Faculty of Engineering and Survey
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Item Watershed management index based on the village watershed model (VWM) approach towards sustainability(International Soil and Water Conservation Research, 2023-02-17) Ignatius Sriyana; J.G. De Gijt; Sri Kumala Parahyangsari; John Bosco NiyomukizaIn the current study, we examine the Indonesian government’s watershed management program, which was established in 2001. In 2005, the Coordination Team for Rescue of Water Resources (CTRWR) was established to execute the program on a national level. However, at the time, field implementation was a sectoral interest due to the lack of program integration. To this end, the Indonesian government promoted integrated watershed management in 2009, which since then has been implemented by all stakeholders (in Tope Down management form), with application limited to preparing and planning documents. This is mainly driven by the stakeholders’ lack of understanding with regard to watershed systems as integrated management units. Field implementation results have not yet been realized, including the promotion of community-based watershed management (through Bottom Up management). The purpose of our research was to determine the index numbers by measuring the level of cooperation between watershed management workers based on the Village Watershed Model (VWM) specifically surface water which includes six variables: planning, participation, institutional, fund sharing, gender, and management systems. The method used was an ordinal measure with the Likert scale. Our data showed successful watershed management, in which five of the six VWM variables planning, participation, institutional, fund sharing, and management systems were in the “good” category with indices ranging from 73.08 to 78.27. The gender variable index (69.12) was in the “medium” category.Item Use of waste glass powder in improving the properties of expansive clay soils(Global NEST Journal, 2025-02-17) John Bosco Niyomukiza; A. Eisazadeh; J. Akamumpa; M. Kiwanuka; A. Lukwago; P. TibotiExpansive soils pose a danger to the foundations of engineering structures due to their poor engineering properties. These soils are usually treated using mechanical techniques, and chemical stabilizers. However, the production of these chemicals is not friendly to the environment, thus a need to adopt waste materials. Therefore, this research investigated the efficacy of utilizing waste crushed glass to alter the engineering properties of the soil. The study's objectives were achieved by conducting experiments on non-stabilized soil, and waste glass powder (WGP) stabilized soil in the percentages of 3, 5, 7, and 9% of dry weight of the soil. The findings showed that adding glass powder to subgrade soil strengthens it and reduces its susceptibility to volume change. The highest compressive strength was obtained after mixing 7% waste glass powder with the soil, and beyond that, the strength reduced. The study found that the inclusion of 7% waste glass powder content is suitable for the stabilization of the soil possessing properties similar to the ones in the study area.Item The Effect of Curing Time on the Engineering Properties of Sawdust and lime stabilized expansive soils(Advances in Engineering Research, 2025-02-17) John Bosco Niyomukiza; Sri Prabandiyani Retno Wardani; Bagus Hario SetiadjiSubgrade strength is the main factor in determining the required thickness of any pavement. Therefore, the properties of a pavement subgrade materials must be determined, as they can predict the service life of a pavement. This paper examines the deviation of strength attained by sawdust and lime stabilized expansive soils for subgrade during different curing periods. The methodology used was conducting laboratory tests such as physical properties and mechanical property tests for both treated and untreated soil samples. In the first set-up, the soil was substituted with sawdust in the percentages of 0, 3, 5, and 7% of the dry weight of the soil, and after conducting unconfined compressive strength test, the optimum sawdust percentage obtained was 3%. The 3% sawdust was then mixed with 3% lime and 94% soil for long term tests. The sawdust-lime stabilized samples were cured for 0, 7, 14, and 28 days, and tested for unconfined compressive test and California Bearing Ratio. Based on the analysis of the results, it was concluded that a combination of 3% sawdust and 3% lime significantly improved the California Bearing Ratio and unconfined shear strength, specifically at later curing periods.Item Temporal trends of water quality parameters, heavy metals, microplastics, and emerging organic pollutants in Lake Victoria and its basin: knowns, knowledge gaps, and future directions(Environmental Nanotechnology, Monitoring & Management, 2025-02-17) Ivan Oyege; Richard Katwesigye; Moses Kiwanuka; Hosea Eridadi Mutanda; John Bosco Niyomukiza; Dafrosa John Kataraihya; Solomon Kica; Moses EgorThe deteriorating water quality and increasing pollution of Lake Victoria, Africa’s most important and world’s second-largest freshwater lake, is threatening the critical resource within East Africa, which has profound ecological and socio-economic significance. This comprehensive review investigates the environmental dynamics of the lake, exploring temporal trends in water quality, heavy