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Environmental Flow Requirements of the Fish River and the Orange-Senqu River Mouth


The Orange-Senqu River riparian States (Botswana, Lesotho, Namibia and South Africa) are committed to jointly addressing threats to the shared water resources of the Basin.

This is reflected in bilateral and basin-wide agreements between the riparian states and led to the formation of the Orange-Senqu River Commission (ORASECOM) in 2000. The ‘Orange-Senqu Strategic Action Programme’ Project supports ORASECOM in developing a basin-wide plan for the management and development of water resources, based on Integrated Water Resources Management (IWRM) principles.

The water resources of the Orange-Senqu River are heavily utilised and the system is highly regulated with 23 major dams within its Basin. It is also connected to other river systems for water import and export via six inter-basin water transfer schemes.

ORASECOM acknowledges that future river basin management in the Orange-Senqu River Basin will need to balance competing water uses, and deal with the increasing rates of human-induced change and the mounting concerns about the causes and consequences of this change. One of the main aspects of this will be to ensure that sufficient water is left in the riverine ecosystem for it to continue to function in a predetermined ecological condition and provide for the people in the basin. This water is known as the Environmental Flow (EFlows).

EFlows are defined as the quantity, timing and quality of water flows required to sustain freshwater and estuarine ecosystems and the human livelihoods and well-being that depend on these ecosystems.

This project addresses Environmental Flow Requirements (EFR) of the ephemeral but nevertheless significant Fish River, and the Orange-Senqu River, from its confluence with the Fish River downstream to the Orange-Senqu River mouth.

This section of the basin has not been covered in any detail by the earlier studies, during 2009-2010. The importance of completing the Environmental Flow Requirements picture is important due to the fact that two large dams, one in the Lower Orange (Vioolsdrift Dam) and one in the Lower Fish (Neckartal Dam), are at an advanced state of planning.

Funding Organisation(s):

Global Environment Facility through United Nations Development Programme


Data and Maps

A project website has been established which provides reports, detailed data and an interactive map for the products from this project.

Project Website

Project Interactive Map

Project Interactive Map

Manual for Interactive Maps

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