NRU :: Browsing by Author "Wanyama, Joshua"

Browsing by Author "Wanyama, Joshua"

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Assessing Land Use and Land Cover Changes in the Murchison Bay Catchment of Lake Victoria Basin in Uganda
(Journal of Sustainable Development, 2018) Kiggundu, Nicholas; Abugri Anaba, Listowel; Banadda, Noble; Wanyama, Joshua; Kabenge, Isa
The Murchison Bay catchment in the northern shoreline of Lake Victoria basin is a high valued ecosystem because of the numerous human-related activities it supports in Uganda. The catchment has undergone tremendous human-induced land use/cover changes, which have not been quantified. This study aimed at quantifying the land use/cover changes as well as the rate at which these changes occurred over the last three decades in the catchment. This was achieved using remote sensing techniques and Geographic Information System (GIS) to analyse and contextualize the changes. To that effect, images of Landsat satellites MSS, TM, ETM+ and OLI were interpreted using supervised image classification technique to determine the land use/land cover changes from 1984 to 2015. The obtained results indicated that the catchment has undergone huge land use and land cover transformations over the last three decades attributable to rapid population growth and urbanization. The prevailing changes in footprint between 1984 and 2015 were expansions of built–up land (20.58% to 49.59%) and open water bodies (not detected in 1984 to 1.74%), and decreases in the following sectors: agricultural lands (from 43.88% to 26.10%), forestland (from 23.78% to 17.49%), and wetlands (from 11.76% to 5.08%). The changes pose a threat to the environment and water quality of the Murchison Bay and consequently increases National Water and Sewerage Corporation water treatment costs. Therefore, there is the need to take critical and practical measures to regulate and police land use, water use rights and conserve the environment especially wetlands.
Assessing soil erosion risk in a peri‑urban catchment of the Lake Victoria basin
(Modeling Earth Systems and Environment, 2022) Ssewankambo, Gyaviira; Kabenge, Isa; Nakawuka, Prossie; Wanyama, Joshua; Zziwa, Ahamada; Bamutaze, Yazidhi; Gwapedza, David; Tally Palmer, Carolyn; Tanner, Jane; Mantel, Sukhmani; Tessema, Bezaye
Soil erosion and sedimentation contribute to deteriorating water quality, adverse alterations in basin hydrology and overall ecosystem biogeochemistry. Thus, understanding soil erosion patterns in catchments is critical for conservation planning. This study was conducted in a peri-urban Inner Murchison Bay (IMB) catchment on the northern shores of Lake Victoria since most soil erosion studies in Sub-Saharan Africa have been focused on rural landscapes. The study sought to identify sediment sources by mapping erosion hotspots using the revised universal soil loss equation (RUSLE) model in appendage with field walks. RUSLE model was built in ArcGIS 10.5 software with factors including: rainfall erosivity, soil erodibility, slope length and steepness, land cover and support practices. The model was run, producing an erosion risk map and field assessments conducted to ground-truth findings and identify other hotspots. The percentage areas for RUSLE modelled erosion rates were: 66.8% for 0–2 t ha− 1 year− 1; 10.8% for 2–5 t ha− 1 year− 1; 10.1% for 5–10 t ha− 1 year− 1; 9% for 10–50 t ha− 1 year− 1 and 3.3% for 50–100 t ha− 1 year− 1. Average erosion risk was 7 t ha− 1 year− 1 and the total watershed erosion risk was 197,400 t year− 1, with croplands and steep areas (slope factor > 20) as the major hotspots (> 5 t ha− 1 year− 1). Field walks revealed exposed soils, marrum (gravel) roads and unlined drainage channels as other sediment sources. This study provided the first assessment of erosion risk in this peri-urban catchment, to serve as a basis for identifying mitigation priorities. It is recommended that tailored soil and water conservation measures be integrated into physical planning, focusing on identified non-conventional hotspots to ameliorate sediment pollution in Lake Victoria.
