HYDROGEOLOGY STUDY FOR THE PROPOSED FUEL STATION, … · the weathering of chert and dolomite. Three boreholes were drilled on the site for dolomite stability investigations. These

HYDROGEOLOGY STUDY FOR THE PROPOSED FUEL STATION, ON PORTION 125 OF THE FARM WATERVAL 174 IQ, MOGALE CITY

Report Prepared for

Ntata Investment

Report Number 491398

Report Prepared by

June 2015

SRK Consulting: Project No: 498391 Hydrogeology of Portion 125 of Waterval 174 IQ Page i

MABB/MAHO Hydrogeology Study of Portion 125 of Waterval 174 IQ June 2015

HYDROGEOLOGY STUDY FOR THE PROPOSED FUEL STATION, ON PORTION 125 OF THE FARM WATERVAL 174 IQ, MOGALE CITY

Ntata Investment

SRK Consulting (South Africa) (Pty) Ltd 265 Oxford Rd Illovo 2196 Johannesburg South Africa

e-mail: [email protected] website: www.srk.co.za

Tel: +27 (0) 11 441 1111 Fax: +27 (0) 11 880 8086

SRK Project Number 491398

June 2015

Compiled by: Peer Reviewed by:

Benedict Mabenge Pr Sci Nat Senior Hydrogeologist

Ismail Mahomed Pr Sci Nat Principal Hydrogeologist

Email: [email protected]

SRK Consulting: Project No: 498391 Hydrogeology of Portion 125 of Waterval 174 IQ Page ii


Table of Contents

Disclaimer .................................................................................................................................................... iv

1 Introduction and Scope of Report .................. ............................................................. 1

1.1 Scope of Work ..................................................................................................................................... 1

2 Site Description .................................. .......................................................................... 1

2.1 Locality ................................................................................................................................................ 1

2.2 Climate ................................................................................................................................................ 3

2.3 Geology ............................................................................................................................................... 3

2.4 Hydrogeology ...................................................................................................................................... 5

2.4.1 Groundwater Levels ................................................................................................................ 5

2.4.2 Recharge ................................................................................................................................. 5

2.4.3 Groundwater Use .................................................................................................................... 5

3 Hydrogeological Investigations .................... .............................................................. 6

4 Program Results ................................... ........................................................................ 6

4.1 Site Visit and Hydrocensus ................................................................................................................. 6

4.2 Baseline Water Quality ....................................................................................................................... 9

5 Assessment of Impacts ............................. .................................................................. 9

5.1 Risk Assessment ................................................................................................................................. 9

5.2 Impacts Assessment ......................................................................................................................... 10

6 Conclusions and Recommendations ................... ..................................................... 12

6.1 Conclusions ....................................................................................................................................... 12

6.2 Recommendations ............................................................................................................................ 12

7 References ........................................ .......................................................................... 14

Appendices ........................................ .............................................................................. 15

Appendix A: Impact Assessment Methodology ..................... ..................................... 16

Appendix B: Laboratory Certificates ........................... ................................................ 21

SRK Consulting: Project No: 498391 Hydrogeology of Portion 125 of Waterval 174 IQ Page iii


List of Tables Table 2-1. Summary of site geology ................................................................................................................... 3

Table 3-1. Summary of boreholes installed for geotechnical investigation ........................................................ 6

Table 4-1. Water Sources Identified During Hydrocensus ................................................................................. 7

Table 4-2. Laboratory Results ............................................................................................................................ 9

Table 5-1. Impacts Assessment ....................................................................................................................... 11

List of Figures Figure 2-1. Location of proposed filling station ................................................................................................... 2

Figure 2-2. Mean monthly precipitation .............................................................................................................. 3

Figure 2-3. Site geological map .......................................................................................................................... 4

Figure 4-1. Map showing locations of boreholes identified during hydrocensus ................................................ 8

SRK Consulting: Project No: 498391 Hydrogeology of Portion 125 of Waterval 174 IQ Page iv


Disclaimer The opinions expressed in this Report have been based on the information supplied to SRK

Consulting (South Africa) (Pty) Ltd (SRK) by Ntata Investment (Ntata). The opinions in this Report

are provided in response to a specific request from Ntata to do so. SRK has exercised all due care

in reviewing the supplied information. Whilst SRK has compared key supplied data with expected

values, the accuracy of the results and conclusions from the review are entirely reliant on the accuracy and completeness of the supplied data. SRK does not accept responsibility for any errors

or omissions in the supplied information and does not accept any consequential liability arising from

commercial decisions or actions resulting from them. Opinions presented in this report apply to the

site conditions and features as they existed at the time of SRK’s investigations, and those

reasonably foreseeable. These opinions do not necessarily apply to conditions and features that may arise after the date of this Report, about which SRK had no prior knowledge nor had the

opportunity to evaluate.

