-
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 can be found in Appendix 12.
Anticipated Visual Impacts
Utilising the information reflected in, Table 28 and Table 29 a significance assessment of each visual impact was performed according to the methodology described in Appendix 12. 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 32 and Table 34 respectively.
From Table 35, 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 31 and Table 33. The visual impact of the northern site for the proposed PBMR, seen as a stand-alone structure, would have a lower significance in comparison to the southern site, as indicated by Table 31 and Table 33. 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.
Assessment Of Alternative Sites For Modular Reactor In Terms Of Associated Activities
The anticipated visual impacts for the two alternatives sites based on a subjective visual evaluation of the study area in terms of the associated activities, are indicated in Table 35.
For the purposes of this assessment, the following assumptions were made:
-
that the existing intake water stilling basin will not be extended, and
-
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 32, Table 34 and Table 35 namely the West Coast Road, the National N7 Road and the Koeberg Nature Reserve and deck of the Visitors Centre
Table 30: 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 31: 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
|
|
|
|
|
Table 32: SIGNIFICANCE ASSESSMENT OF IDENTIFIED VISUAL IMPACTS OF THE PROPOSED PBMR (SOUTHERN 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
|
5
|
1
|
4
|
4
|
2 low
|
10 medium
|
Mamre-Darling Road
|
5
|
1
|
4
|
4
|
2 low
|
10 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
|
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
|
2
|
1
|
4
|
4
|
2 low
|
4 low
|
Atlantis industrial area
|
2
|
1
|
4
|
4
|
2 low
|
4 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
|
|
|
|
|
Table 33: SIGNIFICANCE ASSESSMENT OF IDENTIFIED VISUAL IMPACTS OF THE PROPOSED NEW STRUCTURES (NORTHERN SITE), SEEN AS A STAND-ALONE STRUCTURE
VIEWING POINTS
|
PROBABILITY RATING
|
EXTENT FACTOR
|
DURATION
|
¹SEVERITY FACTOR
|
²SEVERITY RATING
|
³SIGNIFICANCE RATING
|
West Coast Road
|
4
|
2
|
3
|
6
|
3 medium
|
12 medium
|
The National N7 Road
|
4
|
2
|
3
|
6
|
3 medium
|
12 medium
|
Otto du Plessis Drive
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Mamre-Darling Road
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Dassenberg Road
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Philadelphia Road
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Brakfontein road
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Melkbosstrand road
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Duynefontyn
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Van Riebeeckstrand
|
2
|
1
|
2
|
2
|
2 low
|
4 medium
|
Melkbosstrand
|
2
|
1
|
2
|
2
|
2 low
|
4 medium
|
Table Mountain
|
2
|
2
|
4
|
8
|
3 medium
|
6 medium
|
The Atlantic Ocean
|
3
|
1
|
4
|
4
|
2 low
|
6 medium
|
Koeberg Nature Reserve & visitors centre(deck)
|
5
|
2
|
4
|
8
|
3 medium
|
15 medium
|
Atlantis residential area
|
3
|
1
|
3
|
3
|
2 low
|
6 medium
|
Atlantis industrial area
|
3
|
1
|
3
|
3
|
2 low
|
6 medium
|
Robben Island
|
2
|
2
|
2
|
4
|
2 low
|
2 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 34: SIGNIFICANCE ASSESSMENT OF IDENTIFIED VISUAL IMPACTS OF THE PROPOSED STRUCTURES
(SOUTHERN SITE), SEEN AS A STAND-ALONE STRUCTURE
VIEWING POINTS
|
PROBABILITY RATING
|
EXTENT FACTOR
|
DURATION
|
¹SEVERITY FACTOR
|
²SEVERITY RATING
|
³SIGNIFICANCE RATING
|
West Coast Road
|
4
|
2
|
3
|
6
|
3 medium
|
12 medium
|
The National N7 Road
|
4
|
2
|
3
|
6
|
3 medium
|
12 medium
|
Otto du Plessis Drive
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Mamre-Darling Road
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Dassenberg Road
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Philadelphia Road
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Brakfontein road
|
3
|
1
|
2
|
2
|
2 low
|
6 medium
|
Melkbosstrand road
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Duynefontyn
|
4
|
1
|
2
|
2
|
2 low
|
8 medium
|
Van Riebeeckstrand
|
5
|
1
|
2
|
2
|
2 low
|
10 medium
|
Melkbosstrand
|
5
|
1
|
2
|
2
|
2 low
|
10 medium
|
Table Mountain
|
2
|
2
|
4
|
8
|
3 medium
|
6 medium
|
The Atlantic Ocean
|
3
|
1
|
4
|
4
|
2 low
|
6 medium
|
Koeberg Nature Reserve & visitors centre(deck)
|
5
|
2
|
4
|
8
|
3 medium
|
15 medium
|
Atlantis residential area
|
2
|
1
|
