Sato Energy Holdings - SRK Consulting Africa

Preliminary Desktop Surface 

Water and Geotechnical Study 

for the proposed SATO holdings 

Photovoltaic project, near 

Aggeneys, Northern Cape 

Report Prepared for 

Sato Energy Holdings (Pty) Ltd 

Report Number 435209_SurfaceWater 

Report Prepared by 

January 2012

SRK Consulting: 435209: Desktop Surface Water & Geotechnical Page i 

Preliminary Desktop Surface Water and 

Geotechnical Study for the proposed SATO 

holdings Photovoltaic project, near Aggeneys, 

Northern Cape 

Sato Energy Holdings (Pty) Ltd 

111 John Adamson Drive 

Montgomery Park 

Johannesburg 

SRK Consulting (South Africa) (Pty) Ltd 

Section A Second Floor 

IBM House 

54 Norfolk Terrace 

Westville 3630 

South Africa 

e-mail: Durban@srk.co.za 

website: www.srk.co.za 

Tel: +27 (0) 31 279 1200 

Fax:+27 (0) 31 279 1204 

SRK Project Number 435209/SurfaceWater 

January 2012 

Compiled by: Peer Reviewed by: 

Murray Sim 

Associate Partner 

Peter Shepherd 

Director 

Email: msim@srk.co.za Email: pshepherd@srk.co.za 

Authors: 

Murray Sim; Colin Wessels; Sagadevan Kisten; 

SIMM/SHEP 435209_SATO_SurfaceWater_GW_Geotechnical_Preliminary_Jan2012_FinalDraft.docx January 2012

SRK Consulting: 435209: Desktop Surface Water & Geotechnical Page ii 

Table of Contents 

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

1 Introduction and Scope of Report ............................................................................... 5 

2 Background and Brief .................................................................................................. 5 

2.1 Background of the project ................................................................................................................... 5 

3 Program Objectives and Work Program ..................................................................... 6 

3.1 Program objectives ............................................................................................................................. 6 

3.2 Work Program ..................................................................................................................................... 6 

3.3 Project Team ....................................................................................................................................... 6 

4 Legal Framework .......................................................................................................... 7 

4.1 National Water Act (36 of 1998) .......................................................................................................... 7 

4.2 National Environmental Management Act No. 107 of 1998 ................................................................ 8 

4.3 Best Practise Guideline (G1) Storm Water Management DWA 2006 ................................................ 8 

5 Hydrological evaluation ............................................................................................. 13 

5.1 Surface water .................................................................................................................................... 13 

5.1.1 Description ............................................................................................................................ 13 

5.1.2 Rainfall................................................................................................................................... 13 

5.1.3 Evaporation ........................................................................................................................... 14 

5.1.4 Extreme events ..................................................................................................................... 14 

5.1.5 Development considerations ................................................................................................. 15 

5.2 Hydrogeology .................................................................................................................................... 15 

5.2.1 Description ............................................................................................................................ 15 

5.2.2 Development considerations ................................................................................................. 16 

5.3 Surface water resources ................................................................................................................... 16 

6 Geotechnical evaluation ............................................................................................ 17 

6.1 Geology ............................................................................................................................................. 17 

6.2 Founding conditions .......................................................................................................................... 18 

6.3 Development considerations ............................................................................................................. 18 

7 Impact Assessment .................................................................................................... 19 

7.1 Construction / Operational Phase ..................................................................................................... 19 

7.1.1 Decrease in surface water quality ......................................................................................... 19 

7.1.2 Increase in surface water quantity ........................................................................................ 21 

7.1.3 Increase in erosion potential ................................................................................................. 22 

7.1.4 Increase in flooding potential and change in flow regime ..................................................... 23 

7.2 Mitigation measures .......................................................................................................................... 24 

8 Conclusions and Recommendations ........................................................................ 24 

8.1 Hydrological ...................................................................................................................................... 24 

8.2 Geotechnical ..................................................................................................................................... 25 


SRK Consulting: 435209: Desktop Surface Water & Geotechnical Page iii 

8.3 Impact Assessment ........................................................................................................................... 26 

8.4 Mitigation Measures .......................................................................................................................... 26 

9 Final Remarks ............................................................................................................. 28 

10 References .................................................................................................................. 29 

Appendices ...................................................................................................................... 30 

Appendix A: Impact Assessment Methodology .......................................................... 31 

Appendix B: Figures ..................................................................................................... 38 

435209/1.1 Regional drainage map ...................................................................... 38 

435209/1.2 Study area ........................................................................................... 38 

435209/1.3 Catchment boundaries and surface water features ........................ 38 

435209/1.4 Surface water runoff potential .......................................................... 38 

435209/1.5 Hydro geological map ........................................................................ 38 

435209/1.6 Geology map ...................................................................................... 38 

List of Tables 

Table 3-1: Project Team ................................................................................................................................ 6 

Table 5-1: Overview/Strategies of Storm Water Management ..................................................................... 9 

Table 6-1: Percentage of time rainfall amount is exceeded and average monthly rainfall ......................... 14 

Table 6-2: Average monthly S-pan evaporation (mm) ................................................................................ 14 

Table 6-3: 24-hour design rainfall depths (mm) .......................................................................................... 14 

Table 8-1: Impact assessment (deterioration in water quality) ................................................................... 20 

Table 8-2: Impact assessment (increase in surface water quantity) ........................................................... 21 

Table 8-3: Impact assessment (increase in erosion potential) .................................................................... 22 

Table 8-4: Impact assessment (increase in flooding potential and change in flow regime)........................ 23 

Table 9-1: Mitigation measures (deterioration in water quality) .................................................................. 26 

Table 9-2: Mitigation measures (increase in surface water quantity) .......................................................... 27 

Table 9-3: Mitigation measures (increase in erosion potential) .................................................................. 27 

Table 9-4: Mitigation measures (increase in flooding potential and change in flow regime) ...................... 27 


SRK Consulting: 435209: Desktop Surface Water & Geotechnical 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 Sato Energy Holdings Pty (Ltd) (SATO). The opinions 

in this Report are provided in response to a specific request from SATO 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: 435209: Desktop Surface Water & Geotechnical Page 5 

1 Introduction and Scope of Report 

Sato Energy Holdings (Pty) Ltd (Sato) proposes to develop a solar energy facility using photovoltaic 

(PV) panels near Aggeneys in the Northern Cape. The farm is located adjacent to the N14 between 

Springbok and Pofadder, in close proximity to the Namibian border. The PV plant is anticipated to 

have an array of photovoltaic panels covering just less than 900 hectares, with 500MW power 

generating capacity. 

SRK Consulting (Pty) Ltd (SRK) has been appointed by Sato as an independent environmental 

consultant to carry out an Environmental Impact Assessment (EIA) as required by the National 

Environmental Management Act (NEMA) Act 107 of 1998. As such, SRK is fulfilling the role of 

environmental assessment practitioner (EAP) as specified in the EIA regulations. Included in the EIA 

process is the need to develop draft and final scoping reports, as well as draft and final EIA reports. 

Subsequent to submission of the Draft Scoping Report (DSR), motivation for splitting the project into 

seven EIAs has been provided to DEA based on Department of Energy (DoE) requirements of 

restricting the capacity per application and environmental authorisation to 75 MW. The format of the 

development is thus now as follows: 6 x 75 MW units and 1 x 50 MW unit; together they comprise 

the original 500 MW project. 

The approach for the Sato PV EIA process will be through the production of a consolidated Final 

Scoping Report (FSR) and environmental impact assessment report (EIR) which includes all seven 

of the PV projects, but which will also allow individual authorisations to be provided for each of the 

projects (reference 12/12/20/2334/1 to 12/12/20/2334/7). 

As part of the EIA process a desktop surface water and geotechnical assessment is required and 

this forms the basis of this report. The study area can be found in Appendix B, Figure 1.2 

2 Background and Brief 

2.1 Background of the project 

SRK has been appointed by Sato as an independent environmental consultant to carry out an 

Environmental Impact Assessment (EIA) and this specialist surface water and geotechnical 

assessment will be incorporated into the final EIA’s. 

The PV Array is proposed to cover approximately 900 ha, divided into seven areas and is anticipated 

to produce 500 MW when developed in its entirety. The aboveground designed footings (strip 

foundation) will be 0.51 m in height, 4.8 m in length and 0.8 m wide. The PV plant will comprise 

seven units (6x 75 MW plus 1x 50 MW). Each of the six 75 MW units will have 15 adjacent sites, 

each of which will produce 5 MW (thus totalling 75 MW for each unit). The seventh unit will have 3.3 

adjacent sites each of which will generate 15 MW (totalling 50 for the unit). The total proposed 

development will comprise about 26 adjacent sites each of 19.23 MW. Each table will in turn consist 

of 85 panels. 

The final number of rows and panels depends on the configuration of the array and power rating of 

the panels. 



3 Program Objectives and Work Program 

3.1 Program objectives 

The main objectives of the specialist study are to assess potential impacts due to the proposed 

development and assist in providing information to enable the project team and authorities in 

decision making. 