metals, microplastics, and emerging organic pollutants in Kenyan, Tanzanian, and Ugandan waters. Assessing the period from January 2000 to December 2022, the analysis integrates research findings from Lake Victoria and its basin. A complex interaction between natural processes and human activity causes fluctuations in the water quality of Lake Victoria. The study reveals substantial variations in key parameters, reflecting the impacts of industrial discharges, agricultural practices, urbanization, and wastewater inputs. Noteworthy among these variations are heavy metal concentrations, with lead consistently surpassing the acceptable levels in Kenyan and Ugandan waters. Zinc concentrations showed varying patterns, and chromium levels in sediments raise concerns by surpassing EPA guidelines in specific locations. The investigation of organic pollutants identified over 170 contaminants, highlighting the dominance of dichlorodiphenyltrichloroethane (DDT) and its derivatives. Microplastics, recognized in the guts of vital fish species and surface water, merge as a growing concern, posing risks to the aquatic ecosystem. This review illuminates the nature of pollutants in Lake Victoria and identifies knowledge gaps in research attention, especially in the northwestern, western, and southwestern lake basins, and the islands of Lake Victoria, overlooked for more than two decades. Scrutinizing existing research, it serves as a compass, pointing towards areas necessitating further investigation and thereby charting future directions in the research communityItem Recent advances in the stabilization of expansive soils using waste materials: A review(IOP Conference Series: Earth and Environmental Science, 2025-02-17) John Bosco Niyomukiza; S P R Wardani; H SetiadjiThe increasing population necessitates infrastructural development, and these civil engineering infrastructures are constructed on soils. Highways, buildings, bridges, railways, and dams need a strong foundation; however, some soils are not suitable for making a strong foundation. An example is expansive or reactive soils. Expansive soils are subjected to volumetric changes, thus the biggest challenge that geotechnical engineers encounter in the field. In an attempt to make these poor soils more appropriate for use in engineering projects, different stabilization techniques are used. However, well-established stabilizers like cement, lime, and bitumen are associated with environmental challenges. This has attracted the attention of the researchers to look for environmentally friendly and sustainable stabilizers. The current study provides a review of the recent trends in improving the geotechnical properties of expansive soils using waste materials, focusing on their efficacy, the optimum percentage, and research gaps. Wastes considered in this study include waste tires, sawdust, and sawdust ash, and fly ash. The review utilized research articles extracted from different databases, such as Science Direct, Google Scholar, Scopus, Web of Science, and Google. This work could give the geotechnical engineers and independent researchers insight into the recent soil stabilization trends that could lead to sustainable development.Item Recent advances in slope stabilization using porous vegetation concrete in landslide-prone regions: A review(Journal of Building Engineering. Elsevier Ltd, 2025-02-17) John Bosco Niyomukiza; Amin Eisazadeh; Amin EisazadehThe risks of soil erosion and landslides in tropical regions are severe. They are triggered mainly by excessive rainfall, which leads to a pore water pressure spike and a lower shear strength of earth materials. In recent years, there has been a growing interest in the application of durable, economical, and sustainable slope stabilization technologies, and porous vegetation concrete (PVC) has proven to be a promising solution. The PVC technique incorporates both porous concrete and vegetation. Combining these two materials aims to achieve dual benefits: immediate slope protection from porous concrete and continued vegetation growth, which positively influence the mechanical and hydrological properties of the slope and enhance its aesthetic appeal. This review presents the latest advancements in the use of PVC for slope stabilization, focusing on material mix designs and properties (porosity, strength, pH, and durability), challenges hindering its effective implementation, such as the type and quantity of vegetation seeds compatible with porous concrete, and prospects for future studies that could improve its application. Furthermore, it highlights the advantages and disadvantages of other slope stabilization techniques. This review serves as a valuable resource for practitioners, researchers, and policymakers to implement new methods of slope protection using PVC.Item Optimizing laterite cement blocks in the construction of masonry using quarry dust(IOP Conference Series: Earth and Environmental Science, 2025-02-17) P Tiboti; John Bosco Niyomukiza; M Kiwanuka; J W Mbujje; J Baiga; A F HaduduLaterite soils mixed with Portland cement are used worldwide in making blocks. However, due to the environmental effects associated with the high usage of cement, quarry dust proved to be a good substitute for partial replacement of Portland cement. This study investigates the optimisation of laterite-cement blocks as walling