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ADDENDUM REPORT II Report 379/RWSP-F4
ENVIRONMENTAL IMPACT ASSESSMENT FOR A NEW REGIONAL LANDFILL SITE
FOR THE CITY OF CAPE TOWN –
SPECIALIST GROUNDWATER STUDY
Prepared by
Dr RP Parsons Parsons & Associates Specialist Groundwater Consultantscc
PO Box 151 Pringle Bay
7196
Submitted to
Cliffe Dekker Hofmeyr
on behalf of
City of Cape Town (Directorate of Water and Waste, Waste Management)
May 2017
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EXECUTIVE SUMMARY
The City of Cape Town needs to develop a new regional waste disposal facility as existing facilities have reached - or are in the process of reaching - the end of their lifespan. A project was initiated in 2000 to identify potential new sites, with an Environmental Impact Report being produced in 2006. Parsons & Associates Specialist Groundwater Consultants
cc participated in the project as the geohydrological
specialists. The outcome of the project was the identification of two potential sites for development as a regional waste disposal facility. Following submission of the Environmental Impact Assessment report for environmental approval in 2006 and subsequent decisions by the provincial Minister and legal challenges thereto, Parsons & Associates was appointed in 2011 to undertake further studies to ensure information previously presented in our 2006 report was relevant and addressed issues raised during the public participation and legal processes, particularly those relating to the Colenso Fault. In response to a legal challenge to the selection of the proposed Kalbaskraal site for development, Parsons & Associates was asked to undertake supplementary geohydrological work at the Kalbaskraal site. The main purpose of the work was to locate a fault inferred to exist directly west of the Colenso Fault and to compile a numerical groundwater flow and contaminant transport model. This required verifying some of the hydrocensus data, conducting two geophysical traverses, drilling and testing four exploratory boreholes and compilation of a numerical model. While this additional work increased the quantified information about the site, the new data did not change earlier interpretations regarding the direction of groundwater flow, groundwater quality or the classification of the aquifer system. EC profiling of all exploratory boreholes across the site revealed a 20 – 40 m thick layer of poor quality groundwater overlying the fractured aquifer. The sub-parallel branch of the Colenso Fault mapped by Gresse was not detected using either the ERT or AMT geophysical methods, while a borehole drilled in the inferred position of the fault was low yielding and the drilling chips did not display any characteristics of a fault. However, the geophysics and drilling revealed a fracture zone further to the west of the inferred sub-parallel fault. This fracturing may be the result of tight synclinal folding or faulting. Even though reasonable yields were obtained for the given geohydrological setting, the results do not warrant changing the classification of the aquifer from a minor aquifer system, as was previously assigned by Parsons & Associates (2006, 2012). In general, yields are moderate to low – with one or two exceptions. Testing in the area has shown fracture dewatering demands a conservative approach when defining sustainable pumping rates and that these have to be confirmed through monitoring. The upper parts of the aquifer system yield poor quality groundwater. The results of numerical modelling showed that only boreholes to the west of the proposed waste site are at risk of being impacted by contamination, if it were to occur. Modern engineering of landfills use multiple barrier systems to prevent groundwater being contaminated. In such instances no groundwater contamination will take place and no groundwater users will be at risk. If the multiple barrier system were to be breached, then it is predicted that the plume will travel at a rate of 10 – 15 m/a. After 130 years the plume will have migrated 1 300 m from the waste pile. The numerical model also showed that the hydraulic properties of Colenso Fault are such that this structure will not influence the migration of contamination, if it were to occur. Similarly, current patterns of groundwater abstraction will also not significantly change the rate and movement of contamination. From a geohydrological perspective, the proposed Kalbaskraal site is considered suitable for development as a regional waste disposal facility. Given the information that we have and the extent to which it has corroborated earlier findings, it is unlikely that further exploratory work or modelling will change this interpretation. The prevention of groundwater contamination will be realized by the design and construction of a multiple barrier system comprising HDPE geomembranes and series of very low permeability clay liners to prevent leachate infiltrating into the groundwater system. For modelling purposes it was accepted that the design presented in the 2012 environmental impact assessment report would be used. It is recommended that the City of Cape Town establishes a formal groundwater monitoring programme at the site. The key objective of this is to detect any groundwater contamination at an early stage so that remedial actions may be implemented if necessary. Monitoring will also allow for the verification of the outcomes of modelling and definition of baseline conditions.
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CONTENTS PAGE Executive Summary List of Contents List of Tables List of Figures List of Appendices List of Abbreviations Acknowledgements Declaration of Independence, Qualification and Experience
LIST OF CONTENTS 1 2 3 4 5 6 7
BACKGROUND TERMS OF REFERENCE INVESTIGATION METHODOLOGY 3.1 Additional geophysical surveys 3.2 Additional exploratory drilling 3.3 Testing of additional exploratory boreholes 3.4 Collection of additional data 3.5 Numerical groundwater flow and contaminant transport model RESULTS 4.1 Position of faults 4.2 Borehole yields 4.3 Hydraulic properties 4.4 Groundwater levels 4.5 Groundwater quality 4.6 Aquifer classification 4.7 Conceptual model NUMERICAL GROUNDWATER FLOW AND CONTAMINANT TRANSPORTMODEL DISCUSSION
CONCLUSIONS AND RECOMMENDATIONS
1
2
3 3 3 4 5 5
7 7
10 11 13 13 13 14
17
19
22
REFERENCES 23
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LIST OF TABLES
1 2 3 4 5 6
Summary of the additional exploratory boreholes drilled at the proposed Kalbaskraal site Summary of pumping tests conducted at the proposed Kalbaskraal site during March 2017 and April 2017 Yields of the additional exploratory boreholes Hydraulic properties of geohydrological units prevalent at the proposed Kalbaskraal site determined from site-specific testing South African aquifer system management classification Hydraulic properties assigned to the different components of the aquifer system
4
4
9 11
13 15
LIST OF FIGURES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Location of the proposed Kalbaskraal and Atlantis sites for the new regional landfill site for the City of Cape Town Position of geophysical traverses undertaken at the proposed Kalbaskraal waste site Map showing high resolution aeromagnetic data over the western two thirds of the proposed site and the position of the two geophysical traverses Outcome of the ERT and AMT survey undertaken along Kal-1, Kalbaskraal Outcome of the ERT and AMT survey undertaken along Kal-2, Kalbaskraal Position of the additional exploratory boreholes in relation to the anomalies identified from the geophysical surveys EC profiles of the additional exploratory boreholes drilled at the proposed Kalbaskraal site Monitored depth to groundwater at RWS-8a and BG00072 Monitored EC levels at BG00072, RWS9 and BF2 Durov and Schoeller diagrams illustrating hydrochemical changes over time at BG00072, RWS9 and BF2 The position of boreholes at or adjacent to the proposed Kalbaskraal site Published geological map of the proposed Kalbaskraal site (Theron, 1990) Schematic geological cross-section of the proposed Kalbaskraal site Drawdown induced by pumping RWS-14 at 12 L/s for a period of 72 hrs Comparison of the yield of boreholes used for irrigation north of Kalbaskraal, those drilled into the Colenso Fault and in and around the proposed Kalbaskraal site Recently acquired piezometric data (red) supports and confirms the interpreted groundwater elevation map presented by Parsons & Associates (2006) Cross-sections showing the position of the piezometric surface in relation to ground level based on data measured at the site Depth to groundwater level (mbgl) measured at the proposed Kalbaskraal site during the winter of 2010 when the piezometric level was at or near its shallowest Recently acquired EC data (red) supports and confirms the interpreted EC contour map presented by Parsons & Associates (2006). A regional perspective of the spatial distribution of EC in the vicinity of the proposed Kalbaskraal site. Consideration of the central field of a Piper plot indicates that the more saline water has a stronger NaCl character Schematic representation of the conceptual geohydrological model Conceptual design of a multiple barrier system proposed for the Kalbaskraal site Results of the modelling of the movement and growth of the contaminant plume under Scenario 2 A comparison of the area Parsons (2006) identified as potentially being impacted by the site footprint (green line) and that delineated from the outcome of contaminant transport modelling (yellow line)
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LIST OF APPENDICES
A B C D E F
Geophysics report Borehole logs Pumping test graphs Interpreted hydraulic parameters Hydrochemistry data Updated hydrocensus data
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LIST OF ABBREVIATIONS
AMT audio-magnetotelluric
DWS Department of Water and Sanitation
(formerly Department of Water Affairs)
EC electrical conductivity
EIA Environmental Impact Assessment
ERT electrical resistivity tomography
hrs hours
iLEH Irene Lea Environmental and Hydrogeology
K hydraulic conductivity
km kilometres
L litres
L litres per hour
L/s litres per second
m metres
Ma million years
m/a metres per annum
mamsl metres above mean sea level
mbgl metres below ground level
m/d metres per day
min. minutes
mm millimetres
mm/a millimetres per annum
mS/m milliSemens per metre
m3/a cubic metres per annum
m2/d square metres per day
S storativity
SANS South African National Standard
T transmissivity
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ACKNOWLEDGEMENTS
The provision of monitoring data by the Department of Water and Sanitation – and in particular Ms Nicolette Vermaak – is gratefully acknowledged. The diligence and work ethic of the contractors – Steyn’s Drilling and AB Pumps – allowed for reliable information to be collected.
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DECLARATION OF INDEPENDENCE, QUALIFICATION AND EXPERIENCE
Project: Regional waste site project
City of Cape Town
Groundwater Specialist Study
EIA Consultants: SLR Consulting
(formerly CCA Environmental (Pty) Ltd)
DECLARATION OF INDEPENDENCE
I hereby declare that I have no financial or other interest in the proposed development of a regional waste disposal site for the City of Cape Town other than the remuneration for work performed.
QUALIFICATIONS AND EXPERIENCE
I have a Ph.D. degree in geohydrology from the University of the Free State and have practiced as a geohydrologist since 1984. Prior to establishing Parsons & Associates Specialist Groundwater Consultantscc in 1996, I worked for the Department of Water Affairs: Directorate of Geohydrology (1984 – 1990) and the CSIR: Groundwater Programme (1990 – 1996). I am a registered Professional Natural Scientist (400163/88) and a Fellow of both the Institute of Waste Management of Southern Africa (IWMSA) and the Water Institute of South Africa (WISA). Currently I am the Western Cape Branch Chair of the Ground Water Division of the Geological Society of South Africa. I regularly attend conferences, lectures and training courses to remain abreast of developments in my field.
Dr Roger Parsons
Ph.D. (U.F.S.) Pr.Sci.Nat.
19 May 2017
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1. BACKGROUND
The City of Cape Town needs to develop a new regional waste disposal facility as existing facilities have reached - or are in the process of reaching - the end of their lifespan. A project was initiated in 2000 to identify potential new sites (Ball, 2002), with an Environmental Impact Report being produced by CCA Environmental (2006) 1. Parsons & Associates Specialist Groundwater Consultantscc participated in the project as the geohydrological specialists (2002, 2006). The outcome of the project was the identification of two potential sites for development as a regional waste disposal facility for the City of Cape Town (Figure 1). Following submission of the Environmental Impact Report for environmental approval in 2006 and subsequent decisions by the provincial Minister and legal challenges thereto, Parsons & Associates was appointed to undertake further studies to ensure information previously presented in our 2006 report was relevant and addressed issues raised during the public participation and legal processes, particularly those relating to the Colenso Fault. The outcome of this additional work was documented in an addendum report (Parsons & Associates, 2012) and included in an updated Environmental Impact Assessment report (2012). Parsons & Associates was asked to undertake supplementary geohydrological work at the Kalbaskraal site following the receipt of further affidavits from the applicants in litigation regarding the regional landfill site. Contentions regarding the location and extent of faulting and claims by the applicants based on their preliminary groundwater model (Imrie and Rosewarne, 2016) required additional geophysical traverses, drilling and pumping tests be undertaken and a numerical groundwater and contaminant transport model (hereafter referred to as the numerical model) be compiled. This report forms an addendum report to the earlier specialist geohydrological reports of Parsons & Associates (2006, 2012); and must be read in conjunction with them.
1 Now SLR Consulting.
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2. TERMS OF REFERENCE
In terms of the proposal dated 9 November 2016 (ref. 347/RWSP – prop2) and which was accepted on 2 December 2016, Parsons & Associates was appointed by Cliffe Dekker Hofmeyr on behalf of the City of Cape Town to undertake the following additional geohydrological work: Additional hydrocensus:
Conduct a hydrocensus on the farm Geodgewag from which we were previously barred
Measure the electrical conductivity (EC) of all boreholes claimed to be used for domestic purposes within 1 km of the proposed waste site
Collect additional information from other properties which may be deem necessary during the course of the investigation
Additional geophysical surveys:
Conduct electrical resistivity and magnetotellurics surveys at the site to further investigate the presence (or otherwise) of the faults on the site, and particularly the sub-parallel fault in the northern central parts of the proposed site (as mapped by Gresse)
Additional drilling
Drill four additional exploratory boreholes to depths of between 75 m and 100 m to calibrate the results of the additional geophysical surveys and investigate the presence of faults
Testing of additional boreholes
Test the four additional exploratory boreholes by means of both step drawdown tests and 72 hr constant discharge tests (with recovery), and interpret the aquifer test data to determine aquifer hydraulic parameters. These data would then be used to inform the numerical model
On completion of the testing, water samples were to be collected to determine the hydrochemical character of the groundwater and its potability
Numerical groundwater flow and contaminant transport model
Review the Imrie & Rosewarne (2016) groundwater model
In collaboration with the numerical modeller, compile a conceptual model of the site using available information
Review the numerical model to be compiled by Irene Lea Environmental & Hydrogeology (iLEH)
The outcomes of the additional geohydrological work were to be documented in a geohydrological report and, after review, presented to the client.
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3. INVESTIGATION METHODOLOGY
3.1 Additional Geophysical Survey
Mr Martin de Klerk of Cape Geophysics and Mr Jan van der Walt of GEC Consulting were respectively appointed to undertake the Electrical Resistivity Tomography (ERT) and Audio-magnetotelluric (AMT) surveys. Their report is presented in Appendix A. Prior to this phase of investigation, 9 ERT traverses, 2 magnetometer traverse and 2 electromagnetic traverses had been conducted across the site (Figure 2). As part of this supplementary work, additional airborne geophysical data were sourced from Prof. Edgar Stettler by Mr van der Walt (see Appendix A). Recently acquired high resolution aeromagnetic data were superimposed on the low resolution data that informed the 1 : 250 000 scale geological map produced by Theron (1990) to produce an image of the total magnetic field. The data were processed using a tilt angle algorithm which, together with existing geological maps, Prof. Stettler used to interpret the position of possible geological structures and faults. These interpreted positions were used to select the positions of the ERT and AMT traverses undertaken during this study (Figure 3). Note: The high resolution aeromagnetic data were not available for the entire site proposed as a regional waste disposal facility, only covering the western two-thirds of the proposed site. Note: Prof. Stettler annotated possible faults (and structures) as dashed lines marked with a f? This convention is used to indicate the inferred presence and positions that have not been verified through ground truthing using tools such as geological mapping, geophysics or drilling.
Two traverses were carried out about 150 m apart from each other in a southwest – northeast orientation. The length of the ERT traverses were respectively 1 100 m and 1 000 m (Figures 4 and 5), but the AMT traverses could not extend further north-eastwards because of interference from overhead power lines and the railway line. 3.2 Additional Exploratory Drilling After a tender process in which five drilling companies were invited to submit tenders, Steyn’s Drilling was appointed to drill four additional exploratory boreholes. The position of the boreholes in relation to the outcome of the geophysical work is shown in Figure 6 while information about the boreholes are summarised in Table 1. Drilling took place between 16 March 2017 and 21 March 2017 using the rotary percussion method. The logs of the exploratory boreholes are included in Appendix B. The boreholes were initially drilled at a diameter of 200 mm until solid formation was encountered. Steel casing with a diameter of 177 mm was then installed, after which drilling continued at a diameter of 165 mm until the end of the borehole. Samples of the drilling chips were collected every 1 m, while the yield of each water strike was measured using a V-notch. A water sample was also collected directly after significant water strikes. On completion of drilling, each borehole was cleaned and developed for a period before a final measurement of the blow yield was recorded. The water samples were submitted to Bemlab in Somerset West for analysis, the results of which are included in Appendix E.