3.2 Work Program 

The activities undertaken in the work program have been divided into a hydrological and 

geotechnical desktop evaluation based on the available data at hand. 

3.3 Project Team 

The project team is presented in Table 3-1. 

Table 3-1: Project Team 

Team Member Role Specialist Area 

Peter Shepherd Project Reviewer Water regulation and strategic water management 

Murray Sim Project Manager Water engineering 

Sagadevan Kisten Principal Scientist Hydrogeological specialist 

Colin Wessels Senior Geologist Geotechnical specialist 



4 Legal Framework 

Only those relevant to surface water have been included and there are many other legal 

requirements which would be covered in the other disciplines. 

4.1 National Water Act (36 of 1998) 

The surface water management for the proposed development and related infrastructure falls under 

legislation contained in, amongst others, the National Water Act (No 36 of 1998) (NWA). Section 4 

deals with prevention of contamination: The person who owns and/or controls, occupies or uses the 

land in question is responsible for taking measures to prevent pollution of water resources. If these 

measures are not taken, the catchment management agency concerned may itself do whatever is 

necessary to prevent the pollution or to remedy its effects, and to recover all reasonable costs from 

the persons responsible for the pollution. This can be broadly summarised as follows: 

• Separate “clean” and “dirty water”; 

• Water contaminated by activities / infrastructure may not be discharged to surface or 

groundwater resources; and 

• Prevention of erosion. 

Extracts from National Water Act No 36 of 1998, Section 4 

(1) An owner of land, a person in control of land or a person who occupies or uses the land on which - 

(a) any activity or process is or was performed or undertaken; or 

(b) any other situation exists, which causes, has caused or is likely to cause pollution of a water 

resource, must take all reasonable measures to prevent any such pollution from occurring, continuing 

or recurring. 

(2) The measures referred to (above) may include measures to - 

(a) cease, modify or control any act or process causing the pollution; 

(b) comply with any prescribed waste standard or management practice; 

(c) contain or prevent the movement of pollutants; 

(d) eliminate any source of the pollution; 

(e) remedy the effects of the pollution; and 

(f) remedy the effects of any disturbance to the bed and banks of a watercourse. 

Regulations relating to capacity requirements of “clean” and “dirty” water systems 

Every person in control of an activity must- 

a) confine any unpolluted water to a clean water system, away from any dirty area; 

b) collect the water arising within any dirty area, into a dirty water system; 

c) design, construct, maintain and operate any dirty water system so that it is not likely to spill into 

any clean water system more than once in 50 years; 

The following water use activities will require authorisation and possibly licensing from the DWA prior 

to commencement of said activities: 



Extract from the National Water Act, Section 21 

For the purposes of this Act, water use includes - 

(a) taking water from a water resource; 

(b) storing water; 

(c) impeding or diverting the flow of water in a watercourse; 

(d) engaging in a stream flow reduction activity contemplated in section 36; 

(e) engaging in a controlled activity identified as such in section 37 (1) or declared under section 

38 (1); 

(f) discharging waste or water containing waste into a water resource through a pipe, canal, sewer, sea 

outfall or other conduit; 

(g) disposing of waste in a manner which may detrimentally impact on a water resource; 

(h) disposing in any manner of water which contains waste from, or which has been heated in, any 

industrial or power generation process; 

(i) altering the bed, banks, course or characteristics of a watercourse; 

(j) removing, discharging or disposing of water found underground if it is necessary for the efficient 

continuation of an activity or for the safety of people; and 

(k) using water for recreational purposes 

4.2 National Environmental Management Act No. 107 of 1998 

Chapter 7 of the National Environmental Management Act deals with compliance, enforcement and 

protection and Section 28 deals specifically with duty of care and remediation of environmental 

damage. 

Extract from the National Environmental Management Act no 107 of 1998 

(1) Every person who causes, has caused or may cause significant pollution or degradation of the 

environment must take reasonable measures to prevent such pollution or degradation from 

occurring, continuing or recurring, or, in so far as such harm to the environment is authorised by 

law or cannot reasonably be avoided or stopped, to minimise and rectify such pollution or 

degradation of the environment. 

(2) Without limiting the generality of the duty in subsection (1), the persons on whom subsection (1) 

imposes an obligation to take reasonable measures, include an owner of land or premises, a 

person in control of land or premises or a person who has a right to use the land or premises on 

which or in which - 

(a) any activity or process is or was performed or undertaken; or 

(b) any other situation exists, which causes, has caused or is likely to cause significant pollution 

or degradation of the environment. 

(3) The measures required in terms of subsection (1) may include measures to - 

(a) investigate, assess and evaluate the impact on the environment; 

(b) inform and educate employees about the environmental risks of their work and the manner 

khkkhkh in which their tasks must be performed in order to avoid causing significant pollution or 

degradation of the environment; 

(c) cease, modify or control any act, activity or process causing the pollution or degradation; 

(d) contain or prevent the movement of pollutants or the causant of degradation; 

(e) eliminate any source of the pollution or degradation; or 

(f) remedy the effects of the pollution or degradation. 

4.3 Best Practise Guideline (G1) Storm Water Management DWA 2006 

The Storm Water Management DWA 2006 guidelines are geared towards the mining industry but 

there are definite similarities which need to be incorporated where relevant. 



Table 4-1: Overview/Strategies of Storm Water Management 

Section Guidelines (BPG G2) Measures (combination of BPG G2 

and Reg. 704) 

General 

objectives 

Primary 

principles 

Protection of life (prevent loss of 

life) and property (reduce damage 

to infrastructure) from flood 

hazards 

Planning for drought periods during 

operation 

Ensuring continuous operation and 

production through different 

hydrological cycles 

Prevention of land and 

watercourse (bed and banks) 

erosion (especially during storm 

events) 

Minimising the impact of 

operations on downstream users 

by maintaining the downstream 

water quantity and quality 

requirements. 

Preservation and protection of the 

natural environment in terms of 

quality, quantity and ecological 

integrity (water courses and their 

ecosystems) 

‘Clean’ water must be kept clean 

and routed to the natural water 

course 

All storm water management 

infrastructures are designed to 

withstand a 1:50 year flood. 

Energy dissipaters and erosion 

protection measures are in place, 

including along roads and at 

culvert/channel outlets. 

The quality and quantity 

requirements of downstream users 

will be assessed. Dirty areas will be 

minimised and all dirty water will be 

contained up to the 1:50 year event. 

Operating levels of containment 

facilities will be set to ensure 

adequate capacity for a 1:50 year 

event. ‘Clean’ water will be diverted 

back to the catchment but will be 

contained for controlled release after 

the storm event if the volume of the 

runoff poses a risk. 

‘Dirty’ areas will be minimised and all 

‘dirty’ water will be contained up to 

the 1:50 year event. Clean water will 

be diverted back to the catchment. 

The definition of 'dirty' for the site will 

be negotiated with DWA in terms of 

the water quality objectives set for 

the catchment. 

‘Clean’ areas will be maximised and 

‘clean’ runoff will be returned to the 

receiving water 

environment/catchment; maximize 

reuse of dirty water where feasible 

e.g. through separation of less dirty 




and Reg. 704) 

‘Dirty’ water must be collected and 

contained 

water, and minimize seepage and 

overflows from containment facilities; 

separate less dirty water where 

feasible 

‘Dirty’ areas will be minimised and 

reuse of dirty water will be 

maximised where feasible. Specific 

measures include separation of less 

dirty water for reuse in 

operations/areas where a better 

quality water is required and 

minimising seepage and overflows 

from containment facilities 

Sustainability over life cycle Sustainability over the development 

life cycle and over different 

hydrological cycles will incorporate 

principles of risk management 

including the consideration of the 

consequences of extreme events 

(extreme rainfall and emergency 

events), as well as potential water 

shortfalls in areas subject to drought. 

The SWMP has full commitment from 

management and staff and will be 

regularly reviewed and revised 

accordingly. 

Consideration of regulations and 

stakeholders 

Other principles Precautionary approach and being 

proactive 

Consideration of a range of 

management measures and 

options 

All stormwater management 

measures are in compliance with 

Regulation 704 under the National 

Water Act, Act 36 of 1998 and 

Regulation 527 under the MPRDA. 

The interests of stakeholders will be 

considered and incorporated and 

communication channels will be 

established with the Catchment 

Management Agency once these are 

up and running. 

Regular auditing is required to 

develop such an approach. 

Investigations are required to 

identify potential management 

measures and options specific for the 




and Reg. 704) 

Issues that 

need to be 

taken into 

account 

Implementation, operation, 

monitoring and auditing 

SIMM/SHEP 435209_SATO_SurfaceWater_GW_Geotechnical_Preliminary_Jan2012_FinalDraft.docx January 2012 

site. 

Management support, resources and 

adequately trained staff will be 

provided. Performance of the SWMP 

will be reviewed regularly (including 

design performance validation, 

operational and environmental 

considerations) and where necessary 

modified. 