Assessing the Effect of Irrigation Water Management Strategies on Napier Productivity—A Review
(Agricultural Sciences, 2021) Ntege, Ivan; Kiggundu, Nicholas; Wanyama, Joshua; Nakawuka, Prossie
Napier, a fast growing and perennial grass has a dry matter (DM) yield potential of 78 tons/ha/yr. However, under water availability constraints Napier’s yield potential reduces to 62 tons/ha/yr. In an effort to attain Napier’s yield potential, irrigation management strategies have been integrated into its production to provide the highest productivity. This review assesses the effect of irrigation water management strategies on Napier productivity and also looks at future perspectives. Application of these strategies i.e. , precision irrigation, deficit irrigation, and application of biophysical models, can increase Napier’s yield potential to 112 tons/ha/yr. Review findings revealed that there is a need to close the knowledge gap on response of Napier productivity to different irrigation water management strategies. The future perspective explores the potential of the FAO AquaCrop model in provision of pre-season decision-making on irrigation strategies due to its relatively low cost and simplifications required in parameterization.
Assessing the Extent of Historical, Current, and Future Land Use Systems in Uganda
(Land, 2018) Mwanjalolo, Majaliwa Gilbert Jackson; Barasa, Bernard; Mukwaya Isolo, Paul; Wanyama, Joshua; Kutegeka, Sophie; Nakyeyune, Cotilda; Nakileza, Bob; Diisi, John; Ssenyonjo, Edward; Nakangu, Barbara
Sustainable land use systems planning and management requires a wider understanding of the spatial extent and detailed human-ecosystem interactions astride any landscape. This study assessed the extent of historical, current, and future land use systems in Uganda. The specific objectives were to (i) characterize and assess the extent of historical and current land use systems, and (ii) project future land use systems. The land use systems were defined and classified using spatially explicit land use/cover layers for the years 1990 and 2015, while the future prediction (for the year 2040) was determined using land use systems datasets for both years through a Markov chain model. This study reveals a total of 29 classes of land use systems that can be broadly categorized as follows: three of the land use systems are agricultural, five are under bushland, four under forest, five under grasslands, two under impediments, three under wetlands, five under woodland, one under open water and urban settlement respectively. The highest gains in the land amongst the land use systems were experienced in subsistence agricultural land and grasslands protected, while the highest losses were seen in grasslands unprotected and woodland/forest with low livestock densities. By 2040, subsistence agricultural land is likely to increase by about 1% while tropical high forest with livestock activities is expected to decrease by 0.2%, and woodland/forest unprotected by 0.07%. High demand for agricultural and settlement land are mainly responsible for land use systems patchiness. This study envisages more land degradation and disasters such as landslides, floods, droughts, and so forth to occur in the country, causing more deaths and loss of property, if the rate at which land use systems are expanding is not closely monitored and regulated in the near future.
Assessing the Impact of Management Options on Water Allocation in River Mubuku-Sebwe Sub-Catchments of Lake Edward-George Basin, Western Uganda
(Water, 2021) Mwebaze, Caroline Ednah; Mwanjalolo Majaliwa, Jackson-Gilbert; Wanyama, Joshua; Gabiri, Geoffrey
Limited studies in East Africa and particularly in Uganda have been carried out to determine and map water use and demands. This study aimed at assessing the impact of management options on sustainable water allocation in environmentally sensitive catchments of Mubuku and Sebwe of Lake Edward-George basin in Western Uganda. We used hydro-meteorological data analysis techniques to quantify the available water. We applied Mike Hydro model to allocate water to the different ongoing developments in the catchment based on 2015 and 2040 water demand management scenarios. We used the Nile Basin Decision Support System to assess the sustainability of the different water management scenarios for sustainable water resources use. Reliability computation did not consider hydropower in this study. Results show that water available in 2015 was 60 MCM/YR and 365 MCM/YR for Sebwe and Mubuku, respectively and is projected to decrease by 15% and 11% by the year 2040 under climate scenario RCP8.5. We project water demand to rise by 64% for domestic, 44% for livestock, 400% for industry, 45% for hydro power and 66% for irrigation by 2040. Mubuku water demand is projected to increase from 5.2 MCM in 2015 to 10.7 MCM in 2040. Mubuku available water is projected to fall from 364.8 to 329.8 MCM per annum. Sebwe water demand is projected to increase from 9.7 MCM in 2015 to 22.2 MCM in 2040 and its available water is projected to fall from 60 to 52 MCM per annum by the year 2040 from 2015. Water managers ought to allocate water based on the reliable water allocation which prioritizes domestic and environmental water demands, allocates 90% of industrial demand, 70% of irrigation and 60% of livestock demand. We recommend institutionalizing this model to guide water allocation in the Mubuku-Sebwe sub catchments. Water users should employ more efficient water use techniques to achieve high reliability and sustainable water resources management.
