Introduction

The yield from a water resource system is the volume of water which can be abstracted at ascertain rate over a specified period of time. Available water, however, refers to all water which can be available for practical application to desired uses. The total yield locally available includes the yield from both local surface water and groundwater resources as well as contributions to the yield by usable return flows from the non-consumptive component of upstream water use in the area under consideration. Total water available includes the total local yield plus water transferred from elsewhere (DWAF, 2002a).

Assessment of Data

The bulk (65%) of water resources available in Mpumalanga comes from surface water resources, with water tranfers into the province providing 19% of total water availability, while groundwater accounts for 6% of available water. Ten percent results from return flows from the mining, industrial and urban sectors and from irrigation. There are pronounced differences in water availability within each of the Water Management Areas (WMA's) and in Mpumalanga the total local yield of surface water resources is 2106 million m³/annum (based on 2000 figures). Water resources available per capita (expressed in cubic metres per person per annum) have been presented in the graph below for the WMA's that fall within Mpumalanga. The Falkenmark threshold indicates a water stress index based on approximate minimum level of water required per capita to maintain an adequate quality of life in a moderately developed country in the arid zone.