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Table 1: Summary of the additional exploratory boreholes drilled at the proposed
Kalbaskraal site
PARAMETER RWS-13 RWS-14 RWS-15 RWS-16
Latitude Longitude Ground elevation (mamsl) Total depth (m) Depth of 177 mm steel casing (m) Final blow yield (L/s) Final EC (mS/m) Static water level (mbgl)
33.63973 18.66564
95 100 18 2.5 90
8.84
33.63807 18.66564
95 97 38 5.6 102 9.52
33.639955 18.662657
85 90 24 10 50
0.00
33.637855 18.669367
103 100 31 0.8 126
13.14
Electrical conductivity profiles of all exploratory boreholes were recorded using a Solinst LTC levelogger on 11 April 2017 (Figure 7). EC profiling clearly demonstrated groundwater quality stratification in the northern parts of the site, with poor quality groundwater being prevalent in the top 20 - 40 m of the aquifer. At depth the groundwater was usually of good quality (50 – 100 mS/m), with RWS-16 being the exception with an EC of 180 mS/m. 3.3 Testing of Additional Exploratory Boreholes
The four additional exploratory boreholes were subjected to both step drawdown and constant discharge pumping tests conducted by AB Pumps (Table 2). Testing was conducted between 16 March 2017 and 11 April 2017. During the pumping tests conducted on RWS-13, RWS-14 and RWS-15, the two boreholes closest to the pumped borehole were used as observation boreholes. Only measurements collected in the pumped borehole were used to interpret the hydraulic properties at RWS-16, as no change in groundwater level was observed in logged data from RWS-8a. The outcomes of the pumping tests are presented graphically in Appendix C and the hydraulic parameters interpreted from each pumping test are presented in Appendix D. The purpose of the step drawdown tests was to establish the yield at which the borehole could be tested, while pumping the borehole at a constant rate allowed for characteristic flow conditions to be assessed and the hydraulic properties of the aquifer to be determined. Table 2: Summary of pumping tests conducted at the proposed Kalbaskraal site during
March 2017 and April 2017
PARAMETER RWS-13 RWS-14 RWS-15 RWS-16
Pump inlet depth (m) Available drawdown (m) Step drawdown test Monitored recovery period (hr) Duration of constant discharge test (hr) Rate of test (L/s) Maximum recorded drawdown (m) Monitored recovery period (hr) Observation boreholes
84 75.2
6 x 1hr 6
72 5.4
10.50 24
RWS-14 RWS-15
75 64.5
6 x 1hr 6
72 12.0
10.39 24
RWS-13 RWS-15
75 75.0
6 x 1hr 6
72 12.0
14.67 48
RWS-13 RWS-14
75 61.9
4 x 1hr 4
48 1.0
26.86 1
RWS-8a
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A water sample was collected on completion of each step drawdown test and each constant discharge test. The samples were submitted to Bemlab for analysis, the results of which are included in Appendix E. The constant discharge test of RWS-13 had to be restarted after the pump failed 26.5 hrs into the initial test. The test was restarted after a recovery period of 21.5 hrs and the piezometric level had recovered to within 0.5 m of its static or rest level. The data logger installed in RWS-8a was used to observe the effect of pumping of RWS-16 on RWS-8a. The boreholes are 415 m apart. No change in the water level of RWS-8a coincidental to the pumping of RWS-16 was observed. The pumping test data were analysed using standard interpretation techniques described by Driscol (1986), Kruseman and de Ridder (1990), van Tonder et al. (2002) and others to determine the hydraulic parameters of the aquifers and to assess the sustainable yield of the boreholes. The Cooper-Jacob straight line method was principally used as it allowed consideration to be taken of observed fracture flow characteristics. The sustainable yield of the boreholes was assessed using the Cooper-Jacob wellfield model developed by Murray et al. (2012) and confirmed using the numerical groundwater flow model compiled by Lea (2017) (see Section 3.5). 3.4 Collection of Additional Data During the fieldwork phase of the project, additional geohydrological data were collected where possible. This included:
The identification of borehole BN7 which is used for mining purposes;
A hydrocensus of the farm Goedgewag;
Verification of EC levels of all operational boreholes within 1 km of the proposed Kalbaskraal site 2;
Measurement of groundwater and EC levels in the general vicinity of the proposed site; and
Sourcing of monitored data from RWS-8a, RWS-9, BG00072 and BF2 from the Department of Water and Sanitation (DWS). These data are graphically presented in Figures 8, 9 and 10.
An updated list of information of boreholes surveyed as part of the groundwater assessment of the proposed Kalbaskraal site is presented in Appendix F. The positions of boreholes referred to in this report are shown in Figure 11. 3.5 Numerical Groundwater Flow and Contaminant Transport Model
The City of Cape Town appointed iLEH to develop a numerical groundwater flow and contaminant transport model of the proposed Kalbaskraal site. A site visit was undertaken with Ms Lea on 21 February 2017 during which she was shown features of the site and surrounding area to allow her to orientate herself. The geohydrological work undertaken as part of the environmental impact assessment (EIA) groundwater specialist study was described to her and she was provided with copies of geohydrological data and reports. This included a copy of the draft Imrie and Rosewarne (2016) preliminary groundwater
2 Permission was not granted to take a water sample from BN1, while a sample was not taken from BH6
as the borehole yielded dirty red water which did not clear after 5 mins of pumping.
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model report. Contact was maintained with Ms Lea during the execution of the project to share information with her and to develop the conceptual geohydrological model which was to form the basis of the numerical model. The modelling of the site and the outcomes thereof are described by Lea (2017).
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4. RESULTS
4.1 Position of Faults
4.1.1 Preamble The Klipheuwel Group - which underlies the proposed Kalbaskraal site (Figure 12) - has its origins in the folding, faulting and rifting of the Malmesbury Group and intrusion of the Cape Granite Suite. Gaucher et al. (2009) recorded that the Cape Granite Suite intruded into the Tygerberg Formation some 552 – 540 Ma. The main phase of continental collision and associated magnetism occurred about 540 Ma, while the youngest intrusive rocks of the Cape Granite Suite are in the order of 510 Ma. After a period of weathering and erosion, the Klipheuwel Group was deposited in low-lying areas. This geological unit comprises sediments derived from both the lower Malmesbury Group and the Cape Granite Suite; and mostly occurs in fault-bounded basins in the Malmesbury Group or granites from the Cape Granite Suite (Villaros, 2006). Four relatively small outcrops are shown on the 1 : 250 000 scale geological map 3318 Cape Town (Theron, 1990), with the outcrop at Klipheuwel - Kalbaskraal being the largest at 70 km2. The age of the Klipheuwel Group, which unconformably overlies the Malmesbury Group (Johnson et al., 2006), has been set at less than 520 Ma. This age was confirmed by Barnett et al. (1997) and Armstrong et al. (1998) by dating detrital zircon from the basal units of the Cape Supergoup at between 520 - 515 Ma (as quoted by Kisters et al. 2002). Consequently the Klipheuwel Group was deposited after the Colenso Fault was formed. The Colenso Fault is a regionally extensive geological structure that separates the southwestern terrane of the Malmesbury Group from the central terrane. In the study area the two terranes are respectively represented by the Tygerberg Formation and the Moorreesburg Formation (Figure 12). Villaros (2006) set the earliest displacement of the Colenso Fault at 547 Ma (+/- 6 Ma) 3 and which continued until 520 Ma. Kisters et al. (2002) argued the synkinematic emplacement of granitoids into, and along, the Colenso Fault. This indicates that the age of the Colenso Fault correlates to that of Cape Granite Suite. The area was subjected to further tectonic events that resulted in folding and faulting subsequent to the deposition of the Malmesbury Group, and continued at least until the breakup of Gondwana (~132 Ma). Deformation of the Klipheuwel Group is comparable to that of the Malmesbury Group, as reflected by the structural information recorded by Gresse on his field map. The landscape was further defined by erosion to produce the current topography of a broad flat plain. 4.1.2 Geological maps The published 1 : 250 000 scale geological map 3318 Cape Town (Theron, 1990) formed a basis for understanding the geology of the site. In turn, parts of this map were informed by field mapping done by Dr Pieter Gresse in 1980 (Parsons & Associates, 2012). The current study was also informed by more recent maps:
The 1 : 500 000 hydrogeological map of Cape Town (Meyer, 2001)
1 : 50 000 geotechnical map 3318DA Philadelphia (Stapelberg, 2005)
Interpretation of aeromagnetic data in conjunction with existing geological maps by Prof. Stettler
3 This is the same age as the Darling Pluton that outcrops directly west of the proposed Kalbaskraal site.
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It is instructive that the Colenso Fault was not mapped by Stapelberg (2005) on the geotechnical map of the Philadelphia area, yet a site in close proximity to the Colenso Fault is indicated on the map as being a favourable location for a waste site. In the remaining instances, it would appear the mapping of Gresse also formed the foundation on which subsequent maps were based. In considering the information, the following is noted:
There is general agreement as to the position of the Colenso Fault in the vicinity of the proposed Kalbaskraal site. This is because the fault is visible at surface in places. There is less agreement where the fault is not exposed, with DWS officials disagreeing as to its position northeast and south east of the proposed site:
o Gresse mapped a sub-parallel branch of the Colenso fault which extends into the northern parts of the proposed site, but not as far as the footprint of the waste pile;
o This is an inferred position as the area is covered by a much younger and laterally extensive sand horizon 4 and the fault is not visible at surface; and
o Neither the geophysical surveys (four ERT profiles, one AMT profile) nor drilling (RWS-16) have confirmed the existence of the branch of the fault mapped by Gresse.
A regionally extensive fault was mapped on the hydrogeological map by Meyer (2001) some 2.5 km east of the Colenso Fault. The existence of such a fault is not supported by Theron (1990) - or others.
In interpreting the aeromagnetic data, Prof. Stettler inferred four structural features which he marked with dashed lines annotated with “f?” (Appendix A) (Figure 3). It was confirmed with Prof. Stettler by Mr van der Walt that his interpretation was based on aeromagnetic data and available geological maps:
o It is accepted that the easternmost structure interpreted by Prof. Stettler is the Colenso Fault (No. 1);
o The interpreted westernmost structure (No. 4) coincides with the contact of the Populierbos Formation and the Magrug Formation, as mapped by Gresse and displayed on the regional geological map. No faulting was mapped by Gresse;
o A prominent magnetic anomaly was mapped to the southwest of the proposed site which coincides with an outcrop of granite. The same magnetic anomaly is mapped on the 1 : 250 000 scale geological map; and
o The existence of the two central structures (No. 2 and No. 3) is less convincing, but cognisance of them was taken in laying out the two geophysical traverses and siting the additional exploratory boreholes.
The above discussion highlights uncertainties associated with mapping geology in general and structures in particular when the geology cannot be seen at surface. Inferences and interpretations are made based on the extrapolation of known information – whether it be geological outcrops, remote sensing, geophysical surveys, drilling, topography and / or vegetation. During the geohydrological investigation of the proposed Kalbaskraal site, attempts were made to confirm the existence of the sub-parallel branch of the Colenso Fault mapped by Gresse. The existence of the Colenso Fault was confirmed (Parsons & Associates, 2012); but its exact position is not always certain where covered by sand. The position of an inferred sub-parallel fault west of the Colenso Fault – often referred to as the off-shoot fault and labelled No. 2 on Figure 3 – has not been confirmed by either geophysical
4 Uncertainty relating to the existence of this fault is highlighted by Gresse in his affidavit of 26 April
2016 when he states “fault trace A may extend further to the southeast under cover” and “it is possible that
fault trace A extends along the strike south-eastward and below the surface of the proposed landfill.”
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surveys or drilling. No anomalies were observed in the ERT or AMT traverses in the vicinity of the inferred position of the fault (Figures 2, 4 and 5); while RWS-16 – sited to intersect the fault – was low yielding and the drilling chips did not display evidence of faulting or fracturing.
Note: Geophysicists measure the geophysical properties of the earth using a range of techniques. They then plot these values and compare them relative to each other. Where a local variation occurs relative to background values, they refer to this as an anomaly; and the anomaly is ascribed to a variation in rock (lithological, weathering) or geological structures (faults, fractures, folds). Until verified through ground truthing, the cause of the anomaly remains a matter of interpretation.