Statutory requirements All stormwater management 

measures are in compliance with 

Regulation 704 under the National 

Water Act, Act 36 of 1998 and 

Regulation 527 under the MPRDA. 

Catchment objectives that need to 

be met or protected 

Management of risk, precipitation 

event or recurrence interval 

Water balance management (refer 

to BPG G2) 

Interaction with regulators and the 

community. 

Operational and emergency 

monitoring and documentation 

The Catchment Management 

Strategy has not yet been developed 

but a catchment-based approach will 

be followed to identify current and 

potential water management issues 

in the catchment. 

Risks associated with stormwater 

management have been minimised 

as follows: all dirty and clean water 

facilities will be capable of handling 

the 1:50 year event or sequential 

events that have the cumulative 

impact of a 1:50 year event; 

maximum storage of water for reuse 

will take place prior to the start of dry 

periods; etc. 

The water balance has been 

optimised to maximise reuse of water 

and ensure maximum returns of 

clean water runoff to the catchment 

in accordance with BPG G2 to 

minimise the loss of catchment yield. 

Suitable forums should be 

established. 

Reference the Emergency 

Preparedness and Response



and Reg. 704) 

Integration with 

other water 

management 

aspects 

(refer to BPG G3) Procedure and the Aspects and 

Impact Register as maintained in 

terms of ISO140001. 

Provide for incidents and 

accidents, and contingencies 

associated with incidents and other 

emergencies 

Water quality: downstream 

contamination of natural 

watercourses due to runoff or 

spillage of contaminated storm 

water. 

Reference the Emergency 

Preparedness and Response 

Procedure and the Aspects and 

Impact Register as maintained in 

terms of ISO140001. 

‘Dirty’ areas will be minimised and all 

dirty water will be contained up to the 

1:50 year event. Where feasible, less 

polluted water will be separated from 

more polluted water to maximise 

reuse of water (BPG H3). ‘Clean’ 

water will be diverted back to the 

catchment. Materials and waste 

handling will be in designated areas 

to prevent spillages in clean areas 

and the subsequent potential 

pollution of clean water runoff. 

Energy dissipaters and erosion 

protection measures are in place to 

minimise sediment loads entering the 

catchment. 

Performance indicators Suitable performance indicators will 

be developed. 

Training and research All contractors and personnel 

responsible for the stormwater 

management systems will undergo 

suitable training, which will be 

reinforced on a regular basis. Where 

new technology is employed, 

experiences and findings will be 

captured and disseminated via 

published articles/presentations. 

Water reuse and reclamation (see 

BPG H3) 

Impact prediction (see BPG G4) 




and Reg. 704) 

Water and salt balances (see BPG 

G2) 

Water monitoring systems (see 

BPG G3) 

5 Hydrological evaluation 

5.1 Surface water 

5.1.1 Description 

The preferred site is located between the Windhoek se Berge in the south, Skelmberg in the west 

and the low lying pans in the north. The catchment starts in the south and drains towards Windhoek 

se Poort, east of the Skelmberg and down to the low lying pans in the north. The slopes are 

extremely flat with the majority of the surface water runoff flowing as sheet wash. There are various 

localised drainage lines around Skelmberg and any runoff rapidly dissipates and infiltrates on 

reaching the flat open sandy soils. There is one defined watercourse towards the north which drains 

under the N14 and gravel roads, also discharging into the pans but does not cross the preferred site 

location. The regional drainage map and the catchment boundaries including surface water features 

can be found in Appendix B, Figures 1.1 and 1.3 respectively. 

There is little evidence of erosion occurring around the flat open sandy soils due to the low velocities 

but there is more evidence of erosion along the slopes of the Skelmberg and Windhoek se Berge. 

The site can be summarized into two distinct hydrological soil groups which give an indication of the 

runoff potential: 

• Group A: Low stormflow potential (Infiltration rate is high and permeability is rapid in this group); 

and 

• Group D: High stormflow potential (Soils in this group are characterized by very slow infiltration 

rates and severely restricted permeability. Very shallow soils and those of high shrink-swell 

potential are included in this group). 

Group A consists of the sands characterized by a low runoff and erosion potential whereas Group D 

consists of Skelmberg and the Windhoek se Berge with high runoff and erosion potential. The map 

indicating surface water runoff potential can be found in Appendix B, Figure 1.4 

5.1.2 Rainfall 

Monthly rainfall depths were extracted from the closest weather station (approximately 10 km from 

the site) from 1950 - 2000. The selection of Aggeneys station 0246555_W is based on the fact that 

this is the closest weather station to the study area, with a good reliable record, and little patching of 

data was required (patching of rainfall requires filling in the missing data with data from nearby 

stations based on statistical rainfall parameters). As more reliable data becomes available the 

above data set can be refined and updated but 50 years of data is deemed adequate for this desktop 

investigation. 

The rainfall in the area is low with an average annual rainfall of approximately 107 mm. The monthly 

rainfall data was obtained from SAWS (South African Weather Services) and the period of data was 



from 1950 to 2000. The maximum and minimum MAP (Mean Annual Precipitation) was 272 mm 

(1976) and 8 mm (1999) respectively. A statistical analysis for the rainfall period was undertaken and 

the results are presented in Table 6-1. The table should be read as follows: - “Approximately 10% of 

the time 24 mm or more rainfall falls during October”. 

Table 5-1: Percentage of time rainfall amount is exceeded and average monthly rainfall 

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Annual 

Maximum 52 49 83 79 122 91 122 67 58 86 39 46 272 

10% 24 17 21 27 34 45 29 18 15 16 12 19 194 

30% 5 3 2 6 19 25 13 8 7 6 7 4 126 

50% 2 1 0 1 4 8 7 4 4 3 3 2 99 

Average 7 6 7 8 14 18 14 8 7 8 5 6 107 

70% 1 0 0 0 0 3 2 1 1 2 1 0 72 

90% 0 0 0 0 0 0 0 0 0 0 0 0 43 

98% 0 0 0 0 0 0 0 0 0 0 0 0 21 

Minimum 0 0 0 0 0 0 0 0 0 0 0 5 8 

5.1.3 Evaporation 

WRSM2000 

Region 

14A 

The S-Pan evaporation was abstracted from the WRSM2000 (Water Research Commission (2005), 

Water Resources of South Africa) reports and is presented in Table 6-2 

Table 5-2: Average monthly S-pan evaporation (mm) 

5.1.4 Extreme events 

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Annual 

252 297 340 346 291 273 196 131 99 97 136 192 2650 

The 24 hour design rainfall depths for the area were taken from "Rainfall Statistics for Design Flood 

Estimation in South Africa" (WRC Project K5/1060), by JC Smithers and RE Schulze. The 24 hour 

design rainfall depths are indicated in Table 6-3. 

Table 5-3: 24-hour design rainfall depths (mm) 

Return Period (Years) 1:2 1:5 1:10 1:20 1:50 1:100 1:200 

Rainfall depth (mm) 24 41 55 70 93 114 138 

These values are to be used for determining the peak flows and volumes when designing any of the 

relevant infrastructures. This would also be used for determining any floodlines on the site if and 

where required. 

The 1:100 year peak flows were generated using TR137 (Regional Maximum Flood Peaks) which is 

an empirical method based on historical data. The SDF (Standard Design Flood Method) was also 

used which is a numerically regionally calibrated version of the Rational method. These methods are 

more commonly used on large regional catchments but there are no applicable site-specific methods 

or gauging data available for the area. 

The main catchment commands a catchment area of 690 km 2 and drains from the south towards 

Windhoek se Poort, east of the Skelmberg and across the proposed site into the low lying pans in 



the north. This catchment does not have an outlet (endoreic) and the surface water reaching the 

pans during a storm event temporarily ponds and evaporates or infiltrates within the catchment 

before even reaching the pans. 

The 1:100 year peak flow is estimated to be between 150 – 200 m 3 /s using the above empirical and 

calibrated rational methods. There is no well defined channel and the surface water flows as sheet 

flow across the site to a depth of approximately 200 mm – 300 mm during an extreme event (1:100 

year storm event). These flows are not expected to cause any significant damage due to the low 

velocities (less than 1 m/s) associated with flat gradients and wide open plains. 

There will be some significant localised run-off at the foot of the Skelmberg but this will rapidly 

dissipate on reaching the flat sandy gradients, resulting in sheet wash across the site. 

5.1.5 Development considerations 

The following should be considered during the development of the site: 

• There is a well defined watercourse located north of the proposed site which drains under the 

N14 and the old gravel road before discharging into the low lying pans. The only large catchment 

which may have an impact on the site has its watershed south of the proposed site and drains 

east of the Skelmberg from south to north across the proposed site at sheet wash. There are, 

however, small erosion gullies along the steep slopes which would need to be taken into account 

during the detailed design; 

• Although it is difficult to demarcate the 1:100 year floodlines due to the terrain, the proposed 

development would still need to manage the sheet flow and/or drainage lines crossing the site 

and may require minor diversion channel/berms/culverts to protect the relevant infrastructure; 

• Depending on the layouts, any hard surface areas create by the new development would need 

to adequately drain and dissipate prior to discharging back into the environment to prevent 

downstream erosion potential; 

• All clean and dirty water needs to be separated; 

• Any water being used to wash the panels and discharging as surface water back into the natural 

environment needs to comply with relevant authorities water quality standards; and 

• Any waste/ water treatment discharging as surface water back into the natural environment 

needs to comply with the relevant authorities water quality standards. 

