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Sea level rise and coastal
erosion adaptation:
Coastal Development Set
Back lines
By
Andrew A. Mather
eThekwini Municipality, P.O. Box 680, Durban, 4051, South Africa. mathera@durban.gov.za
Presentation outline
• Definition of a coastal set back line
• Difference between “physical
process” and “limited development”
coastal set back lines
• Need for set back lines
• Progress in South Africa
• Challenges
Definition
A development set-back line is defined as the line landward of which fixed structures may be built in order to be reasonably safe against the physical impact of coastal processes
Coastal set back line (s)
PHYSICAL
PROCESSES LINE
OR
HAZARD LINE
A line which
predicts the future
limit of the
physical
processes
A line which buffers
the physical
processes line by
incorporating
environment,
heritage and social
factors
LIMITED
DEVELOPEMENT
LINE
Coastal set back line (s)
PHYSICAL
PROCESSES LINE
OR
HAZARD LINE
A line which
predicts the future
limit of the
physical
processes
A line which buffers
the physical
processes line by
incorporating
environment,
heritage and social
factors
LIMITED
DEVELOPEMENT
LINE
SEASONAL
BEACH
CHANGE
SEASONAL
BEACH
CHANGE
SEA LEVEL RISE
PHYSICAL
PROCESSES
LINE
SLR
Amanzimtoti in Jan 2007
Amanzimtoti in July 2007
Av. 100 m
SEASONAL
BEACH
CHANGE
SEASONAL
BEACH
CHANGE
SEA LEVEL RISE
SLR
Need for coastal setback lines
• Legal requirement of the Integrated
Coastal Management Act
Need to complete ~3000 kms in South Africa
by Dec 2013.
• Rapid development of the coastal zone
has increased from 28% in 1994 to over
50% in 2006 (Cilliers 2006) transforming
vast areas of coastline.
Need for coastal setback lines
• To protect the public from themselves
• Climate change
Sea level rise (Mather 2007, Mather et al. 2009)
changes in ocean storminess and
changes in predominate wave direction (Corbella
and Stretch 2011- Session D earlier today
Mather, A.A., Garland, G.G. and Stretch, D.D. 2007. Linear and Nonlinear sea level changes at
Durban, South Africa, South African Journal of Science, November/December 2007.
Mather, A.A., Stretch, D.D. and Garland, G.G. 2009. Southern African sea level: corrections,
influences and trends. African Journal of Marine Science, 31(2), 145-156.
PROGRESS IN SOUTH AFRICA
• Richards Bay 11 kms completed
• Durban 100 kms completed
• KwaZulu-Natal 609 kms in progress
• Port Elizabeth 100 kms in progress
• Overberg 300 kms in progress
Still to complete ~2000kms in 30 months
Challenges
• Provinces are tasked with rolling out
Coastal set back lines
• Each Province is adopting a slightly
different approach
• At a National level there is uncertainty
about what methodology should be
adopted
Challenges (cont.)
• Rollout is very much dependant on funding
availability
• Some provinces are funding this work
while others do not have budget allocated
to implement
• Shortage of firms in South Africa (3 or 4)
capable of implementing coastal set back
lines
Challenges (cont.)
• Only two coastal municipalities (Cape
Town and Durban) have the capacity to
undertake this work in house
• Virtually all other Local Government
officials have little experience of this type
of work resulting in a lack of buy in to the
process/ little financial budget allocation.
Thank you.
See you at COP 17.
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