4.1.3 Geophysical traverses ERT traverses carried out in 2004, 2005 and 2010 were used to try to locate the inferred faults in the field (Figure 2). This was successfully achieved in the case of the Colenso Fault, but the existence of the sub-parallel branch of the Colenso Fault could not be confirmed. It was recognised that the electrical signature of the Colenso Fault was not always clear or distinctive. The AMT method was used in conjunction with the ERT technique to investigate the subsurface. While the eastern limit of the AMT traverses was limited by interference from power lines and the railway line, Kal-1 extended over the inferred position of the sub-parallel branch of the Colenso Fault (Figure 4). No indication of the existence of the fault or any other structure was evident in the deeper penetrating AMT data, but a slight change in near surface resistivity was observed in the vicinity of the inferred position of the sub-parallel branch of the Colenso Fault. Consequently this motivated the drilling of RWS-16 at this location. The very low resistivity (< 20 Ω.m) observed near surface in the ERT data correlated well with the poor quality groundwater profiled in the boreholes. Beneath the low resistivity layer, both the ERT and ATM techniques indicated thicker low resistivity material in the southwest and thinner low resistivity material in the northeast. A fairly uniform resistive material was observed at depth in the northeast, while lower and more variable resistivities characterised the southwest (Figures 4 and 5). This variability is somewhat surprising given that all boreholes were completed in maroon shale. During drilling it was found there was little to no sand in the southwest (RWS-13, RWS-15), but a sand horizon of up to 30 m was encountered in the northeast (RWS-14, RWS-16). A blue-grey siltstone was drilled into beneath the sand, followed by maroon shale. In addition to these lithological differences, the maroon shale encountered in RWS-15 from 10 m onwards contained a prominent speckling of what was interpreted to be calcite – a mineral often deposited in fractures in the subsurface. This is usually indicative of some sort of fracture or fracture zone. A similar speckling was observed in RWS-13, but it was only 8 m thick. A less prominent speckling was logged in the last 40 m of RWS-14. The relatively high yields obtained in these three boreholes are indicative of secondary geohydrological conditions. 4.1.4. Summary Neither the geophysical work nor the drilling provided any indication that the fault sub-parallel to the Colenso Fault – as mapped by Gresse – exists. The geophysical work, however, indicated that conditions along the southwestern parts of the traverse differed from
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the more uniform conditions evident along the northeastern sections of the traverses. Drilling yielded evidence of a fracture zone in the southwest; and this fracturing could be the result of either faulting or tight synclinal folding as evidenced from the structural data recorded on Gresse’s map. This is illustrated in a schematic geological cross-section of the site (Figure 13). 4.2 Borehole yields
4.2.1 Sustainable borehole yields Reasonable yields were obtained from three of the additional exploratory boreholes, with only RWS-16 being low yielding (Table 3). While the blow yield measured during drilling provides an indication of the yield of a borehole, the sustainable yield has to be confirmed through pumping tests and ongoing monitoring of aquifer response to abstraction over the long term. Table 3: Yields of the additional exploratory boreholes
BOREHOLE AVAILABLE DRAWDOWN
(m)
BLOW YIELD (L/s)
SUSTAINABLE YIELD (L/s)
WELLFIELD YIELD (L/s)
RWS-13 RWS-14 RWS-15 RWS-16
70 40 40 20
2.5 5.6 10 0.8
4 8 7
0.3
3.5 4.0 2.0 0.2
Determination of the sustainable yield of each borehole was made difficult by the observed fracture dewatering during pumping. This is illustrated in Figure 14 where the slope of the drawdown graph changes according to the dominant flow pattern at that time. Hydraulic flow theory of fractured aquifers is well established in the literature (Kruseman and de Ridder, 1990; van Tonder et al., 2002). During the early stages of testing, fracture flow dominates until the fracture is dewatered, whereafter bilinear flow prevails. At this time flow from both the fractures and the matrix rock contributes to the yield of the borehole. During the late stages of testing RWS-16 a second period of fracture flow is evident. This pattern of fluctuating flow dominance will continue until the fractures are mostly dewatered and most water is contributed by the matrix. By that stage the area influenced by pumping is large; and local heterogeneities become less important and the fractured aquifers starts to behave in a pattern similar to that of a homogeneous aquifers. This is referred to as pseudo-radial flow and it is the hydraulic parameters determined at this time that control the long-term sustainable yield of the aquifer. While pumping tests of 72 hr duration is the industry norm for testing boreholes, longer periods of pumping are required to observe further fracture dewatering and ensure pseudo-radial flow is induced. An approach to dealing with uncertainty related to fracture flow conditions is to adopt a conservative approach when setting the operational yield of a borehole; and then to monitor the response of the aquifer to on-going pumping. 4.2.2 Wellfield yield The sustainable yield of each additional borehole interpreted from the pumping tests is presented in Table 3. In assessing the yield of the aquifer, it was important to recognise that the boreholes cannot be pumped simultaneously at their interpreted sustainable yield
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because of interference between them (Appendix C). This is also well illustrated in Figure 14 where the drawdown induced in the observation boreholes while pumping RWS-14 is evident. Borehole RWS-15 is 350 m distant from the pumped borehole, yet experienced a drawdown of almost 60% of that of the pumped borehole. Based on an analysis using the C-J Wellfield model (Murray et al. 2012), it was estimated that the combined yield of the four boreholes is in the order of 10 L/s. This was based on the hydraulic parameters determined at each of the additional exploratory boreholes, while other boreholes within a 2 km radius of the site were assigned T and S values deemed representative of the matrix (see Sections 4.3 and 4.7). Drawdown was limited to 60 m and it was assumed that all boreholes would be pumped continuously for a period of 1 year. Simulations using the numerical groundwater flow model supported this assessment. Lea (2017) showed that 10 L/s could be abstracted from the four boreholes, but that this would induce a drawdown of 11 m in WV5 located some 600 m to the northeast. This may affect the rate at which WV5 can be pumped. 4.2.3 Regional perspective SRK Consulting (1996) reported that two boreholes that they had drilled into the Klipheuwel Group at Chatsworth (10 km northwest of the proposed Kalbaskraal site) respectively yielded 0.6 L/s and 0.06 L/s. The harmonic mean of the yield of 13 boreholes drilled into the same geology at the proposed site or directly on its border is 0.7 L/s. This includes the relatively good yields of RWS-14 and RWS-15. A comparative statistic of 10 boreholes drilled into the Colenso Fault (or very close to it) is 2.8 L/s. This includes two boreholes with reported blow yields of 7 L/s and 15 L/s not confirmed by pumping tests. Most of these boreholes are thought to be associated with Malmesbury Group sediments, but borehole logs are not available for all of them. Hydrocensus work in the area directly north of Kalbaskraal by DWS in 2009 and 2011 (Vermaak, pers.comm.), Umvoto Africa (2009) and Parsons & Associates (2015) identified high yielding boreholes drilled into weathered and fractured rocks of the Malmesbury Group that are being used to irrigate lands using centre pivots. This area is evident on the satellite imagery presented in Figure 15. The harmonic mean of the operational yield of 13 boreholes on the farm Dieprivier was 10.8 L/s, with yields ranging between 1.9 L/s and 55 L/s. A visual comparison of the yield of boreholes drilled into the Klipheuwel Group, those drilled into the Colenso Fault and those drilled into the productive Malmesbury Group north of Kalbaskraal is shown in Figure 15. While the high yielding boreholes drilled into the argillaceous rocks on the eastern side of the Colenso Fault northeast of the village of Kalbaskraal are considered unusual, Figure 15 illustrates the difference in yield expected from a major aquifer system and a minor aquifer system. This graphic illustrates that geohydrological conditions north of the site are different to those at the site (with yields being substantially higher), and that the original decision to focus on the area within a 2 km radius of the site – as specified by the Minimum Requirements (DWAF, 1998a) – was correct. 4.3 Hydraulic Properties
Data collected during the testing of the additional exploratory boreholes was assessed using standard pumping test interpretation techniques (Driscoll, 1986; Kruseman and de Ridder, 1990; van Tonder et al., 2002 and others) to determine the hydraulic properties of different geohydrological settings. The interpreted parameters from each test are presented in Appendix D and summarised in Table 4. Table 4 was also informed by reinterpretation of pumping tests previously conducted at the proposed Kalbaskraal and Atlantis sites (Parsons
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& Associates, 2006, 2012) and consideration of pumping test graphs presented by SRK Consulting (1996, 1998). These data were required to inform the parameterisation of the numerical model (Lea, 2017). Because of its limited outcrop, little information is available regarding the hydraulic properties of the Klipheuwel Group. Information presented in Table 4 about this aquifer unit is thus new. In spite of their widespread occurrence, little primary data or information about the hydraulic properties of the Malmesbury Group or the Cape Granite Suite could be sourced. These two units are often considered in the context that they form the impermeable base beneath the Cape Flats Aquifer and the Atlantis Aquifer. Adelana et al. (2010) presented transmissivity (T) and storativity (S) values for the Malmesbury Group aquifer at the University of the Western Cape test site of 19 and 2.3 x 10-4, but acknowledged that the T value was reflective of linear flow in a fracture. Primary data from the proposed Atlantis site (Parsons & Associates, 2006) and that presented by SRK Consulting (1996, 1998) allowed for the quantification of the hydraulic properties of this aquifer type. No similar data were found for the granitic aquifer, and it was thus assumed that the properties of the weathered and fractured granitic aquifer are similar to those of the Klipheuwel Group and Malmesbury Group. No site-specific information is available regarding the hydraulic properties of the mostly thin sand horizons at the proposed site. Low yielding water strikes were obtained directly beneath the sand in RWS-14 (0.3 L/s) and RWS-16 (0.8 L/s). The sand horizons had to be cased off to prevent the collapsing of the sand and ensure that the borehole remained open. The hydraulic properties of the primary aquifers in and around Cape Town are well documented (Bredenkamp & Vandoolaeghe, 1982; Fleisher, 1990; Henzen, 1973; Wessels & Greeff, 1980 and others), and for the purpose of parametising the numerical model it was assumed that the sand has a K and S of 0.5 m/d and 0.15 respectively. Table 4: Hydraulic properties of geohydrological units prevalent at the proposed Kalbaskraal site determined from site-specific testing
GEOHYDROLOGICAL UNIT T K S
(m2/d) (m/d)
Klipheuwel Group Aquifer
Weathered 7.5 0.027 -
Fracture 81 - 0.00007
Bilinear 37 - 0.00009
Matrix 2.7 - 0.00024
Malmesbury Group Aquifer
Weathered 0.26 0.035 -
Fracture 10 - -
Bilinear - - -
Matrix 3.1 0.025 -
Colenso Fault 19.0 - -
Note:
Values presented above are the harmonic means determined from site-specific data and that from Parsons & Associates (2006, 2012) and SRK Consulting (1996, 1998).
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4.4 Groundwater Levels
Re-measurement of depth to groundwater in boreholes on the site and new information yielded from the additional exploratory boreholes has not changed earlier interpretations by Parsons & Associates (2006) about depth to groundwater nor groundwater flow patterns (Figure 16). Interpretation of depth to groundwater data shows that (Figure 17):
The area where the piezometric surface is at or above ground level is limited to the northwestern corner of the site;
Depth to groundwater in the middle of the site is deep (~20 m), and probably influenced by the interaction between groundwater and the Mosselbank River; and
The piezometric surface is at least 4.5 m below ground level in the footprint of the planned area of disposal.
Monitoring by DWS of two boreholes at and adjacent to the proposed site has shown that the variation of piezometric surface differs (Figure 8). The range of fluctuations observed in RWS-8a was in the order of 1 m, while at BG00072 the range was 3.5 m. It is also noteworthy that recharge is evident by a rise in piezometric level when average to above rainfall is experience (2009, 2013 and 2014), but no or little recharge is observed when rainfall is below average (2010, 2011, 2015, 2016). Analysis of rainfall data and an appreciation of seasonal groundwater fluctuations in the Western Cape indicate that depth to groundwater levels measured in the winter of 2010 represent (near) maximum elevations of the piezometric surface. This period followed above average rainfall during 2007, 2008 and 2009 and is when the seasonal variation of the piezometric surface is at its shallowest following winter recharge. Consequently, the depth to groundwater measurements shown in Figure 18 represents the shallowest level to which the piezometric level will rise. Cognizance must be taken of this in the design of the proposed site. 4.5 Groundwater Quality
New information has not changed the interpreted spatial distribution of EC presented by Parsons & Associates (2006), but rather confirmed the good quality groundwater found in the northern and central parts of the proposed site (Figure 19). Poor quality groundwater is found to the north, west and south of the site. Profiling EC with depth, however, has revealed a 20 – 40 m thick layer of poor quality groundwater overlying good quality groundwater found at depth (Figure 7). A regional perspective of groundwater quality is shown in Figure 20. Here it is apparent that the more saline groundwater has a stronger NaCl character and that groundwater in the near vicinity of the site has a poor quality, often exceeding the drinking water standard of 170 mS/m set by SANS (2015). The hydrochemical data also supports the notion that the characteristics of groundwater north of Kalbaskraal differ significantly from that at the proposed site (see Section 4.2.3). 4.6 Aquifer Classification
Previously Parsons & Associates (2006, 2012) classified the aquifer in the vicinity of the proposed Kalbaskraal site as a minor aquifer system (Table 5) 5. It was acknowledged that
5 Using the system developed by Parsons (1995) and adapted by DWAF (1998b, 2000).
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the aquifer is of local importance and used to supply water for domestic use and stock watering to some farms in the area - this in spite of its poor quality. Classification of this aquifer system as a minor aquifer system 6 was driven by:
The low to moderate yields of borehole on and around the proposed site; and
The variable groundwater quality, ranging from good quality groundwater in the central parts of the site to very poor quality groundwater directly to the north, west and south which far exceed standards for drinking water.
Additional exploration and testing at the proposed Kalbaskraal site has not revealed any new information that warrants changing the classification of the aquifer. While reasonable blow yields were obtained during drilling, the results of testing and observed fracture dewatering caution that a conservative approach be adopted when setting the sustainable yield of each borehole. Also, interference between the boreholes will prevent them being pumped simultaneously at their interpreted sustainable yields (Table 3) and the collective yield of the boreholes was estimated to be 10 L/s. The interpreted sustainable yields and / or the wellfield yield have to be confirmed through monitoring aquifer response to on-going abstraction. Table 5: South African aquifer system management classification AQUIFER TYPE DESCRIPTION
Sole-source aquifer
An aquifer used to supply 50% or more of urban domestic water for a given area and for which there are no reasonably available alternative sources of water.
Major aquifer A high-yield aquifer system of good quality water.
Minor aquifer A moderate-yield aquifer system of variable water quality.
Poor aquifer A low- to negligible-yield aquifer system of moderate to poor water quality.
Special aquifer An aquifer system designated as such by the Minister of Water Affairs and Forestry, after due process.
(from DWAF, 2000)
The close proximity of poor quality groundwater – both vertically and horizontally – indicates a risk of inducing poor quality groundwater into that part of the aquifer into which the additional exploratory boreholes were drilled. This consideration also does not support a change in the classification of the aquifer. 4.7 Conceptual model
A conceptual understanding of the geohydrology of the area formed the basis of the numerical model. Any conceptual model is founded on knowledge of an area (including site-specific measurements), past experiences in other areas and a series of interpretations and assumptions. The conceptual model of the site is presented schematically in Figure 21 and summarised below:
The proposed Kalbaskraal site is underlain by the Klipheuwel Group comprising both the Magrug Formation and the Populierbos Formation. The Klipheuwel Group was deposited unconformably in fault-bounded troughs and this outcrop covers an area of some 70 km2.
6 Previously, DWAF(1998b) defined a minor aquifer as a “moderately yielding aquifer of acceptable
quality or high yielding aquifer of poor quality water”.
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The Klipheuwel Group has been fractured (through folding and possibly faulting) and weathering; and therefore forms a secondary aquifer.
A generally thin, but extensive sand horizon covers most of the site. In places the sand has been removed through mining. For the purpose of this study it was conceptualised that the sand is 10 m thick across the site.
The upper parts of the aquifer system have been weathered and are generally intergranular in character. This layer is about 30 m thick. The deeper parts of the aquifer system are fractured and is assumed to be 100 m thick.
The aquifer is semi-confined in character.
The regionally extensive Colenso Fault is positioned east of the proposed site. This structural feature separates the Klipheuwel Group from the Moorreesburg Formation of the Malmesbury Group.
A zone of fracturing – either caused by folding or faulting – is located in the western parts of the site and is sub-parallel to the Colenso Fault.
A thin elongated outcrop of granite from the Cape Granite Suite outcrops 1.5 km west of the site. This rock intruded into the Tygerberg Formation (Malmesbury Group) which outcrops west of the granite.
The site is generally flat lying. It is located on a slight northwest – southeast trending ridge, with a very gentle slope to the northeast and a slightly steeper and longer slope to the southwest toward the Mosselbank River.
The piezometric surface across the site is at least 4.5 m below ground level, except in the northwestern parts where the piezometric surface is at or above ground level. The site footprint does not extend to the artesian area.
Groundwater flows in a general southwesterly direction. The hydraulic gradient ranges between 0.015 and 0.026 across the site.
It is expected that some groundwater discharges into the Mosselbank River and Diep River in the winter months, thereby influencing localised groundwater flow patterns. However, little or no groundwater discharges into the rivers in summer when they are dry.
Groundwater quality is highly variable ranging from 50 mS/m in the central parts to 300 mS/m in the south and almost 900 mS/m in the north. Significant groundwater quality stratification was also observed, with the upper weathered aquifer yielding groundwater with an EC of 300 mS/m, while the deeper fractured aquifer yields good quality groundwater (50 – 100 mS/m).
The groundwater has a NaCl character, with the more saline water having a more pronounce NaCl character.
In spite of the variable groundwater quality, groundwater is used on some farms for domestic supply, stock watering and mining.
If the proposed site is developed, groundwater abstraction for mining purposes from BF2 and BN7 will cease. Also, the Record of Decision stipulates that BN1 can no longer be used for domestic water supply.
The fractured aquifer is recharged by rainfall. Average rainfall amounts to 400 mm/a – as measured in Malmesbury between 2006 and 2016. Almost 80% of the rain falls in the winter months between April and September.
Based on observed groundwater level trends (Figure 8) little or no recharge occurs in those years that receive below average rainfall, but above average rains result in the replenishment of the aquifer. Recharge to the secondary aquifers has been calculated to be between 1.7% and 3.3% MAP (Lea, 2017).
Considering recharge rates in nearby Atlantis, recharge to the upper sandy aquifer was set at about 10% of MAP.
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It was assumed that the Magrug Formation and the Populierbos Formation are geohydrologically similar. Based on the outcome of the pumping tests, the same assumption was applied to the Malmesbury Group.
No information was available relating to the hydraulic properties of the granite. Consequently it was assumed that this geological unit had similar characteristics to the Malmesbury Group and Klipheuwel Group.
Table 6: Hydraulic properties assigned to the difference components of the aquifer system
AQUIFER T K S
(m
2/d) (m/d)
Sand 1 0.15
Weathered Aquifer 7.5 0.25 0.0002
Fractured Aquifer
Fracture 80 0.8 0.00007
Matrix 3 0.03 0.0002
Colenso Fault 19 0.19 0.00007
Note:
K determined by dividing T by aquifer thickness
K of the fractures could be very variable, depending on the size of the fracture apertures
The controlling factor in the average rate of groundwater flow is the interconnectivity of fractures and the hydraulic property of the matrix. More rapid movement in the fractures may be possible over short distances.
In addition, contaminant transport is influenced by attenuation processes such as dispersion, sorption, diffusion and dilution.
