appendix c2 - erm · 13-347 13 may 2015 page ii kangra discard facility surface water study:...

Appendix C2 Hydrology Report

63 Wessel Road, Rivonia, 2128 PO Box 2597, Rivonia, 2128 South Africa

Tel: +27 (0) 11 803 5726 Fax: +27 (0) 11 803 5745 Web: www.gcs-sa.biz

GCS (Pty) Ltd. Reg No: 2004/000765/07 Est. 1987

Offices: Durban Johannesburg Lusaka Ostrava Pretoria Windhoek

Directors: AC Johnstone (Managing) PF Labuschagne AWC Marais S Pilane (HR) W Sherriff (Financial)

Non-Executive Director: B Wilson-Jones

www.gcs-sa.biz

Kangra Discard Facility Surface Water Study: Hydrology, Storm Water and Water Balance

Report

Version – 01

13 May 2015

Kangra Coal

GCS Project Number: 13-347

Kangra Kangra Discard Facility

13-347 13 May 2015 Page ii

Kangra Discard Facility Surface Water Study: Hydrology, Storm Water and Water Balance

Report

Version – 01

13 May 2015

Kangra Coal

13-347

DOCUMENT ISSUE STATUS

Report Issue Draft

GCS Reference Number GCS Ref - 13-347

Client Reference GCS Surface Water Study – Proposed Discard Facility

Title Kangra Discard Facility Surface Water Study: Hydrology,

Storm Water and Water Balance

Name Signature Date

Author Maxwell Ndou

June 2014

Co-Author Daniel Fundisi May 2015

Document Reviewer Karen King

May 2015

Director Pieter Labuschagne

May 2015

LEGAL NOTICE This report or any proportion thereof and any associated documentation remain the property of GCS until the mandator effects payment of all fees and disbursements due to GCS in terms of the GCS Conditions of Contract and Project Acceptance Form. Notwithstanding the aforesaid, any reproduction, duplication, copying, adaptation, editing, change, disclosure, publication, distribution, incorporation, modification, lending, transfer, sending, delivering, serving or broadcasting must be authorised in writing by GCS.


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EXECUTIVE SUMMARY

GCS Water and Environment (Pty) Ltd. (GCS) were appointed by Kangra Coal (Pty) Ltd.

(Kangra) to conduct a hydrological assessment study for the proposed discard facility at

Kangra Coal Mine, in the Mpumalanga Province of South Africa. The components of the

hydrological assessment include Water Quality (WQ) analysis, a Water Balance (WB), a Storm

Water Management Plan (SWMP), a Flood Line Analysis and a Risk Assessment. The Kangra

Coal Mine is situated approximately 40km from Piet Retief Town along the N2 National Road.

The proposed site for the discard facility falls on the border between quaternary catchments

W51B and W52A.

The SWMP was undertaken in accordance with the General Notice 704 (GN704) of the South

African National Water Act (Act 36 of 1998) which stipulates guidelines for the prevention or

reduction of pollution of natural surface water resources (South Africa, 1998). The WB was

conducted to adhere to the Department of Water Affairs (DWA) – now the Department of

Water and Sanitation (DWS) - Best Practice Guidelines (BPG) G2: Water and Salt balances

(DWA, 2006). In order to ensure that the proposed developments comply with GN704, 1:50-

year and 1:100-year flood levels for rivers within the vicinity of the proposed discard facility

were calculated and the exclusion zones were determined.

This report details the methodology, results, conclusions and recommendations emanating

from the hydrological assessment study components as outlined above.

Methodology

Industry-accepted algorithms and methodologies were used in undertaking the

aforementioned study components. Results of the Water Resources of South Africa Study;

WRC Reports TT 380 to 382/08 (WRC, 2005), used for base-line runoff data. Three small

subcatchments (areas < 15km2) were delineated using ArcGIS software. The Rational Method

was used to calculate peak flows for the delineated catchments since it is a widely used

method developed for small catchments that is proven for producing acceptable results. The

point precipitation data used was taken from the South African Weather Service (SAWS)

station number 0443807 – Brereton Park.


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Regional Climate

The Mean Annual Precipitation (MAP) of the project was calculated as 877.5 mm while the

Mean Annual Evaporation (MAE) stands at 1654.2 mm (GCS, 2013). The maximum

temperatures for the site average around 260C, while the minimum temperatures in winter

drop as low as 40C (GCS, 2013).

Peak Flows

The 1:50-year and 1:100-year flood depths showed no significant difference due to small

channels with steep river banks (See Table 5.11).

