IMPACT ASSESSMENT

Methodology for Impact Significance Scoring

The significance (quantification) of potential environmental impacts identified during the Basic Assessment have been determined using a ranking scale, based on the following (terminology has been taken from the Guideline Documentation on EIA Regulations, of the Department of Environmental Affairs and Tourism, April 1998): Occurrence

Probability of occurrence (how likely is it that the impact may occur?)

Duration of occurrence (how long may it last?) Severity

Magnitude (severity) of impact (will the impact be of high, moderate or low severity?)

Scale/extent of impact (will the impact affect the national, regional or local environment, or only that of the site?) Each of these factors has been assessed for each potential impact using the following ranking scales:

The environmental significance of each potential impact is assessed using the following formula:

Significance Points (SP) = (Magnitude + Duration + Extent) x Probability

The maximum value is 100 Significance Points (SP). Potential environmental impacts were rated as high, moderate or low significance on the following basis:

Probability Duration 1 - very improbable (probably will not happen 2 - improbable (some possibility, but low likelihood) 3 - probable (distinct possibility) 4 - highly probable (most likely) 5 - definite (impact will occur regardless of any prevention measures)

1 - of a very short duration (0–1 years) 2 - of a short duration (2-5 years) 3 - medium-term (5–15 years) 4 - long term (> 15 years) 5 - permanent

Extent Magnitude 1 - limited to the site 2 - limited to the local area 3 - limited to the region 4 - will be national 5 - will be international

0 - small and will have no effect on the environment 2 - minor and will not result in an impact on processes 4 - low and will cause a slight impact on processes 6 - moderate and will result in processes continuing but in a modified way 8 - high (processes are altered to the extent that they temporarily cease) 10 - very high and results in complete destruction of patterns and permanent cessation of processes

< 30 significance points = LOW environmental significance. 31- 60 significance points = MODERATE environmental significance > 60 significance points = HIGH environmental significance

The table below summarises all the identified impacts and their significance ratings without and with mitigation, while detailed descriptions of each impact are provided there under.

Note there are no feasible alternatives for the gabion construction at the Moreleta Spruit EXCEPT the NO GO Alternative. 1. IMPACTS THAT MAY RESULT FROM THE PLANNING AND DESIGN, CONSTRUCTION,

OPERATIONAL, DECOMMISSIONING AND CLOSURE PHASES AS WELL AS PROPOSED MANAGEMENT OF IDENTIFIED IMPACTS AND PROPOSED MITIGATION MEASURES

Provide a summary and anticipated significance of the potential direct, indirect and cumulative impacts that are likely to occur as a result of the planning and design phase, construction phase, operational phase, decommissioning and closure phase, including impacts relating to the choice of site/activity/technology alternatives as well as the mitigation measures that may eliminate or reduce the potential impacts listed. This impact assessment must be applied to all the identified alternatives to the activities identified in Section A (2) of this report. Note: There are no planning and design phase impacts associated with the proposed development. Refer below for the construction phase, operational phase, decommissioning phase impacts identified and assessed.

CONSTRUCTION PHASE POTENTIAL IMPACTS Activity Impact summary Significance Proposed

mitigation

Alternative 1 (preferred alternative)

Direct impacts: Temporary Vegetation Clearing: During the installation of the gabion structures, vegetation occurring along the river banks was removed to allow for easy accessibility to the site. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

1 4 1 3 18

Low

Ensure that rehabilitation measures for the site include re-vegetation of stripped areas. Monitoring of the bare ground must ensure that any signs of soil erosion are immediately addressed.

Direct impacts: Increased Traffic in the Wetland: foot and vehicle traffic through the wetland areas may result in damage to naturally

Low

Ensure that rehabilitation

Activity Impact summary Significance Proposed mitigation

occurring plant and animal species, especially smaller vertebrates. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland impacts

Duration Magnitude Extent Probability Significance

1 2 1 3 12

measures for the site include re-vegetation and remediation of foot paths and vehicle tracks.

Direct impacts: Soil disruption: excavation activities on site will cause subsoil to become exposed, and can lead to more soil erosion and leaching of stored chemicals in the system. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

1 2 1 3 12

Low

Excavated soil stockpiles must be protected from wind erosion, by covering with a tarpaulin. Stockpiles should also be situated away from the watercourse so as not to be susceptible to run-off.

