Nature of Impact Duration of Can impact be Will ...

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08
Table 9: Table Assessment Of Identified Potentially Significant Impact [Regulation 31

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
SOIL Construction managed? lost?
Direct Local phase (short-
Erosion of term) Yes – can be No
managed
stockpiled

material (stone,

sand and gravel).

Risk of Direct Local Construction Yes – can be No
Local phase managed
contamination to Local (short-term)

soil and sand

during concrete

mixing.

Potential onsite Direct Construction Yes – can be No
Direct phase managed
erosion of (short-term)

exposed soil

banks during

excavation and

before

rehabilitation is

completed.

Erosion of Operation – Yes – the impact No
(infrequent) can be managed
neighbouring / mitigated

beaches

(2) (k, l)i-vii] (Impacts Are Relevant To All Alternatives Unless Otherwise Specified)

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

Medium High Material must be stocked in such a Low Low

way that it cannot fall or cause Low Low
Low Low
injury or damage to properties or

the natural environment.

Stockpiles must not exceed 2m in

height and must be covered if

exposed to heavy wind or rain.

Alternatively, low walls or berms

must be constructed around the

stockpiles. No material may be

stored on the beach. An

Environmental Management

Programme (EMPr) has been

designed to manage construction

activities and is included in

Appendix 4.

High High Cement mixing will need to take

place on a hard surface or cement

mixing trays. Cement mixing will

not be permitted to occur on the

beach where it can be introduced

into the ocean. Construction will

be monitored by an ECO who will

manage compliance with the

construction EMPr (Appendix 4).

Medium High The duration of exposed soil must

be kept to a minimum and

rehabilitation must be initiated as

soon as construction is completed.

Medium High Alternative 1: An essential means Low Low
of mitigation (which may be Page 39 of 112
implemented in addition to sand
supply) would be the employment
of soft structures at the either end

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

of the seawall (as suggested by

the Stemele Bosch design). These

structures would have to

incorporate appropriate designs in

accordance with the erosion which

is calculated to be possible. As

described for the above case of

profile effects, a suitable mitigation

in the event of a major storm

would be post-storm

replenishment of sand (of suitable

grain size distribution) of the

volume that would have been

naturally “supplied” from the dune

during the storm, should a dune

solution have been employed. The

required volume can be calculated

from surveys and/or storm erosion

modelling.

Alternative 2: the hybrid design

includes a “soft”, sloped section

adjacent to the neighbouring

properties which mitigates the

local flanking erosion. A possible

mitigation in the event of a major

storm would be post-storm

replenishment of sand (of suitable

grain size distribution) of some

fraction of the volume that would

have been “supplied” from the

original, natural dune during the

storm. However, volume would be

difficult to quantify and would

agreement with relevant parties,

informed by an assessment by a

coastal engineer/coastal

processes specialist. Such an

assessment should take into

account measured changes to the

beach profile both at and adjacent

Page 40 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

STORMWATER

Contaminated Direct Local Construction Yes – can be No
phase managed
stormwater runoff (short-term)

entering the

ocean.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

to the hotel property, which would
require both regular and post-
storm surveys.

Alternative 3: The design of the

soft solution should ensure that

erosion of neighbouring beaches

is minor. However, as described

for the above, a suitable mitigation

in the event of aggravated erosion

to neighbouring beaches due a

major storm would be post-storm

replenishment of sand (of suitable

grain size distribution) which

Specialist Study: Reconstruction of

Seawall in front of Salt Rock Hotel

would have been naturally

“supplied” from the dune during

the storm, should a dune solution

have been employed. However, it

is estimated that with an

appropriate soft structure design,

this will be negligible.

Alternative 4: From a coastal

processes point of view, no impact

of a well-designed dune on

neighbouring properties is

envisaged.

High High No contaminated runoff will be Low Low

permitted to leave the site. Trucks

should not be washed on site.

Any grey water i.e. from washing

of equipment etc must be collected

and disposed of either into

conservancy tanks or as

hazardous waste. Separate waste

bins for each of the waste streams

generated must be provided. The

waste containers must be

Page 41 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

SURFACE WATER

Deposition of Indirect Local; Construction Yes – can be No
however phase prevented.
sediment or potential (short-term)
regional
contaminants into impact
dependin
the ocean. This g on the
scale of
in turn could the
pollution
affect the water

quality of

surrounding

areas.