Flood Lines

A flood line analysis was undertaken for the following rivers: The Gude, Voor, Mpundu,

Assegaai and Hlelo Rivers. The flood lines were calculated in HEC-RAS (US Army Corps of

Engineers, 1995) and the Rational Method flood depths were used as input flows. No

encroachment of the infrastructure into the Flood lines and Exclusion zones was noted.

Therefore, the risk of flood inundation as a result of the investigated flood events (1:50-year

and 1:100-year) is unlikely.

Downstream Water Uses

The Water Authorisation Registration Management System (WARMS) database of the

Department of Water and Sanitation (DWS) revealed that commercial forestry and irrigated

agriculture dominate water use in the downstream segment of the Discard Dump site. Mining

and industrial water uses were observed to take an insignificantly small proportion of the

downstream water allocation (See Section 5.7).


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Baseline Water Quality

Water quality evaluations were undertaken at 6 sampling points in and around the site area;

these points can be seen in Figure 6.1. The water samples indicated relatively good water

quality in compliance to the South African Water Quality Guidelines (SAWQG) and the South

Africa National Standards (SANS), except for one sample (Maquasa Surface Water 2 (Maq-SW

2)) which had a non-compliant sulphate concentration (Table 6-2). This sample was collected

closer to the Maquasa East Pits and probably lies within the flow direction of effluent from

these pits. It is recommended that the PCD to be constructed to contain effluent from the

Discard Dump should also be designed to contain the excess effluent from these Maquasa East

Pits, in order to prevent the seepage of contaminated water into the environment. Sumps

should be placed at the bottom of these pits with the effluent finally destined for the PCD.

All recommended mitigation measures can be seen in Section 7, which describes the

separation of clean and dirty water catchments to avoid the contamination of clean water

sources.

SWMP

The channelisation and containment of all dirty water, including water containing sediments,

is fully described in the Section 7. Drains are recommended to channel storm water and berms

are recommended for the interception of runoff to ensure that there is no mixing of clean

and dirty water at the Discard Dump site (see Figure 7.3).

WB

The WB recommends a PCD with a minimum capacity of 1 485 400 m3 in order to contain the

effluent from the Discard Dump as well as from back-filled mine pits located to the east of

the discard facility. This figure agrees with the 1 450 000 m3 value recommended by Geo Tail

(2014). Some of the waste water can be recycled and re-used within the mine operations,

thereby minimising the amount of waste water to be discharged into the environment.

Risk Assessment

The identified risks posed by the construction and operation of the Discard Facility, including

all supplementary activities, can be mitigated by adhering to the recommended SWMP and

the mine’s waste disposal plan. Continuous WQ Monitoring is recommended to assess the

effectiveness of the SWMP and to identify any need to either augment or upgrade the existing

system in order to ensure continued compliance to the relevant environmental legislation.


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CONTENTS PAGE

1 INTRODUCTION .......................................................................................................................... 2

2 SCOPE OF WORK ........................................................................................................................ 3

3 METHODOLOGY ......................................................................................................................... 4

4 SITE LOCATION ........................................................................................................................... 5

5 CATCHMENT HYDROLOGY .......................................................................................................... 7

5.1 CATCHMENT DELINEATION, CHARACTERISATION AND PROPERTIES ............................................................ 7 5.2 REGIONAL CLIMATE ........................................................................................................................ 7 5.3 MEAN ANNUAL RAINFALL (MAP) AND MEAN ANNUAL EVAPORATION (MAE) ......................................... 7 5.4 MEAN ANNUAL RUNOFF ................................................................................................................. 8 5.5 FLOOD FLOWS AND VOLUMES .......................................................................................................... 8 5.6 FLOOD LINES ............................................................................................................................... 11

Approach......................................................................................................................... 13 Analysis ........................................................................................................................... 17 Results ............................................................................................................................. 18 Modelling accuracy ......................................................................................................... 20

5.7 DOWNSTREAM WATER USES .......................................................................................................... 22

6 BASELINE WATER QUALITY ....................................................................................................... 23

7 CONCEPTUAL STORM WATER MANAGEMENT PLAN ................................................................ 27

7.1 GUIDELINES CONSIDERED............................................................................................................... 27 7.2 CLEAN AND DIRTY WATER CATCHMENT DELINEATION ........................................................................ 28 7.3 CLEAN WATER DIVERSION .............................................................................................................. 29 7.4 DIRTY WATER CONTAINMENT ......................................................................................................... 32 7.5 SOIL EROSION MEASURES .............................................................................................................. 33