SRK Consulting: Project No: 498391 Hydrogeology of Portion 125 of Waterval 174 IQ Page 1


1 Introduction and Scope of Report Ntata Investment appointed SRK Consulting to complete a hydrogeological study at Portion 125 of

the Farm Waterval 174 IQ, Mogale City. The property lies in Tarlton, 12 km west of the town of

Krugersdorp. Ntata Investment is compiling an Environmental Impact Assessment (EIA) for the

establishment of a fuel service station on the property.

The objective of this study is to identify and rate the impacts associated with proposed development on groundwater.

The study area is located within quaternary catchment A21D and within the Crocodile West and

Marico Water Management Area.

1.1 Scope of Work We understood the scope of work to be as follows:

• Desktop study of existing available data;

• Hydrocensus and site visit;

• Review of gravimetric survey and borehole drilling information supplied by Geotechnical

Engineering study;

• Sampling of groundwater and baseline water quality assessment;

• Impacts assessment.

2 Site Description

2.1 Locality The property is situated at the junction of the R24 to Krugersdorp and a link road to the N14 highway

to Rustenburg (Figure 2-1). The proposed development will cover an area of 2.3 ha and will

comprise of a fuel filling station and a retail component - convenience store, fast food restaurant and parking facilities for long haul heavy vehicles. The area slopes very gently towards the east, with an

average elevation of 1623.5 metres above mean sea level (mamsl).

A small retail shop is currently situated in the eastern corner of the property. The property has

access to municipal water, but no municipal sewer. The local municipality is amicable to alternative

measures to be implemented to deal with sewerage (Tarlton Truckstop Development Business Plan, June 2015).

The general land use within the area is residential rural, comprising of residential plots and some

agriculture. The study site is flanked by a farm on the northern boundary, and a small filling station

(Baobab Filling Station) is situated 200 m to the northeast of the site.



Figure 2-1. Location of proposed filling station



2.2 Climate The area is characterised by a temperate climate, with a mean annual precipitation of 750 mm. Most

of the precipitation comprises of rainfall which falls during the warm summer months (Figure 2-2).

The average midday temperatures range from 16.6 °C in June to 26.4 °C in January.

Figure 2-2. Mean monthly precipitation

2.3 Geology The site is underlain by dolomites of the Malmani subgroup, of the Transvaal Supergroup

(Figure 2-3). Geotechnical test pits excavated to an average depth of 1.6 m at the site exposed a

surface colluvium of dark reddish brown silty fine sand underlain by a chert residuum derived from the weathering of chert and dolomite.

Three boreholes were drilled on the site for dolomite stability investigations. These boreholes

encountered the transition from highly weathered material to a leached and fresh dolomite at an

average depth of 39 m (Africa Exposed, 2015). A summary of the site geology exhibited in the boreholes is shown in Table 2-1.

Table 2-1. Summary of site geology

Depth (mbgl) Description

0.0 – 7.0 Silty SAND and GRAVEL: Light reddish brown, silty fine sand with occasional gravel. Colluvium

7.0 – 13.0 Silty clayey SAND and FERRICRETE: Reddish to orangish brown silty and clayey sand with several angular ferricrete nodules

13.0 – 31.0 CHERT RESIDUUM: Dark orangey brown mottled white and red silty sand and weathered chert fragments

31.0 – 39.0 CHERT and WAD: Dark greyish brown to black mottled white clayey silt (wad) approx. 10-15%, with many angular weathered chert fragments

39.0 – 50.0 LEACHED DOLOMITE: Abundant angular slightly weathered chert and leached dolomite fragments in a matrix (5-15%) of dark grey silty clay

50.0 – 61.0 DOLOMITE: Light grey, slightly weathered to fresh dolomite

0

20

40

60

80

100

120

140

160

Rai

nfal

l (m

m)

Mean Monthly Precipitation



Figure 2-3. Site geological map



A gravity survey was carried out as part of the dolomite study and concluded that the site poses a

medium level risk of sinkhole and doline formation (Africa Exposed, 2015). The survey established

that no receptacles or open voids exist within the shallow weathered material, nor in the dolomite bedrock. Karsts are however known to be present in the region.