A preliminary design for the proposed Kalbaskraal site was presented in the project description of the EIA report (CCA Environmental, 2006, 2012). This included a multiple barrier system – or landfill liner - that complied with the Minimum Requirements (Figure 22). It might be required that the design be reviewed to conform with the more recent Waste Classification and Management Regulations (DEA, 2013), but for modelling purposes it was assumed that the 2012 design would be used. The objective of multiple barrier systems is to prevent the migration of leachate from the waste pile into the aquifer system. Leachate generated in the waste pile is collected and treated. Prior to this modern approach to waste management and groundwater protection, waste sites had significant negative impacts on groundwater. This is well reflected in the scientific literature. However, no peer-reviewed scientific literature could be found documenting instances where modern landfills have caused groundwater contamination. Even if such literature does exist, it is apparent that groundwater contamination by modern engineered facilities is not commonplace. It was therefore prudent to consider a scenario where no leachate penetrates through the multiple barrier into the aquifer system i.e. no contamination of the underlying aquifer. A second scenario entailing some leachate escaping into the aquifer system was considered using an approach documented by Giroud (1997) to estimate the rate of leachate migration through a defective composite liner.
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5 NUMERICAL GROUNDWATER FLOW AND CONTAMINANT TRANSPORT MODEL
The numerical groundwater flow and contaminant transport model compiled by Lea (2017) comprised three layers (sand, weathered aquifer, fractured aquifer). The Colenso fault and a western sub-parallel fracture zone were included in the fractured aquifer layer (layer 3). As is modelling practice, the model was compiled using interpreted hydraulic properties, but then these were refined during the calibration process. While models aim to replicate actual conditions, a degree of uncertainty is inevitable because of aquifer heterogeneity and anisotropy, assumptions that have to be made and limitations imposed by the availability of both spatial and temporal data. The numerical model was run at two time steps, namely at the end of the operational lifespan of the site (30 years) and 100 years after the closure of the site (i.e. 130 years after the site becomes functional). Notwithstanding the assumptions, limitations and uncertainties associated with numerical modelling, Lea (2017) compiled a calibrated and verified groundwater model that showed that:
If the multiple barrier system is not breached and leachate does not infiltrate into the groundwater system (Scenario 1), no groundwater contamination will occur.
If the multiple barrier system is breached (Scenario 2), most of the contamination will occur in the weathered aquifer. The rate of migration will be in the order of 10 – 15 m/a (Figure 23).
Some contamination of the fractured aquifer will occur, but at a slower rate and lower concentrations compared to the overlying weathered aquifer (Figure 23).
Modelling showed that the Colenso Fault and the sub-parallel fracture zone are not expected to play a role in the migration of contamination, if it were to occur. It also showed that any contaminant migration other than toward the southwest will be minimal.
Consideration of existing groundwater abstraction by surrounding farms indicated that such abstraction would not significantly alter the spread of contamination, if it were to occur. Consequently the only boreholes at risk of being impacted under Scenario 2 are on the western side of the proposed waste pile i.e. BN1, BN7 (Figure 23).
Under Scenario 2 the contamination plume would not reach the Mosselbank River within the 130 year simulation period.
No preferential flow was observed in the simulations undertaken using Scenario 2 (Figure 23). A theoretical exercise was then undertaken to test whether increased groundwater abstraction would induce preferential flow along faults or fractures (Scenario 3). Slight differences were observed under the two scenarios, with preferential flow from the waste pile to RWS-15 when this borehole is pumped and the multiple barrier system breached. These differences are not considered significant. In contrast to the findings of Imrie and Rosewarne (2016), numerical modelling indicated that contaminated groundwater would not flow upgradient toward the east and toward the Colenso Fault; and that groundwater flow patterns are expected to remain similar to pre-construction conditions. Modelling also showed that RWS-15 could be used as a scavenger well (a borehole used to control the movement of groundwater, and in particular contaminated groundwater). The use of scavenger wells within 300 m of the waste pile provides a potential remedial option, should it be required.
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Numerical modelling remains a useful tool for understanding prevailing geohydrological conditions and predicting future behaviour. Monitored data is required to improve the confidence in the results of modelling; including the monitoring of the piezometric surface using data loggers, groundwater quality and groundwater use. However, it is motivated that the numerical groundwater flow and contaminant transport model is of sufficient confidence to support decision-making regarding the suitability of the site for development as a waste disposal site based on geohydrological criteria.
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6 DISCUSSION
Repeated attempts to confirm the existence of the inferred sub-parallel branch of the Colenso Fault mapped by Gresse using geophysical means have failed. Research conducted since the field mapping (Kisters et al., 2002; Villaros, 2006) indicates that the Colenso Fault predates the Klipheuwel Group. If correct, this has two important ramifications for this study:
If it exists, the sub-parallel fault mapped by Gresse cannot be related to the Colenso Fault; and
The Colenso Fault has no hydrogeological significance in those areas where the Klipheuwel Group abuts the fault as the Klipheuwel Group was deposited against the fault (rather than fractured by it). However, the adjacent sediments of the Malmesbury Group may be fractured and their ability to transmit groundwater enhanced.
Unless a fault can be seen on the ground and mapped as such, a degree of uncertainty exists regarding its position and extent. Geologists use indirect methods to infer the position of a fault, but this has to be confirmed through other means such as geophysics and drilling. Where exposed at surface, the position of the Colenso Fault can be accurately mapped. Its position is less certain when covered by sand. The existence of faults on the proposed Kalbaskraal site have to date not been confirmed by geophysics. Additional geophysical work and drilling revealed the existence of a fracture zone in the northwestern part of the proposed site. This fracture zone could be the result of tight synclinal folding of the Klipheuwel Group (as interpreted from the geological map of the area) or faulting. Irrespective of the cause of fracturing, the secondary processes have enhanced the water bearing properties of the argillaceous sedimentary rock. Statistical analysis indicated that the yield of boreholes drilled into the Klipheuwel Group would typically be in the order of about 0.7 L/s, but exceptions such as those obtained during the current drilling programme can be found. The relatively high yields are the result of intersecting the fracture zone described above. Observations during the pumping tests dictate that a conservative approach is required when setting the sustainable yield of boreholes and cognisance has to be taken of borehole interference. Further statistical analysis suggested that boreholes drilled into or directly adjacent to the Colenso Fault yield about 2.8 L/s. Again, exceptions can be found and cognisance has to be given to aquifer response to pumping and borehole interference. While the higher transmissivity of the Colenso Fault dictates that the fault will be an area of preferential flow, this was not evident in the results of the numerical modelling. Modelling showed that if the integrity of the multiple barrier system were breached, then the contamination plume would not reach the Colenso Fault. Modelling of pumping from RWS-15 showed that contamination would migrate toward this borehole, but neither the Colenso Fault, fracture zone nor current abstraction would significantly influence the migration of contamination, if it were to occur. Groundwater quality at the site is variable, and in places far exceeds standards for drinking water. A 20 – 40 m thick layer of poor quality groundwater overlies the fractured aquifer, providing a risk of impacting the quality of groundwater in the deeper fractured aquifer. It is instructive that the results of the numerical modelling indicate that most of the contamination will take place in the weathered aquifer, i.e. that part of the aquifer system that naturally contains poor quality groundwater.
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Historical evidence shows that the uncontrolled disposal of waste almost inevitably caused significant levels of groundwater contamination. This led to much research into the matter (particularly during the 1980s and 1990s) and a better understanding of the impact of waste disposal on groundwater emerged. Since then waste disposal facilities are engineered with multiple barrier systems specifically aimed at preventing groundwater contamination. Consequently it is not prudent to consider the establishment of a waste disposal facility without a multiple barrier system. The purpose of the multiple barrier system – now required by law – is to prevent leachate generated in the waste pile percolating down into the groundwater system. Under this scenario, no groundwater contamination will occur and no groundwater users will be at risk from contamination. If all of the layers of the multiple barrier system were to be breached simultaneously for whatever reason, then leachate could enter the subsurface and potentially place groundwater users at risk. The area at risk has been identified through modelling, and mostly coincides with the area Parsons (2006) delineated as potentially being impacted by the site footprint (Figure 24). The rate of migration will be in the order of 10 – 15 m/a. Of the currently used boreholes, only BF2, BN1 and BN7 are considered to be at risk of contamination. BF2 will have to be decommissioned and plugged as it will be under the waste pile. As BN7 is currently used for mining purposes by the present owners of the property, it is expected that abstraction from this borehole will cease when the site is developed as a waste disposal facility. Modelling indicates that WV5 – located on the eastern side of the waste pile - is not at risk of impact. The identity of groundwater users who might be affected by a total failure of the liner therefore remains as before. The only farm potentially affected is Bonnie Doon, as its borehole BN1 is situated within the flowpath of the potential contamination plume. It is acknowledged that all models suffer from limitations; and that the results of numerical modelling are subject to some degree of uncertainty. A calibrated and verified numerical model was used to determine the rate and direction of contaminant migration (if it were to occur) and demonstrate that the Colenso Fault would not act as a preferential flow path along which contamination would migrate. Monitored data is required to improve the confidence in the results of modelling; but it is motivated that the numerical groundwater flow and contaminant transport model is of sufficient confidence to support decision-making regarding the suitability of the site for development as a waste disposal site. A key objective of systematic and organised monitoring at waste disposal sites is to detect groundwater contamination at an early stage so that remedial actions can be implemented. As specified in the Record of Decision of 28 August 2013, groundwater monitoring will be required. It is recommended that a geohydrologist be appointed to design a groundwater monitoring programme for the site in accordance with the Minimum Requirements (DWAF, 1998b). Once approved by the authorities the programme must be implemented as soon and before the disposal of any waste. The design of the proposed monitoring programme is to specifically address:
The optimal siting and construction of the monitoring boreholes;
The existence of an upper weathered aquifer and a deeper fractured aquifer as well as groundwater quality stratification;
Seasonal and inter-seasonal fluctuations in piezometric surface;
Linkage or potential linkage between the groundwater system and the Mosselbank River;
Monitoring methods and protocols; and
The frequency of monitoring and reporting.
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All boreholes underlying the footprint of the site (i.e. the area to be covered by waste) must be properly plugged and sealed with bentonite (or a similar material). At present this includes BF2, RWS-13 and RWS-16. Boreholes RWS-8, RWS8aa, RWS-10, RWS-11 and RWS-14 may also be affected by construction and the need to plug them should also be considered once the final design of the site has been completed. The geohydrology of the proposed Kalbaskraal site has been studied in detail, and the level of assessment exceeds that required by the Minimum Requirements (DWAF, 1998a) and the Waste Classification and Management Regulations (DEA, 2013). While additional work undertaken at the proposed site has improved the knowledge of prevailing geohydrological conditions, the outcomes of the investigation have not changed the assessment of the suitability of the site for development as a waste disposal facility. It is unlikely that further exploratory work or modelling will change the interpretation that the site is suitable for development as a regional waste disposal facility. Modern landfill design, construction and management will be employed to protect the minor aquifer system from contamination, while monitoring will be used to detect the unlikely failure of the multiple barrier system and allow timeous implementation of remedial actions. Consequently, no additional geohydrological work other than monitoring is required to support a decision regarding the development of the proposed Kalbaskraal site as a regional waste disposal facility outside of the implementation of long-term groundwater monitoring.
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7 CONCLUSIONS AND RECOMMENDATIONS
Additional geohydrological investigation at the proposed Kalbaskraal site included verifying hydrocensus data, conducting two geophysical traverses, drilling and testing four exploratory boreholes and compilation of a numerical model. While this additional work increased the quantified information about the site, the new data did not change earlier interpretations regarding the direction of groundwater flow, groundwater quality or the classification of the aquifer system. EC profiling of all the exploratory boreholes across the site revealed a 20 – 40 m thick layer of very poor quality groundwater overlying the fractured aquifer. The sub-parallel branch of the Colenso Fault mapped by Gresse was not detected using either the ERT or AMT geophysical methods, while a borehole drilled in the inferred position of the fault was low yielding and the drilling chips did not display any characteristics of a fault. However, the geophysics and drilling revealed a fracture zone further to the west. This fracturing may be the result of tight synclinal folding or faulting. Even though reasonable yields were obtained for the given geohydrological setting, the results do not warrant changing the classification of the aquifer from a minor aquifer system, as was previously assigned by Parsons & Associates (2006, 2012). In general, yields are moderate to low – with one or two exceptions. Testing in the area has shown fracture dewatering demands a conservative approach when defining sustainable pumping rates and that these have to be confirmed through monitoring. The upper parts of the aquifer system yield very poor quality groundwater. The results of numerical modelling showed that only boreholes to the west of the proposed waste site are at risk of being impacted. Modern engineering of landfills use multiple barrier systems to prevent groundwater being contaminated. In such instances no groundwater contamination will take place and no groundwater users will be at risk. If the multiple barrier system were to be breached, then it is predicted that the plume will travel at a rate of 10 – 15 m/a. After 130 years the plume will have migrated some 1 300 m from the waste pile. The numerical model also showed that the hydraulic properties of Colenso Fault are such that this structure will not influence the migration of contamination, if it were to occur. Similarly, current patterns of groundwater abstraction will also not significantly change the rate and movement of contamination. From a geohydrological perspective, the proposed Kalbaskraal site is considered suitable for development as a regional waste disposal facility. It is unlikely that further exploratory work or modelling will change this interpretation. The prevention of groundwater contamination will be realized by the design and construction of a multiple barrier system comprising a series of impermeable to very low permeability liners to prevent leachate infiltrating into the groundwater system. For modelling purposes it was accepted that the design presented in the 2012 EIA report would be used. It is recommended that the City of Cape Town establish a formal groundwater monitoring programme at the site. The key objective of this is to detect groundwater contamination at an early stage so that remedial actions can be implemented. Monitoring will also allow for the verification of the outcomes of modelling and definition of baseline conditions. Dr Roger Parsons Ph.D. (U.F.S.) Pr.Sci.Nat.
