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Presented by: Simon Malose Ngoepe and Beason MwakaPresented by: Simon Malose Ngoepe and Beason MwakaPresented by: Simon Malose Ngoepe and Beason MwakaPresented by: Simon Malose Ngoepe and Beason Mwaka

IntroductionIntroduction

Numbers

Especially in the water resource-related

industries

Grant yourself a learner’s permit.

Tools for manage our water resources

Numbers

Especially in the water resource-related

industries

Grant yourself a learner’s permit.

Tools for manage our water resources

Examples of ToolsExamples of Tools

stoch

other

wrsm acru other

otherwrym

otherwrpm

otherrain

otherwqs

PPs

other

MF (DWS)

Various

Rainfall

Stream flow

Resource

potential

Intervention

& operationsplanning

Typical modelling processTypical modelling process

Reservoir

Water user

Target

abstraction

Evaporation

Evapo-

transpiration

Groundwater

storage

Stream

flow

Rainfall

Module 2

Module 3

Module 4

Module 5 & 6

Module 7

rain

PPs

wrsm

wrpm

stochwrymPPs

- Before HO -- Before HO -

How much water do we get?How much water do we get?

After Dent, Lynch & Schulze (1989)

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Climate Water Zones : Delineation

according to climatic features and rainfall patterns

Climate Water Zones : Delineation

according to climatic features and rainfall patterns

Zone5

Zone6

Zone2

Zone1

Zone4

Zone3

Zone5

Zone6

Zone2

Zone1

Zone4

Zone3

Available flowAvailable flow

Mo

nth

ly f

low

vo

lum

e (

mill

ion

m3)

Year0 1 2 3 4 5 6 7 8 9 10

40

35

30

25

20

15

10

5

0

Available flow

Average flow

100

80

60

40

20

0

Yield results for 41 sequencesYield results for 41 sequences

Yie

ld / t

arg

et

dra

ft (

millio

n m

3/a

)

5 10 15 20 25 30 35 40

Target draft =95 million m3/a

Sequence number

41 stochastic sequences ; Period length (n) = 60 years

100

80

60

40

20

0

Yield results sortedYield results sortedBreak point

Base yield line

19

Yie

ld / t

arg

et

dra

ft (

millio

n m

3/a

)

Sequence number41 stochastic sequences ; Period length (n) = 60 years

5 10 15 20 25 30 35 40

100

80

60

40

20

0

Yield-reliability curveYield-reliability curve

RI =

1:2

00

year

RI =

1:1

00

year

RI =

1:2

0 y

ear

RI =

1:5

0 y

ear

0 10 20 30 40 50 60 70 80 90 100

Reliability of supply, Ep (as % of sequences observed)

Yie

ld / t

arg

et

dra

ft (

millio

n m

3/a

)

Ep =51.2 %

Rn =48.8 %

41 stochastic sequences ; Period length (n) = 60 years; Plotting base = 60 years

100

80

60

40

20

0

Available resourceAvailable resource

Yie

ld / t

arg

et

dra

ft (

millio

n m

3/a

)

RI =

1:2

00

year

RI =

1:1

00

year

RI =

1:2

0 y

ear

RI =

1:5

0 y

ear

Total requirement = 100 million m3/a

100

11

67

22

Reliability of supply, Ep (as % of sequences observed)41 stochastic sequences ; Period length (n) = 60 years; Plotting base = 60 years

0 10 20 30 40 50 60 70 80 90 100

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Yield vs. ReliabilityYield vs. Reliability Operating Rules (Restrictions)Operating Rules (Restrictions)

Based on 45% Storage on 1 May 2013, supply 50% of domestic use

15% irrigation use

Operating Rules: PurposeOperating Rules: Purpose

Regulate water resources releases, transfers,

storage, etc. in order to

- Mitigate risk of failure to supply

- Minimize losses & improve system performance

- Minimize (pumping) costs

- Manage water quality

Regulate water resources releases, transfers,

storage, etc. in order to

- Mitigate risk of failure to supply

- Minimize losses & improve system performance

- Minimize (pumping) costs

- Manage water quality

Monthly Reservoir Storage ProjectionMonthly Reservoir Storage Projection

Integrated Vaal River System Storage comparison in Vaal subsystemsStorage comparison in Vaal subsystems

