Designing a stormwaterharvest system in new smart cities in KwaZulu-Natal, South Africa

Abstract

The nexus between climate change and water management represents one of the contemporary challenges confronting economic development and sustainable livelihoods in many cities the world over. Thus, assessing the impacts of climate change for evolving smart-city water management, especially for a country like South Africa that is classified as a “water-stressed” country, constitutes an innovative way to water management. This study aimed at proposing an alternative water supply augmentation source that is sustainable for new smart cities under different climatic scenarios within the KwaZulu-Natal Province of South Africa. The specific objectives of the study were to assess the impacts of climate change and the imperativeness of a sustainable and efficient stormwaterharvesting (SWH) system in the new smart city; determine the social, economic and technical barriers to an efficient SWH system; evaluate the technical and financial feasibility of stormwaterharvesting system integration in smart cities; and design a prototype sustainable and efficient pilot-scale engineering SWH system. To address these objectives, the aggregated views of stakeholders within the Water/ Climate change sector were solicited through questionnaires and interviews collected data were analysed using a statistical package and thematic classification. The triangulation method was used to justify acceptable opinions where both the qualitative and quantitative responses were in opposing positions. The standardised rainfall anomaly index (SRAI), simple precipitation ratio (SR), coefficient of variation in rainfall distribution (CV), precipitation concentration index (PCI), and the seasonal precipitation index (SPI) were used to evaluate the impacts of climate change on rainfall variability; whilst different inferential statistics techniques like Mann Kendal, Sen slope, regression, correlations, multifactor analysis (MFA), and chi-square test values- interpreted using the p-values- were used to identify the abrupt changes, trend patterns and significant impacts of climate change on the hydrological water balance for the study area, which in turn influenced decision-making in designing a new smart city. Based on a monthly water balance evaluation, the technical and financial feasibility of stormwater harvest system integration in smart cities was thematically deduced from survey interviews conducted and validated with simple component costing for SWH design and operation. The design of a sustainable and efficient pilot-scale engineering SWH system was synthesised through an extensive literature review for future adaptation. The various analyses and results in ranking the socio-economic and technical barriers to SWH system integration into smart cities connotes ageing infrastructure; the lack of proactive maintenance; and a lack of finance as the biggest challenges to efficient stormwaterharvesting system implementation. The study concludes that SWH presents a viable alternate source for water that might improve urban water self-sufficiency sustainability under different climatic smart city assessments, whilst recommending capacity development where climate change experts transfer knowledge, skills and expertise to upcoming researchers.