Angola Namibia About Tutorial Glossary Documents Images Maps Google Earth go
Please provide feedback! Click for details
Home The River Basin People and the River Governance Resource Management
Resource Management
Water Demand
Water Infrastructure
 Dams and Associated Infrastructure
 The Kunene River Scheme
 Infrastructure for Hydropower in Angola
 Infrastructure for Water Supply
 Water Security
Water Storage & Flow Control
 Bulk Transfer Schemes
 Groundwater Services & Infrastructure
 Irrigation Infrastructure
 Operation and Maintenance of Infrastructure
 Rehabilitation and Future Development
 Wastewater Infrastructure
The Value of Water
Resource Monitoring
Research & Development



send a comment



Water Storage and Flow Control  

Water storage in a river can serve several purposes:

  • Controlling the river flow through controlled water release and thus mitigating droughts or floods;
  • Providing a reserve of water that can be used for domestic water supply or irrigation;
  • Establishing a certain water level for hydroelectric power generation;
  • Providing or improving particular ecological areas;
  • Providing a recreational area; and
  • Ensuring a minimum water depth for navigation.

In the Kunene River basin, storage is mainly intended to serve the first three of these purposes, whilst at the same time changing ecological areas and providing recreation possibilities.

The Gove dam was intended to regulate the flow of the Kunene River.
Source: Mendes 2011
( click to enlarge )

The purpose of river flow regulation is to mitigate problems associated with the variation of the flow, for example those associated with floods or droughts. Flow regulation provides more uniform flow conditions along the river course. A regulated flow in the Kunene would enable an optimal generation of electricity in the power stations at Matala and Ruacana and for future hydropower stations.

The average long term annual flow of the Kunene River at Ruacana is around 5 km³ (5 000 Mm³). The total annual rainfall varies across the basin from over 1 000 mm in the Upper Kunene to less than 100 mm in the lower reaches of the river with, 90 % of the rain occurring between November and April (see Climate in the Basin). From year to year the rainfall can vary from between 50 % to 200 % of long term averages and there are prolonged periods of drought.

The result is that the flow of the Kunene River varies widely from month to month and from year to year. This has serious consequences for users of the river.

Monthly flow volumes in m³/s at Ruacana from 1963 to 1968.
Source: Feio 1970
( click to enlarge )

At Ruacana, the weir provides only very limited storage and no flow regulation, low flows have a serious impact on electricity generation at the hydroelectric station there. Electric power generation is thus unpredictably variable from year to year, und indeed during any given year.

In the 1969 Third Water Use Agreement for the Kunene River foresaw the use of the Gove Dam in the Upper Kunene to provide a regulated flow of 80 m³/s at Ruacana. However the completion of the Gove dam coincided with the outbreak of war in Angola and the dam has never served to fully regulate the flow of the Kunene. In 2010 however work was underway to complete the Gove dam and ensure it fulfils its intended function.

The storage and controlled release of water in the Kunene River could provide a more useful contribution to flow regulation in the river and ensure a more uniform flow. With over 80 % of water storage on the Kunene River being behind the Gove dam, it has a key role to play in flow regulation. The other main storage areas along the river can be seen in the table and are described in Dams and Infrastructure.

Storage of Water from the Kunene River


Storage capacity

Gove dam

2 570 Mm³

Matala weir

60 Mm³

Calueque weir

475 Mm³ (design volume)

Ruacana diversion weir

20 Mm³

Olushandja Dam

42 Mm³

Total storage of Kunene River water

3 167 Mm³

Source: Adapted from Heyns 2005, NamWater 2006




Explore the sub-basins of the Kunene River

Video Interviews about the integrated and transboundary management of the Kunene River basin

View information on the dams and weirs of the Kunene Basin

Examine the virtual water trade and water footprints of SADC countries

Explore how hydroelectric dams work