HEALTH & SAFETY

Temporary Direct Local Construction Yes – can be No
phase managed.
restrictions of (short-term)

access to the

beach may be

required during

construction.

Lack of toilet Direct Local Construction Yes – can be No
Direct Local phase prevented.
facilities resulting (short-term)

in unsanitary Construction
phase
conditions. (short-term)

Improper disposal Yes – can be No
prevented.
of toilet waste

from chemical

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

appropriate to the waste type

contained therein and where

necessary should be lined and

covered. Construction will be

monitored by an ECO who will

manage compliance with the

construction EMPr (Appendix 4).

High High The duration of exposed soil must Low Low
be kept to a minimum and
rehabilitation must be initiated as
soon as construction is completed.
Materials must not be stored on
the beach where they can be
washed into the sea. Hazardous
materials must be stored on hard
surfaced areas which have been
bunded and are under cover and
may not be stored on the beach.
Sand and rubble may not be
stored on the beach where it could
be washed into the sea.

High High The contractor must notify Low Low

neighbours and hotel guests of

potential restrictions to access

prior to construction activities.

Construction would need to

comply with designated working

hours (07h00 to 17h00).

Construction will be monitored by

an ECO who will manage

compliance with the construction

EMPr (Appendix 4).

High High Adequate toilet facilities will be Low Low
High High
provided for all staff members as

standard construction practice.

The chemical toilets to be provided Low Low
must be from a registered Page 42 of 112
company and all sewage must be

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?
Direct Local
toilets resulting in No

contamination of

the surrounding

environment.

Wave overtopping Operational Yes can be

may result in a managed

safety risk.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

disposed of at an appropriate
facility. Safe disposal certificates
must be kept on record.

Medium High Alternative 1: Mitigation of Low Low

excessive wave overtopping would

be to raise the wall and/or to

incorporate a recurve within the

wall. A recurve is a seaward

curved protrusion near the top of

the wall which directs wave run-up

offshore, thus reducing the

overtopping.

Alternative 2: When wave

overtopping is obviously severe on

rare occasions, it is proposed that

the hotel take the responsibility of

warning guests by posting a guard

and/or fencing off the shoreward

region and/or erecting signage. In

the event that excessive wave

overtopping occurs frequently (e.g.

due to sea-level rise) this can be

addressed by raising the structure

crest level or (in the case of

reinforced concrete seawall

sections only) incorporating a

recurve within the wall. A recurve

is a seaward curved protrusion

near the top of the wall which

directs wave runup offshore, thus

reducing the overtopping.

Alternative 3: This could be

mitigated by extending soft

protection higher up the slope in

vulnerable areas. Extending

protection to an elevation of some

7m to 8 m MSL would ensure no

virtually wave overtopping in this

Page 43 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Protection of Alternative 1, 2 and 3 - Positive Impact – No mitigation measure required

ground floor flats

from wave attack

No protection of Direct Local Operation No The
infrastructure
ground floor flats and peoples
safety is at
from wave attack risk.

resulting in a

safety risk.

FLORA

Alternative 1: Direct Local Operational Yes – can be No
phase - Long reversed
Will limit the term

potential for

establishment of a

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation region. mitigation mitigation

Alternative 4: The only form of
mitigation (apart from a retreat of
infrastructure) of storm erosion
would be to introduce soft or hard
coastal protection. The small risk
of flooding could be mitigated by
means of a low wall.
Entrances/access points where
the wall does not protect the
hinterland could be blocked with
sandbags in the event of a major
storm, or can incorporate raised
profiles to limit water entering the
buildings.

High Low Alternative 4: This cannot be High High

Cannot be Cannot be mitigated against. Erosion due to
mitigated/ mitigated/
No No extreme storms in the order of up
mitigation mitigation
to 20 m is predicted (Section

4.2.2) by the storm erosion model

and erosion of this extent occurred

during the March 2007 storm. The

hotel ground floor flats are

between some 30 m and 40 m

from the high water mark.

Considering the model accuracy,

and considering the potential for

sea-level rise, coincident shoreline

retreat (order of 5 to 10 m) and

increased storm activity, this

setback distance is not considered

to be adequate.

Alternative 1 – Cannot be Cannot be Cannot be
mitigated. The establishment of
the wall will mean that a natural mitigated/ mitigated/ No
dune and associated vegetation
No mitigation

mitigation required

Page 44 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

semi-permanent

dune and

associated dune

vegetation.