5.2 Hydrogeology 

5.2.1 Description 

The surface geology at the site comprises Quaternary Age Kalahari Sands (Qs) which is likely to be 

underlain by Tertiary Age calcrete deposits. Lithologies at greater depth are likely to comprise an 

assemblage of low to medium grade metamorphic rocks ranging from pelitic schist to sillimanite 

bodies. Typically the aquifers associated with these lithologies are integranular and fractured and 

according to the 1:500 000 hydrogeological map sheet (2718, Upington) has yields ranging from 0.1- 

0.5 L/s. The hydro geological map can be found in Appendix B, Figure 1.5 

The Mean Annual Precipitation (MAP) for the area is 107 mm (WRSM 2000, Region 14A) and 

recharge is expected to be at negligible levels. Due to the site’s location in a quaternary catchment 

that displays characteristics of an endoreic pan, which does not appear to be in continuity with 

surface drainage in adjacent quaternaries, shallow groundwater flow (if any) is expected to mimic the 

surface water drainage patterns towards the topographic low which is located to the north of the site. 



According to the Groundwater Resources Map of the Republic of South Africa, Sheet 2, recharge 

occurs in the range of 1-5 mm/annum which can be considered low, implying that the baseflow 

contributed by groundwater to rivers is negligible. Groundwater levels are at an approximate depth of 

45 metres below ground level (mbgl) and the regional groundwater flow direction is northwest 

towards the Orange River. 

Groundwater analytical data received from the National Groundwater Archives (NGA) is summarised 

below: 

• The nearest groundwater user (Site I.D. 89747) is located >10 km north of the site. The average 

Total Dissolved Solids (TDS) is 845 mg/L, chloride (Cl) is 296 mg/l, sodium (Na) is 113 mg/L and 

sulphate (SO4) is 237 mg/L; 

• In comparison, groundwater users located to the north (>15 km from the site) indicate the 

average Total Dissolved Solids (TDS) at 1599 mg/L, chloride (Cl) at 602 mg/l, sodium (Na) at 

330 mg/L and sulphate (SO4) at 237 mg/L; and 

• The elevated TDS and chloride levels recorded can relate to a groundwater system 

characterised by low recharge and longer residence time. 

5.2.2 Development considerations 

Based on the available desktop groundwater data for the site, the following characteristics should be 

considered towards identifying sensitivities around the proposed development: 

• The aquifer type is integranular and fractured with yields ranging from 0.1 to 0.5 L/s; 

• Regional groundwater level is at 45 mbgl; 

• The site is located in an endoreic pan which does not appear to be in continuity with surface 

drainage in adjacent quaternaries. Shallow groundwater flow (if any) is likely to mimic 

topography and flow to the north; 

• The nearest groundwater user is located >10 km to the north of the site; and 

• The elevated TDS and chloride levels are indicative of a groundwater system receiving low 

recharge and having a longer residence time. 

Based on these characteristics, the impact to the groundwater environment due to the proposed 

development is expected to be low but falls outside of the current scope of works. 

5.3 Surface water resources 

The proposed site falls within drainage region D, quaternary sub-catchment D82C which was taken 

from WRSM2000 water resource reports.The WRSM2000 model is a “mathematical model, which 

simulates the movement of water through an interlinked system of catchments, river reaches, 

reservoirs and irrigation areas” (Midgley, Pitman and Middleton, 1994). WRSM2000 has its origin in 

the Stanford Watershed Model developed in the United States of America by Crawford and Linsley 

(1966). 

Sub-catchment D82C is considered to be an endoreic area which means that the rivers terminate in 

inland lakes or pans and the surface runoff does not contribute to any of the surrounding drainage 

systems which eventually end up at the ocean. The degree of endoreism is clearly a function of the 

rainfall and normally located in arid, semi-arid and dry sub-humid drylands. 

The low lying pans towards the north remain dry most of the time and the pans temporarily pond only 

when enough surface runoff is generated. 

Due to the low rainfall and high evaporation, surface water abstraction from any of the rivers, pans 

and/or open storage areas is not a viable option. Therefore, the majority of water in the vicinity is 

currently obtained from the ground water system via boreholes or piped to the site from the nearby 



town. At this stage it is our understanding that the water would be obtained from the local 

municipality which forms part of the original water supply for the Black Mountain mining operations. 

If water is not available from the Municipality and a borehole is required, then a yield and water 

quality test on any existing boreholes would need to be carried out. If this does not meet the required 

water demand and water quality standards, then additional boreholes may be required which may 

also require a small desalination plant. 

Other options which are being considered would be to truck the water in from neighbouring 

municipalities or sourcing directly from the Orange River. The viability of these two options needs to 

be investigated further. A feasibility study has been completed by JIS Environmental Engineers 

(2012) on the water requirements and demands. 

A significant volume of water would normally be required for washing of the panels but it is our 

understanding that an option of cleaning the panels with compressed air will decrease the water 

demand significantly. The viability of this option needs to be investigated further. 

6 Geotechnical evaluation 

6.1 Geology 

The proposed site is underlain by the following sands and rock: 

• Quaternary deposits (Q-s1) – Red windblown sand and dunes; 

• Quaternary deposits (Q-s2) – Sand, scree, rubble and sandy soil; 

• Tertiary deposits (T-c) – Calcrete; 

• Wortel formation rocks (Kwr) – A layered sequence of medium to thick bedded, white quartzite 

and pelitic schist with interbedded sillimanite bodies. Contains minor lenses of quartzite, biotite 

gneiss, and massive amphibolite/calc-silicate gneiss; and 

• Konkyp gneiss formation (Nky) – Grey, megacrystic biotite augen gneiss (occurs over a 

relatively small area in the south western corner of the study area). 

The site is generally flat, with outcrop of metamorphic rock across the area and forming 

approximately 200 m high hills in the north western corner. The flatter areas are mainly overlain by 

Quaternary red windblown sands and Quaternary sand, scree and rubble. These sands generally 

have a loose consistency and exhibit a collapsible fabric. It may be possible to found light structures 

on these sands using various foundation techniques/treatments, but for heavy structures it may be 

necessary to found on rock below these sands. 

Hardpan and/or gravel calcrete often lies beneath these sands and over underlying rock. The 

consistency of calcrete may indicate suitable founding material, however, as it is a calcium 

carbonate it may become weaker over time and founding below the calcrete on rock is 

recommended. The depth to rock in this area is generally expected to vary between 1.0 m and 

3.0 m, but this depends on the structure of the underlying rock formations and topography. The 

sands can be in excess of 6.0 m deep in places where they have filled up paleo channels. Quartzite 

and schist of the Wortel formation is expected to underlie most of the sands in the area. The geology 

for the area can be found in Appendix B, Figure 1.6 



6.2 Founding conditions 

Rock is the ideal founding medium, but the topography of the outcrop where it occurs in the area is 

not expected to provide a suitable foundation solution (this would be verified during the detailed 

investigation), and it is likely that excessive hard rock excavation (blasting) may be necessary. 

The far south west corner intersects a very small area of surface calcrete (Nky) (probably where the 

sands have been eroded away). These areas consist of sandy calcrete gravel often over relatively 

shallow rock. 

For founding the solar panels, we suggest investigating the northern half of the area (Q-sands). 

During the detailed investigation one would need to verify the depth of the rock as this can have a 

major impact on the type of foundation required, which is normally the highest civil cost on the 

project. 

The estimated guidelines for maximum safe bearing capacity (shallow footings) for vertical loadings 

have been included below: 

Cohesive Soils 

Very soft clays, sandy clays, silty clays, clayey silts, clayey sands 0 – 50 kPa 

Soft clays, sandy clays, sandy silts, silty sands 50 – 100 kPa 

Firm clays, sandy clays, sandy silts, silty sands 100 – 200 kPa 

Stiff clays, sandy clays, silts, silty sands 195 – 390 kPa 

Very stiff clays, sandy clays, silty clays, sandy silts, silty sands 390 – 490 kPa 

Non-cohesive soils 

Compact, well graded gravels, sands and gravel mixtures (dry) 390 – 490 kPa 

Compact, well graded gravels, sands and gravel mixtures (wet) 200 – 250 kPa 

Compact, poorly graded gravels, sands and gravel mixtures (dry) 200 – 390 kPa 

Loose sands by test only 

Rock 

Fresh rock, massively bedded, intact, igneous, metamorphic sedimentary 4900 kPa 

Fresh rock, fractured or jointed 980 kPa 

These values are typical values and would depend on various other site specific conditions. 