Assessment of a Cattle Manure Vermicomposting System Using Material Flow Analysis: A Case Study from Uganda
(Sustainability, 2019) Jjagwe, Joseph; Komakech, Allan John; Karungi, Jeninah; Amann, Arabel; Wanyama, Joshua; Lederer, Jakob
Growth in cattle population is associated with increased manure generation whose current management in low-income countries is associated with health and environmental problems as well as low utilization rates. This trend can be reversed by promoting better manure management technologies. This study assessed vermicomposting as one of the technologies to manage organic wastes, using the case study in Uganda. A vermicomposting system using cattle manure and earthworms (Eudrilus euginea) was monitored for one year with the harvesting of products (compost, earthworm biomass) after every three months. Vermicompost samples from the beginning of the experiment and after every harvest were analyzed for the following parameters: pH, ash content, volatile and total solids, nutrients N, P, K, and C. Emissions of CO2, CH4, NH3, and N2O were also measured. Material flow analysis was used to determine the flows and retention of nutrients within the system. Results showed that total solids, ash, N, P, and K content significantly increased, while contents of volatile solids and C, as well as the pH, significantly decreased over time. Of the materials that entered the vermicomposting system, 46% went to vermicompost, 2% into earthworms, and 52% was lost to the atmosphere. Substance flow analysis showed that 30% of C went to vermicompost, 69% was emitted to the atmosphere, and 2% ended up in earthworms while 75% of N was transferred to vermicompost, 7% went to earthworms, and 18% escaped into the atmosphere. The cumulative emissions were 102 g CO2 kg􀀀1 waste, 7.6 g CH4 kg􀀀1 waste, and 3.943 10􀀀5 g N2O kg􀀀1 waste on a dry basis, while NH3 was not detected throughout the measurement time. Compared to other manure management methods, vermicomposting demonstrated good potential in conserving nutrients as well as reducing greenhouse gas emissions.
Assessment of irrigation water distribution using remotely sensed indicators: A case study of Doho Rice Irrigation Scheme, Uganda
(Smart Agricultural Technology, 2023) Wamala, Fawaz; Gidudu, Anthony; Wanyama, Joshua; Nakawuka, Prossie; Bwambale, Erion; Chukalla, Abebe D.
The rising competition for scarce land and water resources and the need to satisfy the global food demand from an ever-growing population necessitates novel methods to monitor irrigation scheme performance for improved water use efficiency. The traditional methods employed in sub-Saharan Africa to assess irrigation performance are point-based, expensive, and time-consuming, making monitoring and evaluation of these capital-intensive projects difficult. This study aimed at employing satellite data with high spatial and temporal resolution in assessing the performance of Doho Rice Irrigation Scheme through estimations of actual evapotranspiration. Actual evapotranspiration (ETa) was modelled from Landsat 7 imagery using the surface energy balance system algorithm on five clear days between January and April 2020. Using equity and adequacy metrics, the derived ETa was used to assess the irrigation performance of the scheme. Results showed that the equity indicator was generally fair, with the coefficient of variation between 0.11 and 0.08, close to the 0.10 threshold implying irrigation water is fairly distributed within the scheme. The average adequacy was 0.87, above the 0.65 threshold, indicating adequate water supply throughout the scheme. The study’s findings can be used in future research and benchmarking with other irrigation schemes to address the country’s water resource management challenges.