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REFERENCES
Adelana, S, Xu, Y and Vrbka, P (2010) A conceptual model for the development and management of the Cape Flats aquifer, South Africa; WaterSA, Vol.36 No. 4, pp 461 -474. Ball, J (2002) Identification of a Regional Landfill to Serve the City of Cape Town – Candidate Landfill Site Identification and Ranking Report – Second Draft Report. Prepared by Jarrod Ball and Associates in association with Africon. Bredenkamp, DB and Vandoolaeghe, MAC (1982) Die Ontginbare Grondwater Potensiaal van die Atlantisgebied; Technical Report Gh 3227, Directorate of Geohydrology, Department of Water Affairs. CCA Environmental (2006) Environmental Impact Assessment for a new regional landfill site to service the City of Cape Town: Final Environmental Impact Report; Report CMC/03/RWS/3, CCA Environmental, Cape Town. CCA Environmental (2012) Environmental Impact Assessment for a new regional landfill site to service the City of Cape Town: Supplementary Environmental Impact Report; CCA Environmental, Cape Town. Council for GeoScience (2007) Pebble bed modular reactor demonstration power plant (PBMR DPP) environmental management programme - Specialist study for environmental impact report - Geology and seismic hazard; Report 2007-0277, Council for GeoScience, Bellville. Department of Environmental Affairs (2013) Waste classification and management regulations; Government Gazette Vol. 578, No. 10008, Pretoria, 23 August 2013. Department of Water Affairs of Forestry (1998a) Waste Management Series – Minimum Requirements for Waste Disposal by Landfill - Second Edition; Department of Water Affairs and Forestry, Pretoria. Department of Water Affairs and Forestry (1998b) Waste Management Series – Minimum Requirements for Monitoring at Waste Management Facilities - Second Edition; Department of Water Affairs and Forestry, Pretoria. Department of Water Affairs and Forestry (2000) Policy and strategy for groundwater management in South Africa; Water quality management series - First edition, Department of Water Affairs and Forestry, Pretoria. Driscol, FG (1986) Groundwater and wells; Second edition, Johnson Screens, St Paul, Minnesota. Fleisher, JNE (1990) Atlantis Groundwater Management Programme – The Geohydrology of the Witzand Field; Report 2/90, Division of Water Technology, Groundwater Programme, Bellville. Gaucher, C, Sial, A, Halverson, G and Frimmel, H (eds.) (2009) Neoproterozoic-Cambrian Tectonics, Global Change and Evolution, Volume 16 - 1st Edition - A Focus on South Western Gondwana; Elsevier Science. Giroud, JP (1997) Equations for calculating the rate of liquid migration through composite
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
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Parsons & Associates 24 May 2017
liners due to geomembrane defects; Geosynthetics International, Vol. 4 Nos. 3-4, pp. 335-348. Henzen, MR (1973) Die herwinning, opberging en ontrekking van gesuiwerde rioolwater in die Kaapse skiereiland; Council for Scientific and Industrial Research, Cape Town. Imrie, S and Rosewarne, PN (2016) Preliminary groundwater model report for the proposed Kalbaskraal waste disposal site; Report No. 479224/2, SRK Consulting, Cape Town. Johnson, MR, Anhaeusser, CR and Thomas, RJ (2006) The Geology of South Africa; The Geological Society of South Africa and Council for Geoscience. Kisters, AFM, Belcher, RW, Scheepers, R, Rozendaal, A, Jordan, LS and Armstrong, RA (2002) Timing and kinematics of the Colenso Fault: the early Paleozoic shift from collisional to extensional tectonics in the Pan-African Saldania Belt, South Africa; S.A.J.Geol., vol. 105, no. 3, pp 257 – 270. Kruseman, GP and de Ridder, NA (1990) Analysis and evaluation of pumping test data; Second edition, ILRI publ. 47, International Institute for Land Reclamation and Improvement, The Netherlands. Lea, I (2017) Numerical groundwater flow and contaminant transport model for the Kalbaskraal waste disposal facility; Final report iLEH-PA KAL 02-17, Irene Lea Environmental & Hydrogeology, Dunnotar. Meyer, PS (2001) An Explanation of the 1:500 000 General Hydrogeological Map – Cape Town 3317, October 2000. Directorate: Geohydrology, Department of Water Affairs and Forestry, Pretoria. Murray, EC, Baker, K, Ravenscroft, P, Musekiwa, C and Dennis, R (2012) A groundwater planning toolkit for the Main Karoo Basin: Identifying and quantifying groundwater development options incorporating the concept of wellfield yields and aquifer firm yields; WRC Report No. 1763/1/11, Water Research Commission, Pretoria. Parsons, RP (1995) A South African aquifer system management classification; WRC Report No. 77/95, Water Research Commission, Pretoria. Parsons & Associates (2006) Environmental Impact Assessment for a new regional landfill site for the City of Cape Town – Specialist groundwater study; Final report 149/RWSP-F2 prepared for CCA Environmental (Pty) Ltd; Parsons & Associates, Somerset West. Parsons & Associates (2012) Environmental Impact Assessment for a new regional landfill site for the City of Cape Town – Specialist groundwater study – Addendum report; Final report 278/RWSP-F3 prepared for CCA Environmental (Pty) Ltd; Parsons & Associates, Pringle Bay. Parsons & Associates (2015) Dieprivier – historic and current status of groundwater use; Report 352/GOR-D1, Parsons & Associates, Pringle Bay. South African National Standard (2015) Drinking water, SANS 241:2015; Standards South Africa, Pretoria. SRK Consulting (1996) Riverlands / Chatsworth groundwater investigation; Report SIMA/hill 19 April 1996, SRK Consulting Engineers and Scientists, Cape Town.
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
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SRK Consulting (1997) Performance report – pump testing at Kalbaskraal; Report 231541 17 March 1997, SRK Consulting Engineers and Scientists, Cape Town. SRK Consulting (1998) Riverlands drilling and test pumping; Report 247799 March 1998, SRK Consulting Engineers and Scientists, Cape Town. Stapelberg, FDJ (2005) The engineering geology of Philadephia and environs, Western Cape, South Africa – Explanation Sheet 3318DA scale 1 : 50 000; Council for Geoscience, Pretoria. Theron, JN (1990) 1:250 000 Geological Series 3318 Cape Town; Geological Survey, Pretoria. Umvoto Africa (2009) Skaapkraal groundwater investigation and hydrocensus; Report 761/01/01/2009 31 July 2009, Umvoto Africa, Cape Town. van Tonder, G, Bardenhagen, I, Riemann, K, van Bosch, J, Dzanga, P and Xu, Y (2002) Manual on pumping test analysis in fractured rock aquifers; WRC Report No. 1116/1/02, Water Research Commission, Pretoria. Villaros, A (2006) The Cape Granite Suite: a short introduction; http://www.academic.sun.ac.za Wessels, WPJ and Greef, GJ (1980) ‘n Ondersoek na die optimale benutting van Eersterivierwater deur opberging in sandafsettings of ander methodes; Department of Civil Engineering, Stellenbosch University, Stellenbosch.
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FIGURES
Figure 1. Location of the proposed Kalbaskraal and Atlantis sites for the new regional landfill site for the City of Cape Town
Proposed
Kalbaskraal Site
N7 National
Road
AtlantisKalbaskraal
Philadelphia
Klipheuwel
Duynefontein
Melkbosstrand
km
2 640
Proposed
Atlantis Site
Site
Footprint Site
Footprint
Figure 2. Position of geophysical traverses undertaken at the proposed Kalbaskraal waste site (red outline)
m
9000 1 800
Figure 3. Map showing high resolution aeromagnetic data over the western two thirds of the proposed site (red outline) and the position of
the two geophysical traverses (yellow line). The inferred positions of faults interpreted by Prof. Stettler are indicated as black dashed lines,
which have been numbered for ease of reference.
Kal-1
1. Colenso Fault
2. Sub-parallel
branch of
Colenso fault
Kal-24
Granite
outcrop
3
km
1.50 3.0
Figure 4. Outcome of the ERT and AMT survey undertaken along Kal-1, Kalbaskraal
m
2000 400
Figure 5. Outcome of the ERT and AMT survey undertaken along Kal-2, Kalbaskraal
m
2000 400
Figure 6. Position of the additional exploratory boreholes in relation to the anomalies identified from the geophysical surveys
RWS-13
RWS-14
RWS-15
RWS-16
m
2000 400
Figure 7. EC profiles of the exploratory boreholes drilled at the proposed Kalbaskraal site
Figure 8. Monitored depth to groundwater at RWS-8a and BG00072
2004 2008 2012 2016
Time
0
100
200
300
400
500
600
EC [mS/m]
CT3061
CT3050
CT3012
SANS 241:2005 (-, -, 150, 370)
Electrical conductivity
Figure 9. Monitored EC levels at BG00072, RWS9 and BF2
BG00072
RWS-9
BF2
BF2
RWS09
BG00072
EC [mS/m] (10-1000)
pH (6-10)
Cl
SO4
T.Alk Na+K
Mg
Ca
Figure 10. Durov and Schoeller diagrams illustrating hydrochemical changes over time at BG00072, RWS9 and BF2
Figure 11. The position of boreholes at or adjacent to the proposed Kalbaskraal site. The unused boreholes are not labelled.
2 km radius
LEGEND
Exploratory borehole
Used borehole
DWS monitoring borehole
Borehole not used
EL1RWS-11
BG00073
BF2BN1
BN7
RWS-7BF1
RWS-10
DVI1
DVI3
DVI2
GL3GL1
GG1
GG3
BG00072
WV2 WV3
BH7
BH6KS1
MPS3MPS4
KE1
BP4
KE2
see insert
RWS-9
RWS-15
RWS-14
RWS-13
RWS-16
RWS-8aWV5
m
1 8000 3 600OPT3
OPT2
MRG1
G2N0535
RWS-9
WV5
Figure 12. Published geological map of the proposed Kalbaskraal site (Theron, 1990). The
position of the cross-section SW-NE presented in Figure 13 is illustrated with a black line
Boundary of proposed
site
Tygerberg
Formation
Moorreesburg
Formation
Darling
Pluton
Paardeberg
Pluton
Magrug
Formation
Populierbos
Formation
Springfontein
Formation
Klipheuwel
Group
Cape
Granite
Suite
Malmesbury
Group
LEGEND
km
1 320
SW
NE
Waste site
Colenso Fault
Granite
(Darling pluton)
Granite
(Paardeberg pluton)
Populierbos Fm
Magrug Fm
Moorreesburg Fm
Tygerberg
Fm
Thin sand cover
SW NE
Figure 13. Schematic geological cross-section of the proposed Kalbaskraal site
Figure 14. Drawdown induced by pumping RWS-14 at 12 L/s for a period of 72 hrs
Fracture flow
Fracture flow
Bilinear flow
Figure 15. A comparison of the yield of boreholes used for irrigation north of Kalbaskraal and those drilled into the Colenso Fault and in
and around the proposed Kalbaskraal site
Kalbaskraal
Klipheuwel
Centre pivot irrigation
22
7
15
30
Proportional circle scale
Borehole yield (L/s)km
30 6
110
90
70
50
30
m
500 150010000
Boundary of
proposed site
Groundwater
contours (mamsl)
LEGEND
Groundwater
flow direction
Boreholes
66m
89m
90m
89m
86m
85m
Figure 16. Recently acquired piezometric data (red) supports and confirms the interpreted groundwater elevation map presented by
Parsons & Associates (2006)
1 2
3
44
3
1 2
0 m
10 m
20 m
1 000 m500 m0 m
SW NE SW NE
NW SE
NW SE
Figure 17. Cross-sections showing the position of the piezometric surface in relation to ground level based on data measured at the site
Figure 18. Depth to groundwater level (mbgl) measured at the proposed Kalbaskraal site during the winter of 2010 when the piezometric
level was at or near its shallowest
m
7500 1 500
3.3
14.1
2.819.7
1.8
+0.3
11.8
9.213.2
m
500 150010000
Boundary of
proposed site
Boreholes
EC contour
(mS/m)
LEGEND
500
400
300
200
100
50
64
2
210mS/m
148mS/m
126mS/m
102mS/m
90mS/m
52mS/m
Figure 19. Recently acquired EC data (red) supports and confirms the interpreted EC contour map presented by Parsons & Associates
(2006). Note that measurements made during pumping were used to compile this map.
Value < 150
150 < Value < 370
Value > 370
EC (mS/m)
20%
40%
80%
20%
40%
60%
80%
20%
40%
60%
80%
20%
40%
60%
80%
60%
Figure 20. A regional perspective of the spatial distribution of EC in the vicinity of the proposed Kalbaskraal site. Consideration of the
central field of a Piper plot indicates that the more saline water has a stronger NaCl character
km
30 6
Waste site
Cole
nso F
ault
SW NE
Figure 21. Schematic representation of the conceptual geohydrological model
30 m
100 m
Weathered
Fractured
Recharge by rainfall
Groundwater
flow
Piezometric surface
Mosselbank River
10 m Sand
Figure 22. Conceptual design of a multiple barrier system proposed for the Kalbaskraal site (CCA Environmental, 2012).
Weathered aquifer – 30 yrs
Fractured aquifer – 130 yrsFractured aquifer – 30 yrs
Weathered aquifer – 130 yrs
Figure 23. Results of the modelling of the movement and growth of the contaminant
plume under Scenario 2 (after Lea, 2017)
Figure 24. A comparison of the area Parsons (2006) identified as potentially being impacted by the site footprint (green line) and that
delineated from the outcome of contaminant transport modelling (yellow line). Boreholes that are currently being used for water supply
are shown as red dots while unused boreholes are shown as white dots. Exploratory boreholes are indicated by green dots.
Footprint of
proposed waste pile
BN1
BN7
BF2
WV5
m
7500 1 500
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDICES
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDIX A
GEOPYSICS REPORT
AMT & DC Resistivity(ERT) Survey, Kalbaskraal.
Western Cape
January 2017
Prepared for:
Parsons & Associates
Pringle Bay South Africa
----------------------------------------------------------------------
J.J. van der Walt (GEC Consulting)
92 Rauch Avenue
Georgeville, 0184
South Africa
M de Klerk (Cape Geophysics)
P.O. Box 1240
Stanford
7210
South Africa
----------------------------------------------------------------------
Table of Contents
Page
1. Introduction 1
2. Objectives 2
3. Geo-electrical Survey Methods and Instrumentation 4
4. Results 4
5. Discussion of Results 7
Appendices
A ERT Imaging Method 8
B AMT 2D Method 10
C AMT Sounding Curves 14
Page 1
1. Introduction
Dr. R. Parsons of Parsons & Associates, Pringle Bay, requested Cape Geophysics, Stanford and GEC (Geo Electrical Consulting), Pretoria to conduct two geophysics traverses across
inferred splay/s of the Colenso fault with the Magneto Telluric (AMT) as well as the DC
Resistivity (ERT) method, on the Kalbaskraal site approximately 22km south of Malmesbury
(Figure-1).
Figure 1: Locality map
The geology map (Figure 2.) indicates the inferred position of the primary Colenso fault as
running along and parallel to the eastern boundary of the survey site with a parallel splay (also inferred) towards the centre of the survey site crossing its northern boundary.
Figure 2: 1:250 000 Geological Map (3318 Cape Town)
Page 2
This report documents the AMT and ERT data acquired during January 2017.
Results from previous ERT, ground magnetics and electromagnetic surveys, conducted on
this specific site, are presented in the Google Earth(Colenso Fault 2017.kmz) file that
accompanies this report.
2. Objectives
The objective of this exercise was to use modern, high resolution geophysics in order to
establish the occurrence and position of the Colenso fault and its splays within the boundaries
of the indicated survey site.
The structures indicated on the government geology maps as “inferred” were historically
interpreted from aerial photography and regional (low resolution) aero magnetic data. As a
first step, in order to optimize the placement of survey traverses in the field, data from a more recent (high resolution) aeromagnetic survey across this specific site was sourced from Prof.
EH Stettler. This data was processed using the proprietary “tilt angle” algorithm and Prof.
Stettler’s interpretation (pers comm.) of the structure positions are indicated in Figures 3 & 4.
Figure 3: Total Field Magnetic image with interpreted structures / faults.
Recent high resolution
magnetic data set Older low resolution data set
Page 3
Figure 4: Aero Magnetic (tilt angle) image with interpreted faults.
Figure 4. presents the processed magnetic data image overlayed onto the topographical sheet
indicating the survey site boundaries and the survey traverse positions for the geo-electrical
investigation. The inferred fault positions were overlaid from the mapped geology and then extended and added to. Prof. Stettlers interpretation adds a SE continuation to the centre
splay and he also postulates faulting along the mapped geological contacts to the south west.
Note that the “centre” splay coincides with the geological contact between the Populiersbos
Formation (Cpo) to the west and the Magrug Formation (Cm) to the east, although this is
almost entirely blanketed by quartenary (Springfontein Formation) material within the
boundaries of the survey site. The indicated fault along the western boundary appears to be within the Populiersbos Formation and is also blanketed by quarternary material.
It is important to note that the aeromagnetic data is only used as an indicator for possible structures and that “ground truthing” is accomplished using the electrical methods. The “tilt
angle” image is derived through application of the following steps:
1. The total field magnetic data is reduced to pole and the analytical signal is calculated.
The effect of this is to change the dual pole nature of the magnetic anomalies into a
single positive anomaly plotting on top of the causative body.
2. The first vertical derivative of the analytical signal is calculated in order to narrow the
anomalies down to a more definitive size and shape.
3. The “tilt angle” is calculated using the formula: Tilt angle= Tan^-1 (Z 1 st
der/(SQRT(X 1st der^2+Y 1st der^2)).
4. The resulting positive “tilt angles” will now theoretically plot on top of the rock units that display a magnetic susceptibility contrast with its surrounding host.
Page 4
3. Geo-electrical Survey Methods and Instrumentation
For the geo-electrical surveys, the GEOMETRICS “STRATAGEM” EH 4 AMT instrument
and the ABEM Terrameter resistivity imaging system were used. Both systems measure bulk
resistivity from the surface as apparent resistivity (Rho) vs frequency (AMT) and apparent
resistivity vs a geometric factor (ERT) which is then converted to true resistivity vs depth during the interpretation process. The AMT and ERT methods are briefly discussed in
Appendices A&B.
4. Results
The calculated images for the completed ERT and AT traverses are presented in the figures
below. Note that position “0m” on the AMT models coincides with posion 100m on the ERT
models. The ERT station positions are used as reference for the discussion below as well as
for elected drill site positions.