There are a number of founding options available depending on the above infrastructure which could 

include strip footings, large bored piles/ drilled anchors, augured piles and mini-piles/anchors. The 

adopted foundation has a significant cost implication and would depend on the depth to bedrock and 

the above infrastructure to be constructed. This would be confirmed during a detailed geotechnical 

investigation. 

6.3 Development considerations 

As previously discussed the ground conditions will influence the choice of foundation for the 

infrastructure which has a major impact on the civil construction costs. It is recommended that the 

detailed geotechnical assessment for the preferred site be looked at in correlation to the proposed 

layouts to establish the most economical founding option. 



The following should be considered during the development of the site: 

• Determine the depth to bedrock across the proposed site and demarcate appropriate zones; 

• Assign the correct founding for the appropriate depth zone; and 

• Consider where the nearest suitable borrow pit and quarry is located (sand and stone) for the 

concrete foundations as importing the concrete would be an expensive option. 

7 Impact Assessment 

The impacts posed to the surface water by the solar operations were assessed based on criteria 

explained in the impact methodology in Appendix A. Potential water management impacts that may 

arise from the proposed activities and associated infrastructure relate to both the quantity and quality 

entering or leaving water resources. These include the following: 

• Altered availability to downstream water users due to changes in water quantity or flow regime; 

• Reduced availability of water to downstream water users due to changes in water quality; 

• Reduced availability of water to surrounding water users due to physical obstruction of flow from 

infrastructure; 

• Damage to the aquatic ecosystem due to substances contained in releases from the proposed 

activities; 

• Scouring effect on drainage lines due to run-off from hard surface areas; and 

• Increased erosion from areas of exposed soils. 

The potential impacts listed above are normally assessed for each stage of the development: 

• Pre-construction; 

• Construction; 

• Operation; and 

• Decommissioning and Post-closure. 

The Decommissioning and Post-closure will be rehabilitation back to pre-construction conditions 

(farmlands) according to legislation requirements and, therefore, the impact assessment has been 

done on the construction and operational phases only. 

Due to the phased construction over a seven year period, the construction and the operational phase 

will be occurring simultaneously and have, therefore, been assessed accordingly. 

7.1 Construction / Operational Phase 

Project construction is anticipated to be undertaken using a phased approach, initially with 75 MW 

being constructed following authorisation, where after further units of approximately 80 MW units is 

to be completed over 5 to 7 years in all. 

7.1.1 Decrease in surface water quality 

Water quality, required by downstream users and in particular the aquatic ecology can be impacted 

in two main ways: point sources discharging and diffuse pollution. The two point sources would be 

the outlet from the water/waste water treatment plant and the discharge during the washing of the 

panels. In both instances these are very small volumes and would not remain at the surface, rapidly 



infiltrating into the sand soils. These points would also need to comply with the authorities’ water 

quality guidelines. 

Potential impacts will also arise from accidental point sources and diffuse sources. Accidental point 

source pollution can arise from the following activities, which are more difficult to detect and control 

than intentional point source discharges, but this can be managed with appropriate systems in place: 

• Spills from any pipelines and vehicles (fuel, oil or grease); 

• Uncontrolled discharges (burst pipes, overflows or pump failures); and 

• Flooding causing mixing of any clean and dirty water areas. 

Diffuse pollution, which is often more difficult to manage, can arise from: 

• Seepage of any dirty water containment areas (parking areas, sewage and water/waste 

treatment works); and 

• Run-off from exposed areas carrying increased sediment load. 

Sediment in any runoff will potentially come from exposed areas during construction but higher 

sediment loads may naturally be introduced along the drainage lines (low lying areas) due to 

increased frequency and intensity of flooding, large-scale erosion and sediment movement. Table 8- 

1 below indicates the impact assessment for the potential decrease in surface water quality. 

Table 7-1: Impact assessment (deterioration in water quality) 

Deterioration in surface water quality due to proposed activities 

Construction 

Impact 

before 

Magnitude Duration Scale Consequence Probability SIGNIFICANCE +/- Confidence 

Moderate Medium - 

term 

Management measures: 

Site/Local Medium Definite Medium - Medium 

Minimum disturbance to existing topography during implementation and incorporate into construction program. 

Any surface water discharging to environment during washing of panels to comply with authorities water quality standards. 

Any surface water discharging to environment from water/waste treatment works to comply with authorities water quality 

standards. 

Separate clean and dirty water at point source. 

Strategically placed hessian/geo-fabric attached to rows of stakes to prevent sediment washing downstream of the site during 

construction. 

Impact 

after 

Operational 

Impact 

before 

Moderate Medium - 

term 

Site/Local Medium Unlikely Low - Medium 


Minor Long - 

term 





standards. 

Separate clean and dirty water at point source. 



Impact 

after 

Minor Long - 

term 

7.1.2 Increase in surface water quantity 

There are three potential areas where there will be an increase in the surface water quantity: 

• Increase in surface water run-off during a storm event due to additional hard surface areas 

(panels, roads, buildings etc). During minor storm events this would only occur for a short period 

of time before rapidly infiltrating into the sandy soils; 

• Increase in surface run-off during washing of the panels (assumes the water quality meets the 

authorities’ water quality standards). These volumes are relatively small (approximately 7 m 3 per 

day) which rapidly dissipates and infiltrates into the sandy soils. This may fall away if a 

compressed air system is installed to clean the panels; and 

• Increase in surface run-off when discharging from waste water plant, sewer soak-away 

(assumes the water quality meets the authorities’ water quality standards). These volumes are 

relatively small which would more than likely not even daylight (soak-away system) or if used for 

irrigation would dissipate and infiltrate into the sandy soils. This may be reduced or fall away if a 

dry sanitation system is installed for the sewer system. 

Due to the current low surface water run-off at the site any clean additional surface water would 

improve conditions for any local surface water uses within the site or directly downstream of the 

proposed development. Table 8-2 below indicates the impact assessment for the increase in surface 

water quantity. 

Table 7-2: Impact assessment (increase in surface water quantity) 

Increase in surface water quantity due to proposed activities 

Construction 

Impact 

before 



Minor Medium 

- term 


Site/Local Low Possible Low + Medium 

Local surface water run-off will increase due to hard surfaces created during construction and would need to be 

dissipated back to sheet flow (see erosion protection). 

Impact 

after 

Operational 

Impact 

before 

Minor Medium 

- term 

Site/Local Low Possible Low + Medium 


Moderate Long - 

term 


Site/Local Medium Definite Medium + Medium 

Local surface water run-off will increase due to hard surfaces (panels, roads, infrastructure, etc) and would need 

to be dissipated back to sheet flow (see erosion protection). 



Impact 

after 


term 

7.1.3 Increase in erosion potential 

There are two areas where there will be an increase in the erosion potential due to higher surface 

water flows: 

• During a storm event the hard surface areas will generate higher surface water flows resulting in 

higher velocities and erosion potential. This would occur locally, directly downstream of the hard 

surface areas (discharge from panels, roads, buildings, etc.). During the construction period 

exposed areas will also have a higher erosion potential; and 

• During washing of the panels there will be a small chance of erosion occurring when flowing off 

the panels but this would be insignificant when compared to the storm flows; 

High erosion may naturally be introduced along the drainage lines (low lying areas) due to increased 

frequency and intensity of flooding, large-scale erosion and sediment movement. Table 8-3 below 

indicates the impact assessment for the increase in erosion potential. 

Table 7-3: Impact assessment (increase in erosion potential) 

Increase in erosion potential from proposed activities 

Construction 

Impact 

before 

Site/Local Medium Definite Medium + Medium 


Moderate Medium 

- term 




Any surface water discharging to environment during washing of panels to be adequately dissipated back to sheet flow. 

Any surface water discharging to environment from water/waste treatment works needs to be adequately dissipated. 

Increased peaks due to hard surfaces requires adequate dissipation and erosion protection to ensure concentrated flows 

back to sheet flow, minimising erosion potential. This can be achieved by strategically placing appropriate sized stone 

downstream of the hardened surface areas (including panels). 

Strategically placed hessian/geo-fabric attached to rows of stakes to decrease the velocities during construction. 

Impact 

after 

Operational 

Impact 

before 


- term 



Minor Long - 

term 










Impact 

after 

Minor Long - 

term 


7.1.4 Increase in flooding potential and change in flow regime 

There are two areas which may impact on the flooding potential and the change to the flow regime: 

• From a regional perspective there may be an increase in the flooding potential due to the 

infrastructure changing the original flow path during an extreme storm event. There is no 

evidence of a defined watercourse channel and, therefore, the surface water flows as sheet flow 

across a wide floodplain. The maximum flow depth would be approximately 200 mm – 300 mm 

and would flow between and below the panels across the site; and 

• From a local perspective there may be an increase in flooding potential just downstream of the 

hard surface areas but this is expected to reach original flow regime just downstream of the site; 

Flooding may naturally occur along the drainage lines (low lying areas) due to increased frequency 

and intensity of storms, large-scale erosion and sediment movement. 