Direct impacts: Hydrocarbon Spills: hydrocarbon spills can occur from machinery leaking oil onto the ground. Spillage can also occur during refuelling of equipment on-site. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

1 4 1 2 12

Low

Machinery should be regularly serviced and maintained to ensure that there are no oil leaks. Refuelling should be undertaken on an impermeable

Activity Impact summary Significance Proposed mitigation

service and a drip tray used.

Direct impacts: Habitat disturbance: the construction of the gabions has resulted in damming of the Moreleta Spruit, and hence poses a hindrance to the free movement of aquatic species and can result in habitat fragmentation. As a result there would be a Moderate significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

4 6 2 3 36

Moderate

Gabions should be constructed in a manner that minimises the damming of water by loosely packing the material within the reno-mattress to allow permeability.

Direct impacts: Noise Impacts: heavy machinery and earthmoving machinery can cause noise disturbance to surrounding residents and businesses As a result there would be a Low significance impact (Negative).

Significance Table: Noise Impacts

Duration Magnitude Extent Probability Significance

1 0 2 4 12

Low

Construction activities should be limited to daylight hours (07h00 – 17h00). Further mitigation can include the installation of mufflers onto machinery.

Indirect impacts: Groundwater contamination: hydrocarbon spills can occur from machinery leaking oil onto the ground. This can permeate through to the subsurface, resulting in groundwater contamination or pollution. As a result there would be a Low significance impact (Negative).

Low

Machinery should be regularly serviced and maintained to ensure that there

Activity Impact summary Significance Proposed mitigation

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

1 4 2 2 14

are no oil leaks. Refuelling should be undertaken on an impermeable service and a drip tray used.

No-go option

Direct impacts: Damage to the fuel pipeline: should the fuel pipeline remain exposed, the pipeline may become damaged either by vandalism or accidental high impact to the exposed area. This will cause environmental, and health and safety impacts, as well as interruption in fuel supply. As a result there would be a Moderate significance impact (Negative).

Significance Table: Infrastructure damage

Duration Magnitude Extent Probability Significance

2 8 3 4 52

Moderate

Undertake measures to protect and prevent damage to the fuel pipeline.

Indirect impacts: Surface Water Pollution and Soil Contamination: should the fuel pipeline remain exposed, the pipeline may become damaged which could result in petroleum spills into the Moreleta Spruit and onto the ground around the pipeline, resulting in pollution and contamination of the surface water in the watercourse and the ground surface. As a result there would be a Moderate significance impact (Negative).

Significance Table: Wetland impacts

Duration Magnitude Extent Probability Significance

3 8 3 4 56

Moderate

Undertake measures to protect and prevent damage to the fuel pipeline.

Indirect impacts:

Activity Impact summary Significance Proposed mitigation

Fire and explosion risks: rupture of the fuel pipeline can lead to fire or explosion if the liquid petroleum is exposed to open flame or sparks. This poses a health and safety risk to residents and adjacent property owners. As a result there would be a Moderate significance impact (Negative).

Significance Table: Health and Safety

Duration Magnitude Extent Probability Significance

1 8 2 4 44

Moderate

Undertake measures to prevent damage to the fuel pipeline.

Indirect impacts: Health and safety risks: petroleum spills can result in health impacts due to the toxicity and carcinogenic properties of liquid petroleum. As a result there would be a Moderate significance impact (Negative).

Significance Table: Health and Safety

Duration Magnitude Extent Probability Significance

4 8 3 4 60

Moderate

Undertake measures to prevent damage to the fuel pipeline.

OPERATIONAL PHASE POTENTIAL IMPACTS Activity Impact summary Significance Proposed

mitigation

Alternative 1 (preferred alternative)

Activity Impact summary Significance Proposed mitigation

Direct impacts: Habitat disturbance: the construction of the gabions has resulted in damming of the Moreleta Spruit, and hence poses a hindrance to the free movement of aquatic species and can result in habitat fragmentation. As a result there would be a Moderate significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

4 6 2 3 36

Moderate

Gabions should be constructed in a manner that minimises the damming of water by loosely packing the material within the reno-mattress to allow permeability. The design alternatives contained in section 2 of this report and the specialist reports (Appendix D) should be implemented.