Assessment of Municipal Organic Solid Waste, as a Potential Feedstock for Briquette Production in Kampala, Uganda
(Uganda. Journal of Sustainable Bioenergy Systems, 2020) Abondio, Richard B.; Komakech, Allan J.; Kambugu, Robert K.; Kiggundu, Nicholas; Wanyama, Joshua; Zziwa, Ahamada; Kyamanywa, Samuel
The current shortage of energy resources coupled with environmental degradation problems resulting from deforestation in Uganda has contributed to increased demand for renewable energy resources including municipal organic solid waste and agricultural residues. However, organic waste from Municipal Solid Waste (MSW) may contain contaminants that are harmful to public health and the environment. This study determined the heavy metal concentration in MSW in Kampala City, Uganda. Also, the physicochemical properties of briquettes produced from the MSW were compared with charcoal. The waste samples were collected from residential, institutional and market areas over a period of two weeks. They were then analyzed for the presence of heavy metals. Briquettes were made from the bio-waste and were subjected to calorific and proximate analysis. Results indicated that the mean concentrations of Cd, Cr, Cu, Fe, and Pb were 1.25 mg/kg, 2.04 mg/kg, 38.2 mg/kg, 3.97 mg/kg and 1.99 mg/kg respectively while Hg was not detected. The calorific values of briquettes ranged from 8.9 to 15.3 MJ/kg and were lower than those of charcoal. Heavy metal concentrations in bio-waste collected were below the permissible acceptable limits. These findings indicate that the sampled MSW does not pose a health hazard arising from the presence of such heavy metals and therefore could be a safe source of renewable energy
Bio-Filtration Technologies for Filtering Ammonia in Fish Tank Effluent for Reuse—A Review
(Journal of Environmental Science and Engineering, 2019) Grism Obeti, Lawrence; Wanyama, Joshua; Banadda, Noble; Candia, Alphonse; Onep, Samuel; Walozi, Ronald; Ebic, Andrew
Peri-urban fish farms with limited access to open natural water bodies draw fresh water from urban water supply and dug wells, which is unreliable and costly. Reuse of fish pond effluent is also limited by high ammonia concentration (> 0.3 mg/L) that renders water toxic and is stressful to fish. Despite the existence of several fish effluent treatment methods, not all may be appropriate for a particular location. This review article therefore examines the various fish effluent treatment methods to aid selection of the most suitable one(s) for peri-urban areas. The key parameters considered in their comparison were: initial, operational and maintenance costs; ammonia removal efficiency; energy consumption and land requirement. The effluent treatment methods are both conventional and non-conventional. Despite a slight higher treatment efficiency and less space requirement by conventional methods, they mainly require reliable power supply for continuous running, highly skilled labor for operation and maintenance leading to high operational costs. In addition, their investment costs are higher than non-conventional methods, hence not widely applied in developing countries and majority have broken down. On the other hand, non-conventional methods such as constructed wetlands are widely in use for treating effluent mainly due to their cost effectiveness and no or little energy requirement. Constructed wetlands were found most suitable bio-filtration system for treating fish effluent because they are cost effective, require less skilled labor and still have better effluent treatment though space required is slightly more. Vegetables (lettuce, collards, etc.) have potential to grow in constructed wetlands thus form vegetable-based bio-filtration units which serve not only as bio-filters but also provide additional sources of nutrition and income. This review indicated limited information on the appropriate size and performance of vegetable-based bio-filtration unit utilizing indigenous vegetables and recommended further research to explore the idea.
