The Department of Water and Sanitation (DWS) continues to closely monitor the status of the major water storage facilities forming part of the Integrated Vaal River System (IVRS), following the latest State of Reservoirs Report that indicates a significant improvement in the overall storage position of the system, with the IVRS increasing from 96.7% last week to 99.7% this week. The improvement reflects the combined effect of inflows, rainfall and catchment runoff, transfers, controlled releases, evaporation and water use across the interconnected system.
The IVRS comprises an interconnected network of reservoirs and water-resource infrastructure that plays a strategic role in supporting water requirements in Gauteng and other areas supplied by the system. It supports domestic, industrial, agricultural and other socio-economic water requirements.
The increase from 96.7% to 99.7% represents a significant improvement in the system's overall storage position over the reporting period and places the IVRS close to the 100% reference level.
Vaal Dam has increased from 99.7% last week to 105.3% this week, representing a substantial improvement in storage. The latest reading is above the dam's defined Full Supply Level (FSL) and reflects increased water availability following improved inflows and catchment conditions. Storage levels above 100% should be understood in the context of the operational management of the reservoir and its defined reference level. Dam levels can fluctuate in response to rainfall, runoff, inflows from upstream areas and operational releases.
Bloemhof Dam has increased from 108.2% to 109.0%, maintaining its position significantly above its defined FSL. The 109.0% reading is an operational storage indicator and should not, on its own, be interpreted as meaning that the dam is overflowing.
Grootdraai Dam has recorded a notable increase from 98.4% last week to 102.9% this week. The reservoir has therefore moved from below its FSL to above the 100% level. The increase reflects improved storage and contributes to the overall strengthening of the IVRS. As with other reservoirs in the system, the level is subject to fluctuations resulting from inflows, rainfall, releases and water use.
Sterkfontein Dam has remained unchanged at 98.8%, compared with 98.8% last week. The stable level indicates that the reservoir continues to maintain a strong storage position, remaining close to its FSL. Sterkfontein Dam forms an important component of the broader IVRS, and its continued stable storage contributes to the system's overall water-resource resilience.
Katse Dam has increased significantly from 79.0% last week to 86.3% this week. Although the reservoir remains below its defined FSL, the increase represents a substantial improvement in its storage position. The latest level indicates that the dam continues to hold a significant volume of water and contributes to the broader storage capacity of the interconnected system.
Mohale Dam has recorded a substantial increase from 94.1% last week to 104.7% this week, moving from below its FSL to above the 100% level. The increase represents a marked improvement in the reservoir's storage position. As part of the interconnected water-resource system, changes at Mohale Dam are influenced by inflows, transfers, releases and the operational management of water resources across the broader IVRS.
The recent improvement across several major reservoirs highlights the important role played by rainfall and catchment response in replenishing water resources. However, rainfall does not necessarily translate immediately or uniformly into increased dam levels.
The impact of rainfall depends on several factors, including where the rainfall occurs, its intensity and duration, soil moisture conditions, runoff, river flows and the location of rainfall within the catchment. Water can also enter or leave reservoirs through transfers and controlled releases as part of normal system operations.
The improvement in storage across several reservoirs indicates that the IVRS currently has substantial water reserves. Nevertheless, favourable storage levels do not remove the need for continued monitoring and responsible water-resource management.
The Department will continue to monitor dam levels, rainfall, catchment conditions, inflows, transfers, releases and water use to support the sustainable management of available water resources.
Water users are encouraged to continue using water responsibly and avoid wastage. Water conservation remains important regardless of current dam levels, as sustainable water use is essential to maintaining the resilience of the water-resource system over the longer term.
Enquiries:
Wisane Mavasa
Spokesperson for the Department of Water and Sanitation
Cell: 060 561 8935
E-mail: mavasaw@dws.gov.za
Maria Lebese
Gauteng DWS: Communication
Cell: 082 611 9264
E-mail: lebesem@dws.gov.za
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