Alternative 2:

Will allow partial

establishment of a

semi-permanent

dune and

associated dune

vegetation

Alternative 3 and

4: Will allow for

establishment of a

semi-permanent

dune and

associated dune

vegetation.

SENSITIVE ENVIRONMENTAL AREAS

Pollution of the Direct Local; Short term – Yes - can be No

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation
required
required cannot be established. Once the required
wall is in place, the dune cannot
be re established or re-planted.

Alternative 2 - Positive Impact -
No mitigation required. There will
be at least some connection with
the beach and establishment of
some dune vegetation.

Alternative 3 - Positive Impact -

No mitigation required. This should

allow establishment of indigenous

dune species which can hold and

stabilize the dune. A vegetated

dune can be aesthetically pleasing

and would be a reinstatement of a

more natural situation. This can

improve slope stability, consolidate

beach sediment and reduce wave

energy and provides a greater

opportunity for continuation of

natural coastal processes and

beach amenities (Breetzke 2008).

Alternative 4 - Positive Impact -

No mitigation required. This should

allow establishment of indigenous

dune species which can hold and

stabilize the dune. A vegetated

dune can be aesthetically pleasing

and would be a return to a more

natural situation. This can

improve slope stability, consolidate

beach sediment and reduce wave

energy. Provides a greater

opportunity for continuation of

natural coastal processes and

beach amenities (Breetzke 2008).

Med ium- High No contaminated run off must be Low Low
Page 45 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
during managed? lost?
however construction
ocean and potential phase managed
surrounding regional
beaches. impact
dependin
g on the
scale of
the
pollution

Construction Direct Local Short term – Yes - can be No
(within during managed
vehicles may construct construction
ion site) phase
cause damage or

contamination of

the beach.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

High permitted to leave the site. Trucks

should not be washed on site.

Any grey water i.e. from washing

of equipment etc must be collected

and disposed of either into

conservancy tanks or as

hazardous waste. Separate waste

bins for each of the waste streams

generated must be provided. The

waste containers must be

appropriate to the waste type

contained therein and where

necessary should be lined and

covered. Waste must not be

allowed to accumulate on site but

should be disposed of regularly by

a reputable contractor. Any

construction equipment that could

leak oil must be placed on a drip

tray. All equipment must be in

good working order to reduce the

likelihood of oil leaks occurring.

Any re-fuelling of equipment must

occur on a hardened surface,

within a designated re-fuelling

area where any spills can be

contained. A designated

hazardous store will be set up

which must be located within a

bunded area on a hardened

surface and under cover.

Medium High The wall should be constructed Low Low

manually. Where possible, the wall

components should be pre cast to

avoid cement pouring and use of

shuttering (associated oils) on the

beach. However, if the need

arises for the use of construction

vehicles (removal of cross walls),

a permit must be applied for and

issued by DAEA before any

Page 46 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Possible Direct Local Operational No mitigation No
interference with phase
the littoral drift. required

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

vehicles may be allowed to access

the beach. In terms of vehicles

and construction equipment, track

machinery should be avoided. A

TLB fitted with tyres can operate

without causing significant

furrowing of the beach. By

dropping tyre pressure, the depth

to which machinery will sink will be

reduced. The area of operation

and turning areas must be

carefully established and

demarcated prior to construction.

Turning arcs of machinery should

be reduced as much as possible.

All greasing, servicing and

washing must not be carried out

on the beach. Vehicles must be

parked outside the high water

mark.

No No Alternative 1 - No mitigation No No mitigation
mitigation mitigation mitigation required
required required required. According to the required

specialist reviews, there is no

impact of the wall on littoral drift

under normal sea conditions and

under high sea conditions, the

impact is negligible. This is due to

the presence of the rock headland

in front of the hotel. If no headland

existed, wave action would

approach the beach at an oblique

angle, eroding it and depositing

sand northwards (simplified

description). Due to the presence

of the headland the beach to the

north of this headland is protected

from this action as the erodibility of

the northerly long shore drift and is

associated wave action is

interfered with and reduced by the

presence of the headland.

Page 47 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Potential Direct Local Operational Yes - can be No
phase managed
promotion of the

reflection or

focusing of wave

energy.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

Therefore because of the location
of this particular wall, the nature of
the structure (hard or soft) has no
bearing on this action.

