1. 2015 National Water Week Event Launch of the WR2012 Website
Water Resource Planning in South Africa : An Overview
Protea Hotel, Centurion, 19 March 2015
Presented by:
Dr. Ronnie McKenzie, WRP (Pty) Ltd

2. Distribution of surface runoff in SA
D(Rem)
0,4%
Notes:
Due to the extreme variation in rainfall and evaporation, the distribution of runoff is highly skewed.
Most runoff occurs in the East.
Runoff drops markedly as you move towards the West.
Not only is the runoff very unevenly distributed in space, it is also erratic with regards to time. In SA, many areas experience drought periods in excess of 10 years with the result that large surface storage reservoirs are needed to provide a reliable and continuous supply of water.

3. The results of climatic extremes
Notes:
During severe droughts, the reservoirs can experience shortages.
The water resources in South Africa must be managed in order to survive the long drought events caused by the climatic extremes.
Drought conditions can continue for up to 15 years in some areas.
In order to overcome such extreme drought events, SA has developed a very complex system of water transfers to facilitate the movement of water from areas of surplus to areas of deficit.

4. Major transfers in South Africa
Notes:
As a result of the skewed distribution of water resources and the high demands in the central interior of South Africa, many inter-basin transfers schemes have been developed.
Each arrow represents a transfer.
The purpose is to move water from areas of surplus to areas of deficit.
The transfer schemes are large and very expensive.
It is expected that upon completion, Phases 1a and 1b of the Lesotho Highlands Water Project will cost in excess of $ 3 billion (at today’s prices).

5. Slide Courtesy Elias Nel from DWS : Hydrology
Compiled by E A Nel
Slide Courtesy Elias Nel from DWS : Hydrology

6. Slide Courtesy Elias Nel from DWS : Hydrology

7. Deepest Mine in the World at 4.5km deep
Mopaneng Gold Mine
Deepest Mine in the World at 4.5km deep

8. Produces >30% of SA’s Petrol/Diesel from coal
Sasol Petrochemical Plant Secunda
Produces >30% of SA’s Petrol/Diesel from coal
Largest synthetic fuel plant in world

9. SA generates over 50% of electricity in Africa > 40 000 MW
Power Stations
SA generates over 50% of electricity in Africa
> MW

10. Vaalharts Weir and main canal

11. Origins of Models Based on ARSP Model from Acres of Canada – 1983
Prof Fontanne – Colorado State
Prof Loucks – Cornell
Prof Stedinger – Cornell
Prof O’Connell – Newcastle
Prof Pegram – Natal
Prof Grieg – Colorado State
Resource Software design by Rick Allan, Ronnie Mckenzie and Pieter van Rooyen
Stochastic Software by Steffan van Biljon and Prof Pegram.

12. Yield and Planning Model Development
Algorithms developed by Dr O Sigvaldeson of ACRES in Canada
Originally designed for hydropower optimisation
Original model had no stochastic capabilities
Hydrology in Canada had short critical periods – no real need for stochastics
Acres model selected after tour to identify world’s best practice

13. Software Development : Cont
ARSP initially developed on VAX/780 Platform using VAX VMS operating system – 1982
In SA, first VAX mainframe was imported to SA from USA in 1984
Subsequent VAX 750 and Microvax computers imported by SA government for model use
SA was first in world to run models on PC based computer – used Lahey Fortran compiler

14. VAX 780 (1980)

15. Microvax (1987)

16. Software Development : Cont
First main system analysis was Vaal River System in 1985
Orange/Senqu River System Analysis commenced in 1987 and was first study to identify impacts of full 5 Phase LHWP on remainder of Orange/Senqu River
Namibian Central Area Water Masterplan in 1993

17. Creating a System Model

18. Locality of the Caledon-Modder System

19. Network model of the Caledon-Modder System

20. Penalty Structure

21. Internal Node and arc network

23. Mokolo Catchment Crocodile Catchment Vaal Catchment
Existing Transfer Schemes
Proposed Transfer Schemes
Mokolo Catchment
Crocodile Catchment
Vaal Catchment

24. Integrated Orange /Vaal system
Thank You

25. Point out selected characteristics that will be referred to later in the presentation:
Vaal Dam and Bloemhof Dam.
Transfer to Crocodile via. Rand Water supply system.
LHWP – Proposed Polihali Dam (upstream of Orange).
Dilution in Vaal Barage (downstream of Vaal Dam).

26. Upper Orange Lesotho
Hololo & Hlotse
Metolong
Makhaleng

27. Orange/Senqu System Model
87 Large Dams
279 Small Dams
± Abstractions/Demand Centres
8 integrated subsystems and 8 stand alone subsystems
± channels/arcs

28. Modelling Structure showing Yield and Planning Models

29. Stochastic yield analysis : why bother ?

30. Historical firm yields Why do they always seem to decrease ?

31. Basic Hydrology 1920 - 1990 Yield 18 24 29 40 28 30 33 42 51 100 24
120 28 29 40 30 60 50 45 24 29 40 59 29 81 72 63 59 45 63 50 40 60 18 40
Yield 18

32. Basic Hydrology 1920 - 2004 Yield 18 24 29 30 28 40 42 33 51 100 12060 50 45 24 29 40 59 24 29 40 28 30 29 81 33 42 72 63 59 45 63 50 40 60 18 40
Yield 18

33. Basic Hydrology 1920 - 2014 Yield 15 24 29 40 28 30 33 42 51 100 24
120 28 29 40 30 60 50 45 24 29 40 59 24 29 40 28 30 29 15 33 42 72 63 59 45 63 50 40 60 18 40
Yield 15

34. Projected system volume trajectories

35. Percentage of sequence results exceeding given value
Min % 5.0 % 25 % 50 % 75 % 95 % Max %
Percentage of sequence results exceeding given value
Results for sequences

36. Projected system volume trajectories

37. Projected system volume trajectories

38. Restrictions lifted Historical reservoir levels Restrictions imposed
Levels below which
curtailments are imposed

39. THANK YOU