Natural Sciences
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- ItemEffects of sedimentation on water-linked sectors in the Lusitu river catchment in southern Zambia.(The University of Zambia, 2023) Singubi, NordoftThe problem of sedimentation and drying-up of rivers is very pronounced globally, continentally, and nationally. In Southern Zambia and, Lusitu River Catchment in particular, sedimentation and eventual drying up of the river during most parts of the year punctuated diverse environmental and socioeconomic problems, which this study investigated to contribute to the ongoing epistemic debates around the problem. Lusitu River supports a large population of over 20,000 Gwembe Tonga People who were relocated into Lusitu Catchment in 1958, following the construction of Kariba Dam. The overall aim of the study was to assess how sedimentation affected water-linked sectors in the Lusitu River Catchment to formulate strategies for mitigation of negative effects. The objectives of the study were to: (i) investigate main drivers of sedimentation in the Lusitu River; (ii) determine the magnitude of sedimentation in the downstream section of the Lusitu River; (iii) to assess how sedimentation of Lusitu River affected water-linked sectors and (iv) to design an integrated restorative framework for the Lusitu River Catchment. The study was informed by analytic eclecticism paradigm and used mixed methodology, particularly concurrent design so that where applicable, both quantitative and qualitative data were collected. Data on objective one was collected using observation and semistructured interviews and was analysed using descriptive statistics namely, mean, standard deviation, coefficient of variation and thematic analysis. Data on objective two was collected using sediment coring method and was analysed using Inverse Distance Weighted (IDW) in ArcGIS10.4. Data on objective three was collected using semi-structured interviews and was analysed using thematic analysis. Data on objective four was gathered using Focus Group Discussions and was analysed using thematic analysis. The results showed that agricultural activities particularly, dry season crop field preparation prior to the onset of rainfall and intensive soil tillage farming practices were the major drivers of sediment. Sand mining was the least contributor. Geomorphic factors driving sedimentation of Lusitu River were gully erosion, loose soils (Leptosols), unstable riverbanks and weak sedimentary rock formations. There was large-scale siltation in the downstream section which measured 2,863,913.78m3 with mean sediment depth of 3.13m. Due to heavy sedimentation, the downstream of the Lusitu River was found to have lost 68.34% of its channel storage capacity. The intensity of riverbank gardening varied in relation to Lusitu River flow regime. The drying up of the Lusitu River led to water shortage for crop irrigation and livestock watering, but improved supply of drinking water. Small-scale crop farmers and livestock farmers experienced serious water shortage, with the former being the most hit. Time taken to draw water for domestic use increased in relation to the drying up of the river. The study found that local people adapted to water shortage by digging wells on the dry riverbed which were complimented by small sandy reservoirs dug by the local authority on the same for livestock watering. The study proposed river restoration framework, which constitutes nature-based solutions, engineering, conservation agriculture strategies, indigenous knowledge, and sediment business development model, among others. The study concluded that both soil erosion processes such as gully erosion, and upstream anthropogenic activities such as crop cultivation were the main drivers of sedimentation in the Lusitu River Catchment. Water shortage due to severe river sedimentation reduced income from crop farmers. It also reduced the number of livestock farmers reared thereby, perpetuating rural poverty. The study designed an integrated catchment restoration framework for Lusitu River Catchment to restore the river to perennial status, halt and reverse land degradation. The study recommends piloting of the framework for subsequent full-scale implementation.
- ItemRainwater harvesting practices among residents of Mutamabweengwa of Pemba district.(The University of Zambia, 2024) Sinzala, MuchimbaCommunity rainwater harvesting (RWH) systems are seen as an instrument in increasing resilience in recurring droughts and enhancing food security in dry lands of Zambia. Harvested rainwater can be used for agriculture or water supply for households and other domestic uses. This study investigated the practices of rainwater harvesting among residents of MutamaBweengwa area in Pemba district, Southern province. This study used mixed methods approach. A convergent parallel design was used. A total sample of 379 residents were randomly sampled for interviews. 11 key informants were purposively sampled for interviews. The study was done using primary sources, interviews and direct observation. The methods employed in the qualitative data analysis included thematic analysis. Descriptive statistics were used to summarize quantitative data in charts and graphs. The study showed that the residents of Mutama-Bweengwa practice rainwater harvesting using different methods such as dams, buckets, wells, trenches, and soil bunds. However, the study revealed that rainwater harvesting is mainly directly and depended on social, economic and physical factors. Factors that promote rainwater harvesting included technology availability, good environment, good type of roofing, adequate rainfall, good structures and adequate finances. On the other hand, lack of awareness and technical knowledge were key factors that hinder rainwater harvesting. Affordability and accessibility were also identified as potential barriers, emphasizing the importance of considering the financial capabilities and resources of the community in implementing rainwater harvesting systems. The study reviewed that the majority of participants recognized the potential benefits of rainwater harvesting, including improved water security, access to clean water, and enhanced sustainability, etc. However, the study also identified some concerns and challenges that need to be addressed. Therefore, this study recommends for the need for actors of rural development actors such as International Development Agencies, Private Sector, Non-Governmental Organizations as well as Government to provide training and extension services to the residents of Mutama-Bweengwa area so as to develop and disseminate more effective and affordable types of rainwater harvesting and storage technologies as alternatives and to design and develop policy instruments and social institutions that facilitate adoption of Rainwater harvesting and storages practices.