Contextual investigation of factors affecting sludge accumulation rates in lined pit latrines within Kampala slum areas, Uganda
(Water SA, 2016) Zziwa, Ahamada; Lugali, Yvonne; Wanyama, Joshua; Banadda, Noble; Kabenge, Isa; Kambugu, Robert; Kyazze, Florence; Kigozi, Julia B.; Tumutegyereize, Peter
Pit latrines in slums areas of Uganda fill up faster than might be expected from some estimates owing to inappropriate use and failure to consider critical factors affecting sludge accumulation rates at the planning, design and construction stages. This study sought to investigate factors affecting filling rates of lined pit latrines in slum areas of Kampala with the goal of contributing to accurate planning, design, construction, emptying and overall maintenance. Fifty-five pit latrines were selected from the five divisions of Kampala city using stratified random sampling. Data collected included: number of users, frequency of emptying, years taken since last emptying, type of non-faecal materials deposited, cross-sectional dimensions of the pit, rate of sludge degradation and geo-physical factors of pit location. Methods used were: field surveys, questionnaires and key informant interviews plus on-site depth measurement. Mass loss tests to investigate the rate of sludge degradation were carried out in the laboratory at moisture content levels similar to those in pit latrines. Sludge accumulation rates were calculated using volume of sludge in the pit, number of users and time taken since last emptying. Statistical analyses included correlation and one-way ANOVA. Results revealed that number of users and type of material deposited in the pit latrines, especially non-faecal matter, had a significant (p < 0.05) effect on sludge accumulation rate. Public pit latrines with a higher number of users had lower sludge accumulation rates and this was attributed to greater degradation taking place and greater restriction on entry of non-faecal matter. The rate of sludge degradation was higher at 90–100% than 80–90% moisture content, due to better degradation conditions. Tighter restrictions on non-faecal material deposition into pit latrines are recommended to reduce filling rates of pit latrines in slum areas.
Determinants for the adoption of residential rainwater harvesting systems on the slopes of Mt. Elgon, East‑Africa. How do they perform?
(Sustainable Water Resources Management, 2020) Barasa, Bernard; Wanyama, Joshua; Winnie, Nandutu
In recent years, the mountainous regions are becoming more susceptible to devastating climatic shocks causing food insecurity and environmental degradation. In response, farmers with small landholding are gaining interest in deploying Residential Rainwater Harvesting Systems (RRWHS) to improve water supplies in homes, though diminutive consideration has been given to the performance evaluation of these systems in a mountainous landscape in the tropics. Our study intended to explicitly understand the determinants for the household adoption of RRWHS and evaluate their performance to improve domestic water supplies in the study area. The study took a cross-sectional design were 444 respondents were selected using a cluster sampling method, and administered with semi-structured questionnaires. The indicators used to assess system performances were: reliability, cost-effectiveness and efficiency. The results of this study showed that system/component price-subsidies, household income-status, landholding-size, availability of technical support and farmer education-level were the most significant determinants for the uptake of RRWHS (P < = 0.05). Performance-wise, the most reliable systems were corrugated metallic-tanks and concrete-ferro-cement tanks. The most cost-effective system was plastic jerrycans; while the most-efficient were concrete ferro-cement and plastic tanks. This study reveals that tax exemptions on the manufacture and importation of RRWHS components can increase their acquisition. The high-capacity storage RRWHS systems are preferred by the farmers due to improved water supplies to sustain domestic usage and farming requirements but also safeguard the environment from surface run-off and overexploitation. Plastic-storage facilities are preferred, because they did not react with water compared to metallic systems.