2.4 Hydrogeology The aquifers underlying the region are associated with the highly weathered zone, karst cavities,

fractures and joints within the chert and dolomite. Dolomites constitute some of the most important

aquifers in South Africa, with recharge values of between 9 and 13%. Groundwater yields are

excellent, and 50% of boreholes yield more than 5 L/s (DWS). The groundwater quality within the dolomites is typically of a calcium-magnesium-bicarbonate nature and generally of acceptable quality

for a variety of uses including drinking.

The presence of interconnected karst, fractures and joint systems within the dolomites makes the

aquifers vulnerable to pollution and allows the rapid migration of contaminants. The karst aquifers

are characterised by modest (<100 m2/d) to extremely high (>1000 m2/d) transmissivity values and moderate storativity values (Bredenkamp et al, 1986). Boreholes drilled for the dolomite study did not

intersect any open receptacles or voids within the weathered zone. Wad associated with Karst is

however present.

2.4.1 Groundwater Levels

Data sourced from the National Groundwater Archives (NGA) shows that the groundwater levels within a 1 km radius of the site vary from 6.7 metres below ground level (mbgl) to 59.82 mbgl. The

NGA data also shows that groundwater was intersected at depths ranging from 6.7 mbgl to 78 mbgl.

During the drilling of three dolomite study boreholes on the site groundwater was intersected at

depths of 28 to 30 mbgl. Interpolation of the groundwater level data shows that the groundwater

flows in a north easterly direction across the site.

2.4.2 Recharge

Groundwater recharge for the area is estimated at 11 % of MAP (Vegter, 1992), or approximately

81 mm of rainwater per annum percolating through the weathered zone to reach the groundwater

table.

2.4.3 Groundwater Use

The major groundwater users within the immediate vicinity of the proposed development are the Levante farm, to the north, which uses groundwater for irrigation and the Baobab filling station for

their domestic and industrial use. The residential properties along the R24 to the east of the site

largely use municipal water and use groundwater as backup for domestic purposes.



3 Hydrogeological Investigations A site visit was carried out on the 8th of June 2015 and was undertaken with the assistance of

personnel from Ntata Investment. The SRK hydrogeologist made a visual assessment of the site,

carried out a limited hydrocensus of surrounding groundwater users and collected three samples for

hydrocarbon analysis.

Three, 165 mm diameter, boreholes (Table 3-1) drilled during the geotechnical and dolomite studies were inspected and found to have collapsed as no casing had been installed following completion.

Ntata Investment provided the geotechnical and dolomite study reports that were compiled by Africa

Exposed in May and June 2015. Geological logs of these boreholes were provided with the reports.

Table 3-1. Summary of boreholes installed for geote chnical investigation

BH ID Locality X (m)

Y (m)

Drilled Depth (m)

Current Depth (m)

Water strike (mbgl)

Comments

VW1 Study Site 2880402 -0699156 54 16 28

Geotech holes, drilled 40m, collapsed, could not sample groundwater

VW2 Study Site 2880402 -069145 61 5 30

VW3 Study Site 2880466 -069151 56 6 30

4 Program Results

4.1 Site Visit and Hydrocensus The hydrocensus carried out within the vicinity of the site found that the majority of the households in

the area rely on the local municipality for their water supply. Some of the properties, however, have boreholes which provide a backup supply of water and used to water gardens. The Levante farm,

which is north west of the site, has a borehole that is used to provide water for irrigation. Access to a

number of the properties was a challenge as residents were absent, however the expectation is that

many of the residential and agricultural plots located to the north of the site have boreholes.

A summary of boreholes located on the surrounding properties is given in Table 4-1 and shown on

Figure 4-1. The depth to water level could not be measured in any of the boreholes visited as pumps

are installed. Water samples were collected in 100 ml and 500 ml glass bottles from three of the

boreholes visited. The samples were stored in a cooler box with ice packs until delivery to laboratory.

Basic water quality parameters were measured on-site before the collection of each water sample. No purging of the boreholes was necessary as all three boreholes were pumping at the time of

sampling.