Alternative 2 - No mitigation

required. The soft elements of the

structure would be placed further

inland and would ordinarily have

less impact on long shore drift

than a hard structure due to its

retreat – however in this instance

as with alternative 1, the effect of

longshore drift are nullified by the

headland. The combination of

both options should not have

much effect in this case due to the

nullification of the littoral drift

action by the headland.

Alternative 3 and 4 - No

mitigation required. The soft

structure/ dune would be placed

further inland and would ordinarily

have less impact on long shore

drift than a hard structure due to

its retreat – however in this

instance as with alternative 1, the

effect of longshore drift is nullified

by the headland.

Low High Alternative 1 - The primary issue Low Low

relating to wave refraction would

be refraction of wave energy onto

adjoining properties causing

damage. This has been

thoroughly assessed in all

specialist reports and impacts

are seen as unlikely and

insignificant. This can be

mitigated by changing the

structure of the wall at each end.

Page 48 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

It is recommended by the

engineers that each end should

have a footing within a short rock

revetment created with 4 ton

Enviro Rock bags in a sawtooth

arrangement which would be

placed along the base of the wall.

This should assist the diffraction

(lateral spreading of wave energy),

refraction and bottom friction

(WSP, 2009; Subtech, 2008). The

headland will also act to refract

much of the wave energy that

would normally act on the beach

such that waves will approach the

wall with less energy. Therefore

under the conditions experienced

in this particular section of beach,

there is less energy that can be

reflected or focused by the wall.

The undulations in the design of

the wall will act to further reduce

energy refracted by the wall.

Subtech has indicated that the

creation of alcoves at either end of

the wall will refract waves in a

random pattern and retard the flow

along the wall.

Alternative 2 – As per alternative

1, the primary issue relating to

wave refraction would be

refraction of wave energy onto

adjoining properties causing

damage. All reports have

indicated that this impact is

unlikely to be significant. The

soft parts of the structure should

assist the diffraction (lateral

spreading of wave energy),

refraction and bottom friction

(WSP, 2009; Subtech, 2008). The

Page 49 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

planting of vegetation in these
areas should also act to reduce
refraction of energy. This can be
mitigated further by changing the
structure of the wall at each end.
It is recommended by the
engineers that each end should
have a footing within a short rock
revetment created with 4 ton
Enviro Rock bags in a sawtooth
arrangement which would be
placed along the base of the wall.
This should assist the diffraction
(lateral spreading of wave energy),
refraction and bottom friction
(WSP, 2009; Subtech, 2008). The
headland will also act to refract
much of the wave energy that
would normally act on the beach
such that waves will approach the
wall with less energy. Therefore
under the conditions experienced
in this particular section of beach,
there is less energy that can be
reflected or focused by the wall.
The undulations in the design of
the wall will act to further reduce
energy refracted by the wall.
Subtech has indicated that the
creation of alcoves at either end of
the wall will refract waves in a
random pattern and retard the flow
along the wall.

Alternative 3 - As with

alternatives 1 & 2, the primary

issue relating to wave refraction

would be refraction of wave

energy onto adjoining properties

causing damage. The soft

structure should assist the

Page 50 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Localised scour of Direct Local Operational Yes - can be No
phase managed
the profile and

denial of natural

dune sand supply

during large

storms

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

diffraction (lateral spreading of

wave energy), refraction and

bottom friction (WSP, 2009;

Subtech, 2008). The planting of

vegetation should also act to

reduce refraction of energy. The

headland will again act to refract

much of the wave energy that

would normally act on the beach

such that waves will approach the

soft structure with less energy.

Therefore under the conditions

experienced in this particular

section of beach, there is less

energy that can be reflected or

focused by the structure.

Alternative 4 – No mitigation

required. The dune should not

have a negative impact in this

instance (WSP, 2010), and should

assist the diffraction (lateral

spreading of wave energy),

refraction and bottom friction. The

planting of vegetation should also

act to reduce refraction of energy.