Traverse 1
Inferred aero magnetic fault “1” (position ~ 190m): No distict electrical anomaly is observed
on either the ERT or AMT models.
Inferrred aero magnetic fault “2” (position 320m): Prominent trough-like anomaly (zone of
lower ground resistivities) visible 70m to the north-east on the AMT model and is interpreted
as a fault zone that tapers out with depth. The ERT model shows a marked change in lateral
ground resistivities (step displacement) at position 390m which is also 70m to the north-east of position 390m. This step displacement can be interpreted as a geological fault.
Inferred aero magnetic fault “3” (position 770m): The ERT model shows only a small near surface anomaly of low ground resistivity below position 770 - 790m.
Note:
There is a railway track towards the east of the survey site and the AMT sensors started to register the electrical noise from this source during attempted measurements further along this
traverse.
Traverse 2
Inferred aero magnetic fault “1” (position 190m): A thicker conductive upper layer (Populierbos Formation) is observed and the AMT model shows a distinct lower resistive
zone which can be interpreted as confirmation of this structure, tapering out and tightening up
with depth.
Inferered aero magnetic fault “2” (position 280m): Weak ERT and AMT corresponding
anomaly observed just to the north-east of the indicated structure position. The AMT image
indicates that this structure rapidly tapers out and becomes tight (resistive) at depth.
Inferred aero magnetic fault “3” (position 760m): Very weak ERT anomaly observed at this
position. The AMT traverse did not extend over this position.
A small but distinct trough shaped anomaly is present below position 490m on the AMT
model. This zone of lower ground resistivities could have been caused by preferential
weathering around a geological fault.
Page 5
Figure 5: Traverse-1, ERT & AMT models.
Page 6
Figure 6: Traverse-2, ERT & AMT models.
Page 7
5. Discussion of results The models depict a two layer case with the upper conductive layer associated with shales and
mudstone of the Populierbos Formation overlaying the more resistive conglomerate, grit and
sandstone of the Magrug Formation. On the electrical images, geological faults are associated with
trough-like feaures of lower resistivity (more conductive) in the more resistive bedrock or vertical displacement in the bedrock in the form of a step.
The geo-electrical images appear to confirm the occurrence of the structures as indiated by the aeromagnetic image. These structures however appear to be very much contained to the near surface
and the geo-electrical profile becomes resistive with depth. The indicated anomalies will need to be
tested with drilling to determine the extent of the indicated tapering out of these structures .
Proposed drill sites (indicated on the ERT models): Traverse-1: Positions 390m and 780m
Traverse-2: Positions 150m and 490m
Jan J. van der Walt (Pr.Sci.Nat)
Geophysicist
M de Klerk (Pr.Sci.Nat)
Geophysicist
February 2017
Page 8
Appendix A
ERT imaging method
DC resistivity techniques, sometimes referred to as electrical resistivity, electrical resistivity
imaging/tomography (ERT) or vertical electric sounding are used to measure earth resistivity by driving a direct current (DC) signal into the ground and measuring the resultant potentials (voltages)
created in the earth. The electrical properties of the sub-surface are derived from this data.
The electrical resistivity varies between different geological materials, depends mainly on variations
in water content and dissolved ions in the groundwater. Resistivity investigations thus are used to
identify zones with different electrical properties, which can then be referred to different geological strata. Resistivity is also called specific resistance, which is the inverse of conductivity or specific
conductance. The most common mineral-forming soils and rocks have very high resistivity in a dry
condition; therefore, the resistivity of soils and rocks is normally a function of the amount and quality of water in pore spaces and fractures, as well as the degree of tropical weathering of the formation.
Consequently, the variation may be more limited to a confined geological area and variations in
resistivity, within a certain soil or rock type, will reflect variations in physical properties. For example, the lowest resistivities encountered for sandstone and limestone imply that the pore spaces
in the rock are saturated with water, whereas the highest values represent strongly consolidated
sedimentary rock or dry rock above the groundwater surface. Sand, gravel and sedimentary rock may
also have very low resistivities, provided that the pore spaces are saturated with saline water.
Fresh crystalline rock is highly resistive, despite the fact that it may contain certain conductive ore
minerals; however, weathering commonly produces highly conductive clay-rich saprolite. Variation in characteristics within one geological material type necessitates calibration of resistivity data against
geological documentation, from, for example, surface mapping, test pit exposures or drilling.
However, this applies to all geophysical methods.
The degree of saturation, of course, will affect the resistivity; the resistivity above the groundwater
level will be higher than that below this level, i.e. if the material is similar. Consequently, this method
can be used to determine the depth to the water table, where a distinct water table exists. However, if the content of fine-grained material is significant, the water content above the groundwater surface,
held by hygroscopic and capillary forces, may be large enough to dominate the electrical behaviour of
the material. The resistivity of the pore water is determined by concentrations of ions in solution, the type of ions and temperature. The presence of clay minerals strongly affects the resistivity of
sediments and weathered rock. The clay minerals may be regarded as electrically conductive particles,
which can absorb and release ions and water molecules on its surface through an ion exchange
process.
Page 9
Field survey method.
An Abem SAS 1000 Terrameter and ES 10-64 switching unit was used in the field survey. Four
multicore cables and stainless steel pegs were used with the “roll-along” survey method.
Measurement of the resistivity of the ground is carried out by transmitting a controlled current (I) between two electrodes inserted in the ground, while measuring the potential (V) between two other
electrodes. Direct current (DC) or a very low frequency alternating current is used; the method is
often called DC-resistivity. The resistance (R) is calculated using Ohm’s law.
Two ERT traverses were conducted during January 2017 using the Schlumberger measuring protocol,
at an electrode spacing of 10 meters. Maximum investigation depth is approximately 80m. Data (measured apparent resistivities) was of good quality and hardly any filtering of the raw data was
necessary. Profile coordinates were obtained with a hand-held GPS.
Data Reduction.
The RES2Dinv (GEOTOMO) version 3.52-inversion program was used to invert the measured apparent resistivities. The inversion routine used by the program is based on the smoothness-
constrained least-squares method (de Groot-Hedlin and Constable 1990, Sasaki 1992). One advantage
of the method is that the damping factor and flatness filters can be adjusted to suit different types of data. The 2-D model used by this program divides the subsurface into a number of rectangular blocks
that will produce an apparent resistivity pseudo section that agrees with the actual measurements. A
forward modelling subroutine is used to calculate the apparent resistivity values, and a non-linear
least-squares optimisation technique is used for the inversion routine. The optimisation method basically tries to reduce the difference between the calculated and measured apparent resistivity
values by adjusting the resistivities of the model blocks. A measure of this difference is given by the
root-mean-squared (RMS) error. However the model with the lowest RMS error can sometimes show large and unrealistic variations in the model resistivity values and might not always be the “best”
model from a geological perspective. In general the most prudent approach is to choose the model at
the iteration after the RMS error does not change significantly.
It is important to note that the inversion process that translates raw resistivity data into a resistivity
cross section is non-unique. The inversion program chooses the smoothest, least heterogeneous,
solution. This solves the mathematical problem of non-uniqueness, but produces a slightly blurred image of the actual geology. Abrupt transitions between layers become gradational transitions in the
resistivity section. Second, the data are collected along a line and inverted assuming two-dimensional
geologic structure. This assumption is reasonable for a layered earth or for dipping layers if the data are collected perpendicular to strike.
A detailed description of the different variations of the smoothness-constrained least-squares method
can be found in the free tutorial notes by Loke (2001), www.geoelectrical.com.
Page 10
Appendix B
AMT 2D Method
The magneto-telluric method is defined through the relationships between magnetic micro-pulsations, telluric currents and conductivity structure. These relationships were explained independently and
almost simultaneously by Professors L. Cagniard in France (1953) and A. Tikhonof in the USSR
(1950).
Traditionally, the MT method was used to deduct the deep structure of the earth (> 1 km) through the
measurement of both orthogonal magnetic and electric fields at surface over a wide but low frequency range (0.001 – 100 Hz) to derive soundings of apparent resistivity vs frequency and interpreted as true
resistivity vs depth. The source field for these measurements is provided by magneto-telluric pulses,
which are generated naturally in the ionosphere or magnetosphere. As MT measurements were
carried out at higher frequencies, it became increasingly desirable to augment natural source fields with applied fields – above 1 kHz and particularly around the 2 kHz region where the natural field
signals are weak or absent. Goldstein and Strangway (1975) summarized the theory for a grounded
electric dipole on a layered earth and presented field and model results to extend their method, now called the controlled source AMT or CSAMT method.
The central problem of the MT technique is the fact that the electric fields on the surface of the earth vary directly with near-surface resistivity (and topography) which means that the measurement of
these electric fields are subject to spatial aliasing if they are sampled with finite length dipoles at
separate sites. This “static distortion” or “shift” are often observed as quite a dramatic shift in the
apparent resistivity curves of stations quite close together. The correct solution to a spatial aliasing problem is to sample the data adequately following the established Nyquist criterion. In the case of
magneto-tellurics, this can be achieved by sampling the electric field continuously by means of
profiles of contiguous dipoles. This idea was introduced by F.X. Bostick (1986) and a more detailed description is presented by Torres-Verdin and Bostick (1992). Once the data have been adequately
sampled, near-surface distortions can be recognized and more importantly, they can be reduced by
means of spatial filtering. This means that a filter can now be designed whose width varies inversely
with frequency. At high frequencies, the filter is narrow and near-surface features are recovered. At lower frequencies, the filter is widened to average out the shallow features and reveal the undistorted
response of deeper targets.
Field Survey Method - Instrumentation and Measurement Procedure
The Stratagem EH4 system by Geometrics Inc. utilizes a portable transmitter (2 vertical loops) for frequencies in the band from 1000 Hz to 100 kHz. To be in the EM far field (plane wave assumption)
for this configuration requires a relatively small source-receiver separation. The field survey entails a
series of soundings along profiles at fixed, regular station intervals (Figure 3.). Normally a “+” shape
dipole set-up is used where the Ey dipole and Hy magnetic receiver are set out perpendicular to the traverse and the whole array is moved from station to station along the traverse. The transmitter
(when used) is moved periodically and placed in such a position that the inducing field satisfies the
plane wave (EM far field) requirement. This transmitter - receiver distance can be calculated by the operator in the field and is normally about three “skin depths” (at 1 kHz), where a skin depth is the
depth at which the inducing field has attenuated to 37 % of its original strength and is calculated from
the formula:
Page 11
where:
p = Apparent Resistivity as measured in Ohm-m at
= frequency in Hz
Stratagem MT sounding array
Note: Ex – Electric Dipole along traverse and perpendicular to geological strike.
Hy – Magnetic Coil parallel to geological strike.
Ex and Hy form spectral pair for Transverse Magnetic (TM) mode of survey. The Ey – Hx pair is referred to as the TE or Transverse Electric mode.
Ey
Ey
Ey
Ey
Ex
Ex
Ex
Transmitter
HyHx
HyHx
Stratagem uses 2 Magnetic Coils and 2 Electrical dipolesto measure the E and H components of the secondary H field(Natural Field Signal from 10 Hz - 1 kHz provides deeper info)
Controlled SourceTransmitter placed 3 skindepths awayprovides signal in the 1 kHz - 100 kHz band(near surface resolution)
500f
Page 12
Example of data acquisition screen
Stratagem MT sounding data plot (xy, yx).
Page 13
The sounding plot as illustrated is derived from the spectral data and is a combination of Apparent
resistivity (Ohm-m), impedance phase (deg) and data coherency plotted as a function of frequency (and stored in the impedance or Z** files in the data archive). The right hand plot shows true
resistivity versus depth based on the results of the “Bostick” transformation.
The power spectra data (X** files) are calculated from the time series (Y**) as illustrated in Figure 4. These time series are recorded over discrete time windows of 300 ms each (single segment)for the
low frequency section of the sounding and 21 ms for the high frequency section.
A particular relationship is expected between the apparent resistivity curve and the impedance phase
curve for valid sounding results. This relationship applies to either of the directional measurement
modes (TE and TM ) and is given by:
where Φ is impedance phase, ρ is apparent resistivity and T is period. This means that one should observe a dip in phase response for an increase in apparent resistivity as the period increases and
conversely, an increase in the phase response should accompany a decrease in apparent resistivity as
period increases. Slight departures from this relationship are expected because of normal low-level
scatter in the data but when an entire portion of the curve fails to obey it, the probable cause is that bias was introduced by noise sources.
Theoretically, the apparent resistivity and impedance phase curves should also be smooth. As a rule, if the impedance phase is excessively high, the noise source is inductive. Similarly, noise signals that
depress the phase below its expected value are due to grounded electrical sources or elevated
electrode noise arising from high contact resistance in those portions of the sounding where the signal strength is weak – i.e the “dead zone” around 2 kHz and the very high frequency end of the spectrum.
Data Processing Standard data processing is done on the IMAGEM software package from EMI Inc. For each
sounding, the individual time segments can be viewed and either added to the total “stack” or rejected.
Excessively noisy data are automatically rejected during the acquisition phase where too many saturations occur. The manual stacking of time segments can be a time consuming process but is
essential for noisy data sets (where longer stacking times are also required) and can radically improve
the noise characteristics of a particular sounding. After time series editing, frequencies which are still
noisy or do not obey the phase / apparent resistivity relationship as discussed above can be masked or “marked as dead” and will not be used in the 2D spatial filtering process.
The data is imported into the IP2Iwin software to test the internal consistency of the relevant Rho
and phase angle pairs for each sounding and to calculate the closest 1D curve fit for each station
along the measured profile. The 1D model curves are imported into the MT2D software, where the Occam inversions are calculated and "stitched" together to produce 2D resistivity images as presented
in this report. The Occam inversion routine provides, in general, the simplest solution in a geo-
electrical sense that fits the data set. This is most often also the most correct solution and provides in
general, a significantly higher resolution image than the original spatially filtered model.
Appendix C
AMT Sounding Curves
41
(log )
(log )T
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDIX B
BOREHOLE LOGS
Project No. 379/RWSP Locality Kalbaskraal - Bottlefontein
Client City of Cape Town Latitude
Contractor Steyns Drilling Longitude
Driller Johan Collar elevation (mamsl)
Drilling Method Air percussion Borehole depth (m)
Logged by Roger Parsons Groundwater level (mbc)
Date Completed 17/03/2017 Blow yield (L/s)
Electrical conductivity (mS/m)
WATER STRIKES CASING & CONSTRUCTION
1 2 3 4 5 6 7 8
Lockable cap embedded in concrete slab
0 - Bentotite sanitary seal - 95
SHALE: light brown, highly weathered, soft
5 - SHALE: light brown, highly weathered, clay-like - 90
10 - 165mm steel casing - 85
SHALE: reddish brown, highly weathered, sand-like
15 - - 80
20 - - 75
25 - SHALE: maroon, highly weathered, powder-like - 70
30 - - 65
wet
35 - - 60
40 - - 55
45 - - 50
0.8 L/s
DEPTH
(m)
RWS-13
DIAMETER
200 m
m
2.5
PENETRATION RATE
(m/min.)
165 m
m
ELEVATION
(mamsl)
LITHOLOGY
33.63973
90
8.84
100.0
18.66564
95
50 - - 45
SILTSTONE: maroon to blue grey (large chips)
55 - - 40
Open borehole construction
60 - - 35
65 - - 30
70 - - 25
SHALE: maroon with calcite speckles
75 - - 20
80 - - 15
2.5 L/s
85 - SHALE: maroon - 10
90 - - 5
95 - - 0
100 - - -5
Comments
Project No. 379/RWSP Locality Kalbaskraal - Bottlefontein
Client City of Cape Town Latitude
Contractor Steyns Drilling Longitude
Driller Johan Collar elevation (mamsl)
Drilling Method Air percussion Borehole depth (m)
Logged by Roger Parsons Groundwater level (mbc)
Date Completed 19/03/2017 Blow yield (L/s)
Electrical conductivity (mS/m)
WATER STRIKES CASING & CONSTRUCTION
1 2 3 4 5 6 7 8
Lockable cap embedded in concrete slab
0 - Bentotite sanitary seal - 99
SAND: light grey, medium to fine grained
5 - - 94
10 - 165mm steel casing - 89
SAND: orange-red, medium to fine grained
15 - - 84
20 - - 79
SAND: fleshy-brown, medium to fine grained
25 - - 74
30 - - 69
35 - - 64
SILTSTONE: blue-grey, powdery
40 - - 59
0.3 L/s
45 - - 54
ELEVATION
(mamsl)
LITHOLOGY
33.63807
102
9.52
97.0
18.66564
99
DEPTH
(m)
RWS-14
DIAMETER
200 m
m
5.6
PENETRATION RATE
(m/min.)