materials using quarry dust. Physical properties of experimental soil were determined, and other tests such as compressive strength, density, water absorption were conducted on sample blocks under curing periods of 7, 14, 21, and 28 days. The blocks comprised of different percentages of laterite soil (76%, 81%, 85% and 87%), quarry dust (9% and 10% by weight of the soil) and ordinary Portland cement (3%, 5%, 10% and 15% by weight of the soil. The results showed that cement content of 10% and 9% quarry dust was suitable for the block at any curing period above 7 days. The compressive strength increased with an increase in the curing period no matter the percentage of the materials used in the study. The study recommends the usage of quarry dust in cement laterite blocks. However, further investigation on other vital parameters like abrasion resistance test could be conducted.Item Investigating the effect of PET plastic bottle strips on the strength and compressibility properties of clayey soil(IOP Conference Series: Earth and Environmental Science, 2025-02-17) John Bosco Niyomukiza; A Bitekateko; J Nsemerirwe; B Kawiso1; M KiwanukaThe production of plastic bottles by the manufacturing industry has increased drastically over the last six decades across the globe. This rapid production has led to the generation of many waste plastic bottles, thus causing environmental pollution. About 180 tonnes of plastics are generated daily in Kampala, the capital city of Uganda, and around 50% is dumped into the Kiteezi landfill. Instead of putting pressure on the landfill, these plastic bottle wastes could be reused in stabilizing soils with poor engineering properties. The current study investigates the engineering properties of clayey soil reinforced with Polyethylene-terephthalate waste plastic bottle strips. In order to achieve the objectives of the study, the geotechnical and engineering properties of the soil reinforced with waste plastic bottle strips at 0.1, 0.2, 0.3 and 0.4% of the dry unit weight of the soil and non-stabilized soil were determined by conducting laboratory tests, such as particle size distribution, Atterberg limits, compaction test and California Bearing Ratio. The results revealed that the California Bearing Ratio of the soil reinforced with Polyethylene-terephthalate waste plastic bottle strips increased with the increase in the percentage of Polyethylene-terephthalate waste plastic bottle strips up to 0.3%. Beyond 0.3%, a drop in California Bearing Ratio was observed. It indicates that 0.3% Polyethylene-terephthalate waste plastic bottle strips is the optimum percentage for stabilizing low plasticity clayey soils.Item Flood analysis and hydraulic competence of drainage structures along Addis Ababa light rail transit(Journal of Environmental Science and Sustainable Development, 2025-02-11) Moses Kiwanuka; Seleshi Yilma; Joel Webster Mbujje; John Bosco NiyomukizaThe occurrence of flooding events and the associated risks are increasing in the urban areas of most developing countries. Flooding in any circumstance causes major stresses on affected area’s economic, social and environmental regimes. Therefore, the current study presents a flood analysis and hydraulic competence of existing drainage structures on some selected roads of Addis Ababa City, after integration with Addis Ababa Light Rail Transit (AALRT) Drainage Systems. The existing side drains and cross drainage structures located within the study area were inspected and assessed to ascertain different aspects relating to their performance. Different watersheds were delineated. Hydrological analysis was then carried out using Geospatial tools such as ARCGIS, ARCSWAT, and HEC GEOHMS to determine the different watersheds contributing to the flows. The flows were obtained from the rational method for areas less than 0.5 km2 and HEC HMS for areas greater than 0.5 km2. The hydraulic analysis was carried out using HY-8 for the culvert and the Hydraulic toolbox for side drains. It was found from field surveys and measurements that the existing side drain of 900 mm circular pipe could not convey the maximum flow. The existing box culvert, which comprised of one barrel was able to convey the design flow of 29.52 m3/s with a headwater elevation of 2300.94 m. The existing box culvert was sufficient in conveying the designed flow since its headwater elevation was lower than that of the roadway elevation. However, observations like the presence of accumulated silt, debris within most side drains, and an undersized side drain reduced its hydraulic competence. The undersized side drain was redesigned by increasing its diameter to 1200 mm. The study acts as a yardstick for drainage assessment, especially for existing structures, an indicator for identifying the most flood-prone areas along the railway track. It recommended an intermediate cross culvert before Lancha, regular desilting, and putting screens at inlets of side drains and some distance before the entrance of the culverts. Periodic maintenance of the existing drainage structures and widening of the pipe conduits for the side drains to about 1200 mm for easy maintenance is also necessaryItem Enhancing properties of unfired clay bricks using palm fronds and palm seeds(Results in Engineering. Science direct, 2025-02-11) John Bosco Niyomukiza; Karen Cathy Nabitaka; Moses Kiwanuka; Paul Tiboti; Joseph