Medium High Alternative 1 - A suitable Low Low

mitigation would be post-storm

replenishment of sand (of suitable

grain size distribution) which would

have been naturally “supplied”

from the dune during the storm,

should a dune solution have been

employed (as suggested by Dean,

1986). Such mitigation measures

are employed in the USA (Basco,

2004). The required sand supply

could be estimated through the

monitoring of nearby profiles (that

incorporate appropriate set-back

soft solutions) experiencing similar

Page 51 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

wave conditions by means of

regular surveys. The amount of

sand denied during storm erosion

can be estimated from pre- and

post-storm surveys and this

volume should then be supplied to

the beach zone – preferably in

eroded areas where it is most

needed. Alternatively the amount

of sand supply required could be

estimated by means of a

calibrated storm erosion model. It

is assumed that supply would be

conducted such that impacts

during the process are negligible.

Alternative 2 - A possible
mitigation to this effect of reduced
eroded sand supply would be the
post-storm replenishment of sand
(of suitable grain size distribution)
which would have been naturally
“supplied” from the dune during
the storm (as suggested by Dean,
1986). Such mitigation measures
have been employed in the USA
(Basco, 2004). This possible
mitigation approach is considered
severe, given that sand eroded
from a dune is returned to the
shore by onshore wave- and wind-
driven sand transport and thus no
net loss of sand occurs.
Furthermore, the sandbag section
of the hybrid coastal protection will
tend to accumulate wind-blown
sand, which will be “fed” to the
profile (via erosion) during storms.

Alternative 3 – As described for
the above (alternative 1), a

Page 52 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

suitable mitigation in the event of a
major storm would be post-storm
replenishment of sand (of suitable
grain size distribution) which would
have been naturally “supplied”
from the dune during the storm,
should a dune solution have been
employed. However, it is deemed
likely that the amount of sediment
denied to the near shore zone
would be negligible.

Alternative 4 – A dune would

erode relatively freely during a

storm, resulting in considerable

supply of sand to the lower beach

profile (below water-level).

According to model predictions,

the volumes of sediment eroded

from the dune would be in the

region of 37 to 44 m3. According

to storm erosion model

predictions, due to a 1:50 storm a

retreat of the shoreline or +2 m

MSL contour of 11.5 m can be

expected. A 1:100 storm is

predicted to cause a retreat of 13

m (Section 4.2.2). Considering that

this erosion would be further

aggravated by collapse of the

dune slope (adding an additional 6

m or so) an erosion retreat

distance of some 15 to 20 m could

be expected in total for a major

storm. This effect would be

temporary since sand would be

expected to return to the beach via

wave-driven onshore sand

transport and onto the dune via

windblown sand transport (the

recovery of the profile at the Salt

Page 53 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

WASTE

Improper storage Direct Local Construction Yes – can be No
Direct phase prevented.
and disposal of Local (short-term)
Local
hazardous waste

i.e. used oils from

vehicles, old

cement bags etc.

resulting in

possible

contamination of

the surrounding

environment.

Littering around Construction Yes – can be No
the site. phase managed.
(short-term)

Improper storage Direct Construction Yes – can be No
phase prevented.
and disposal of (short-term)

general waste

materials

generated during

construction

resulting in

possible

contamination of

the surrounding

environment.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

Rock following the March 2007
storm is evidence of this recovery
process) This natural variation in
the beach profile is not
considered to be an impact
unless it affects property.

High High Hazardous waste must be stored Low Low

on a hard surface within a bunded

area and must not be allowed to

enter storm water drains and the

surrounding environment. Waste

must be disposed of regularly by a

reputable contractor. Hazardous

waste such as oils, contaminated

rags etc. must be disposed of at a

hazardous class landfill. Safe

disposal certificates must be

provided.

High High Littering will not be permitted on Low Low
High High Low Low
the site and general housekeeping

will be enforced. Construction will

be monitored by an ECO who will

manage compliance with the

construction EMPr (Appendix 4).

Waste must be stored in the bins

within the waste collection area in

the Construction Camp and must

not be allowed to blow around the

site, be accessible by animals, or

be placed in piles adjacent the

skips / bins. Separate waste bins

for each of the waste streams

generated must be provided. The

waste containers must be

appropriate to the waste type

contained therein and where

necessary should be lined and

covered. Waste must not be

allowed to accumulate on site but

should be disposed of regularly by

Page 54 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Improper disposal Direct Local Construction Yes – can be No
phase prevented.
of rubble i.e.: (short-term)

burying or

neglecting

building rubble

resulting in direct

mechanical

damage to

surrounding

beaches.

