Water availability and demand in the humid and arid regions within development regions of South Africa

’n Metode is ontwikkel om ’n onderskeid te maak tussen die watervraag en -beskikbaarheid in dié ontwikkelingstreke waar ’n duidelike skeiding tussen ariede tot subariede en humiede gebiede bestaan. Ontwikkelingstreke A en D toon groot onderlinge klimaatsverskille en is in die navorsing ondersoek. Die streke is verdeel in ariede en humiede gebiede. ’n Landdrosdistrik met ’n gemiddelde jaarlikse reënval van meer as 400 mm oor meer as 50 persent van sy totale oppervlakte word as humied gereken. Die watervraag en -beskikbaarheid vir elkeen van die landdrosdistrikte is bereken as ’n dee! van die oppervlakte wat die distrikte van die verskillende sekondêre dreineringstreke bestaan. Die resultate van die navorsing lei tot die gevolgtrekking dat die verdeling van streke in ariede en humiede gebiede die belofte inhou van akkurater en meer gedetailleerde beplanning in die ontwikkelingstreke.A method has been developed to distinguish between water supply and demand in individual development regions which contain distinct humid and arid to subarid areas. Development regions A and D have heterogeneous climatic distributions within their borders and are dealt with in this regard. These regions can be divided into arid and humid areas. A magisterial district was considered to be humid when the average annual rainfall is more than 400 mm over more than 50 percent of its total area. The water availability and demand for each of the districts (whether humid or arid) were calculated on a pro rata basis according to the area each district occupies within the various secondary drainage basins. The results obtained in this study show great promise to divide the regions into arid and humid areas for more accurate and detailed planning within the development regions