Sasol Effluent Irrigation Sasol Effluent Irrigation WorkshopWorkshop

Groundwater Aspects (Numerical Modelling)29 November 2002

Louis Botha (JMA)

TopicsTopics

Contamination StatusHydraulic CharacteristicsNumerical Modelling

TopicsTopics

Contamination StatusHydraulic CharacteristicsNumerical Modelling

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Dam10Dam10

(Background: EC, Na, F)(Background: EC, Na, F)STATUSSTATUS

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IndabaIndaba GoedehoopGoedehoop

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Dam10Dam10 TRENDTREND

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IndabaIndaba GoedehoopGoedehoop

TopicsTopics

Contamination StatusHydraulic CharacteristicsNumerical Modelling

Dam10 (Medium Wet)Dam10 (Medium Wet)

Indaba (Dry)Indaba (Dry)

MiningMining

GoedehoopGoedehoop (Wet)(Wet)

TopicsTopics

Contamination StatusHydraulic CharacteristicsNumerical Modelling

Pollution MechanismModelling ApproachModel Results

Pollution MechanismPollution Mechanism

Overburden

Weathered Hard Rock

Fractured Hard Rock

Non-FracturedHard Rock

Zone

1:

Shal

low

Wea

ther

edZo

ne A

quife

r

Zone

2:

Dee

p Fr

actu

red

Aqu

ifer

Zone

3:

Dee

p N

on-

Frac

ture

d A

quife

r

12m

>35m

60m

80m

170mMine

0m

22m

80m

CHARACTERISED:CHARACTERISED:••Hydraulics (Hydraulics (HydrHydr. Conduct., . Conduct., StorativityStorativity, Porosity, …), Porosity, …)••Attenuation (Attenuation (DillutionDillution, , Diffusion, Dispersion, ChemicalDiffusion, Dispersion, ChemicalReactions, …)Reactions, …)

Pollution MechanismPollution Mechanism

Overburden

Weathered Hard Rock

Fractured Hard Rock

Non-FracturedHard Rock

Zone

1:

Shal

low

Wea

ther

edZo

ne A

quife

r

Zone

2:

Dee

p Fr

actu

red

Aqu

ifer

Zone

3:

Dee

p N

on-

Frac

ture

d A

quife

r

12m

>35m

60m

80m

170mMine

0m

22m

80m

INFILTRATION:INFILTRATION:••VolumeVolume••TimeTime

?? ?? ?? ??

-2

0

2

4

6

-100

0

100

200

300

400

500

1998 1999 2000 2001 2002

REGM-13 REGM-44 REGM-45 CRD

Dam10

-2

0

2

4

6

-100

0

100

200

300

400

500

1998 1999 2000 2001 2002

REGM-13 REGM-44 REGM-45 CRD

Indaba

-0.5

0

0.5

1

1.5

2

-100

0

100

200

300

400

500

1998 1999 2000 2001 2002

REGM-28 REGM-30 CRD

Goedehoop

CRDCRD&&

Groundwater Groundwater LevelsLevels

TopicsTopics

Contamination StatusHydraulic CharacteristicsNumerical Modelling

Pollution MechanismModelling ApproachModel Results

Modelling Approach

OPTIONS:OPTIONS:••Water balance (Volume, Time => water level)Water balance (Volume, Time => water level)••Constant concentrationConstant concentration

TopicsTopics

Contamination StatusHydraulic CharacteristicsNumerical Modelling

Pollution MechanismModelling ApproachModel Results

Thank you for your attentionThank you for your attention