Streamflow

Streamflow – the movement of water through river channels – is one of the most fundamental measurements in hydrology and water resource management. It provides the basis for water availability assessments, flood frequency analysis, ecological flow determinations, drought monitoring, dam operations, and catchment-scale water balance studies. South Africa operates an extensive national network of river gauging stations managed by the Department of Water and Sanitation (DWS), collecting continuous streamflow records at hundreds of sites across the country. Long-term streamflow records are among the most valuable datasets in the water sector, enabling trend analysis, the detection of land use and climate change impacts, and the calibration and validation of hydrological models.

The resources below provide access to South Africa's national streamflow monitoring network, downloadable gauge data, decision support tools, and international streamflow datasets.

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National Streamflow Data

DWS Hydrological Monitoring Stations – Google Earth KML Files A spatial overview of all active and historical DWS streamflow monitoring stations across South Africa, viewable in Google Earth. Allows users to identify stations by location, river system, and Water Management Area.

DWS Hydrological Services – Downloadable Station Data The primary national portal for downloading verified daily streamflow records for individual gauging stations across South Africa. Data is available for a wide range of historical periods and is the standard reference dataset for hydrological research and water resource assessments in the country.

National Integrated Water Information System – NIWIS (DWS) An integrated web platform providing access to real-time and historical surface water, groundwater, dam level, and water quality data — including streamflow — across South Africa's monitoring network.

Decision Support & API Access

InWaRDS – Integrated Water Resources Decision Support A decision support system for integrated water resource management in the Olifants catchment, demonstrating advanced use of DWS streamflow data. An example of a programming interface (API) to DWS flow data is available here — useful for researchers and developers looking to automate data retrieval and analysis.

WHAT – Web-based Hydrograph Analysis Tool An online tool for baseflow separation from streamflow hydrographs, enabling analysis of the groundwater contribution to river flows — particularly useful for understanding low-flow conditions during dry periods.

International & Global Streamflow Data

Global Runoff Data Centre (GRDC) An international archive of river discharge data maintained by the German Federal Institute of Hydrology, providing streamflow records from stations worldwide including southern Africa — useful for regional and transboundary river analysis.

GloFAS – Global Flood Awareness System A global ensemble river flow forecasting system operated by the EU Copernicus Emergency Management Service, providing river discharge forecasts and historical reanalysis data at global scale.

Ecological Flow

Streamflow is directly linked to the ecological health of rivers and the determination of the Ecological Reserve — the quantity and quality of water required to protect aquatic ecosystems as mandated by the National Water Act. For resources related to ecological flow requirements and reserve determinations, see the Ecological Flow page and the Catchment Water Information System for catchment-specific streamflow data.