Potential for Indirect Local Construction Yes – can be No
phase prevented.
construction (short-term)

waste to be

disposed of at

incorrect landfill

resulting in

contamination at

the landfill site.

HAZARDOUS CHEMICALS / FUELS

Potential Direct Local Construction Yes – can be No
phase prevented.
contamination of (short-term)

groundwater, the

beach and the

ocean from

hazardous

substances such

as cement, oil

leaks from

vehicles, storage

of lubricants etc

on site.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

a reputable contractor and must Low Low

be disposed of at an appropriate Low

landfill site.

Low- High All excess material and rubble
Medium
must be removed from the site so

not to restrict the rehabilitation

process. All excess material and

rubble must go to an approved,

designated landfill and a safe

disposal certificate must be

obtained.

Low- High Recycling should be undertaken Low
medium where possible to limit waste
added to the Landfill site. Waste to
be sent to registered landfills and
safe disposal certificates must be
retained for hazardous waste.

High High Cement mixing will need to take Low Low
Page 55 of 112
place on a hard surface or cement

mixing trays will need to be used.

If the creation of a permanent

bunded area is not feasible, these

materials must be stored on drip

trays capable of holding at least

110% of the spilled volume.

Cement mixing will not be

permitted to occur on the beach

where it can be introduced into the

ocean. Any construction

equipment that could leak oil must

be placed on a drip tray. All

equipment must be in good

working order to reduce the

likelihood of oil leaks occurring.

Any re-fuelling of equipment must

occur on a hardened surface,

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

NOISE

Noise generated Direct Local Short term – Yes - can be No
(within during managed
by construction construct construction
ion site) phase
workers,

machinery and

construction

vehicles

disturbing

surrounding

residents, tourists

and hotel patrons.

AIR QUALITY

Emissions Direct Local Construction Yes – can be No
phase managed.
generated from (short-term)

construction

vehicles.

RESOURCE USE & CONSERVATION

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

within a designated re-fuelling

area where any spills can be

contained. A designated

hazardous store will be set up

which must be located within a

bunded area on a hardened

surface and under cover.

Construction will be monitored by

an ECO who will manage

compliance with the construction

EMPr.

Medium Medium Excessive noise must be Low Low

controlled on site. Workers will be

trained regarding noise on site and

construction hours will be kept to

working hours (07h00 to 17h00).

The construction will need to be

monitored by an ECO who will

ensure compliance with the

construction EMPr. All precautions

must be taken to ensure that noise

generation is kept to a minimum.

If excessive noise is expected

during certain stages of the

construction, residents must be

notified prior to the event. An

Environmental Management

Programme (EMPr) has been

designed to manage construction

activities and is attached under

Appendix 4.

Medium Medium Vehicles that are not in good Low Low
working order must be removed
from site. Emissions generated
from construction vehicles will be
minimal and is not expected to
significantly affect surrounding
residents or hotel patrons.

Page 56 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
Sourcing of raw Direct Local Construction managed? lost?
phase No
materials i.e.: Indirect Local (short-term) Yes – can be
prevented. No

(gravel, stone,

sand, cement and

water) from

unsustainable

sources resulting

in illegal sand

winning and

mining operations

causing

significant

environmental

damage.

Alternative 3: Construction Yes – can be
phase managed.
Requirements of (short-term)

more sand to be

imported to fill

geotextile bags.

TRAFFIC

Increase in traffic Direct Local Construction Yes – can be No
Direct Local phase managed.
disruptions on (short-term)

surrounding

access roads i.e.

Basil Hulett Drive

during

construction as a

result of

construction

vehicles.

VISUAL

Alternative 1: Operational Yes – can be No
phase managed.
Improve the (permanent)

aesthetics of the

hotel and

beachfront.

Alternative 2, 3
and 4: Reduced

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation All materials must be obtained mitigation mitigation
High from a registered and sustainable
Low- source and all delivery notes and Low Low
medium slips must be made available to
the Environmental Control Officer
e.g. mined material such as stone
must only be obtained from
permitted quarries.

High High Imported sand must match sand Low Low
High High Low Low
found on the beach and must not

contain any foreign materials

(rubble, rocks etc). It must be

obtained from approved sources

and proof provided. Sand may not

be removed from the beach.

A flagman could be appointed to
assist with traffic. Construction
vehicles should avoid using roads
during peak times and should
avoid accessing the beach.