8 WATER BALANCE ...................................................................................................................... 35

9 RISK ASSESSMENT .................................................................................................................... 39

9.1 SURFACE WATER IMPACTS ASSESSMENT .......................................................................................... 39 9.2 KEY ISSUES AND SCENARIOS ........................................................................................................... 42

Changes to water quality of the rivers ............................................................................ 43 Changes in catchment runoff characteristics .................................................................. 43 Changes in Catchment Characteristics............................................................................ 44

10 CONCLUSIONS AND RECOMMENDATIONS ............................................................................... 48

11 REFERENCE ............................................................................. ERROR! BOOKMARK NOT DEFINED.


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LIST OF TABLES

Table 5-1 Mean annual runoff for catchments W52A and W51B ............................... 8 Table 5-2 Design rainfall depths ..................................................................... 8 Table 5-3 Main catchment areas and their parameters ........................................ 10 Table 5-4 Storm flows for sub-catchments within catchment A. ............................. 10 Table 5-5 Storm flows for sub-catchments within catchment B. ............................. 11 Table 5-6 Storm flows for sub-catchments within catchment C. ............................. 11 Table 5-7 Criteria for cross section selection .................................................... 13 Table 5-8 factors influencing flood line determination [Adapted from: .................... 15 Table 5-9 Criteria assigned to cross sections ..................................................... 17 Table 5-10 Average slopes of river sections analysed ............................................ 17 Table 5-11 Flood levels ................................................................................ 18 Table 5-12 Froude numbers & channel flow velocities........................................... 18 Table 5-13 Summary of downstream water uses .................................................. 22 Table 6-1 Water quality type ........................................................................ 24 Table 6-2 Chemical analysis results ................................................................ 25 Table 7-1 Summary of flood peak calculations [Adapted from: Geo Tail (Pty) Ltd, 2014] 31 Table 7-2 Channel sizing and parameters ......................................................... 31 Table 7-3 Channel sizing and parameters ......................................................... 33 Table 8-1 Annual average water balance ......................................................... 37 Table 9-1: Risk Assessment Significance Value.................................................... 41 Table 9-2: Risk Rating Matrix ......................................................................... 42 Table 9-3 Construction phase risk assessment ................................................... 45 Table 9-4 Operational phase risk assessment .................................................... 46 Table 9-5 Closure phase risk assessment .......................................................... 47

LIST OF FIGURES

Figure 4-1 Kangra Coal: Maquasa Site Location .................................................... 6 Figure 5-1 Catchments considered for peak flows [Adapted from: GCS 2013] .............. 12 Figure 5-2 Initially selected cross sections [Adapted from: GCS 2013] ....................... 14 Figure 5-3 Profile plot (top view) ................................................................... 19 Figure 5-4 Profile plot (side view) .................................................................. 19 Figure 5-5 Proposed Kangra Discard Facility 100m river buffer areas ........................ 21 Figure 6-1 Sampling Point Location ................................................................. 26 Figure 7-1 Cross section of the proposed earth channel and berm ........................... 29 Figure 7-2 Sketch depicting the proposed culvert ............................................... 32 Figure 7-3 Layout indicating proposed storm water infrastructure ........................... 34 Figure 8-1 Kangra discard dump process flow diagram .......................................... 36


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GLOSSARY OF TERMINOLOGY

Berm: A wall designed and constructed to change the direction of a natural surface water flow

path.

Catchment: That area from which any surface runoff will naturally drain to a specified point.

Clean water: Natural runoff water from a catchment area that has not been contaminated

through contact with known pollutants.

Dirty water: Water that has been, or could potentially become, contaminated through contact

with known pollutants.

Dirty water system: Any systems designed to collect, convey, contain, store or dispose of

dirty water.

Drainage channel: An artificial flow path designed to convey water.

Hydrology: The study of natural water cycles that includes rainfall, evaporative and

transpiration losses and resulting surface flows.

Pollution Control Dams (PCD): Specialised storage dams designed to prevent environmental

pollution by containing and storing dirty water runoff for safe disposal through evaporation or

by any other environmentally responsible process.

Raw Water Dam (RWD): Specialised storage dams designed to use water storage for

operational and process purposes.

Runoff: Water that falls as rainfall and is not lost through evaporation, transpiration or deep

percolation into the ground. This water either does not penetrate soils but flows directly

across the soil surface, or re-emerges from local soils to flow on the surface along natural flow

paths or watercourses.