It should be noted that with the proposed development in place there will be no increase in flooding 

potential to neighbouring properties but one still needs to manage the flooding potential on the 

proposed infrastructure. Table 8-4 below indicates the impact assessment for the increase in 

flooding potential. 

Table 7-4: Impact assessment (increase in flooding potential and change in flow regime) 

Increase in flooding potential and change in flow characteristics from proposed activities 

Construction 

Impact 

before 



- term 


Site/Local Medium Definite Medium - Low 

From a regional perspective ensure all the relevant infrastructure is constructed outside of the envisaged flood plain 

assumed a potential flow depth of 200 mm – 300 mm during an extreme flood event. This can be achieved by raising the 

floor level of the affected infrastructure or relocating some of the buildings. 

From a local perspective any concentrated surface water discharging from Skelmberg would need to be adequately diverted 

away from any relevant infrastructure. This can be achieved by constructing earth berms to divert the surface water away 

from the infrastructure and back to original sheet flow path. 

Any local surface water flowing towards the N14 would also need to be managed by diverting along the side of the road in 

the form of an earth channel/berm, until an appropriate crossing under the N14. 

Impact 

after 

Operational 

Impact 

before 


- term 

Site/Local Medium Possible Medium - Low 



term 


Site/Local Medium Definite Medium - Low 


assumed a potential flow depth of 200 mm – 300 mm during an extreme flood event. This can be achieved by raising the 

floor level of the affected infrastructure or relocating some of the buildings. 



From a local perspective any concentrated surface water discharging from Skelmberg would need to be adequately diverted 

away from any relevant infrastructure. This can be achieved by constructing earth berms to divert the surface water away 

from the infrastructure and back to original sheet flow path. 

Any local surface water flowing towards the N14 would also need to be managed by diverting along the side of the road in 

the form of an earth channel/berm, until an appropriate crossing under the N14. 

Impact 

after 


term 

7.2 Mitigation measures 

The suggested mitigation measures have been covered in the above impact assessment. These 

mitigation measures are based on standard engineering approaches but there are alternative options 

available to achieve the same result. 

8 Conclusions and Recommendations 

The conclusions and recommendations for the desktop study have been divided into hydrological, 

geotechnical and the impact assessment including relevant mitigation measures. 

8.1 Hydrological 

Site/Local Medium Possible Medium - Low 

The following pertinent issues have been summarised below: 

• The site is located in a low rainfall zone (MAP 107 mm) with the majority of the site having a low 

run-off potential with a high Infiltration rate and rapid permeability; 

• Nearly 50% of the average monthly rainfall occurs between February and March; 

• Besides the local runoff from Skelmberg there is only one major catchment of 690 km 2 draining 

from the south to Skelmberg and into the low lying pan north of the proposed site; 

• The catchment is considered to be an endoreic area which means that the rivers terminate in 

inland lakes or pans and the surface runoff does not contribute to any of the surrounding 

drainage systems which normally ends up at the ocean. The degree of endoreism is clearly a 

function of the rainfall and normally located in arid, semi-arid and dry sub-humid drylands; 

• The 1:100 year peak flow was generated using TR137 and SDF. These methods are normally 

used on regional catchments but there are no applicable site-specific methods available for this 

area. Due to the locality, terrain and climate there is a high possibility that most of the surface 

water draining from the upper catchments would not even reach the site; 

• The following development considerations need to be considered: 

I. There is a well defined watercourse located north of the proposed site which drains 

under the N14 and the old gravel road before discharging into the low lying pans. The 

only large catchment which may have an impact on the site is the catchment which has 

its watershed south of the proposed site flowing towards Skelmberg from south to north 

across the proposed site at sheet flow. There are, however, small erosion gullies at the 

foot of the Skelmberg which would need to be taken into account during the detailed 

design; 



II. Although it is difficult to demarcate the 1:100 year floodlines due to the terrain, the 

proposed development would still need to manage the sheet flow/drainage lines 

(approximately 200 mm – 300 mm) crossing the site and may require minor diversion 

channel/berms/culverts to protect the relevant infrastructure. In addition, any of the 

operational buildings needs to be constructed on the higher ground; 

III. All clean and dirty water needs to be separated; 

IV. Depending on the layouts, any hard surface areas created by the new development 

would need to adequately drain and dissipate prior to discharging into the existing 

drainage lines to prevent downstream erosion; 

V. Any water being used to wash the panels and discharging back into the natural 

environment as surface water needs to comply with authorities water quality standards; 

and 

VI. Any waste/ water treatment discharging as surface water back into the natural 

environment needs to comply with authorities water quality standards. 

• Based on the available desktop groundwater data for the site, the following should be 

considered towards identifying sensitivities around the proposed development: 

I. The aquifer type is integranular and fractured with yields ranging from 0.1 to 0.5 L/s; 

II. Regional groundwater level is at 45 mbgl; 

III. The site is located in an endoreic pan which does not appear to be in continuity with 

surface drainage in adjacent quaternaries. Shallow groundwater flow (if any) is likely to 

mimic topography and flow to the north; 

IV. The nearest groundwater user is located >10 km to the north of the site; 

V. The elevated TDS and chloride levels are indicative of a groundwater system receiving 

low recharge and having a longer residence time; and 

VI. Based on these characteristics, the impact to the groundwater environment due to the 

proposed development is expected to be low. 

8.2 Geotechnical 

Although the geotechnical assessment does not have a direct input into the impact assessment it is 

important to be aware of the issues as it can have a major financial implication which could modify 

the layout of the proposed development. The following pertinent issues have been summarised 

below: 

• The area is generally flat, with outcrop of metamorphic rock across the area and forming 

approximately 200 m high hills in the north western corner. The flatter areas are mainly overlain 

by Quaternary red windblown sands and Quaternary sand, scree and rubble. These sands 

generally have a loose consistency and exhibit a collapsible fabric. It may be possible to found 

light structures on these sands using various foundation techniques/treatments, but for heavy 

structures (solar masks assuming they are heavy) it is necessary to found on rock below these 

sands. Hardpan and/or gravel calcrete often lies beneath these sands and over underlying rock. 

The consistency of calcrete may indicate suitable founding material, however, as it is a calcium 

carbonate it may become weaker over time and founding below the calcrete on rock is 

recommended. The depth to rock in this area is generally expected to vary between 1.0 m and 

3.0 m, but this depends on the structure of the underlying rock formations and topography. The 

sands can be in excess of 6.0 m deep in places where they have filled up paleo channels. 



Quartzite and schist of the Wortel formation is expected to underlie most of the sands in the 

area. 

• The following development considerations need to be considered: 

I. Determine the depth to bedrock across the preferred site and demarcate appropriate 

zones; 

II. Assign the correct founding for the appropriate depth zone; and 

III. Consider where the nearest suitable borrow pit and quarry is located (sand and stone) 

for the concrete foundations as importing the concrete would be an expensive option. 

8.3 Impact Assessment 

The following pertinent issues have been summarised below: 

I. The impact assessment (negative) for deterioration in water quality changes from a 

medium to a low with management measures in place during construction and during 

the operational phase; 

II. The impact assessment (positive) for increase in water quantity remains low with 

management measures in place during construction and changes to medium during 

operational phase; 

III. The impact assessment (negative) for increase in erosion potential changes from a 

medium to a low with management measures in place during construction and during 

the operational phase; 

IV. The impact assessment (negative) for increase in flooding potential remains medium 

with management measures in place during construction and operational phase. 

8.4 Mitigation Measures 

The surface water management measures have been summarised below: 

Table 8-1: Mitigation measures (deterioration in water quality) 

Deterioration in surface water quality due to proposed activities 

Construction 





standards. 

Separate clean and dirty water areas. 

Strategically placed hessian/geo-fabric attached to rows of stakes to prevent sediment washing downstream of the site 

during construction. 

Operational 




standards. 

Separate clean and dirty water areas. 



Table 8-2: Mitigation measures (increase in surface water quantity) 

Increase in surface water quantity due to proposed activities 

Construction 


Local surface water run-off will increase due to hard surfaces created during construction and would need to be 


Operational 


Local surface water run-off will increase due to hard surfaces (panels, roads, infrastructure etc) and would need to be 


Table 8-3: Mitigation measures (increase in erosion potential) 

Increase in erosion potential from proposed activities 

Construction 








Strategically placed hessian/geo-fabric attached to rows of stakes to decrease the velocities during construction. 

Operational 







Table 8-4: Mitigation measures (increase in flooding potential and change in flow regime) 

Increase in flooding potential and change in flow characteristics from proposed activities 

Construction 



assumed a potential flow depth of 200 mm – 300 mm during an extreme flood event. This can be achieved by raising 

the floor level of the affected infrastructure or relocating some of the buildings. 

From a local perspective any concentrated surface water discharging from Skelmberg would need to be adequately 

diverted away from any relevant infrastructure. This can be achieved by constructing earth berms to divert the surface 

water away from the infrastructure and back to original sheet flow path. 

Any local surface water flowing towards the N14 would also need to be managed by diverting along the side of the road 

in the form of an earth channel/berm, until an appropriate crossing under the N14. 



