The Institute for Water Research has a long history of association with the concepts and principles of environmental flow and water quality requirements of rivers. It was almost inevitable that the IWR would play a central role in the inclusion of such concepts (as the Ecological Reserve) in the revision of the South African Water Act during the mid 1990s, as well as in the development of the methods, tools, models and data analysis procedures that would be required to give effect to the ecological Reserve.

The development of the models and tools has been strongly linked to the parallel development of the SPATSIM (Spatial and Time Series Information Modelling) software package. This has become the preferred software package through which many of the available ecological Reserve determination techniques are applied. As SPATSIM also includes many standard water resource and hydrological data analysis procedures, as well as a wide range of frequently used simulation models, it represents a truly integrated data processing environment for Reserve studies.

The following links can be accessed to obtain more information about the various methods that have been developed at the IWR, or to access some of the research reports that have been produced:

Hydrology and the Reserve:The links between hydrological data and the Ecological Reserve (river water quantity) determination process.


Download the Desktop Model for the Reserve(33337 KB install file)


The Flow-Stressor Response approach to Reserve determinations.


SPATSIM and Reserve determination models and tools.


Implementing the Reserve: Issues, problems and some solutions.

Last Modified: Tue, 09 May 2017 10:57:25 SAST