High High Alternative 1 – Positive impact High Medium
not requiring mitigation. Once the Page 57 of 112
seawall has been reconstructed it
will improve the aesthetics of the
area as it will retain the same
appearance as the remaining wall
not damaged during the storm. A
well designed wall can be an

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

impact on the

aesthetics of the

hotel and

beachfront.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

attractive feature when compared
to a sand bag structure.

Alternative 2 – Once the seawall

part of the hybrid structure has

been reconstructed it will improve

the aesthetics of the area as it will

retain the same appearance as the

remaining wall not damaged

during the storm. The mixed

structure may have a visual impact

incorporating both elements and

where soft structure elements are

set back, there will be loss of

available space to the hotel and

beach.

Alternative 3 – Cannot be

mitigated. The use of geo bags

would require a tiered (stepped)

construction with a gentle slope

such that at least 10 to 20m of

coastal property would be lost

once it was established. The soft

structure would require some

coastal retreat causing loss of

beach front. This would reduce

available space for beach users

and detract from the tourism

appeal. Geobag structures are

prone to progressive failure in

contradiction to reinforced

concrete walls. The cost of

maintenance is high and is

considered prohibitive by the

applicant. Unsightly waste would

be created if the structure were to

be destroyed. However, this

should not be difficult to clean.

Bags can be removed and

replaced. (WSP, 2009; Subtech,

Page 58 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Alternative 1: Direct Local Operational Yes – can be No
phase reversed.
The hard (permanent)

structure will take

up less space on

the beach and on

the property

leaving more

beach front area

for tourism and

beach users

Alternative 2:

The areas of soft

structure will take

up more space on

the beach leaving

less beach front

area for tourism

and beach users.

Alternative 3:
The soft

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

2008). Coastal property owners

should prepare for erosion events

by purchasing and storing

appropriate sand bags (Breetzke,

2008).

Alternative 4 – Cannot be

mitigated. The establishment of a

dune system would entail

construction of a gentle slope of

1:2 such that at least 10 to 20m of

coastal property would be lost

once it was established. The dune

system would require some

coastal retreat causing loss of both

beach front and hotel property.

This would reduce available space

for beach users and detract from

the tourism appeal.

No No Alternative 1 - No mitigation No No mitigation
mitigation mitigation mitigation required
required required required. The hard structure will required

take up less space on the beach

and on the property leaving more

beach front area for tourism and

beach users. The visible portions

of the wall will measure 550cm in

width which will be narrower than

the space required for a tiered soft

structure will take more beach

space (10 -20m).

Alternative 2 - No mitigation
required. The areas of soft
structure will take up more space
on the beach leaving less beach
front area for tourism and beach
users. As with the impacts of the
hard and soft structures, the hard
structures will take up less beach
space while the soft structures will
be set back and taking up more

Page 59 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

structures will

take up more

space and result

in loss of hotel

property leaving

less beach front

area for tourism

and beach users.

Alternative 4:

The dune will take

up more space

and result in loss

of hotel property

leaving less

beach front area

for tourism and

beach users.

Interference with Indirect Local Construction Yes – can be No
appearance and phase managed.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

space.

Alternative 3 - No mitigation
required. The soft structures will
take up more space and result in
loss of hotel property leaving less
beach front area for tourism and
beach users. The use of geo bags
would require a tiered (stepped)
construction with a gentle slope
such that at least 10 to 20m of
coastal property would be lost
once it was established. The soft
structure would require some
coastal retreat causing loss of both
beach front and hotel property.
This would reduce available space
for beach users (reduce caravan
park space) and detract from the
tourism appeal.

Alternative 4 - No mitigation

required. The dune will take up

more space and result in loss of

hotel property leaving less beach

front area for tourism and beach

users. The establishment of a

dune system would entail

construction of a gentle slope of

1:2 such that at least 10 to 20m of

coastal property would be lost

once it was established. The dune

would require some coastal retreat

causing loss of both beach front

and hotel property. This would

reduce available space for beach

users (reduce caravan park space)

and detract from the tourism

appeal.

High Medium This cannot be mitigated but will Low Low
Page 60 of 112
be temporary. The beach must be

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
(short-term) managed? lost?

aesthetics of the

beach during

construction.

Dismantling of Direct Local Construction Yes – can be No
phase managed.
existing areas of (short-term)

wall not destroyed

by storm.