Operational 



assumed a potential flow depth of 200 mm – 300 mm during an extreme flood event. This can be achieved by raising 

the floor level of the affected infrastructure or relocating some of the buildings. 

From a local perspective any concentrated surface water discharging from Skelmberg would need to be adequately 

diverted away from any relevant infrastructure. This can be achieved by constructing earth berms to divert the surface 

water away from the infrastructure and back to original sheet flow path. 

Any local surface water flowing towards the N14 would also need to be managed by diverting along the side of the road 

in the form of an earth channel/berm, until an appropriate crossing under the N14. 

9 Final Remarks 

Due to the nature of the proposed development, the locality of the site and assuming all the relevant 

surface water management measures are in place, the potential negative impact on the surrounding 

environment is expected to be minimal. 

Prepared by 

Murray Sim 

Associate Partner 

Reviewed by 

Peter Shepherd 

Director 

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. 



10 References 

Alexander WJR, (2001), Flood Risk Reduction Measures incorporating Flood Hydrology for Southern 

Africa; 

Dent, M.C., Lynch, S.D. and Schulze, R.E. (1989). Mapping mean annual and other rainfall statistics 

over Southern Africa. Water Research Commission, Pretoria. Report 109/1/89; 

Department of Water Affairs and Forestry (1998). The National Water Act, Act 36 of 1998. Pretoria; 

Department of Water Affairs and Forestry (1988). Regional Maximum Flood Peaks in Southern 

Africa, TR137; 

Department of Water Affairs and Forestry (2006). Best Practise Guideline (G1) Storm Water 

Management; 

Hamlin, M.J., 1983. The significance of rainfall in the study of hydrological processes at basin scale. 

Journal of Hydrology, 65, 73-94; 

Institute for Commercial Forestry Research, Daily Rainfall Data Extraction Utility KwaZulu-Natal 

University, User Manual Version 1.2; 

Magagula S JIS Environmental Engineers 2012, Feasibility Study on the Water Requirements for 

SATO PV Project: Zuurwater Farm, Northern Cape Province. Report JIS/R/2012/01/18; 

Midley DC, Pitman, WV and Middleton, BJ (1981) Surface water resources of South Africa Volumes I 

to VI. Hydrological Research unit Report Nos 8/81 to 13/81, University of Witwatersrand, 

Johannesburg; 

Midley DC, Pitman, WV and Middleton, BJ (1994) Surface water resources of South Africa 1990 

Water Research Commission Report Nos. WRC 298/1/94 to 298/6.2/94, Pretoria; 

Pitman WC (1973). A mathematical model for generating monthly river flow from the 

Hydrometeological data in South Africa. Hydrological Research Unit Report No. 2/73, University of 

the Witwatersrand , Johannesburg; 

Schulze, R.E., 1995. Hydrology and Agrohydrology. A theory text to accompany the ACRU 3.00 

Agrohydrological Modelling System. Water Research Commission, Pretoria. Report TT69/95; 

Schulze, R.E., 1995. Hydrology and Agrohydrology. A practical text to accompany the ACRU 3.00 

Agrohydrological Modelling System. Water Research Commission, Pretoria. Report TT70/95; 

Schulze, R.E., 1997. South African Atlas of Agrohydrology and Climatology, Water Research 

Commission Report. School of Bio Resources Engineering and Environmental Hydrology; 

SCS-SA (1992). User, Flood estimation for small Catchments in Southern Africa, Manual, PC-Based 

SCS Design; 

Smithers JC and Schulze RE (2000), Long duration design rainfall estimates for South Africa, WRC 

Report No. 811/1/00; 

Smithers JC and Schulze RE (2000), Rainfall Statistics for Design Flood Estimation in South Africa" 

(WRC Project K5/1060); and 

Water Research Commission (2005), WRSM2005 Water Resources of South Africa, Report 

numbers: 380/08, 381/08, 382/08. Pretoria. 



Appendices 



Appendix A: Impact Assessment Methodology 



Impact Assessment Methodology 

The environmental impact assessment has been undertaken according to SRK 

Consulting’s standard criteria for impact assessment which are detailed below. This 

methodology is compliant with the NEMA regulations. 

All specialists working on the EIA have been asked to use a common, systematic and 

defensible method of assessing significance that will enable comparisons to be made 

between impacts across different disciplines. It will also enable all relevant parties to 

understand the process and rationale upon which impacts have been assessed. 

The following section contains the methodology to be used by specialists to assist them in 

identifying, defining and evaluating the impacts. 

A. Method 

Generally, impact assessment is divided into three parts: 

• Issue identification 

• Impact definition 

• Impact evaluation 

Iteration of these parts occurs in each stage of an EIA process (screening, scoping, impact 

studies, reporting etc) to a varying degree. As the study progresses through the EIA 

stages, the main emphasis shifts from issue identification, through impact definition, then to 

impact evaluation. 

Identification of issues 

Each specialist was asked to evaluate the ‘aspects’ arising from the project description and 

ensure that all issues in their area of expertise have been identified. ‘Aspects’ is a term for 

the “mechanisms” by which project activities impact on receptors (people, economy, 

infrastructure, institutions and natural environment). 

Impact Definition 

Positive and negative impacts associated with these issues (and any others not included) 

then need to be defined – the definition statement should include the activity (source of 

impact), aspect and receptor. Impacts are identified and defined where there is a plausible 

pathway between the activities and receptors. 

Specialists will be asked to ensure that the suite of potential direct, indirect and cumulative 

impacts 1 are clearly defined. Direct impacts require a quantitative assessment wherever 

1 An indirect impact is an effect that is related to but removed from a proposed action by an intermediate step or process. An 

example would be increased hunting and illegal logging in the concession area (following mining) as a result of inmigration 

and improved access. Cumulative impacts occur when: a) Different impacts of one activity or impacts of different activities 

on the natural and social environment take place so frequently in time or so densely in space that they cannot be assimilated; 

or b) Impacts of one activity combine with the impacts of the same or other activities in a synergistic manner. Specialists 

should consider areas/stakeholders potentially affected by reasonably foreseeable further planned development of the project 

and other activities that may result in cumulative impacts. 



possible. Indirect and cumulative impacts should be described qualitatively, but where data 

exist these should be quantified. 

Specialists will also be asked to identify fatal flaws i.e. very significant adverse impacts 

which cannot be avoided or mitigated and which will jeopardise the project and/or activities. 

All conclusions need to be backed up by scientific, economic and technical evidence or 

where this is not possible, based on specialist experience. 

Impact evaluation 

The last step is to evaluate the impact significance. Impact evaluation is not a purely 

objective and quantitative exercise. It has a subjective element, often using judgement and 

values as much as science-based criteria and standards. The need therefore exists to 

clearly explain how impacts have been interpreted so that others can see the weight 

attached to different factors and can understand the rationale of the assessment. 

With recognition that impact evaluation is generally relative, there is a need to set it in 

context. To achieve this it is important to: 

clearly describe the sensitivity of the receiving environment/ receptors; 

define the impact – the effect on the receiving environment/ receptors; 

explain the level of stakeholder 2 concern; 

explain the significance of impacts in a logical and justifiable way. 

There are many ways in which significance can be determined. Impacts are likely to be 

significant if they: 

are extensive over space or time; 

are intensive in concentration or in relation to assimilative capacity; 

exceed or approximate to standards or thresholds; 

do not comply with policies, land use plans, sustainability strategy; 

affect ecologically sensitive areas and heritage resources; and 

affect community lifestyle, traditional land uses and values. 

The basic elements used in the evaluation of impact significance are described in Table 1 

and the characteristics that specialists should use to describe the consequence of an 

impact are outlined in Table 2. 

2 Stakeholders are workers, affected stakeholders and other stakeholders. Affected Stakeholders are people, groups or 

communities who are subject to actual or potential project-related risks and /or adverse impacts on their physical environment, 

health or livelihoods and who are often located in the project’s near geographical proximity. Note that workers are defined as 

employees and other workers directly contracted by AGA to carry out work on the project. 



Table 1: Key elements in the evaluation of impact significance 

Element Description Questions applied to 

the test of 

significance 

Consequence An impact or effect can be described as the change in an 

environmental parameter, which results from a particular 

project activity or intervention. Here, the term “consequence” 

refers to: 

• The sensitivity of the receiving environment, including its 

capacity to accommodate the kinds of changes the project 

may bring about; 

• The type of change and the key characteristics of the 

change (these are magnitude, extent and duration); 

• The importance of the change (the level of public concern/ 

value attached to environment by the stakeholders and the 

change effected by the project). 

• The following should be considered in the determination of 

impact consequence: 

• standards and guidelines (e.g. pollution and emissions 

thresholds); 

• scientific evidence and professional judgement; 

• points of reference from comparable cases; 

• levels of stakeholder concern. 

Will there be a change in 

the biophysical and/or 

social environment? 

Is the change of 

consequence (of any 

importance)? 

Probability Likelihood/ chances of an impact occurring Is the change likely to 

occur? 