50 - 4.2 L/s - 49
55 - - 44
Open borehole construction
SILTSTONE: blue-grey with maroon tinge
60 - - 39
5.6 L/s
65 - - 34
70 - - 29
75 - - 24
80 - - 19
SHALE: maroon with light calcite speckle in places
85 - - 14
90 - - 9
95 - - 4
100 - - -1
Comments
165 m
m
Project No. 379/RWSP Locality Kalbaskraal - Bottlefontein
Client City of Cape Town Latitude
Contractor Steyns Drilling Longitude
Driller Johan Collar elevation (mamsl)
Drilling Method Air percussion Borehole depth (m)
Logged by Roger Parsons Groundwater level (mbc)
Date Completed 18/03/2017 Blow yield (L/s)
Electrical conductivity (mS/m)
WATER STRIKES CASING & CONSTRUCTION
1 2 3 4 5 6 7 8
Lockable cap embedded in concrete slab
0 - Bentotite sanitary seal - 85
SHALE: light brown, highly weathered, soft, clayey
5 - 165mm steel casing - 80
SHALE: light grey-brown, highly weathered
SHALE: whitish grey, powder-like clay
10 - - 75
15 - - 70
165mm steel casing - perforated
20 - wet - 65
25 - - 60
30 - - 55
35 - - 50
4.2 L/s
40 - - 45165 m
m
ELEVATION
(mamsl)
LITHOLOGY
33.63996
50
artesian
90.0
18.66266
85
DEPTH
(m)
RWS-15
DIAMETER
200 m
m
10.0
PENETRATION RATE
(m/min.)
45 - - 40
50 - - 35
55 - - 30
SHALE: maroon with prominent calcite speckles Open borehole construction
60 - - 25
65 - - 20
10 L/s
70 - - 15
75 - - 10
80 - - 5
85 - - 0
90 - - -5
95 - - -10
100 - - -15
Comments
Project No. 379/RWSP Locality Kalbaskraal - Bottlefontein
Client City of Cape Town Latitude
Contractor Steyns Drilling Longitude
Driller Johan Collar elevation (mamsl)
Drilling Method Air percussion Borehole depth (m)
Logged by Roger Parsons Groundwater level (mbc)
Date Completed 20/03/2017 Blow yield (L/s)
Electrical conductivity (mS/m)
WATER STRIKES CASING & CONSTRUCTION
1 2 3 4 5 6 7 8
Lockable cap embedded in concrete slab
0 - Bentotite sanitary seal - 103
SAND: flesh coloured, fine grained
5 - - 98
CALCRETE: light grey-brown, softish
10 - 165mm steel casing - 93
SAND: red, fine grained
15 - - 88
SAND: rusty brown, fine grained
20 - - 83
25 - - 78
SAND: orange red, fine grained
30 - - 73
35 - - 68
SILTSTONE: blue grey with maroon tinge, highly weathered, very soft
0.8 L/s
40 - - 63
45 - - 58
50 - - 53
165 m
m
ELEVATION
(mamsl)
LITHOLOGY
33.63786
126
13.14
100.0
18.66937
103
DEPTH
(m)
RWS-16
DIAMETER
200 m
m
0.8
PENETRATION RATE
(m/min.)
55 - - 48
SILTSTONE: blue grey Open borehole construction
60 - - 43
65 - - 38
70 - - 33
75 - - 28
80 - - 23
85 - - 18
SHALE: maroon, soft (no calcite speckles)
90 - - 13
95 - - 8
100 - - 3
Comments
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDIX C
PUMPING TEST GRAPHS
RWS-13
Q = 5.4 L/s
RWS-14
RWS-15
RWS-16
Q = 1.0 L/s
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDIX D
INTERPRETED HYDRAULIC PARAMETERS
T K S Qrec Site Area Ref Comments
(m2/d) m/d) (L/s)
K F 97.7 0.000029 RWS-14 Kalbaskraal site P&A (2017) obs - pumping RWS-13; early time
K F 48.6 0.000083 RWS-14 Kalbaskraal site P&A (2017) obs - pumping RWS-13; middle time
K F 146.0 0.000101 RWS-15 Kalbaskraal site P&A (2017) obs -pumping RWS-14, middle time
K F 100 0.000250 RWS-15 Kalbaskraal site P&A (2017) obs - pumping RWS-13; middle time
K F 45 RWS-13 Kalbaskraal site P&A (2017) middle time
K F 80.0 RWS-15 Kalbaskraal site P&A (2017) early time
K F 95.0 RWS-15 Kalbaskraal site P&A (2017) recovery
K F 108.0 RWS-14 Kalbaskraal site P&A (2017) early time
K F 136 RWS-13 Kalbaskraal site P&A (2017) recovery
Harmean 82.2 0.000066
n 9 4
K B 57.9 0.000038 RWS-13 Kalbaskraal site P&A (2017) obs -pumping RWS-14, late time
K B 63.8 0.000051 RWS-13 Kalbaskraal site P&A (2017) obs - pumping RWS-14, early time
K B 38.7 0.000097 RWS-15 Kalbaskraal site P&A (2017) obs - pumping RWS-14, late time
K B 31.4 0.000136 RWS-14 Kalbaskraal site P&A (2017) obs - pumping RWS-15, late time
K B 25.8 0.000196 RWS-13 Kalbaskraal site P&A (2017) obs - pumping RWS-15, late time
K B 23.0 0.000227 RWS-13 Kalbaskraal site P&A (2017) obs - pumping RWS-15, late time
K B 33.5 0.000300 RWS-15 Kalbaskraal site P&A (2017) obs - pumping RWS-13, late time
K B 34.5 RWS-15 Kalbaskraal site P&A (2017) late time
K B 45.0 RWS-14 Kalbaskraal site P&A (2017) late time
K B 63.0 RWS-14 Kalbaskraal site P&A (2017) middle time
Harmean 37.1 0.000091
n 10 7
K M 0.6 0.4 RWS-16 Kalbaskraal site P&A (2017) late time
K M 2.6 RWS-16 Kalbaskraal site P&A (2017) recovery
K M 1.2 RWS-16 Kalbaskraal site P&A (2017) recovery
K M 3.8 RWS-16 Kalbaskraal site P&A (2017) recovery
K M 1.0 RWS-16 Kalbaskraal site P&A (2017) middle time
K M 4.6 RWS-16 Kalbaskraal site P&A (2017) early time
K M 5.8 RWS-16 Kalbaskraal site P&A (2017) middle time
K M 7.2 RWS-16 Kalbaskraal site P&A (2017) late time
K M 8.4 RWS-15 Kalbaskraal site P&A (2017) middle time
K M 20.0 RWS-15 Kalbaskraal site P&A (2017) recovery
K M 22.7 0.0002387 RWS-13 Kalbaskraal site P&A (2017) obs - pumping RWS-14, medium
K M 26 RWS-13 Kalbaskraal site P&A (2017) late time
K M 32.8 RWS-13 Kalbaskraal site P&A (2017) recovery
Harmean 2.7 0.000239
n 13 1
K W 0.007 RWS-07 Kalbaskraal site P&A (2006) slug test
K W 0.026 RWS-11 Kalbaskraal site P&A (2006) slug test
K W 9.5 0.31667 2.5 RWS-10 Kalbaskraal site P&A (2006) middle time
K W 0.42 RWS-08a Kalbaskraal site P&A (2006) slug test
K W 9.65 0.56 RWS-09 Kalbaskraal site P&A (2006) middle time
K W 4.5 RWS-09 Kalbaskraal site P&A (2006) early time
K W 5.7 0.7 RWS-09 Kalbaskraal site P&A (2006) late time
K W 16.7 RWS-10 Kalbaskraal site P&A (2006) late time
K W 92 4.0 RWS-13 Kalbaskraal site P&A (2017) early time
K W 98 RWS-10 Kalbaskraal site P&A (2006) early time
Harmean 10.2 0.02651
n 7 5
M F 7.0 SRK1 Riverlands SRK (1996) Colenso fault?
M F 9.3 SRK1 Riverlands SRK (1996) Colenso fault?
M F 20.6 SRK2 Riverlands SRK (1996) Colenso fault?
Harmean 10.0
n 3
M M 4.8 SRK1 Riverlands SRK (1996)
M M 2.0 SRK1 Riverlands SRK (1996)
M M 10.9 SRK2 Riverlands SRK (1996)
M M 2.0 0.025 SRK3 Riverlands SRK (1998)
Harmean 3.1 0.025
n 4 1
M W 0.016 RWS-04 Atlantis site P&A (2006) slug test
M W 0.039 WWS-2a Atlantis site P&A (2006) slug test
M W 0.16 0.055 RWS-01 Atlantis site P&A (2006) slug test
M W 0.69 0.192 RWS-03 Atlantis site P&A (2006) slug test
Harmean 0.3 0.03586
n 2 4
Code
Fault 20 WV5 Kalbaskraal site P&A (2012) Colenso fault - barrier boundary, late time
Fault 34 WV5 Kalbaskraal site P&A (2012) Colenso fault, early time
Explanation
K Klipheuwel Group
M Malmesbury Group
W Weathered
F Fracture flow
B Bilinear flow
M Maxtrix flow
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDIX E
HYDROCHEMISTRY DATA
www.bemlab.co.za
Part of
16 Van der Berg Crescent Gant’s Centre Strand
Tel. (021) 853-1490 Fax (021) 853-1423 E-Mail [email protected]
P O Box 684 Somerset Mall, 7137
Vat Reg. Nr. 4200161414
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CERTIFICATE OF ANALYSES Report Nr.: WT004451.DOC
Dr. Roger Parsons Date received: 24-03-2017
Parsons & Associates P.O. Box 151 Pringle Bay 7129 Sampled by client
Water Analyses Report Origin Lab. pH EC @ 25°C Na K Ca Mg Fe Cl SO4 Mn P NH4-N NO3-N Alkalinity Date Temperature *PO4
Nr. @ 25°C mS/m mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l Sampled at reception (°C) mg/l
RWS- 15- 63M 4451 6.8 57.7 78.3 2.8 12.6 10.4 1.1 146.0 12 0.24 0.01 <0.28 <0.36 82.00 18/03/2017 22.3 0.03 RWS- 14- 52M 4452 6.5 105.3 127.5 10.2 41.7 20.3 1.3 292.0 24 0.69 0.07 0.74 <0.36 109.00 19/03/2017 22.0 0.21 RWS- 13- F 4453 7.2 90.7 103.1 3.9 28.0 18.7 2.8 262.0 20 0.35 0.08 1.11 <0.36 91.00 20/03/2017 22.1 0.24 RWS- 16- 36M 4454 7.6 149.9 202.7 25.1 38.7 26.3 1.0 400.0 33 0.24 0.05 0.92 <0.36 103.00 20/03/2017 22.2 0.15 RWS- 15- 25M 4455 6.6 74.5 116.3 5.3 10.1 16.4 2.1 202.0 18 0.25 0.09 33.72 <0.36 85.00 18/03/2017 22.4 0.28 RWS- 14- 72M 4456 7.2 102.0 135.0 4.5 39.3 20.6 2.3 274.0 25 0.54 0.02 0.47 <0.36 112.00 19/03/2017 21.7 0.06
Origin Lab. Date Nr. Analysed
RWS- 15- 63M 4451 27/03/2017 RWS- 14- 52M 4452 27/03/2017 RWS- 13- F 4453 27/03/2017 RWS- 16- 36M 4454 27/03/2017 RWS- 15- 25M 4455 27/03/2017 RWS- 14- 72M 4456 27/03/2017
* = Not SANAS Accredited REFERENCE NO: 379/ RWSV Statement: The reported results may be applied only to samples received. Any recommendations included with this report are based on the assumption that the samples were representative of the source from which they were taken.
Notes: To ensure sample integrity, samples are stored only for seven days after release of the report. Thereafter it is disposed of and a fresh sample will be required if additional analyses are requested. Results marked with "Not SANAS Accredited" in this report are not included in the SANAS Schedule of Accreditation for this laboratory. These results relate to the items tested.
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This test report shall not be reproduced except in full, without written approval of the laboratory. Refer to website for uncertainty of measurement and referenced methods. Sample condition: Samples received in good condition.
Dr. Pieter Raath Sandisiwe Mbula 04-04-2017 General Manager Technical Signatory(Water chemistry) Date reported
—————END OF REPORT—————
www.bemlab.co.za
Part of
16 Van der Berg Crescent Gant’s Centre Strand
Tel. (021) 853-1490 Fax (021) 853-1423 E-Mail [email protected]
P O Box 684 Somerset Mall, 7137
Vat Reg. Nr. 4200161414
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CERTIFICATE OF ANALYSES Report Nr.: WT005280.DOC
Dr. Roger Parsons Date received: 06-04-2017
Parsons & Associates P.O. Box 151 Pringle Bay 7129 Sampled by client
Water Analyses Report Origin Lab. pH EC @ 25°C Na K Ca Mg Fe Cl SO4 Mn P NH4-N NO3-N Alkalinity Date Temperature *PO4
Nr. @ 25°C mS/m mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l mg/l Sampled at reception (°C) mg/l
RWS- 13 5280 7.0 88.6 83.2 3.5 32.3 15.7 0.3 251.0 17 0.24 <0.01 <0.28 <0.36 101.00 21/03/2017 21.9 0.03 RWS- 13 5281 7.0 84.8 78.9 3.3 31.2 15.0 0.3 221.0 16 0.24 <0.01 <0.28 <0.36 101.00 27/03/2017 21.7 0.03 RWS- 14 5282 6.5 96.4 97.9 3.4 22.7 17.3 5.1 295.0 23 0.41 <0.01 <0.28 <0.36 72.00 06/04/2017 23.0 0.00 RWS- 15 5283 6.5 52.5 58.7 2.1 9.4 8.2 1.1 151.0 9 0.25 0.05 <0.28 <0.36 78.00 31/03/2017 22.1 0.15 RWS- 15 5284 6.5 57.1 63.0 2.2 10.6 9.3 2.0 153.0 9 0.28 0.05 <0.28 <0.36 79.00 04/04/2017 21.9 0.15 RWS- 16 5285 6.2 152.1 162.8 6.8 32.3 29.3 0.2 460.0 33 0.31 <0.01 <0.28 <0.36 50.00 28/03/2017 21.8 0.00 RWS- 16 5286 6.3 127.3 136.6 5.9 26.5 23.6 0.1 350.0 26 0.27 0.02 <0.28 <0.36 70.00 30/03/2017 22.5 0.06
Origin Lab. Date Nr. Analysed
RWS- 13 5280 10/04/2017 RWS- 13 5281 10/04/2017 RWS- 14 5282 10/04/2017 RWS- 15 5283 10/04/2017 RWS- 15 5284 10/04/2017 RWS- 16 5285 10/04/2017 RWS- 16 5286 10/04/2017
* = Not SANAS Accredited REFERENCE NO: 379/ RWSP Statement: The reported results may be applied only to samples received. Any recommendations included with this report are based on the assumption that the samples were representative of the source from which they were taken.
\\172.17.48.240\bemlab\bemlims\reports\2017\water\word\wt005280.doc This Laboratory participate in the Agrilasa proficiency and SABS water testing scheme Page 2 of 2
Notes: To ensure sample integrity, samples are stored only for seven days after release of the report. Thereafter it is disposed of and a fresh sample will be required if additional analyses are requested. Results marked with "Not SANAS Accredited" in this report are not included in the SANAS Schedule of Accreditation for this laboratory. These results relate to the items tested. This test report shall not be reproduced except in full, without written approval of the laboratory. Refer to website for uncertainty of measurement and referenced methods. Sample condition: Samples received in good condition.