No sheen or visual evidence of hydrocarbons was observed in any of the samples collected. The

Baobab filling station borehole valve is housed in a manhole box into which dirty contaminated water

from surface flows. A small amount of water was present in the manhole. The raising main from the borehole is sealed to prevent the contaminated water from flowing into the borehole.

Field Electrical Conductivity (EC) measurements ranged from 21.7 to 28.4 mS/m and the

groundwater is alkaline with a pH range of 8.4 to 9.2. The alkaline pH of the groundwater is typical of

groundwater from a dolomitic aquifer and the EC is well within the drinking water limit of 70 mS/m.



Table 4-1. Water Sources Identified During Hydrocen sus

BH ID Locality X (m)

Y (m)

EC (mS/m) pH Temp

(°C) Water use Distance from site

(m)

BH4 Levante Farm 2888207 -068847 21.7 9.2 19.7 Irrigation 400

BH5 Baobab Filling Station 2888185 -069088 25.3 8.4 20.1 Domestic 300

BH6 VO School 2888228 -069237 - - - Disused 300

BH7 Plot H28 2888354 -069469 28.4 8.6 14.5 Domestic 300



Figure 4-1. Map showing locations of boreholes iden tified during hydrocensus



4.2 Baseline Water Quality The water samples were submitted to M & L Laboratory Services for hydrocarbon content analysis.

The samples were analysed for Total Petroleum Hydrocarbons (TPH), Benzene, Toluene,

Ethylbenzene, Xylenes and Naphthalene (BTEXN) compounds. TAME and MTBE concentrations

were also measured during the analysis. Table 4-2 shows a summary of the laboratory results. The laboratory certificates are attached in Appendix B.

All the organic parameters analysed were found to be within the recommended limits by the United

States of America Environmental Protection Agency (US EPA)1. The alkaline pH measured in the

water suggests that the water is abstracted from the deep dolomite aquifer. The laboratory results indicate that the groundwater within the immediate vicinity of the proposed development site has not

been impacted by hydrocarbon fuels.

Table 4-2. Laboratory Results

Parameter BH4 BH5 BH7 USA EPA Limit (µg/L)

Date Sampled---> 08/06/2015 08/06/2015 08/06/2015

C10-C12 (µg/L) <2 <2 <2 7

C12-C22 (µg/L) <26 <26 <26 86

C22-C30 (µg/L) <13 <13 <13 42

C30-C40 (µg/L) <62 <62 <62 208

Total C10-C40 (ug/l) <103 <103 <103

GRO-C6-C10 (µg/L) <3 <3 <3 11

Benzene (µg/L) <1 <1 <1 1

Ethylbenzene (µg/L) <1 <1 <1 1

MTBE (µg/L) <1 <1 <1 3

Naphthalene (µg/L) <1 <1 <1 2

O-Xylene (µg/L) <1 <1 <1 1

TAME (µg/L) <1 <1 <1 1

Toluene (µg/L) <1 <1 <1 1

m/p-Xylene (µg/L) <1 <1 <1 1

5 Assessment of Impacts The impact assessment was carried out according to the methodology laid out in Appendix A.

The first step of the assessment is to carry out a risk assessment and identify the potential sources

of contamination, contaminant pathways and receptors.

5.1 Risk Assessment A risk assessment entails the evaluation of Source-Pathway-Receptor (S-P-R) linkage. The risk level

is defined by the completeness of the S-P-R linkage together with the severity of the impact:

• High : S-P-R linkage is proven to be complete

• Medium : S-P-R linkage is suspected but not proven

• Low : S-P-R linkage is complete but severity of impact is negligible, or S-P-R linkage is

incomplete and there is no foreseeable mechanism by which it could be realised

1 Note there are no South Africa guideline limits for these compounds



For the study site, the following S-P-R linkage is defined as follows:

• The potential source of contamination will be the fuel from leaks of the underground storage tanks (USTs), associated pipework and relevant filling station surface infrastructure. Sewage

disposal via spectic and French drains if used could also be a source of contamination.;

• Potential pathways for the contamination will be the groundwater via the weathered zone and karst/fractures or joints aquifers;

• The receptors are residential users who abstract boreholes for potable use to the eastern side of the site and the farm on the north.

The risk of groundwater contamination is rated as High as the S-P-R linkage for the site is proven.