Watercourse: Watercourse refers to a river or spring; a natural channel in which water flows

regularly or intermittently; a wetland, lake or dam into which, or from which water flows and

any collection of water which the Minister may by notice in the Gazette, declare to be a

watercourse, and a reference to a watercourse includes, where relevant, its beds and banks

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


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1 INTRODUCTION

GCS Water and Environment (Pty) Ltd. (GCS) were appointed by Kangra Coal (Pty) Ltd.

(Kangra) to conduct a hydrological assessment, water quality analysis, Water Balance (WB),

Storm Water Management Plan (SWMP) and Risk Assessment for their proposed new discard

facility, and to calculate flood lines in the vicinity of the proposed facility. It is understood

that the discard facility will be constructed in three phases with an HDPE liner to limit

groundwater pollution; the liner for each subsequent phase will be constructed while

deposition in the current phase is ongoing and rehabilitation will take place concurrently. It

is further understood that both the discard facility and associated Pollution Control Dam (PCD)

will be lined.

The SWMP was undertaken in accordance with General Notice 704 (GN704) of the South African

National Water Act (36 of 1998) in order to reduce or prevent pollution of natural surface

water resources. This was undertaken by proposing berms and channels around the discard

facility to divert clean water away from the proposed discard facility as well as channelling

dirty water to the proposed PCD. A report detailing a SWMP study that was conducted by

iLanda Water Services for Geo Tail (Pty) Ltd. was used within this study. On the facility,

seepage will be limited owing to the liner used; this will have an impact on the PCD since all

water from the facility will be routed to the PCD (Geo Tail, 2014).

The SWMP was accompanied by a Process Flow Diagram (PFD) and WB which show water

movement within the discard facility and to the proposed PCD, as well as associated losses.

The WB was conducted in accordance with the Department of Water Affairs (DWA) – now the

Department of Water and Sanitation (DWS) Best Practice Guidelines (BPG) G2: Water and Salt

balances (DWA, 2006).

In order to ensure that the proposed developments comply with GN704, flood levels for rivers

within the vicinity of the proposed discard facility were analysed in order to establish the

1:50-year and 1:100-year flood lines. The results indicated that both the 1:50- and 1:100-year

storm events do not cause flood levels that are outside of the 100 m buffer zone, therefore

the 100 m buffer zone was used to delineate the Exclusion Zone, in accordance with GN704

regulations.

The current water quality status of the study area as well as the surrounding areas was also

analysed in order to establish the baseline water quality of the study site. The water quality

samples were collected from six sampling points and were assessed against the SAWQG and

SANS targets.


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A Risk Assessment for the proposed discard facility, with associated mitigation measures, was

undertaken.

2 SCOPE OF WORK

The scope of work for this study included:

• Information collection and literature study:

o A desktop study to review all existing information available.

• Baseline Assessment / Analysis:

o Establishment of the baseline conditions utilising existing information, and

o Description of the affected environment, including downstream water users.

• Hydrology:

o Climate and rainfall evaluation;

o Catchment Delineation;

o Mean Annual Runoff (MAR), and

o Peak flow analysis.

• Water Balance:

o Process Flow Diagram (PFD), and

o Development of an annual average, Excel spreadsheet-based Water Balance

in DWA format.

• Conceptual Storm Water Management Plan (SWMP):

o Developed according to the Best Practice Guideline G1: Storm Water

Management by DWAF, 2006.

• Flood line analyses (modelling)

o Flood line analysis using HEC-RAS software

• Risk Assessment

o A risk assessment for the discard facility, and

o Associated mitigation measures

• Reporting:

o A project draft report detailing the results of all of the activities listed above,

and

o Recommendations made for additional work and data requirements.


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3 METHODOLOGY

This study commenced with the acquisition of relevant data in respect of the hydrology of the

proposed Kangra Discard Facility site. The GCS 2008 hydrology Kangra Proposed Power Station

Hydrology Report (GCS, 2008) provided a significant portion of the basis for this study.

A holistic approach was followed and an attempt was made to link local hydrological, water

quality and environmental studies to regional and national concerns, regulations and

management strategies.

The SWMP was compiled in accordance with the DWA (now DWS) BPG G1: Storm Water

Management (DWA, 2006). The discard facility was delineated as a dirty area and the SWMP

was thus designed such that all discard water and rain water that falls on the discard facility

is contained within the facility. A system of drainage channels and berms was proposed in

order to achieve this. The contained water will then be channelled to the proposed pollution

control dam while all clean water that flows from upstream of the discard facility will be

diverted around the facility.

