ENGLISH ABSTRACT: Guidelines for residential average annual water demand (AADD) based on property size were
introduced to the South African Civil Engineering fraternity in about 1960, with the most recent
publication of such guidelines in 2008. The AADD forms the basis of calculations performed
during the design and analysis of water systems. Over the years technology has improved, scientific
progress was made and demand has changed, resulting in improved and updated guidelines for
AADD. Changes in the guidelines over the years could be considered to be a result of improvement – larger and more accurate data sets are nowadays analysed statistically by improved computer
technology. Also, the changes are considered to be the result of scientific advances in the fields of
metering, modelling and analysis of water demand. Finally, actual changes in demand occur with
time. This research provides the first documented review of the chronological development of
AADD guidelines in South Africa. It is noted that only two guidelines were used for relatively long
periods of time. In both cases the guidelines would not compare favourably to others from a pure
research perspective, but their successful application is the result of a co-ordinated educational
and marketing effort. The value of a sustained guideline structure (AADD versus stand size in this
case) is also underlined.
AFRIKAANSE OPSOMMING: Riglyne vir die beraming van residensiële gemiddelde jaarlikse waterverbruik (GJV) met erfgrootte as
onafhanklike veranderlike is sedert 1960 in Suid-Afrika deur siviele ingenieurs gebruik. Die mees
onlangse publikasie het in 2008 die lig gesien. Die GJV vorm die basis van verskeie berekenings wat
uitgevoer word tydens die ontwerp en ontleding van watertoevoerstelsels. Oor die jare het tegnologie
verbeter, wetenskaplike vooruitgang is gemaak en waterverbruik het verander, met die gevolg dat
riglyne vir GJV dienooreenkomstig verbeter en aangepas is. Eerstens is sodanige verandering te
danke aan verbetering – groter datastelle kan aan die hand van moderne rekenaartegnologie geredelik
statisties ontleed word. Tweedens kan die aanpassings toegeskryf word aan wetenskaplike vooruitgang
aangaande die meting, modellering en ontleding van waterverbruik. Boonop verander waterverbruik
met tyd. Hierdie navorsingstuk voorsien die eerste gedokumenteerde oorsig van die chronologiese
ontwikkeling van GJV riglyne in Suid-Afrika. Daar word opgemerk dat slegs twee riglyne vir relatief
lang periodes toegepas was. In beide gevalle het ’n gekoördineerde opvoedings- en bemarkingsaksie
die latere toepassing van die riglyn bevorder – werk wat andersins sou afsteek by ander publikasies
uit ’n suiwer navorsingsoogpunt. Die waarde van ’n riglynstruktuur (GJV teenoor erfarea in hierdie
geval) wat onveranderd bly kom ook na vore.
