2 low

8 medium

Philadelphia Road

4

1

4

4

2 low

8 medium

Brakfontein road

4

1

4

4

2 low

8 medium

Melkbosstrand road

4

1

4

4

2 low

8 medium

Duynefontyn

4

1

4

4

2 low

8 medium

Van Riebeeckstrand

4

1

4

4

2 low

8 medium

Melkbosstrand

4

1

4

4

2 low

8 medium

Table Mountain

2

2

4

8

3 medium

6 low

The Atlantic Ocean

3

1

4

4

2 low

6 low

Koeberg Nature Reserve & visitors centre(deck)

5

2

4

8

3 medium

15 medium

Atlantis residential area

3

1

4

4

2 low

6 low

Atlantis industrial area

3

1

4

4

2 low

6 low

Robben Island

2

2

2

4

2 low

4 low

¹The Severity factor = Extent factor x Duration factor

 

³The Significance rating = Severity rating x Probability Rating

= 2 x 3

 

 

 

 

= 6

 

 

 

High (Calculated significance rating 16 and more)



 

 

 

Medium (Calculated significance rating 7 to 15)

²Low Severity (Rating 2): Calculated values 2 to 4

 

 

 

Low (Calculated significance rating 4 to 6)

Medium Severity (Rating 3): Calculated values 5 to 8

 

 

 

 

High Severity (Rating 4): Calculated values 9 to 12

 

 

 

 

Very High Severity (Rating 5): Calculated values 13 to 16

 

 

 

 

Severity factors below 3 indicated no impact

 

 

 

 
1   ...   7   8   9   10   11   12   13   14   ...   17


The database is protected by copyright ©ininet.org 2016
send message

    Main page