Stochastic evaluation of per capita domestic water requirements in view of various lifestyles

Crouch, Melissa Lauren (2020-03)

Thesis (MEng)--Stellenbosch University, 2020.

Thesis

ENGLISH ABSTRACT: Water authorities and policymakers are challenged with ensuring water supply for the future in the face of population growth, urbanisation and climate change. The possibility exists that water is being used at a rate that is much greater than is necessary for efficient daily use. It is important to determine daily water use requirements for different lifestyle habits. Other enduse studies have been conducted and household models have been created to evaluate household water use. However, per capita water requirements, for a range of lifestyles, have not been statistically modelled at an activity-based level. For this reason, a stochastic model entitled the litre per capita per day (LCD) model was set up to determine the domestic per capita water requirements for a single person, fully serviced, urban household at different lifestyle levels. The model was linked to Maslow’s hierarchy of needs to define different water use categories. The lifestyle levels considered were the “absolute basic consumption” lifestyle level where only basic health and hygiene needs were met; the “realistic everyday acceptable limited consumption” lifestyle level which limits water use to indoor use, yet allows for the normal functioning of a household; the “esteemed needs” lifestyle level which allowed for indoor and limited outdoor water use and finally the “ultimate consumption” lifestyle level which allowed for unrestricted indoor and outdoor use. Probabilistic distributions were used to describe each model input. A Monte Carlo simulation was run using @Risk software to determine the expected distribution of water use for each lifestyle level. The model results showed that the average absolute basic water requirement to live a hygienic lifestyle is 92 L/c/d; the average realistic everyday acceptable limited consumption is 175 L/c/d, the average esteemed needs water use is 227 L/c/d and the average ultimate consumption is 314 L/c/d, in a fully serviced urban household. The model values were found to be comparable to consumption values found in literature. The results of this study can be used as guidelines for daily target values by water authorities and policymakers.

AFRIKAANSE OPSOMMING: Waterowerhede en beleidmakers word uitgedaag om die watervoorsiening vir die toekoms te verseker te midde van bevolkingsgroei, verstedeliking en klimaatsverandering. Die moontlikheid bestaan dat water gebruik word teen 'n veel groter hoeveelheid as wat nodig is vir doeltreffende daaglikse gebruik. Daarom is dit nodig om daaglikse watergebruiksvereistes vir verskillende leefstylgewoontes te bepaal. Ander eindgebruikstudies is uitgevoer en huishoudelike modelle is opgestel om huishoudelike watergebruik te evalueer. Waterbehoeftes per capita vir 'n verskeidenheid lewenstyle is egter nie op 'n aktiwiteitsgebaseerde vlak statisties gemodelleer nie. Om hierdie rede is 'n stogastiese model, geregtig op die litre per capita per day (LCD) model, opgestel om die huishoudelike behoeftes per huishoudelike per capita te bepaal vir 'n enkele, volwaardige, stedelike huishouding op verskillende lewenstylvlakke. Die model is gekoppel aan Maslow se hiërargie van behoeftes om verskillende kategorieë vir watergebruik te definieer. Die lewenstylvlakke wat oorweeg is, was die “absolute basiese verbruik” lewenstylvlak waar slegs aan die basiese gesondheids en higiënebehoeftes voldoen is; die “realistiese daaglikse aanvaarbare beperkte verbruik” lewenstyl wat die watergebruik tot binnenshuis beperk, maar tog die normale funksionering van 'n huishouding moontlik maak; die “gewaardeerde behoeftes” lewenstyl vlak wat voorsiening maak vir binnenshuise en beperkte watergebruik buite en uiteindelik die “uiteindelike verbruik” lewenstyl vlak wat onbeperkte binne en buite gebruik moontlik gemaak het. Waarskynlike verdelings is gebruik om elke modelinvoer te beskryf. 'n Monte Carlosimulasie is uitgevoer met behulp van @Risk-sagteware om die verwagte verspreiding van watergebruik vir elke lewenstylvlak te bepaal. Die modelresultate toon dat die gemiddelde absolute basiese waterbehoefte om 'n higiëniese leefstyl te leef 92 L/c/d is; die gemiddelde realistiese daaglikse aanvaarbare beperkte verbruik is 175 L/c/d, die gemiddelde gewaardeerde behoeftes aan watergebruik is 227 L/c/d en die gemiddelde uiteindelike verbruik is 314 L/c/d, in 'n volwaardige stedelike huishouding. Die modelwaardes is vergelykbaar met verbruikswaardes in literatuur. Die resultate van hierdie studie kan gebruik word as riglyne vir daaglikse teikenwaardes deur waterowerhede en beleidmakers.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/107873
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