2
|
2
|
2 low
|
4 low
|
Atlantis industrial area
|
2
|
1
|
2
|
2
|
2 low
|
4 low
|
Robben Island
|
2
|
2
|
2
|
4
|
2 low
|
2 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 35: VISUAL IMPACT OF ACTIVITIES OF ALTERNATIVE SITES
ACTIVITIES
|
¹WEST COAST ROAD
|
²NATIONAL N7 ROAD
|
³KOEBERG NATURE RESERVE AND DECK OF THE VISITORS CENTRE
|
Alternative 1 (North)
|
Alternative 2
(South)
|
Alternative 1
(North)
|
Alternative 2
(South)
|
Alternative 2 (North)
|
Alternative 2
(South)
|
CONSTRUCTION PHASE
|
|
|
|
|
|
|
Modular Reactor unit
|
3
|
3
|
3
|
3
|
2
|
3
|
Water supply
|
2
|
2
|
2
|
2
|
2
|
2
|
Intake water stilling basin
|
0
|
0
|
0
|
0
|
0
|
0
|
Transmission network
|
3
|
3
|
3
|
3
|
3
|
3
|
Sewage facilities
|
2
|
2
|
2
|
2
|
2
|
2
|
Roads
|
3
|
3
|
2
|
2
|
3
|
3
|
Residential areas
|
1
|
1
|
1
|
1
|
1
|
1
|
|
14
|
14
|
13
|
13
|
13
|
14
|
OPERATIONAL PHASE
|
|
|
|
|
|
|
Modular Reactor unit
|
2
|
2
|
2
|
2
|
1
|
2
|
Water supply
|
1
|
1
|
1
|
1
|
1
|
1
|
Intake water stilling basin
|
0
|
0
|
0
|
0
|
0
|
0
|
Transmission network
|
3
|
3
|
3
|
3
|
3
|
3
|
Sewage facilities
|
1
|
1
|
1
|
1
|
1
|
1
|
Roads
|
2
|
2
|
1
|
1
|
1
|
2
|
Residential areas
|
1
|
1
|
1
|
1
|
1
|
1
|
|
9
|
10
|
9
|
9
|
8
|
10
|
0: no significance
|
|
|
1: low significance
|
|
|
|
|
2: medium significance
|
|
|
|
|
3: high significance
|
|
|
|
|
¹ Viewed at a 2km distance from the proposed structure
|
|
|
|
|
² Viewed at a 12 km distance from the proposed structure
|
|
|
|
|
³ Viewed at a distance of less than 2km from the proposed structure
|
|
|
|
|
From the above table it can be derived that the visual impact of the proposed pebble bed modular reactor will be considerably higher during the construction phase of the development. Alternative 1(northern site) will have a lower visual impact than alternative 2 (southern site) during the operational phase. However for engineering reasons consideration of this option was discontinued.
Mitigation Measures -
The form of the proposed structure, as well as the material finish, should relate well to the existing structures and the existing landscape. The colour of the sand and the existing vegetation, the typical patterns of light and shade, the horizon line and the spatial characteristics of the landscape will be reflected in the design of the structure.
-
Trees which are endemic to the area, should be grouped along the roads with viewing points towards the proposed structure to simulate natural tree groups to screen the views towards the Modular Reactor, as well as the infrastructure (transmission network, roads, services) associated with the proposed development. Regular spacing and the placement trees in rows should be avoided, in order to simulate natural stands.
-
The provision of large screen planting, endemic to the study area, outside the Koeberg site boundaries, should be considered to act as a screen for the adjacent residential townships.
Conclusion
It is the recommendation of ILA (PTY) Ltd, based on the above visual impact assessment, that the construction of the proposed Pebble Bed Modular Reactor be authorised, conditional to the above recommendations, for the design and construction phases of the proposed project, as its proposed Plant will have a negligible visual impact on the surrounding landscape.
The proposed PBMR would have a medium significant impact on the visual character of the surrounding environment from all the viewing points, in particular the adjacent townships and roads during the construction phase. During the operational phase, however, the visual impact will be less significant.
The proposed design is aesthetically acceptable, and it is recommended that the architectural style of the existing Koeberg structures is continued with the detail design of the PBMR.
Acknowledgements And References
Bentley Alcock Murrain McGlynn Smith: Responsive environments: A manual for designers. Butterworth Architecture: Oxford.
Brown, Rodney. Van Riet & Louw Landscape Architects
Eskom: Koeberg Site Safety Report.
Jacobs, A.: (1993) Great Streets. Cambridge: The MIT Press
Kostoff, S. :(1992) The City Assembled – The elements of Urban Form through history. London: Thames and Hudson Ltd.
Laurie, M: (1978) An introduction to Landscape Architecture. Elsevier North-Holland: Pitman.
Motloch, J.L: (1991) An introduction to Landscape Design. New York: Van Nostrand Reinhold.
Oberholzer, B (1992) Visual and Aesthetic Assessment Techniques in Integrated Environmental Management. unpub. Paper.
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