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The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town
Water is a basic need and a limited resource across the world. Climate change, pollution, population growth, irrigation and urban development, among others, contribute to the issues faced with respect to availability of quality of water resources and security of water supply for consumption. Pressur...
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| Format: | Thesis |
| Language: | English |
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Department of Civil Engineering
2021
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| _version_ | 1867613197584826368 |
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| access_status_str | Open Access |
| author | Alves De Sousa, Melissa |
| author2 | Van Zyl, J E |
| author_browse | Alves De Sousa, Melissa Van Zyl, J E |
| author_facet | Van Zyl, J E Alves De Sousa, Melissa |
| author_sort | Alves De Sousa, Melissa |
| collection | Thesis |
| description | Water is a basic need and a limited resource across the world. Climate change, pollution, population growth, irrigation and urban development, among others, contribute to the issues faced with respect to availability of quality of water resources and security of water supply for consumption. Pressure management, is the most common and feasible demand management initiative implemented by the City of Cape Town Metro. The main focus of these initiatives is to reduce water losses within the water distribution system. Influence of pressure on water consumption is also observed, but has not been as well investigated as with leakage-pressure relationships. This study aims to assess the impact of change in system pressure on consumer water demand. To do this a pressure managed DMA and Control DMA was identified. The billed consumption data was analysed for 11 months before and 11 months after the pressure management period. A control DMA served to verify that the consumption reduction was as a result of pressure management and not any other intervention. Furthermore, this study involved the collection and analyses of the logged system flow data prior to and post commissioning of pressure management. Pressure is not fixed and varies overtime. The Average Zone Pressure was not available from logged data and was calculated by simulating the hydraulic model to reflect the system conditions prior and post commissioning of the pressure managed DMA. Following that, an investigation into how the leakage responds to pressure was performed. Since the latter affects the demand response to pressure. It was then decided to separate the leakage from consumption. In order to do this, various leakage parameters were calculated and randomly distributed across the system. To analyse the leakage before and after pressure management, two types of models were used, namely 1) Epanet Model (based on the Orifice Equation) and 2) the Epaleaks Model (based on the Modified Orifice Equation). N3 is the coefficient of elasticity. This coefficient represents the relationship between pressure and flow rate. Normal N3 analysis was performed on the available data. N3 was calculated for the system consumption, based on the logged data and a sample of the billed consumption records. The power regression model suggests an N3 of approximately 0.05 to 0.06 for the system based on a sample of filtered billed consumption data. However, in the case of the entire system's end use consumption the N3 value is approximately 0.4. Overall, the N3 values compared reasonably well with other studies in the range of 0.04 to 0.29 and in some cases ≈0.5. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/32656 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:18.917Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Department of Civil Engineering |
| publisherStr | Department of Civil Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/32656 The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town Alves De Sousa, Melissa Van Zyl, J E Engineering Water is a basic need and a limited resource across the world. Climate change, pollution, population growth, irrigation and urban development, among others, contribute to the issues faced with respect to availability of quality of water resources and security of water supply for consumption. Pressure management, is the most common and feasible demand management initiative implemented by the City of Cape Town Metro. The main focus of these initiatives is to reduce water losses within the water distribution system. Influence of pressure on water consumption is also observed, but has not been as well investigated as with leakage-pressure relationships. This study aims to assess the impact of change in system pressure on consumer water demand. To do this a pressure managed DMA and Control DMA was identified. The billed consumption data was analysed for 11 months before and 11 months after the pressure management period. A control DMA served to verify that the consumption reduction was as a result of pressure management and not any other intervention. Furthermore, this study involved the collection and analyses of the logged system flow data prior to and post commissioning of pressure management. Pressure is not fixed and varies overtime. The Average Zone Pressure was not available from logged data and was calculated by simulating the hydraulic model to reflect the system conditions prior and post commissioning of the pressure managed DMA. Following that, an investigation into how the leakage responds to pressure was performed. Since the latter affects the demand response to pressure. It was then decided to separate the leakage from consumption. In order to do this, various leakage parameters were calculated and randomly distributed across the system. To analyse the leakage before and after pressure management, two types of models were used, namely 1) Epanet Model (based on the Orifice Equation) and 2) the Epaleaks Model (based on the Modified Orifice Equation). N3 is the coefficient of elasticity. This coefficient represents the relationship between pressure and flow rate. Normal N3 analysis was performed on the available data. N3 was calculated for the system consumption, based on the logged data and a sample of the billed consumption records. The power regression model suggests an N3 of approximately 0.05 to 0.06 for the system based on a sample of filtered billed consumption data. However, in the case of the entire system's end use consumption the N3 value is approximately 0.4. Overall, the N3 values compared reasonably well with other studies in the range of 0.04 to 0.29 and in some cases ≈0.5. 2021-01-22T07:50:57Z 2021-01-22T07:50:57Z 2020 2021-01-22T06:55:08Z Master Thesis Masters MSc http://hdl.handle.net/11427/32656 eng application/pdf Department of Civil Engineering Faculty of Engineering and the Built Environment |
| spellingShingle | Engineering Alves De Sousa, Melissa The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town |
| thesis_degree_str | Master's |
| title | The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town |
| title_full | The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town |
| title_fullStr | The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town |
| title_full_unstemmed | The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town |
| title_short | The relationship between consumer demand and pressure in a selected pressure managed zone in Cape Town |
| title_sort | relationship between consumer demand and pressure in a selected pressure managed zone in cape town |
| topic | Engineering |
| url | http://hdl.handle.net/11427/32656 |
| work_keys_str_mv | AT alvesdesousamelissa therelationshipbetweenconsumerdemandandpressureinaselectedpressuremanagedzoneincapetown AT alvesdesousamelissa relationshipbetweenconsumerdemandandpressureinaselectedpressuremanagedzoneincapetown |