- ItemComputing and data visualisation for selected problems in solar energy using python programming language.(The University of Zambia, 2024) Lungu, MisheckSolar energy plays a vital role in reducing energy deficits by providing a renewable and sustainable power source, and it significantly reduces contributions to climate change compared to fossil fuels. A deeper understanding of the concepts involved in the study of solar energy is crucial for the development of more efficient systems. Many textbooks contain key concepts such as mathematical expressions, tabulated values, and graphical representations that are used as pedagogical tools for the mastery of the subject. However, many of these tools are not interactive and may not be able to provide solutions in real-time. Therefore, this study addresses this gap by developing a user-friendly graphical interface for solving, simulating and visualizing six key solar energy problems. The codes were created using Python 3 and its libraries from the Jupyter Notebook environment. To empower user interaction and variable control, Ipywidgets, a Jupyter Notebook library was used. Later, the codes were migrated to the Tkinter framework for further development. The developed graphical user interface (GUI) applications were converted into executable files which were deployed on Windows systems. By facilitating real-time problem solving and data visualization the applets can enhance learning and empower researchers.
- ItemAssessment of bacterial contamination of groundwater : a case of Chunga dumpsite of Lusaka, Zambia.(The University of Zambia, 2024) Mwansa, ChilambweThe community near dumpsites/landfills depend on groundwater from shallow wells and boreholes for drinking. However, leachates from dumpsites/landfills could be a source of microbial and toxic chemical contamination to the nearby soil and groundwater. Contamination of groundwater will in turn affect the nearby community by causing diseases. Solid wastes come from various sources including; domestic residences, offices, institutions, commercial buildings, restaurants, agriculture, construction, and hospitals. This study assessed whether the bacterial contaminations from the Chunga Dumpsite solid wastes, were able to infiltrate the soil and contaminate the nearby groundwater. Nine (9) soil samples were collected from the Chunga dumpsite, and nine (9) water samples from boreholes near the Chunga Dumpsite. Physical, chemical and microbiological parameters of the collected samples were analyzed. It was found that most of the parameters conformed to WHO and ZABS standards except for nitrate levels of most of the water samples which exceeded the WHO and ZABS standards. Enumeration of bacteria in the water samples was done, to determine the quality of borehole water. Bacteria were isolated from the soil and water samples using culture methods for identification, then the isolated bacteria were confirmed using PCR methods (16S rRNA gene sequencing). The following bacteria were isolated from borehole water; Citrobacter freundi, Kluyvera georgiana, Acinetobacter indicus, Escherishia coli, Proteus hauseri, Pseudomonas sp, Aeromonas caviae, Klebsiella pneumonia and Atlantibacter hermannii, while the following bacteria were isolated from the soil; Bacillus sp, Klebsiella pneumoniae, Bacillus cereus, Morganella morganii, Acinetobacter variabilis, Pectobacterium carotovorum and Bacillus thuringiensis. On the other hand, Klebsiella pneumonia and Acinetobacter sp. were isolated from both the borehole water and dumpsite soil samples. Consequenty, the Drug Susceptibility Test was done on the isolated bacteria to determine which antibiotic the bacteria were susceptible to. The findings indicated that the isolated bacteria were all susceptible to Gentamicin, Chloramphenicol and Ciprofloxacin and resistant to Penicillin and Cefoxitin Therefore, from the findings, it was concluded that the borehole water near the Chunga dumpsite is not safe to drink and that there is need for authorities to improve the waste disposal and management system ., as well as constant monitoring of the groundwater quality, which will help authority to institute appropriate action to control the groundwater contamination, and eventually prevent unnecessary disease outbreaks in the surrounding communities.
- ItemFactors affecting the performance of solar street lights on selected streets of Lusaka district, Zambia.(The University of Zambia, 2023) Kabunda, KarenWell-illuminated streets play a vital role in enhancing the security and well-being of residents in cities and towns. Investing in solar street lighting can reduce costs spent on grid electricity bills. It can also enhance safety and security at the same time uplift the economy of, women and men who sell/work during late hours. Investment in this area will not only align with the call for gender responsiveness in urban planning in Africa but also help in achieving the sustainable development goal (SDG) 7 which stresses ensuring that there is access to clean and affordable energy by 2030. This study focused on the performance of solar street lights within some selected streets of Lusaka, Zambia, with particular emphasis on factors affecting their performance. The research investigated battery types, switching systems, shading, inclination, and orientation effects on the sampled solar street lights. Systematic sampling selection of street lights was done based on the Yamane Taro formula with a 90% confidence interval for the sample size. The primary data were collected through fieldwork measurement observations and questionnaires. Voltage and current readings were taken in the morning and evening for analysis. The primary data was analysed using a statistical package for social science (SPSS) and Python. The study revealed that the choice of switching system, charging system, and battery type significantly influence the performance of solar street lights in Lusaka. Lithiumion batteries and ultra-capacitors outperformed lead-acid batteries, mainly due to their efficiency and reliability. Flooded lead acid batteries had low efficiency, and lower maintenance requirements and were mainly exposed to vandalism. Physical inspections also identified issues with charge controllers, particularly affecting the lithium-ion batteries and ultra-capacitors. The results revealed that many charge controllers had failed thus allowing the batteries to overcharge in most cases to the extent that they swell and burst. The study showed that majority of the solar street lights are oriented in the northeast, with some facing northwest in roads like Lumumba, great north and Mosi-O-Tunya. Solar panels in the northwest along Lumumba road and great north road exhibited an average power output of 89 W while those oriented in the northeast had the average power of 84 W showing the solar panels in northwest generally outperformed those in the northeast. Furthermore, the orientation and inclination of solar panels were found to impact performance. Poorly oriented and inclined panels led to incomplete battery charging and limited night-time illumination. In conclusion, this research underscores the importance of selecting the right components and installing and ensuring proper maintenance for solar street lighting systems.