1. REPORT ON THE STATUS OF THE INTEGRATED VAAL RIVER SYSTEM
Presented by: Celiwe Ntuli
Presented at: Water Conservation/Water Demand Management Best Practices
Date: 15 May 2019

2. Provincial Dam Levels

3. Source:

4. National State of Storage

5. Mine Water Discharge, Return Flows and Diffuse Salt Loads
Dilution Rule
Mine Water Discharge, Return Flows and Diffuse Salt Loads
RUSTENBURG
Vaal Barrage
Vaal
Bloemhof Dam
Katse
Mohale

7. Operating Rule Recommendations
No restrictions for IVRS (2018/2019)
Blending/Dilution
Apply dilution rule in Vaal Barrage (600 mg/l) according to water quality status which needs to be monitored
Thukela transfer
2018/2019 until Sterkfontein Dam is full
Thereafter standard rule till Bloemhof Dam is full
Releases from Bloemhof:
No releases required during 2018/2019

8. IVRS State of Storage Dam Nett Cap 106m3 13 May 2019 06 May
IVRS: Total
Vaal
Sterkfontein
Katse
Mohale
Bloemhof
Grootdraai
10 554
2 603
2 617
1 519
843
1 243
350
74,5%
72,8%
93,4%
35,6%
33,1%
100,5%
77,6%
75,5%
73,4%
93,5%
36,1%
32,5%
106,6% 79,2%

9. Probability distribution (boxplot)
0 % 5.0 % 25 % 50 % 75 % 95 % 100 %
Percentage of sequence results exceeding given value
Results for generated sequences

10. Box plot Description: Vaal Dam
1 May 2018: 104.6%
1 May 2019: 73.5%

11. Thukela Transfers to Sterkfontein
No transfers currently taking place on the Thukela-Vaal Scheme due to safety issues at the pump station

12. Senqu Sub-system (LHWP)
Vaal 2015/16 AOA SOF

13. 1 May 2018: 100%

14. Katse, Mohale, Sterkfontein, Vaal
1 May 2018: 86%
Vaal 2015/16 AOA SOF

15. Total Integrated Vaal System
Last year 89%
This year

16. Water use monitoring

17. Conclusion
The state of storage in Vaal Dam was still below the median by 1 May 2019 decision date
The state of storage within Senqu system is still low and of concern
The LHWP, for the first time in history, will not be able to transfer the full annual allocation from Lesotho – because of the low levels in the Lesotho dams.
Total system storage is tracking below the median projected storage and tracking the 95th percentile
No Restrictions anticipated this year and restrictions in subsequent years dependant on runoff and the integrity of the infrastructure.
Efforts to comply with water conservation and demand management measures are encouraged and must be continued

18. THANK YOU!

19. Draft Preliminary Water Balance (February 2018)
High with target WC/WDM
Desalination for urban use
(from January 2022)
Unlawful removed
Re-use (Tshwane )
High water requirement
Unlawful removed
WC/WDM savings
Tshwane re-use
High water requirement
Unlawful removed
Earliest Date for Yield
Replacement (2030)
Short term availability due to favourable reservoir volumes
System yield accounts for:
Reduction due to excessive dilution prior to desalination of AMD.
Unused storage (yield) in Komati River System.
System
Yield
TWP
Polihali Dam Net Yield
Polihali Dam Yield
Yield increases due to desalination of mine water
Elevated risk of restrictions.
Violation of risk criteria.
Elevated risks without WC/WDM savings
First transfer from LHWP Phase II – Dec 2025 19

20. By 2025 Level 1 Restriction occurs at about 5% risk:
Risk of Restrictions
(Scenario A)
By 2025 Level 1 Restriction occurs at about 5% risk:
50% Irrigation Restriction
30% Urban Restriction
Violation of Risk Criteria
0.5 %
min %
1 %
Min % 0.5 % 1.0 % % 25 % 50 % 75 % 95 %
99 % % Max %
5 %