The Water Balance simulation was developed to understand the movement of water between

the discard facility and the pollution control dam. Both the discard facility and pollution

control dam will have rainfall as a direct water input and evaporation was treated as an

output. It was assumed that runoff will be channelled to the pollution control dam, as

described in the SWMP. The identified water input from mining operations is the water that

will be deposited with the discard material. This water will also be channelled to the pollution

control dam, were it will be stored and can be returned to the process plant. Excess water

will be allowed to evaporate. The decant water that is anticipated to come from pits on the

eastern side of the facility was included in the Water Balance simulation for future scenarios.

The design for the PCD associated with the discard facility was taken from a report by iLanda

Water Services for Geo Tail (Pty) Ltd. (Geo Tail, 2014).

Flood lines were assessed in accordance with the regulations stipulated within the South

African National Water Act (36 of 1998) (South Africa, 1998)It was decided to select 1 cross

section per stream for a basic height determination of flow through the cross section. The

cross section was selected in such a way that the highest possible risk would be captured

(closest to infrastructure). After careful consideration off all the above mentioned aspects, it

was decided to only analyse 6 streams, namely 3, 5, 6, 8, 10, and 14 (Figure 5-1).


13-347 13 May 2015 Page 5

Baseline water quality data was obtained from a study that was conducted by GCS (GCS, 2013).

Six points were sampled and were sent to the laboratory for analysis. The results from the

laboratory were assessed against the SAWQG and SANS standards.

Generally-accepted algorithms and methodologies were used to determine design floods at

various points in the area, in order to estimate flood levels and to draw the flood lines at

these points. Software used in the study includes the following:

• ArcView10.1 (ESRI, 2012) for Geographic Information Systems (GIS) work and

mapping;

• HEC-RAS (US Army Corps of Engineers, 1995) modelling software for hydraulic

calculation of flow depths, and

• Results of the Water Resources of South Africa Study; WRC Reports TT 380 to

382/08 (WRC, 2005), used for base-line runoff data.

4 SITE LOCATION

The site under investigation is situated near Piet Retief within the Usutu catchment area under

the jurisdiction of the Mkhondo Local Council, Mpumalanga Province of South Africa (See

Figure 4-1). By road the site is approximately 27 km north of the town of Dirkiesdorp and 58

km west of Piet Retief.


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FIGURE 4-1 KANGRA COAL: MAQUASA SITE LOCATION


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5 CATCHMENT HYDROLOGY

The 2008 Kangra Hydrology Report compiled by GCS (GCS, 2008) provides a general

understanding of the surrounding catchment area and information on land cover, river bed

characteristics and flood plain areas.

5.1 Catchment delineation, characterisation and properties

The proposed site falls within quaternary catchment W51B, which is the second catchment of

the Assegaai River. The majority of the project area runoff will drain into this river system.

The area draining to the site falls within two quaternary catchments; W52A, which covers

approximately 25% of the area and W51B, which covers the majority of the project area,

approximately 75%.

5.2 Regional climate

The study area lies at an average altitude of approximately 1430m. It is located in the South

African Highveld sub-humid climatic zone, which is a warm, mild summer rainfall region. It is

characterised by warm, wet summers and cool, dry winters. During the warm summer months

of December and January the average daily temperature is between 200C and 260C, while the

minimum temperatures in winter drop as low as 40C.

5.3 Mean Annual Rainfall (MAP) and Mean Annual Evaporation (MAE)

The closest reliable rainfall station to the area is the Piet Retief Weather Station. The record

from this weather station was used in the GCS 2008 Kangra hydrology study. Rainfall was

recorded at this station from January 1935 to January 1979 and evaporation was recorded

from March 1957 to March 1979. Using these data, the monthly average rainfall (MAP) and

evaporation (MAE) were calculated as 877.5 mm and 1654.2 mm, respectively (Refer to Page

9 of the GCS 2008 Kangra Hydrology Report for monthly average rainfall and evaporation).


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5.4 Mean Annual Runoff

The runoff data used was extracted from the WR2005 database (WRC, 2008). The calculated

mean annual runoff can be seen in Table 5-1.