AkampuliraThe building industry has been thriving all around the world. With global advancement, particularly in technology, real estate development is evolving with the ongoing adoption of new tactics. The current study investigates the performance of palm fronds and palm seeds in enhancing the properties of unfired clay bricks as construction materials. The methodologies used to attain the study’s objectives were; determining particle size distribution and Atterberg limits of clay soil, efflorescence, compressive strength, water absorption, and fire resistance of bricks, which were used to give the most appropriate percent of palm fronds and palm seeds for robust bricks. The study required experimental research of the materials used and samples made. Using particle size distribution and Atterberg limits, the soil was classified as clayey soil and low to medium plasticity soil. Batching by weight was achieved using a weighing scale and substitution technique to obtain the proportions of contents in samples. Sample 5, which contained 80% clay, and 20% palm fronds, and sample 6, which contained 65% clay, 25% palm seeds, and 10% palm fronds, passed all the tests. Samples 5 and 6, under efflorescence check, confirmed slight responses where 10% of the brick was covered with a skinny deposit of salts. Under compressive strength, samples 5 and 6 recorded 4.23 N/mm2 and 3.85 N/mm2, respectively, which were more significant than the required minimum compressive strength of fired bricks. For water absorption, they attained a moisture content of 18.1% and 16.1%, respectively, which was in the range of 16–20% under second-class bricks. All bricks passed the fire resistance test, which confirmed that they had a reasonable safety factor. In conclusion, mixes of samples 5 and 6 are recommended to produce robust bricks.Item Effects of using sawdust ash as a stabilizer for expansive soils(E3S Web of Conferences, 2025-02-11) John Bosco Niyomukiza; Yusuf YasirExpansive soils are known to swell and shrink with moisture content changes, rendering them unsuitable for construction without proper stabilization. Cement and lime have conventionally served as common additives for soil stabilization. However, in Uganda, the escalating costs of these additives accentuate the need for alternative solutions. Therefore, this research attempts to investigate the viability of sawdust ash, an affordable agricultural waste, as an effective stabilizer for expansive soils. Through systematic experimentation, various percentages of sawdust ash (ranging from 0% to 10%) were introduced into the soil matrix. The objectives of the study were achieved through a series of laboratory tests, including gradation analysis, Atterberg limit determination, compaction, and California Bearing Ratio (CBR) test. The findings revealed the soil is clay with high plasticity, emphasizing the need for stabilization. Importantly, the addition of sawdust ash resulted in a substantial reduction in the plasticity index, from 35% to 16%, at 0% and 10% sawdust ash content, respectively. Furthermore, the incorporation of sawdust ash led to an increase in the maximum dry density and a reduction in the optimum moisture content as its proportion was augmented. Notably, with 6% sawdust ash content, the CBR value reached its highest point at 14.4%. These outcomes reveal the potential of sawdust ash as an economically attractive alternative to traditional stabilizers such as cement and lime. This research contributes valuable insights to the field of soil stabilization and offers a sustainable solution that addresses both economic and environmental concerns in construction practices.Item Assessment of suitability of drinking water from the springs in Urban slums of Kampala(Environmental Challenges, 2022-12-16) Moses Kiwanuuka; Hosea Eridadi Mutanda; John Bosco Niyomukiza; Erinah NakasaggaAny water source used for domestic purposes should meet World Health Organization water quality standards. In most slums of developing nations, water sources such as springs are critical to the residents. Although spring water is often considered fit for domestic use, poor sanitation practices in slums lead to faecal contamination of spring. The objectives of this study were to assess the faecal contamination risk factors and the water quality from the identified springs in Bwaise, Kampala in the dry and rainy seasons. Parameters that were considered in this study were: pH, Electrical conductivity, apparent colour, turbidity, hardness, Chloride, Nitrate, total coliform and E-coli. The cross-sectional sanitary risk assessment for all springs revealed faecal contamination risks. The physiochemical parameters were within the allowable limits of World Health Organization standards for drinking water in all seasons. E-coli values were between 1.35 -13.75Cfu/ 100ml in all seasons. Both total coliform and E- coli were above the permissible limit of o Cfu/100ml in all seasons. When the water samples were analyzed basing WQI, the indices revealed excellent water during the dry season and good water during the wet season. The index values were between 40.09 to 49.34 in the dry season and 54.24 to 74.17 in the wet season. Therefore, treatment or boiling before drinking should be encouraged in the community. Also, proper solid waste management and pit latrine construction strategies should be used in the area