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Rainfall vs Dam Storage RelationshipRainfall vs Dam Storage Relationship

Reservoir storage capacity, which has controllable water is approximately 60% of total water availability in SA

Reservoir storage capacity, which has controllable water is approximately 60% of total water availability in SA

Water Transfers from the Orange River SystemWater Transfers from the Orange River System

Flood Peaks

941 1707 2314 2973 3949 4779 5698 22628

Exceedance Probability (%)

50 20 10 5 2 1 0.5 RMF22

Flooding (spillage) frequency at Vanderkloof Dam

Flooding (spillage) frequency at Vanderkloof Dam

Ratio of Reservoir Storage to Catchment Rainfall in the Orange River System

Ratio of Reservoir Storage to Catchment Rainfall in the Orange River System

0

20

40

60

80

100

120

140

160

180

31/0

9/1

981

31/0

9/1

983

31/0

9/1

985

31/0

9/1

987

31/0

9/1

989

31/0

9/1

991

31/0

9/1

993

31/0

9/1

995

31/0

9/1

997

31/0

9/1

999

31/0

9/2

001

31/0

9/2

003

31/0

9/2

005

31/0

9/2

007

31/0

9/2

009

31/0

9/2

011

Year ending

Upper Orange: WMA 13Oct 1980 to Sep 2011

Oct Storage (%FSC) at end of Rain Year Mean Annual Rainfall (%Mean) Based on District Rainfall

Trend of the Ratio of Storage to Rainfall in the Orange River SystemTrend of the Ratio of Storage to Rainfall in the Orange River System

0

20

40

60

80

100

120

140

160

180

Year Ending

Upper Orange: WMA 131980/81 to 2010/11

Mean Rainfall (%Mean) Oct Storage (%FSC) Linear (Mean Rainfall (%Mean)) Linear (Oct Storage (%FSC))

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Storage in Major RSA Dams Storage in Major RSA Dams (Cumulative)

Water Storage Trends & Cumulative Rainfall National & Kwazulu NatalWater Storage Trends & Cumulative Rainfall National & Kwazulu Natal

Water Storage Trends & Cumulative Rainfall Eastern Cape & Limpopo Water Storage Trends & Cumulative Rainfall Eastern Cape & Limpopo

Water Storage Trends & Cumulative Rainfall Free State & Gauteng Water Storage Trends & Cumulative Rainfall Free State & Gauteng

Storage Trends & Cumulative Rainfall Mpumalanga & Northern Cape Storage Trends & Cumulative Rainfall Mpumalanga & Northern Cape

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Storage Trends & Cumulative Rainfall North West & Western CapeStorage Trends & Cumulative Rainfall North West & Western Cape

WMA 9 - 12: Weekly Storage Oct to SepWMA 9 - 12: Weekly Storage Oct to Sep

WMA 1 - 4: Weekly Storage Oct to SepWMA 1 - 4: Weekly Storage Oct to Sep

WMA 5 - 8: Weekly Storage Oct to SepWMA 5 - 8: Weekly Storage Oct to Sep

WMA 13 - 16: Weekly Storage Oct to SepWMA 13 - 16: Weekly Storage Oct to Sep

WMA 17 - 19: Weekly Storage Oct to SepWMA 17 - 19: Weekly Storage Oct to Sep

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ConclusionsConclusions

Measurement & data important for systems

management/operation

Models help with data computations into DSS

DSS good for information sharing

Monitoring & early warning systems

Multiple integrated sources – dams, groundwater,

RWH, desalination, etc are good for system

operation efficiency.

Measurement & data important for systems

management/operation

Models help with data computations into DSS

DSS good for information sharing

Monitoring & early warning systems

Multiple integrated sources – dams, groundwater,

RWH, desalination, etc are good for system

operation efficiency.

- Thank You -- Thank You -