Direct impacts: Health and Safety: the health and safety risks associated with exposure to liquid petroleum are minimised due to protection of the fuel pipeline. As a result there would be a Moderate significance impact (Positive).

Significance Table: Health and Safety

Duration Magnitude Extent Probability Significance

4 2 2 5 40

Moderate

Regular maintenance must ensure that the pipeline protection measures remain intact.

Activity Impact summary Significance Proposed mitigation

Direct impacts: Soil erosion: should the gabions not be properly designed and implemented, there may be a potential to exacerbate erosion along the watercourse. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

2 4 2 2 16

Low

Regular maintenance must ensure that the gabions do not promote soil erosion. Design alternatives provided in section 2 of this report and the specialist reports (Appendix D) must be implemented.

Indirect impacts: Increased traffic in the system: the gabions may be used as a bridge across the watercourse, and therefore increase traffic in the system, which will impact on the surrounding vegetation. Maintenance activities required may also impact on vegetation and small animals and insects. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

3 4 2 2 18

Low

Maintenance operations should be limited to the gabion sites, and no unnecessary traffic outside the demarcated area should be undertaken, so as to minimise potential impacts. The use of the gabions as bridges should be restricted.

No-go option

Direct impacts:

The No Go Alternative refers to the development not occurring. As such the following positive benefits would not come to light:

- The protection of the fuel pipeline: the construction of

Moderate environmental significance (Negative)

N/A

Activity Impact summary Significance Proposed mitigation

gabions in the Moreleta Spruit is aimed at protecting the fuel pipeline from further exposure and potential damage and leaks.

- Reduction of soil erosion: the channel erosion upstream from the gabions will be decreased, and the eroded areas will fill up again. The downstream area may also erode less.

- Water table: the water table may be lifted due to the flow

velocity reduction from the gabions, which may improve vegetation quality and wetland functioning.

As noted, the above benefits would not come to light if the project is not authorised and have to be decommissioned. As such the overall cumulative impact of not constructing gabions in the Moreleta Spruit is negative, with a moderate environmental significance.

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

4 8 3 4 60

DECOMMISSIONING PHASE POTENTIAL IMPACTS Activity Impact summary Significance Proposed

mitigation

Alternative 1 (preferred alternative)

Direct impacts: Increased traffic in the system: the demolition of the gabions will increase traffic in the system during this phase of the project, which will impact on the surrounding vegetation. As a result there would be a Low significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

3 4 2 2 18

Low

Demolition operations should be limited to the gabion sites, and no unnecessary traffic outside the demarcated area should be undertaken, so as to minimise potential impacts.

Direct impacts: Soil erosion: the demolition of the gabions will result in restoration of the site prior to construction. This implies that erosion will continue along the banks of the river, particularly at the two sites where the fuel pipeline has been exposed. As a result there would be a Moderate significance impact (Negative).

Significance Table: Wetland Impacts

Duration Magnitude Extent Probability Significance

4 6 2 4 48

Moderate

Alternative methods to protect the pipeline must be investigated.

Activity Impact summary Significance Proposed mitigation

Direct impacts: Waste generation: the demolition of the gabions will result in the generation of building rubble, and therefore increase the volumes of waste disposed to landfill should reuse options not be available. As a result there would be a Moderate significance impact (Negative).

Significance Table: Waste Management

Duration Magnitude Extent Probability Significance

4 4 3 3 33

Moderate

Alternative uses of building rubble generated from demolition activities must be investigated.

Direct impacts: Health and Safety: the health and safety risks associated with exposure to liquid petroleum are increased due to removal of the fuel pipeline protection structures. As a result there would be a Moderate significance impact (Negaitive).

Significance Table: Health and Safety

Duration Magnitude Extent Probability Significance

4 2 2 5 40

Moderate

Regular maintenance must ensure that the pipeline protection measures remain intact.