Dr. Pieter Raath Sandisiwe Mbula 11-04-2017 General Manager Technical Signatory(Water chemistry) Date reported
—————END OF REPORT—————
Environmental Impact Assessment for a New Regional Landfill Site – Specialist Groundwater Study
Addendum Report II
Parsons & Associates May 2017
APPENDIX F
UPDATED HYDROCENSUS DATA
Note
Data recorded in blue collected in 2004 Data recorded in black collected in 2010
Data recorded in red collected in 2017
Site Name Location Owner Use Depth
(m)
Equipment Borehole
Yield
(l/s)
Annual
Abstraction
(m3/a)
EC
/
(ms/m)
Groundwater
Level
(mbgl)
Date Elevation
(mamsl)
Latitude
WGS84
Longitude
WGS84
BF1 Bottlefontein Mr Blackenberg sand mining & domestic submersible 0.6 18250 74 10/08/2004 94 33.66249 18.68762
BF1 Bottelfontein Mr. Mostert (foreman) domestic & stock watering submersible 0.6 18250 76 22/07/2010
BF1 Bottelfontein Mr. Mostert (foreman) domestic & stock watering submersible 88 04/05/2017 92 33.66252 18.68771
BF2 Bottlefontein Mr Blackenberg sand mining & domestic submersible 0.4 3000 62 5.64 10/08/2004 88 33.65102 18.67739
BF2 Bottelfontein Mr. Mostert (foreman) domestic & stock watering submersible 0.4 3000 62 22/07/2010
BF2 Bottelfontein Mr. Mostert (foreman) sand mining & domestic submersible 0.6 3000 74 06/04/2017
BG00072 DWS monitoring 181 none 1.9 0 424 11.84 27/07/2010 104 33.62877 18.66976
BG00073 DWS monitoring 54 none 3.5 0 374 0.94 27/07/2010 97 33.66609 18.70125
BH1 Vrede Braaikuikens Mr Sauer/ Mr Versfeld not used none 0 1.95 10/08/2004
BH1 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 1.58 26/07/2010 67 33.67604 18.69068
BH2 Vrede Braaikuikens Mr Sauer/ Mr Versfeld not used none 0 1.45 10/08/2004
BH2 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 0.90 26/07/2010 60 33.68596 18.69155
BH3 Vrede Braaikuikens Mr Sauer/ Mr Versfeld not used none 0 10/08/2004 33..688337 18.68922
BH3 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 26/07/2010
BH4 Vrede Braaikuikens Mr Sauer/ Mr Versfeld not used none 0 6.25 10/08/2004
BH4 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 26/07/2010 89 33.67222 18.67969
BH5 Vrede Braaikuikens Mr Sauer/ Mr Versfeld not used none 0 10.88 10/08/2004
BH5 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 14.08 26/07/2010 92 33.66840 18.67903
BH6 Vrede Braaikuikens Mr Sauer/ Mr Versfeld domestic & stock watering submersible 1.8 57000 197 10/08/2004
BH6 Vrede Braaikuikens Mr. Sauer/Versfeld domestic & stock watering submersible 1.8 57000 51.98 26/07/2010 84 33.66949 18.68558
BH6 Vrede Braaikuikens Mr. Sauer/Versfeld domestic & stock watering submersible 04/05/2017
BH7 Vrede Braaikuikens Mr Sauer/ Mr Versfeld domestic & stock watering submersible 1.8 57000 185 10/08/2004
BH7 Vrede Braaikuikens Mr. Sauer/Versfeld domestic & stock watering submersible 1.8 57000 233 26/07/2010 89 33.66924 18.68652
BH7 Vrede Braaikuikens Mr. Sauer/Versfeld domestic & stock watering submersible 252 04/05/2017
BH8 Vrede Braaikuikens Mr Sauer/ Mr Versfeld standby borehole submersible 0 10/08/2004
BH8 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 26/07/2010 81 33.66747 18.68854
BN1 Bonnie Doon Mr Liebenberg domestic & stock watering submersible 0.9 7500 185 28.33 16/02/2006
BN1 Bonnie Doon Mr Liebenberg domestic & stock watering submersible 0.9 7500 151 19.73 22/07/2010 88 33.65458 18.67132
BN2 Bonnie Doon Mr Liebenberg not used none 0 34 29.15 16/02/2006
BN2 Bonnie Doon Mr Liebenberg not used none 0 2.75 22/07/2010 66 33.65867 18.66597
BN3 Bonnie Doon Mr Liebenberg not used none 0 10.99 23/08/2004
BN3 Bonnie Doon Mr Liebenberg not used none 0 7.10 22/07/2010 65 33.66448 18.66772
BN4 Bonnie Doon Mr Liebenberg not used none 0 361 1.36 23/08/2004 33.67358 18.66064
BN4 Bonnie Doon Mr Liebenberg not used none 0 0.09 12/08/2010 48 33.67358 18.66064
BN5 Bonnie Doon Mr Liebenberg not used none 0 7.40 22/07/2010 77 33.66612 18.66948
BN6 Bonnie Doon Mr Liebenberg not used none 0 3.77 22/07/2010 75 33.66574 18.67158
BN7 Bottlefontein Mr. Mostert (foreman) sand mining submersible 3.4 13860 210 23.75 16/03/2017 90 33.65694 18.67281
BP1 Blomvlei Farm Astral Foods/ Mr van Rooyen not used submersible 0 5.31 01/02/2002
BP1 Blomvlei Joseph De Witt (Manager - County Fair) not used none 0 27/07/2010 125 33.63551 18.68771
BP2 Blomvlei Farm Astral Foods/ Mr van Rooyen not used none 0 01/02/2002
BP2 Blomvlei Joseph De Witt (Manager - County Fair) not used none 0 27/07/2010 133 33.62945 18.68378
BP3 Blomvlei Joseph De Witt (Manager - County Fair) not used none 0 27/07/2010 120 33.63197 18.68504
BP4 Blomvlei Joseph De Witt (Manager - County Fair) domestic & stock watering submersible 0 5.50 27/07/2010 113 33.61731 18.69437
DVI1 Droevlei Mr S Currie stock watering submersible 20.24 28/08/2004
DVl1 Droevlei Mr. Visser (foreman) stockwatering & domestic submersible 0.7 7.93 27/07/2010 122 33.63572 18.71585
DVl2 Droevlei Mr. Visser (foreman) stockwatering & domestic submersible 0.4 4.90 27/07/2010 117 33.62477 18.70815
DVl3 Droevlei Mr. Visser (foreman) stockwatering & domestic submersible 8.0 0.40 27/07/2010 112 33.63066 18.70537
EL1 Elandsvlei Mr Voigt stock watering submersible 0 5.82 28/08/2004
EL1 Elandsvlei Martin Voegt (0825664038) not used none 0 4.53 17/09/2010 97 33.65200 18.69886
GEO1 Middelpost not used 0 01/01/2006
GEO1 Middelpos no one here stock watering windpump -0.15 21/07/2010 61 33.66785 18.63759
GEO2 Middelpost not used 0 01/01/2006 105 -33.67100 18.64970
GEO3 Middelpost not used 0 01/01/2006 98 -33.67520 18.65010
GG1 Goedgewag Mr van Blerk domestic & stock watering submersible 0.5 4500 897 11.51 01/02/2002 98 -33.62142 18.65550
GG1 Goedgewag Mr van Blerk 27/07/2010
GG1 Goedgewag Mr van Blerk 04/05/2017
GG2 Goedgewag Mr van Blerk not used none 0 7.86 28/08/2004 99 33.62063 18.65576
GG2 Goedgewag Mr van Blerk 27/07/2010
GG2 Goedgewag Mr van Blerk 04/05/2017
GG3 Goedgewag Mr van Blerk domestic submersible 7.88 28/08/2004 99 33.62061 18.65577
GG3 Goedgewag Mr van Blerk submersible 27/07/2010
GG3 Goedgewag Mr van Blerk domestic 60 submersible 336 8.15 04/05/2017
GL1 Glen Lossie Mr van Blerk stock watering windpump 0 10/08/2004
GL1 Glen Lossie Mr van Blerk distribution windpump 27/07/2010 107 33.62119 18.66692
GL1 Glen Lossie Mr van Blerk distribution windpump 370 04/05/2017 107 33.62119 18.66692
GL2 Glen Lossie Mr Vermeulen not used none 0 2.75 10/08/2004
GL2 Glen Lossie Mr van Blerk not used none 0 27/07/2010 106 33.61379 18.67766
GL3 Glen Lossie Mr Vermeulen domestic & stock watering windpump 0.5 1000 802 17.54 10/08/2004
GL3 Glen Lossie Mr van Blerk stock watering windpump 0.5 1000 762 4.44 27/07/2010 125 33.62276 18.67449
KE1 Klein Engeland Mr Schrewe domestic & stock watering submersible 0.4 900 9.31 01/02/2002
KE1 Klein Engeland Mr. Schrewe stock watering & irrigation submersible 0.4 900 7.85 27/07/2010 108 33.61407 18.69359
KE2 Klein Engeland Mr Schrewe domestic & stock watering submersible 0.4 900 330 9.48 01/02/2002
KE2 Klein Engeland Mr. Schrewe domestic & stock watering submersible 0.4 900 8.70 27/07/2010 105 33.61585 18.69390
KS1 Klein Wolwedans Mr. Curry; Foreman: Chris Mouton (0784364776stock watering submersible 94 4.91 17/09/2010 94 33.67120 18.70697
KS2 Klein Wolwedans Mr. Curry; Foreman: Chris Mouton (0784364776not used none 0 17/09/2010 92 33.67123 18.70694
MPS1 Middelpost not used none 0 13.31 23/08/2004 33.67601 18.64259
MPS1 Middelpos no one here not used none 0.0 0 21/07/2010 83 33.67602 18.64261
MPS2 Middelpost not used none 0 23/08/2004 33.67586 18.64255
MPS2 Middelpos no one here not used none 0.0 0 21/07/2010 77 33.67558 18.64264
MPS3 Middelpost stock watering submersible 0.6 5000 13.99 23/08/2004 33.67549 18.64298
MPS3 Middelpos no one here stock watering? submersible 0.6 5000 572 14.04 21/07/2010 80 33.67550 18.64293
MPS4 Middelpos not used windpump 0.40 23/08/2004 33.67069 18.62645
MPS4 * Middelpos no one here domestic? windpump 0.25 21/07/2010 35 33.67074 18.62645
MRG1 Magrug stock watering windpump 0.4 1000 01/01/2006 33.69097 18.64436
MRG1 Magrug stock watering windpump 0.4 1000 492 16.26 21/07/2010 72 33.69103 18.64433
OPT1 Oortmanspoort not used none 0 501 6.68 23/08/2004
OPT1 Oortmanspoort Dirk Niemann (foreman) not used none 0 21/07/2010 62 33.69030 18.66758
OPT2 Oortmanspoort stock watering windpump 0.6 2000 23/08/2004
OPT2 Oortmanspoort Dirk Niemann (foreman) not used windpump 0 21.98 21/07/2010 65 33.69585 18.67499
OPT3 Oortmanspoort domestic submersible 0.4 1500 19.12 23/08/2004
OPT3 Oortmanspoort Dirk Niemann (foreman) cleaning & irrigation submersible 0.4 1500 424 24.84 21/07/2010 78 33.69498 18.67493
OPT4 Oortmanspoort Dirk Niemann (foreman) not used none 0 17.13 21/07/2010 78 33.68999 18.65865
OPT5 Oortmanspoort Dirk Niemann (foreman) not used none 0 21/07/2010 67 33.68890 18.66626
OPT6 Oortmanspoort Dirk Niemann (foreman) not used none 0 502 15.76 21/07/2010 81 33.69001 18.66007
RWS-07 Bottlefontein Mr. Mostert (foreman) exploration 30 none 81 4.83 08/10/2004
RWS-07 Bottelfontein Mr. Mostert (foreman) exploration 30 none 0.3 0 95 3.29 23/07/2010 92 33.66273 18.67931
RWS-07 Bottelfontein Mr. Mostert (foreman) exploration none 0 4.68 16/03/2017
RWS-08a Bottelfontein Mr. Mostert (foreman) exploration 30 none 212 9.93 03/11/2004 104 33.63656 18.67352
RWS-08a Bottelfontein Mr. Mostert (foreman) exploration 29 none 3.0 0 401 9.21 22/07/2010
RWS-08a Bottlefontein Mr. Mostert (foreman) exploration 29 none 0.0 0 10.94 06/04/2017
RWS-09 Bottelfontein Mr. Mostert (foreman) exploration 30 none 146 0.00 27/09/2004
RWS-09 Bottelfontein Mr. Mostert (foreman) exploration 30 none 1.0 0 185 0.30 22/07/2010
RWS-09 Bottlefontein Mr. Mostert (foreman) exploration none 0 1.03 17/03/2017 89 33.63379 18.65713
RWS-10 Bottelfontein Mr. Mostert (foreman) exploration 28 none 3.0 0 65 2.03 04/09/2004 85 33.64731 18.66862
RWS-10 Bottelfontein Mr. Mostert (foreman) exploration 28 none 3.0 0 82 1.80 26/07/2010 84 33.64731 18.66862
RWS-10 Bottelfontein Mr. Mostert (foreman) exploration 28 none 3.0 0 7.68 06/04/2017 85 33.64731 18.66862
RWS-11 Bottelfontein Mr. Mostert (foreman) exploration 22 none 0 40 5.30 27/09/2004 33.65308 18.68340
RWS-11 Bottelfontein Mr. Mostert (foreman) exploration 22 none 0.4 0 45 2.80 26/07/2010 94
RWS-11 Bottelfontein Mr. Mostert (foreman) exploration 22 none 0.4 0 6.43 11/04/2017 94 -33.65306 18.68346
RWS-13 Bottlefontein Mr. Mostert (foreman) exploration 100 none 2.5 0 90 8.84 17/03/2017 95 33.63973 18.66564
RWS-14 Bottlefontein Mr. Mostert (foreman) exploration 97 none 5.6 0 102 9.52 19/03/2017 99 33.63807 18.66564
RWS-15 Bottlefontein Mr. Mostert (foreman) exploration 90 none 10.0 0 52 0.00 18/03/2017 85 33.63996 18.66266
RWS-16 Bottlefontein Mr. Mostert (foreman) exploration 100 none 0.8 0 126 13.14 20/03/2017 103 33.63786 18.66937
Spring Bottlefontein Mr. Mostert (foreman) not used 0 01/01/2006 83 33.63543 18.65876
Spring Bottlefontein Mr. Mostert (foreman) not used 0 dry 21/03/2017
VDE1 Vrede not used none 0 36.87 23/08/2004
VDE1 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 49.50 26/07/2010 90 33.66682 18.68429
VDE2 Vrede not used none 0 23/08/2003
VDE2 Vrede Braaikuikens Mr. Sauer/Versfeld not used none 0 39.18 26/07/2010 73 33.66837 18.68768
WV1 Wintervogel Mr van Dyk domestic & stock watering submersible 0.3 900 4.15 10/08/2004
WV1 Blomvlei Joseph De Witt (Manager - County Fair) not used none 0 4.09 27/07/2010 118 33.64421 18.68574
WV2 Wintervogel Mr van Dyk domestic & stock watering submersible 0.3 900 3.34 10/08/2004
WV2 Blomvlei Joseph De Witt (Manager - County Fair) stock watering submersible 0.3 900 2.60 27/07/2010 82 33.63065 18.68174
WV3 Wintervogel Mr van Dyk domestic & stock watering submersible 0.3 900 360 3.55 10/08/2004
WV3 Blomvlei Joseph De Witt (Manager - County Fair) stock watering submersible 0.3 900 0.70 27/07/2010 125 33.62867 18.68172
WV4 Wintervogel Mr van Dyk not used none 0 10/08/2004
WV4 Blomvlei Joseph De Witt (Manager - County Fair) not used none 0 27/07/2010
WV5 Wintervogel Mr. Van Dijk domestic & stock watering 146 submersible 4.0 63072 148 13.28 17/09/2010
WV5 Wintervogel Mr. Van Dijk domestic & stock watering submersible 253 04/05/2017 104 33.63580 18.67537