Tags: Model, Hydrology, Water Balance, Water Supply, Water Use, Gross Yield, Water Resources, Planning, Scenarios, GIS

Increasing competition for the Republic of South Africa’s (RSA) scarce and unevenly distributed water resources necessitates a planning strategy to cope with inter regional water scarcity. The RSA National Water Act (No. 36 of 1998) therefore requires the development of a national water resources strategy to ensure the sustainable and equitable use of resources. The RSA Department of Water Affairs and Forestry has responded with the development of a model to assist in preparing a suitable strategy.

The model is a water balance based decision support system for reconnaissance level planning. The model is GIS linked and supported by a comprehensive database of spatial water related information. State of the art technology was applied to ensure rapid processing capabilities, user friendliness and effective methods for dealing with scenario analysis. As a result the model is suitable for use in a boardroom or a workshop environment. Strategies for water supply and demand management can be rapidly tested for scenarios of land use, demographic and economic change.

This paper summarises the model and then focuses on novel methods used to overcome issues identified during development. These include variations in data quality and output needs, geographically incompatible administrative and catchment boundaries, large volumes of data and rapid run time requirements. The paper emphasises the sound generic nature of the model and data management system which could facilitate its use for other countries, international water sharing and in global water accounting.

An inter regional water resources planning model.pdf