5.2 Impacts Assessment Any leakage from the underground fuel tanks and spillages from surface connections may reach the

unsaturated zone and be leached down to the water table. This would contaminate the groundwater

with hydrocarbons and users could be exposed. Percolation of contaminates from the sewage disposal, if on-site, could also occur. Abstraction form pumping boreholes could also draw

contaminants towards the supply boreholes.

The impact of the operation of the filling station on the groundwater quality is rated Medium High but

can be mitigated to reduce the potential impacts (see Table 5-1).

Mitigating these impacts require that the construction of the tank farm to contain any leakages, safeguards be implemented to prevent spills and leaks and in the event these occur, the impacts of

any spills be limited.

The excavation, installation and maintenance of the underground storage tanks must follow the

relevant SABS standards, including:

• SANS 10089-3: The petroleum industry Part 3: The installation, modification, and

decommissioning of underground storage tanks, pumps/dispensers and pipework at service

stations and consumer installations

• SANS 50858-1: Separator systems for light liquids (e.g. oil and petrol) Part 1: Principles of

product design, performance and testing, marking and quality control

• SANS 50858-2: Separator systems for light liquids (e.g. oil and petrol) Part 2: Selection of nominal size, installation, operation and maintenance

It worth highlighting that a HDPE liner would need to be installed within the tank farm and that all

stormwater from the forecourt area is controlled and directed to an oil/water separator and compiles with municipal by-laws and SANS guidelines, The discharge from the oil/water separator must be

directed to sewer line or disposed in an acceptable manner.

Careful daily wet stock reconciliation and at least monthly or when leaks are suspected inspection of

tank farm wells is required to identify any leakages quickly.



Table 5-1. Impacts Assessment

Potential impact Activity

Environmental Significance Before Mitigation Recommended

mitigation measures / Remarks

Environmental Significance After Mitigation

S SS D FA FI SIG Rating S SS D FA FI SIG Rating

Impact on groundwater quality

Storage and dispensing of fuel 4 3 4 4 4 88 MH

Construction (HDPE lined, backfill & concrete slabs etc.) of tank farms. Jacketed tanks and spill containment at dispensers etc.. Clean up protocols for all spillages

4 1 4 4 2 54 L

Surface run-off from forecourt

4 3 4 2 4 66 ML

Install hardstanding, stormwater drainage and oil\water separator Appropriate Clean up all spillages

4 2 4 2 3 50 L



6 Conclusions and Recommendations

6.1 Conclusions The following were concluded from the desktop study, the site visit and the laboratory results:

• The aquifers underlying the region are predominantly karstic and associated fracturing and

jointing, with modest to high transmissivity values and modest storativity. Any contaminant

introduced into the subsurface could migrate rapidly to the domestic water users located 300 m down gradient of the site;

• The groundwater within the immediate vicinity of the site is generally of acceptable quality

for a variety of purposes. All the organic parameters analysed were found to be within the recommended limits by the United States of America Environmental Protection Agency (US

EPA), indicating that no historical contamination is evident. No contamination from the

service station located 200 m and to the north is evident.

• The impact to the groundwater quality of the operation of the filling station is rated as Medium High but can be mitigated by complying with industry good practice and the

relevant SANS standards for UST installations.

6.2 Recommendations We recommend the following:

• Implement good practices and good housekeeping during all phases of the project to limit the impacts of leakages and spills.

• A HDPE liner would need to be installed within the tank farm and stringent application of stormwater and leak detection measures would need to be applied.

• Implement and follow measures to prevent and detect leaks as detailed in SANS standards and fuel industry construction protocols. These include amongst others:

o Lined tank farm, jacketed tanks and delivery pipes which are capable of

withstanding the high positive pressure (400 kPa to 1000 kPa);

o Electronic leak detection measures;

o Hardstanding and stormwater drainage;

o Daily wet stock reconciliation;

o At least monthly inspection of monitoring well that will be installed around the tank

farm;

o Annual pressure testing of infrastructure,

o Effective housekeeping and effective protocols for responding to spills and leaks etc.



Prepared by

Benedict Mabenge Pr.Sci.Nat

Senior Hydrogeologist

Reviewed by

Ismail Mahomed Pr.Sci.Nat

Principal Hydrogeologist

Reviewed by

Peter Shepherd. Pr.Sci.Nat

Principal Hydrologist & Partner

All data used as source material plus the text, tables, figures, and attachments of this document

have been reviewed and prepared in accordance with generally accepted professional engineering and environmental practices.



