Development of a procedure for separately allocating water leakage and other types of non-metered water to nodes in the hydraulic model

Van wageningen, Gerrit (2018-03)

Thesis (MEng)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: The correct allocation of water loss to nodes in hydraulic models of water distribution systems is an important consideration for the purposes of designing such systems. Some components of total water demand (e.g. metered-consumption) are relatively simple to determine, for example, by analysing recorded meter consumption data. However, the extent and spatial distribution of non-metered water (including water losses) is often much more challenging to determine. Designers of water distribution system infrastructure and analysts need to be able to distinguish between the water that is lost from a water distribution system due to leakage (real loss) and that which is not accounted for as result of non-metered consumption (e.g. non-metered authorised consumption and apparent loss). A possible shortcoming has been identified regarding the current assumptions for water loss modelling. The customary practice employed by consultants, whereby water loss is distributed among nodes in proportion to the metered consumption at those nodes, is often unrealistic. This research project focused on the evaluation and further development of an already existing technique for incorporating water losses in hydraulic models by segregating leakage from other types of non-metered water, as well as accounting for selected factors that influence water loss spatially. The literature reviewed indicated that limited research had been conducted on techniques for distinguishing between different types of water loss when performing hydraulic analyses. Most earlier research studies focussed on the pressure-leakage relationship and methods for improving the modelling of leakage from distributions systems. Furthermore, not much work could be found on the potential impact that different approaches to estimating leakage would have on the ultimate results obtained from hydraulic models. A computer-based modelling procedure titled SEGLEAK was developed as part of this research study, after which it was implemented and tested on a hydraulic model of a real water distribution system in South Africa, as part of a case study problem. The SEGLEAK procedure provided an effective and practical technique for distinguishing between leakage and non-metered consumption when making use of hydraulic modelling.

AFRIKAANSE OPSOMMING: Die korrekte toewysing van waterverlies aan nodusse in hidrouliese modelle van waterverspreidingstelsels is 'n belangrike oorweging vir die ontwerp van sulke stelsels. Sommige komponente van die totale water aanvraag (bv. gemeetde verbruik) is relatief maklik om te bepaal, byvoorbeeld deur die opname van aangetekende meterverbruiksdata te analiseer. Die omvang en ruimtelike verspreiding van nie-gemeterde water (insluitende waterverliese) is egter dikwels meer uitdagend om te bepaal. Ontwerpers van waterdistribusiestelselinfrastruktuur en ontleders moet kan onderskei tussen die water wat verlore gaan van 'n waterverspreidingstelsel as gevolg van lekkasie (werklike verlies) en wat nie verantwoord word as gevolg van nie-gemete verbruik (bv. nie- gemete gemagtigde verbruik en oënskynlike verlies). 'n Moontlike tekortkoming is geïdentifiseer met betrekking tot die huidige aannames vir waterverliesmodellering. Die gewone praktyk in diens van konsultante, waardeur waterverlies onder nodusse verdeel word in verhouding tot die gemete verbruik by daardie nodusse, is dikwels onrealisties. Hierdie navorsingsprojek het gefokus op die evaluering en verdere ontwikkeling van 'n reeds bestaande tegniek vir die inkorporering van waterverliese in hidrouliese modelle deur lekkasie van ander soorte nie-gemeterde water af te skei, asook om rekening te hou met geselekteerde faktore wat ruimtelike verlies aan waterverlies beïnvloed. Die literatuur wat ondersoek is, het aangedui dat daar beperkte navorsing gedoen is oor tegnieke om te onderskei tussen verskillende tipes waterverlies by die uitvoer van hidrouliese ontledings. Die meeste vroeëre navorsingstudies het gefokus op die druklekkasieverhouding en metodes om die modellering van lekkasie uit verspreidingsisteme te verbeter. Verder kan nie veel werk gevind word oor die moontlike impak wat verskillende benaderings tot skatting van lekkasie op die uiteindelike resultate van hidrouliese modelle sal hê nie. 'n Rekenaargebaseerde modelleringsprosedure met die titel SEGLEAK is ontwikkel as deel van hierdie navorsingsstudie, waarna dit geïmplementeer en getoets is op 'n hidrouliese model van 'n ware waterverspreidingstelsel in Suid-Afrika, as deel van 'n gevallestudieprobleem. Die SEGLEAK-prosedure verskaf 'n effektiewe en praktiese tegniek om onderskeid te tref tussen lekkasie en nie-gemete verbruik wanneer gebruik gemaak word van hidrouliese modellering.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103758
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