2. ENVIRONMENTAL IMPACT STATEMENT Taking the assessment of potential impacts into account, please provide an environmental impact statement that summarises the impact that the proposed activity and its alternatives may have on the environment after the management and mitigation of impacts have been taken into account, with specific reference to types of impact, duration of impacts, likelihood of potential impacts actually occurring and the significance of impacts. As is evident from this report, the motivation for the construction and operation of the gabion structures within the Moreletta Spruit is rooted in the negative impact of uncontrolled erosion on the structural integrity of the Transnet high pressure liquid petroleum pipeline and the subsequent impact on the social and biophysical environment if said structural integrity is compromised. This assessment illustrates that there are various potential negative and positive impacts that may result from the construction and operation of the gabion infrastructure, although with the implementation of applicable mitigation measures, the negative impacts can be satisfactorily minimised.

The alternatives proposed included design alternatives recommended by the specialist as mitigation measures in terms of the unlawful commencement of the activity. Table 1 below is a representation of all identified impacts and the assessment of significance with and without mitigation. Table 1: Potential Impact Summary Report.

ALTERNATIVES A1 (Preferred Alternative) No-Go

CONSTRUCTION PHASE IMPACTS

POTENTIAL IMPACT Without mitigation

With mitigation

Without mitigation

With mitigation

Temporary Vegetation Clearing (Direct Impact)

Low (-) Low (-)

Increased traffic in the wetland (Direct Impact)

Low (-) Low (-)

Soil disruption (Direct Impact) Low (-) Low (-)

Hydrocarbon spills (Direct Impact) Low (-) Low (-)

Habitat Disturbance (Direct Impact) Moderate (-) Low (-)

Noise impacts (Direct Impact) Low (-) Low (-)

Groundwater contamination (Indirect Impact)

Low (-) Low (-)

Damage to Infrastructure (Indirect Impact)

Moderate (-) Moderate (-)

Surface water and Soil contamination (Indirect Impact)

Moderate (-) Moderate (-)

Fire and Explosion (Indirect Impact) Moderate (-) Moderate (-)

Health and Safety (Indirect Impact) Moderate (-) Moderate (-)

OPERATIONAL PHASE IMPACTS

POTENTIAL IMPACT Without mitigation/

enhancement

With mitigation/

enhancement

Without mitigation

With mitigation

Habitat Destruction (Direct Impact) Moderate (-) Low (-) - -

Health and Safety (Direct Impact) Moderate (+) Moderate (+) - -

Soil Erosion (Direct Impact) Low (-) Low (-) - -

Protection of the fuel pipeline (Direct Impact

Moderate (-) Moderate (-)

Decreased Soil erosion Moderate (-) Moderate (-)

Increased traffic in the system (Indirect Impact)

Low (-) Low (-)

DECOMMISSIONING PHASE IMPACTS

POTENTIAL IMPACT Without mitigation/

enhancement

With mitigation/

enhancement

Without mitigation

With mitigation

Increased traffic in the system (Direct Impact)

Low (-) Low (-)

Soil erosion (Direct Impact) Moderate (-) Low (-)

Waste generation (Direct Impact) Moderate (-) Low (-)

Health and safety (Direct Impact) Moderate (-) Moderate (-)

Key:

The table indicates that with the implementation of mitigation measures, all impacts will be of low significance to the receiving environment. However, given the ecological value and considering that the proposed site forms part of the biodiversity corridor of the Faerie Glen and Rietvlei Nature Reserves, the design alternatives suggested in section 2 of this report and the specialist reports (Appendix D) should be implemented to ensure that the positive impacts identified for the gabion structures are highlighted. Health and Safety Impacts is an important environmental aspect requiring careful mitigation and control. The danger of fire or explosion as a result of damage to the exposed fuel pipeline can have detrimental effects such as fatalities and damage to infrastructure. Ensuring that the fuel pipeline remains protected together with implementing the monitoring measures included into the Environmental Management Programme (See Appendix G) is essential to the sustainability of this project. Several mitigation measures have been proposed to minimise the anticipated environmental impacts together with an environmental management programme report to monitor the effectiveness of these mitigation measures.

High negative impact (-) Negative Impact

Moderate negative impact (+) Negative Impact

Moderate positive impact (-) Positive Impact

Low (-) Negative Impact