7 References Africa Exposed. Dolomite Stability Investigation Report: Portion 125 Of The Farm Waterval 174 IQ

Mogale City (2015)

Africa Exposed. Engineering Geological Investigation Report: Portion 125 Of The Farm Waterval 174

IQ Mogale City (2015)

Bredenkamp D.B, Van der Westhuizen C, Weigmans F.E and Kuhn C. Groundwater Supply Potential of Dolomite Compartments West of Krugersdorp. Report No. GH3440. Directorate

Geohydrology. Department of Water Affairs & Forestry. (1986)

South African National Groundwater Archives (2015)

Vegter J.R & Seymour A.J. Saturated Interstices, Mean Annual Recharge and Depth to Groundwater

Level maps. Department of Water Affairs & Forestry (1992)



Appendices



Appendix A: Impact Assessment Methodology



Impact assessment methodology

The first stage of impact assessment is the identification of environmental activities, aspects and

impacts. This is supported by the identification of receptors and resources, which allows for an

understanding of the impact pathway and an assessment of the sensitivity to change. The following definitions therefore apply:

• An “Activity” is defined as a distinct process or risk undertaken by an organisation for which

a responsibility can be assigned. Activities also include facilities or pieces of infrastructure that are possessed by an organisation;

• An environmental “Aspect” is an element of an organisation’s activities, products and

services which can interact with the environment. The interaction of an aspect with the environment may result in an impact.

• Environmental “Impacts” are the consequences of these aspects on environmental

resources or receptors of particular value, sensitivity, for example, disturbance due to noise and health effects due to poorer air quality. Receptors can comprise, but are not limited to,

people or human-made systems, such as local residents, communities and social

infrastructure, as well as components of the biophysical environment such as aquifers, flora

and palaeontology. Impacts on the environment can lead to changes in existing conditions; the impacts can be direct, indirect or cumulative. Direct impacts refer to changes in

environmental components that result from direct cause-effect consequences of interactions

between the environment and development activities. Indirect impacts result from cause-

effect consequences of interactions between the environment and direct impacts.

Cumulative impacts refer to the accumulation of changes to the environment caused by human activities.

Description of the Aspects and Potential Impacts

The cumulative knowledge of the findings of the environmental investigations forms the basis for the

prediction of impacts. Once a potential impact has been determined it is necessary to identify which

development activity will cause the impacts, the probability of occurrence of the impact, and its magnitude and extent. This information is important for evaluating the significance of the impact, and

for determining mitigation and monitoring strategies.

The assessment of significance should be undertaken twice. Initial significance should be based on

only natural and existing mitigation measures (including built-in engineering designs). The subsequent assessment should take into account the recommended management measures

required to mitigate the impacts.



Table A1. Criteria for assessing significance of im pacts

SEVERITY OF IMPACT RATING

Insignificant / non-harmful 1

Small / potentially harmful 2

Significant / slightly harmful 3

Great / harmful 4

Disastrous / extremely harmful 5

SPATIAL SCOPE OF IMPACT RATING

Activity specific 1

Right-of-way specific (within right-of-way) 2

Local area (within 5 km of filling station) 3

Regional 4

National 5

DURATION OF IMPACT RATING

One day to one month 1

One month to one year 2

One year to ten years 3

Life of operation 4

Post closure / permanent 5

FREQUENCY OF ACTIVITY / DURATION OF ASPECT

RATING

Annually or less / low 1

6 monthly / temporary 2

Monthly / infrequent 3

Weekly / life of operation / regularly / likely 4

Daily / permanent / high 5

FREQUENCY OF IMPACT RATING

Almost never / almost impossible 1

Very seldom / highly unlikely 2

Infrequent / unlikely / seldom 3

Often / regularly / likely / possible 4

Daily / highly likely / definitely 5 The method as described above is further explained in the following section in order to give a better understanding on how the Likelihood and Significance of an impact is identified. Attributes contributing to the significance and likelihood will be explained below: a. Spatial Scope: The spatial scope can be defined as the geographical coverage, and will take into account the following factors:

• The physical extent/distribution of the aspect, receptor and proposed impact; and

• The nature of the baseline environment within the area of impact.

For example, the impact of noise is more likely to be confined to a smaller geographical area than that of air emissions, which may be experienced at some distance. The significance of an impact varies spatially. Many will be significant only within the immediate vicinity of the site or within the surrounding community, while others may be significant at a regional or national level.