TABLE 5-1 MEAN ANNUAL RUNOFF FOR CATCHMENTS W52A AND W51B

Month

Runoff (mm)

W52A W51B

Oct 4.43 4.314516

Nov 10.5 8.87

Dec 17.48 13.75

Jan 21.09 17.14

Feb 19.32 14.96

Mar 13.71 10.40

Apr 8.31 6.59

May 4.62 4.23

Jun 2.58 2.98

Jul 1.84 2.42

Aug 1.56 2.02

Sep 1.7 1.98

TOTAL 107.14 89.66

5.5 Flood Flows and Volumes

Design rainfall depths used in the design calculations are shown in Table 5-2. Rainfall is the

primary input needed in order to generate flow sequences. The design rainfall data used was

taken from the SAWB (South African Weather Bureau) station 0443807 – Brereton Park.

TABLE 5-2 DESIGN RAINFALL DEPTHS

Station Name Brereton Park

NUMBER 0443807

Return Period (years) 2 5 10 20 50 100

Design Rainfall (mm) 63 87 106 126 155 180

The rational method was used, in accordance with the Drainage manual 5th edition compiled

by South African Road Agency Limited (SANRAL, 2006), for calculating peak flows for the site.


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The runoff that is generated from a catchment will depend on the:

• Characteristics of the storm event;

• The response characteristics of the catchment, and

• The influence of temporal storage on the run-off.

For the catchments at the proposed Kangra discard facility site, the aforementioned

parameters are listed in Table 5-3.

Table 5-4,


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Table 5-5 and Table 5-6 show the calculated peak flows for 1:50-year and 1:100-year events

for catchments A, B and C, respectively (See Figure 5-1).

TABLE 5-3 MAIN CATCHMENT AREAS AND THEIR PARAMETERS

Catchment Area (km2)

Water course (km)

Height Difference (m)

Catchment A 26.325 12.05 360

Catchment B 10.125 4.61 280

Catchment C 10.35 6.98 270

TABLE 5-4 STORM FLOWS FOR SUB-CATCHMENTS WITHIN CATCHMENT A.

Sub-catchment

Area (km2)

1:50 year (m3/s)

1:100 year (m3/s)

7 3.04 33.54 42.48

8 1.58 17.40 22.02

12 2.03 22.36 28.32

13 1.01 11.18 14.16

14 3.38 37.27 47.20

20 2.81 31.06 39.33

21 0.79 8.70 11.01

22 0.90 9.93 12.59

23 1.46 16.15 20.45

24 1.46 16.15 20.45

32 1.80 19.88 25.17

33 2.02 22.36 28.32

34 3.49 38.51 48.77

35 0.56 6.21 7.87

TOTAL 26.33 290.69 368.13


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TABLE 5-5 STORM FLOWS FOR SUB-CATCHMENTS WITHIN CATCHMENT B.

Sub-catchment

Area (km2)

1:50 year (m3/s)

1:100 year (m3/s)

9 2.81 65.73 83.24

11 2.13 49.95 63.26

25 0.68 15.78 19.98

26 1.69 39.44 49.94

27 2.81 65.73 83.24

TOTAL 10.13 236.63 299.66

TABLE 5-6 STORM FLOWS FOR SUB-CATCHMENTS WITHIN CATCHMENT C.

Sub-catchment

Area (km2)

1:50 year (m3/s)

1:100 year (m3/s)

6 3.04 50.91 64.47

15 2.93 49.02 62.08

18 2.48 41.48 52.53

19 1.91 32.05 40.59

TOTAL 10.35 173.47 219.68

5.6 Flood lines

Flood lines on selected river sections are analysed to evaluate risks associated with potential

flooding of infrastructure and to facilitate the protection of natural resources (GCS, 2013).

Within the GCS 2013 Kangra Hydrology Study, flood lines were calculated to indicate areas

which the proposed infrastructure should not be built. The significant streams/rivers that

were studied are the:

• Gude River;

• Voor River;

• Mpundu River;

• Assegaai River, and the

• Hlelo River.

GN704 stipulates that no mining infrastructure is allowed to be placed and/or constructed

closer than 100m from a river or within the 1:100 year flood line (GCS, 2013). The General

Notice also stipulates that no open cast mining pit is allowed to be placed closer than 100m

or within the 1:50 year flood line of a watercourse. All watercourses that are in close

proximity to existing or proposed infrastructure or pits were identified (Figure 5-1) (GCS,

2013).


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FIGURE 5-1 CATCHMENTS CONSIDERED FOR PEAK FLOWS [ADAPTED FROM: GCS 2013]

appendix c2 - erm · 13-347 13 may 2015 page ii kangra discard facility surface water study:...

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