SOCIO-ECONOMIC

Positive impact - Direct Local Construction Positive impact No
phase
Potential (short-term) no mitigation

temporary required.

employment for

skilled local

community

members during

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

returned to pre construction

appearance. Operational areas

must be restricted and should

move with the working front. The

shape of the beach must be

retained during construction i.e.

any excavation must be evenly

distributed to match the existing

profile of the beach to the north

and south. This will prevent

creation of unsightly piles and

holes. The EMPr must be

adhered to during construction

to ensure that construction

workers maintain good

housekeeping and the site is

kept neat and tidy at all times.

High High Collapse of dune behind the wall Low Low

to be removed would occur to a

small degree and this would need

to be repaired and managed

through construction of the new

structure. Rubble must be

removed from the beach and

disposed of at an approved site.

This may not be re –used on site

or buried and may not be stored

below the high water mark.

Dismantling of the wall will be

monitored by an ECO who will

manage compliance with the

construction EMPr (Appendix 4).

Positive Positive Positive impact no mitigation Positive Positive
required. impact
impact no impact no impact no mitigation no
required.
mitigation mitigation mitigation

required. required. required.

Page 61 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
the construction Construction managed? lost?
Direct Local phase
phase. (short-term) Yes – can be No
managed.
Possible

disruption of

recreational

activities

associated with

the Salt Rock

beach.

Alternative 1: Direct Local Operational Yes – can be No
phase managed.
Protection of the (permanent)

hotel property

from criminals

and flooding.

Alternative 2:

Less security

where soft

structures are in

place.

Alternative 3 and
4: Less protection
for property and
possible security
risk.

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

Cannot be Cannot be Cannot be mitigated. Disruption to Cannot be Cannot be
mitigated mitigated mitigated mitigated
recreational activities will be
High Low
unavoidable. However, this will be

temporary. Where possible,

disruptive construction activities

must take place outside of peak

beach use hours i.e. weekends,

public and school holidays.

Alternative 1 - The wall will Low Low

restrict access of criminals from

the seaward side to the hotel. The

wall is also expected to protect the

property from further backward

erosion (Subtech, 2008). Flooding

and future damaged to the wall

and property can be managed by

mitigating excessive wave

overtopping. This can be done by

raising the wall and/or to

incorporate a recurve within the

wall. A recurve is a seaward

curved protrusion near the top of

the wall which directs wave run-up

offshore, thus reducing the

overtopping. Alternatively, wave

overtopping could be reduced by

locating the wall further landward

(WSP, 2010).

Alternative 2 – As with the soft

structure, a fence would be

required in places where the wall

ends. Mitigation measures

recommended for alternative 1, 2,

3 and 4 could be used to prevent

flooding of the lower flats.

Alternative 3 - The soft structure

Page 62 of 112

EIR – Reconstruction of the seawall in front of the Salt Rock Hotel - DC29/0040/08

Nature of Impact Direct Extent Duration of Can impact be Will
(potential) or of Impact prevented/reve irreplaceable
Indirect Impact rsed or resources be
managed? lost?

Probability Mitigatory Mitigation measure Probability Significance
before Potential after after
mitigation mitigation mitigation

does not restrict access, however

a fence can be constructed at the

top of the structure to restrict

access to the hotel property. As

per the WSP, 2009 report “Even

once established it is unlikely that

a soft structure could provide the

same guarantee of long-term

security of the remaining property

that a seawall would provide.”

Geobag structures are prone to

progressive failure in contradiction

to reinforced concrete walls.

During a storm, vegetation and

geotextile bags will be more

susceptible to wash away. Once

damaged the structure will require

maintenance and repair to re

supply sand and repair the

structure. The cost implications

are significant and must be

considered when a decision is

made regarding the future of the

wall. Unsightly waste would be

created if the structure were to be

destroyed. However, this should

not be difficult to clean. Bags can

be removed and replaced. (WSP,

2009; Subtech, 2008). Coastal

property owners should prepare

for erosion events by purchasing

and storing appropriate sand bags

(Breetzke, 2008). The risk of

flooding could be mitigated by

extending soft protection higher up

the slope (WSP, 2010).

Alternative 4 - The dune does not
restrict access, however a fence
can be constructed at the top of
the structure to restrict access to

Page 63 of 112