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Development of a sustainability index for South African dwellings incorporating green roofs, rainwater harvesting and greywater re-use

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: South African water service providers experience major problems with providing adequate water
services to consumers. Water service providers in South African urban areas rely on traditional
centralised infrastructure, such as bulk supply networks, to provide water services. Alternative
supply and stormwater drainage methods should be encouraged to help mitigate these problems.
The researcher thus aims to quantify the potential impact that three alternative methods may have
on a given dwelling in terms of its dependence on traditional bulk water services. The three
alternatives considered in this thesis are the construction of green roofs, rainwater harvesting and
greywater re-use.
An efficiency of dwelling water use index (EDWI) was developed during this research project. It
was designed in such a way as to show what portion of municipal water services could be
replaced within the given dwelling by using the proposed techniques. The final EDWI-rating is
obtained by using the EDWI-software tool developed as a part of this research. The derived
EDWI-rating ranges from 0 to 100, with a rating of 100 indicating a dwelling requiring only the
removal of a portion of sewage by a municipality, but no external water supply. Such a dwelling
would also not require any water from a municipal network to meet domestic demand and all
stormwater from its roof would be utilised within the plot boundaries. Results presented in this
thesis illustrate how different geographical regions require different system specifications to
obtain optimal EDWI-ratings, thereby lowering their dependence on the respective municipal
water services.
Validation of the EDWI-system proved difficult as no similar index could be found during the
literature review. It was therefore decided to benchmark the EDWI-system using three model
dwellings with nine configurations producing a total of 27 analyses. The EDWI-system provides
a conceptual foundation for sustainable water services to South African households in serviced
urban areas. Future work could further improve the EDWI-system by testing its practical
application so that it may be extended to act as a national barometer, used to compare
decentralised water services in terms of sustainability. / AFRIKAANSE OPSOMMING:Suid-Afrikaanse waterdiensverskaffers ondervind groot probleme met die voorsiening van
voldoende waterdienste aan verbruikers. Waterdiensverskaffers in Suid-Afrikaanse stedelike
gebiede maak staat op tradisionele gesentraliseerde infrastruktuur, soos grootmaatvoorsienings
netwerke, om waterdienste te verskaf. Alternatiewe voorsienings- en stormwater
dreineringsmetodes moet aangemoedig word om hierdie probleme aan te spreek. Die studie poog
dus om die potensiële impak wat drie alternatiewe moontlikhede kan hê op 'n gegewe woning in
terme van sy afhanklikheid van die tradisionele waterdienste te kwantifiseer. Die drie
alternatiewe moontlikhede wat in hierdie studie ingesluit word is die konstruksie van groendakke,
reënwater oes en grys water hergebruik.
'n Huishoudelike water gebruik doeltreffendheids indeks (EDWI) is ontwikkel gedurende hierdie
navorsingsprojek. Die indeks is ontwerp om aan te dui watter gedeelte van munisipale
waterdienste deur die voorgestelde tegnieke vervang kan word. Die finale EDWI-gradering is
verkry deur gebruik te maak van die EDWI-programmatuur wat ontwikkel is gedurende die
navorsing. Die afgeleide EDWI- gradering wissel tussen 0 en 100, met 'n telling van 100 wat ‘n
woning voorstel wat slegs die verwydering van 'n gedeelte van die riool deur die munisipaliteit
vereis, maar wat geen eksterne watervoorsiening benodig nie. So 'n woning vereis dus geen water
van ‗n munisipale netwerk nie, en alle stormwater van die dak word binne die erf gebruik.
Resultate wat in hierdie studie voorgelê word illustreer hoe verskillende geografiese streke ander
stelsel spesifikasies vereis om optimale EDWI-gradering te verkry.
Die navorser kon geen indeks kry wat soortgelyk is aan die EDWI-stelsel om dit mee te vergelyk
nie. Dit was gevolglik besluit om die indeks te standardiseer deur gebruik te maak van drie model
huise met nege samestellings van alternatiewe, waardeur 27 ontledings ontwikkel was. Die
EDWI-stelsel bied 'n konseptuele grondslag vir volhoubare waterdienste vir Suid-Afrikaanse
huishoudings in gedienste stedelike gebiede. Toekomstige navorsing kan die EDWI-stelsel verder
verbeter deur die praktiese toepassing te toets. Die stelsel kan uitgebrei word om ‗n nationale
barometer vorm wat gebruik kan word om desentralisasie van waterdienste te meet in konteks
van volhoubaarheid.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20138
Date03 1900
CreatorsVan Der Walt, Johannes Tinus
ContributorsJacobs, H. E., Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
PublisherStellenbosch : Stellenbosch University
Source SetsSouth African National ETD Portal
Languageen_ZA
Detected LanguageUnknown
TypeThesis
Format171 p. : ill.
RightsStellenbosch University

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