Browsing by Author "Qi, Jihong"

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    Assessment for sustainable water utilization from the Huixian karst wetland in Guilin of China
    (University of the Western Cape, 2025) Qi, Jihong
    Karst wetland as a special type of the inland wetland has significant ecological functions and associates socio-economic values. Huixian karst wetland located in Guangxi Zhuang Autonomous Region in the southwest of China providesthe irreplaceable goods and services for local development, as the focus of the study in this thesis. With the urbanization in terms of population growth and housing construction, however, Huixian wetland was kept in change in land use practices and increase in local use of water resources over time, especially in the past 40 years. The wetland suffers from shrinkage in size at an alarm rate and serious degradation of ecological functioning. It takes much negative effects on local residential livelihood and economic development. This thesis focuses on the core area of Huixian wetland as the study area aiming to assess its water utilization while maintaining the currently ecological health. Considering the complex hydrogeologic regimes of the wetland itself and the lack of historical monitoring data on hydrology locally, a methodology consisting of multimethods and techniques were reviewed and adapted at a macro scale of the problem, including field surveys, water balance, remote sensing (RS), geographic information system (GIS), ecological water requirement and numerical simulation. At the beginning of the study, the dedicated field geomorphological investigations for many times were carried out, which assisted for understanding of the relationship of each component and the water circulation paths of the study area and paved the way for the follow-up methods. The application of the RS and GIS were used to extract the spatial and temporal https://uwcscholar.uwc.ac.za/home 2 change of the hydrological regimes, land use and growth condition of aquatic vegetations over the study area during long-term period, which were used to patch up the absence of long-term monitoring data. Based on the analysis results, ecological water requirement of wetland was determined in terms of selected the indicator of the aquatic vegetation for limiting factor to control the water utilization, in order to avoid continued loss of the wetland function further more. And then, a hydrogeological conceptual model was built to simulate the groundwater flow regime. A zone of mobile groundwater divides within the wetland catchment between Lake Mudong and Fenshui Pond was conceptualized and verified as opposed to a postulated single fixed line of a watershed. The zone or belt of drifting divides occurred, whereas a crucial role of Lake Mudong it the belt formulation was analyzed. Based on this study, it was concluded that the impact of the supply water scenario of less than 20% withdrawal of groundwater recharge for meeting sustainable water utilization of local community was the acceptable margin of the fluctuation in order to maintain the current wetland integrity and health without getting further degradation.
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    Assessment of Huixian Karst wetland for local water augmentation in Guilin, China
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024) Qi, Jihong; Xu, Yongxin; Kanyerere, Thokozani
    Due to the rapid exploitation of water resources in the Huixian karst wetland in the southwest of China in the past decades, the wetland has suffered from shrinkage in size and serious degradation of ecological functioning. To assess how much water within the wetland could still be taken out for local supply purposes while the wetland can still be kept in its normal ecological functioning. Through the use of multi-methods, including field surveys by a multi-disciplinary team, water balance, Remote sensing, GIS and numerical simulation, this paper characterizes the wetland regime of the study area and finally determines scenarios of water resource utilization for local water supply within acceptable parameters of wetland ecological health. Through the analysis of the methods, it was found that the hydrological characteristics of the study area were conditioned by not only the karst water but also the regional precipitation fluctuations. A zone of mobile watersheds for lake Mudong was established as opposed to a conventional single watershed. If the wetland ecosystem is kept at the current status of class III, a scenario of withdrawal of up to 20% of lake inflows could be accommodated. The results and their approaches would provide much-needed information for the protection of the wetland and its sustainable water utilization per se. It would offer a basic reference for similar problems in karst areas of southwest China and other areas alike.