CONSEQUENCE

LIKELIHOOD



b. Duration Duration refers to the length of time that the aspect may cause a change, either positive or negative, on the environment. The environment assessment methodology distinguishes between different time periods by assigning a rating to the duration of an impact. c. Severity The severity of an environmental aspect is determined by the degree of change to the baseline environment and includes consideration of the following factors:

• The reversibility of the impact;

• The sensitivity of the receptors to the stressor;

• The impact duration, its permanency and whether it increases or decreases with time;

• Whether the aspect is controversial or would set a precedent; and

• The threat to environmental and health standards and objectives.

d. Frequency of Activity The frequency of an activity refers to how regularly the activity takes place. The more frequently the activity takes place, the higher potential there is for a related impact to occur. e. Frequency of Impact The frequency of an impact refers to how often the aspect impacts, or may impact, either positively or negatively, on the environment. f. Additional Variables There are additional variables that must be taken into consideration when assessing the impacts of the proposed project. These variables will have a bearing on the significance of the impacts being assessed. These variables may include cumulative impacts and inputs received from I&AP’s. In scenarios where this is applicable, more emphasis will be placed on the management measure requirements. Cumulative and Impact identified by I&AP’s are discussed below:

• Cumulative impacts: These are impacts which are considered where off-site activities take place together with activities associated with the proposed project, resulting in a cumulative

impact imposed on the environment.

• Impacts/Issues raised by I&AP’s: I&AP’s will be consulted during the entire process of the EIA/EMP. Issues and concerns may be raised by the I&AP’s which will bear more weight in

the significance of the impact being assessed.

Determining the Impact Rating This rating methodology is used to evaluate the importance of a particular impact, the consequence and likelihood. The significance of the impact is assessed by rating each variable numerically according to defined criteria as outlined in Table A1. The purpose of the rating is to develop a clear understanding of influences and processes associated with each impact. The severity, spatial scope and duration of the impact together comprise the consequence of the impact and when summed can obtain a maximum value of 15. The frequency of the activity and the frequency of the impact together comprise the likelihood of the impact occurring and can obtain a maximum value of 10. The values for likelihood and consequence of the impact are then read off a significance rating matrix as shown in Table A2.



Table A2. Interpretation of Impact Rating

Consequence

Like

lihoo

d

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 7 14 21 28 35 42 49 56 63 70 77 84 91 98 105 8 16 24 32 40 48 56 64 72 80 88 96 104 112 120 9 18 27 36 45 54 63 72 81 90 99 108 117 126 135 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150

SIGNIFICANCE = CONSEQUENCE X LIKELIHOOD

The model outcome as determined from Table A2 is then assessed in terms of impact certainty and consideration of available information. Where a particular variable requires weighing or an additional variable requires consideration the model is adjusted accordingly. The numerical rating is determined through the use of Table A2. The colour code from Table A2 corresponding to Table A3 is then used to determine the appropriate level of mitigation that will be required to reduce the current rating.

Table A3. Positive/Negative Mitigation Ratings

Colour Code

Significance Rating Value

Negative Impact Management Recommendation

Positive Impact Management Recommendation

Very high 125-150

Improve current management

Maintain current management

High 101-125



Medium High 76-100



Medium Low 51-75 Maintain current

management Improve current management

Low 25-50



Very Low 1-25



Mitigation In assessing the significance of an impact, natural and existing mitigation is taken into account. Natural and existing mitigation measures are defined as natural conditions, conditions inherent to the development design and existing management measures that alleviate impacts. The significance of impacts is assessed taking into account any mitigation measures that are proposed. An EMP, specifying the methods and procedures for managing the environmental impacts of the proposed development, during all phases has been compiled and will be submitted to the competent authority following the final review period.



Appendix B: Laboratory Certificates









SRK Report Distribution Record

Report No. 491398

Copy No. 1

Name/Title Company Copy Date Authorised by

Raveen Ramlakan Ntata Investments 1 01/07/2015

Janavi Jardine Azzuro Environmental 1 01/07/2015

SRK Library SRK 1 01/07/2015

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HYDROGEOLOGY STUDY FOR THE PROPOSED FUEL STATION, … · the weathering of chert and dolomite. Three boreholes were drilled on the site for dolomite stability investigations. These