Effectiveness of the 

management 

measures 

Uncertainty/ 

Confidence 

Significance of the impact needs to be determined both 

without management measures and with management 

measures. 

The significance of the unmanaged impact needs to be 

determined so there is an appreciation of what could occur in 

the absence of management measures and of the 

effectiveness of the proposed management measures. 

Uncertainty in impact prediction and the effectiveness of the 

proposed management measures. Sources of uncertainty in 

impact prediction include: 

• scientific uncertainty – limited understanding of an 

ecosystem or affected stakeholder and the processes that 

govern change; 

• data uncertainty – restrictions introduced by incomplete, 

contradictory or incomparable information, or by insufficient 

measurement techniques; and 

• policy uncertainty – unclear or disputed objectives, 

standards or guidelines. 

Will the management 

measures reduce impact 

to an acceptable level? 

What is the degree of 

confidence in the 

significance ascribed to 

the impact? 



Table 2: Characteristics to be used in impact description 

Characteristics 

used to describe 

consequence 

Sub-components Terms used to describe the characteristic 

Type Biophysical, social or economic 

Nature Direct or indirect, cumulative etc 

Status Positive (a benefit), negative (a cost) or neutral 

Phase of project 

Timing Immediate, delayed 

Magnitude 

Sensitivity of the receiving 

environment/ receptors 

Severity/ intensity (degree of 

change measured against thresholds 

and/or professional judgment) 

Level of stakeholder concern 

Spatial extent or population affected 

The area/population affected by the impact 

The boundaries at local and regional extents will be 

different for biophysical and social impacts. 

Duration (and reversibility) 

Length of time over which an impact occurs and potential 

for recovery of the endpoint from the impact 

During pre-construction (if applicable e.g. 

resettlement), construction, operation, 

decommissioning/post closure 

High, medium or low sensitivity 

Low capacity to accommodate the change (impact)/ 

tolerant of the proposed change 

Gravity/ seriousness of the impact 

Intensity/ influence/ power/ strength 

High, medium or low levels of concern 

All or some stakeholders are concerned about the 

change 

Area/ volume covered, distribution, population 

Site/Local (social impacts should distinguish 

between site and local), regional, national or 

international 

Short term, long term 

Intermittent, continuous 

Reversible/ irreversibility 

Temporary, permanent 

Confidence High, Medium, Low 

B. Management recommendations 

Specialists will be asked to recommend practicable management measures in as much 

detail as possible and should focus on avoidance, and if avoidance is not possible, then to 

reduce, restore, compensate/offset negative impacts, enhance positive impacts and assist 

project design. The significance of impacts must be assessed both without and with 

assumed management measures in place. Unsubstantiated recommendations for further 

studies should be avoided. Specialists should also recommend and describe appropriate 

monitoring and review programmes to track the efficacy of management measures. 



C. Impact significance rating 

The impact significance rating process serves two purposes: firstly, it helps to highlight the 

critical impacts requiring consideration in the management and approval process; secondly, 

it serves to show the primary impact characteristics, as defined above, used to evaluate 

impact significance. 

The impact significance rating system is presented in Table 3 and involves three parts: 

Part A: Define impact consequence using the three primary impact characteristics of 

magnitude, spatial scale/population and duration; 

Part B: Use the matrix to determine a rating for impact consequence based on the 

definitions identified in Part A; and 

Part C: Use the matrix to determine the impact significance rating, which is a function of 

the impact consequence rating (from Part B) and the probability of occurrence. 

Part D: Define the Confidence level. 

Table 3: Method for rating the significance of impacts 

PART A: DEFINING CONSEQUENCE IN TERMS OF MAGNITUDE, DURATION AND SPATIAL 

SCALE 

Impact 

characteristics 

MAGNITUDE 

SPATIAL 

SCALE OR 

POPULATION 

DURATION 

Use these definitions to define the consequence in Part B 

Definition Criteria 

Major 

Moderate 

Minor 

Minor+ 

Moderate+ 

Major+ 

Substantial deterioration or harm to receptors; receiving environment has 

an inherent value to stakeholders; receptors of impact are of conservation 

importance; or identified threshold often exceeded 

Moderate/measurable deterioration or harm to receptors; receiving 

environment moderately sensitive; or identified threshold occasionally 

exceeded 

Minor deterioration (nuisance or minor deterioration) or harm to receptors; 

change to receiving environment not measurable; or identified threshold 

never exceeded 

Minor improvement; change not measurable; or threshold never 

exceeded 

Moderate improvement; within or better than the threshold; or no 

observed reaction 

Substantial improvement; within or better than the threshold; or 

favourable publicity 

Site or local Site specific or confined to the immediate project area 

Regional May be defined in various ways, e.g. cadastral, catchment, topographic 

National/ 

International 

Nationally or beyond 

Short term Less than 18 months 

Medium term 18 months to 5 years 

Long term >5 years 

PART B: DETERMINING CONSEQUENCE RATING 

Rate consequence based on definition of magnitude, spatial extent and duration 



MAGNITUDE 

Minor DURATION 

Moderate DURATION 

Major DURATION 

PROBABILITY 

(of exposure to 

impacts) 

SPATIAL SCALE/ POPULATION 

Site or Local Regional National/ 

international 

Long term Medium Medium High 

Medium 

term 

Low Low Medium 

Short term Low Low Medium 

Long term Medium High High 

Medium 

term 

Medium Medium High 

Short term Low Medium Medium 

Long term High High High 

Medium 

term 

Medium Medium High 

Short term Medium Medium High 

PART C: DETERMINING SIGNIFICANCE RATING 

Rate significance based on consequence and probability 

CONSEQUENCE 

Low Medium High 

Definite Medium Medium High 

Possible Low Medium High 

Unlikely Low Low Medium 

PART D: CONFIDENCE LEVEL 

High Medium Low 

+ denotes a positive impact. 

Using the matrix, the significance of each described impact is initially rated. This rating assumes the 

management measures inherent in the Project design are in place. 



Appendix B: Figures 

435209/1.1 Regional drainage map 

435209/1.2 Study area 

435209/1.3 Catchment boundaries and surface water features 

435209/1.4 Surface water runoff potential 

435209/1.5 Hydro geological map 

435209/1.6 Geology map 


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Path: G:\435209_SATO_PV_JHB\8GIS\GISPROJ\MXD\Water&Geotech\Updated January 2012\435209_F_1_1_SATO_Regional Drainage_A3L_C_02022012.mxd 

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SATO PV: DESKTOP SURFACE WATER AND GEOTECHNICAL STUDY 

Regional Drainage Map 

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19°0'0"E 

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Legend 

Water Features 

Site Boundary 

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Internal Site Boundaries 

Non-Perennial Pans 

Rivers 

Quaternary catchments 

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Projection: Datum: 

TM 

HH94 

Central Meridian/Zone: 

Lo19 

Date: Compiled by: 

01/02/2012 

Project No: 

435209 

MURA 

Fig No: 

1.1 

Revision: A Date: 01 02 2012

29°20'0"S 

To Springbok 

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Windhoek se Berg 

Path: G:\435209_SATO_PV_JHB\8GIS\GISPROJ\MXD\Water&Geotech\Updated January 2012\435209_F_1_2_SATO_Aerial_A3L_C_01022012.mxd 

Skelmberg 

Windhoek se Berg 

Swartberg 

Platjiesvlei se Kop 

Kranskop 


Aerial photograph showing the study area 

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Project Area 

To Kakamas 


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Lo19 


01/02/2012 

Project No: 

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MURA 

Fig No: 

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Revision: A Date: 01 02 2012

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Project No: 

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MURA 

Fig No: 

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Revision: C Date: 01 02 2012

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Path: G:\435209_SATO_PV_JHB\8GIS\GISPROJ\MXD\Water&Geotech\Updated January 2012\435209_F_1_4_SATO_Pot_Runoff_A3L_C_01022012.mxd 

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Soil Group 

Soil Group A 

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Infiltration is high and 

permeability is rapid in this 

group. Overall drainage 

is excessive to well-drained 

Soil Group B 

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potential: 

Moderate Infiltration rates, 

effective depth and drainage. 

Permeability is slightly 

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Soil Group C 

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potential: 

Infiltration is slow or 

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permeability restricted. Soil 

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and soils with a high 

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Data Source: 

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TM 

HH94 


Lo19 


28/11/2011 

Project No: 

435209 

MURA 

Fig No: 

1.4 


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Path: G:\435209_SATO_PV_JHB\8GIS\GISPROJ\MXD\Water&Geotech\Updated January 2012\435209_F_1_5_SATO_Hyrdogeological_A3L_C_01022012.mxd 

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Sub-catchment 

!H Boreholes 



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Groundwater Quality as Electrical Conductivity 

Fractured 

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Lo19 


28/11/2011 MURA 

Project No: Fig No: 

435209 

1.5 


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Project No: Fig No: 

435209 

1.6 



Report No. 

Copy No. 

SRK Report Distribution Record 

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This report is protected by copyright vested in SRK (SA) (Pty) Ltd. It may not be reproduced or 

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