Development of a Water Allocation Model for Equitable Water Distribution at Doho Rice Irrigation Scheme, Uganda
(Hydrology, 2019) Bwambale, Erion; Gathogo Home, Patrick; Messo Raude, James; Wanyama, Joshua
The shortage of irrigation water at the tail reaches of Doho Rice Irrigation Scheme especially in the dry season has resulted in decreased rice production. At Doho Rice Irrigation Scheme, water distribution follows a predetermined rotation system where allocated supplies are unknown and the farmer decides how much water they divert to their plot. This has resulted in water inequalities between the tail end and head end blocks of the scheme. The main objective of the study was to develop a water allocation model for equitable distribution of irrigation water taking into account crop growth stages. This study developed an equitable water allocation model by ensuring that the crop water requirements per block are matched with the available supply in the main canal. A water delivery scheduling model was developed to help deliver the decadal irrigation water requirements by grouping different blocks together. The water allocation model gives required irrigation supplies and recommended supplies depending on the crop growth stage and acreage per block. The results from the water delivery scheduling model suggest a 2 days of irrigation per week for the land preparation, development and late seasons and 3 days of irrigation per decade during the high consumptive stages of initial and midseason stages of rice development.
Economics of Grass Strips Used as Sediment Filters in the Riparian Zones of Lake Victoria, Uganda
(Agroecology and Sustainable Food Systems, 2012) Mugonola, Basil; Kimaro, Didas; Isabirye, Moses; Deckers, Jozef; Poesen, Jean; Wanyama, Joshua; Mathijs, Erik
Land-use change in the riparian zones has lead to flow of sediments and nutrients into Lake Victoria. Using net present value (NPV) and sensitivity analysis techniques, economic viability of Paspalum, lemon, and elephant grasses as sediment filters under maize production are determined. Findings reveal that grass strips in maize production generates NPVs of 1,620 Cha−1, 1,736 Cha−1, and 1,766 Cha−1 for maize + Paspalum, maize + lemon and maize + elephant grass, respectively, at 5% discount rate. Sensitivity analyses show, NPVs are stable to varying discount rates but not to yield declines in maize and grasses. Overall, integrated land use to reduce sediment and nutrient fluxes is a more acceptable solution to land-constrained farmers.
Effect of thermal shock on the grates of improved charcoal cook-stoves made from different materials
(Energy for Sustainable Development, 2021) Tumutegyereize, Peter; Muwanguzi, Simon; Ayaa, Fildah; Kizito, Simon; Wanyama, Joshua
From the current literature on cook stoves, it remains unclear on which is the best temper and the alternative soils that can be used in the production of charcoal cook-stoves that are resistant to thermal shock. To this end, a study was conducted to determine which soil type and mixing ratio that can produce the highest thermal shock resistance when used as grates. The grates made of clay, red and anthill soils each mixed with shale rock in ratios of 1:0; 1:1; and 3:1 were compared. The grates were fired and then heated in a furnace set at 400 °C for 1 h and subjected to two cooling treatments; rapid cooling by quenching inwater and cooling at ambient temperatures, for seven subsequent cycles after being heated. The shock resistance for all the grates made from different soil types and different mix ratios was measured based on crack initiation and propagation according to ASTM C1525-04 standards. The results showed that clay soil mixed with shale rock in the ratio of 3:1 had the highest thermal shock resistance with no crack initiation throughout the heating and cooling cycles, followed by anthill soil mixed with shale rock in the ratio of 1:1. Therefore, charcoal stove users and manufacturers can expect a better quality productwith high durability if shale rock is used to temper the cook-stoves in comparison to burnt bricks that are currently commonly used in Uganda. The method used in this work can be applied in other regions to come up with more material ratios that are resistant to thermal shock.
Effects of Incorporating Biochar into the Soil using Power Tiller and Ox Plough
(Sustainable Agriculture Research, 2017) Ndhlovu, Masauso; Kiggundu, Nicholas; Wanyama, Joshua; Banadda, Noble
Existing knowledge about biochar is derived from trials where biochar incorporation into the soil is done by hands, a practice too tedious to scale-up to commercial levels. To enhance scalability, biochar incorporation needs to be integrated into conventional mechanised tillage systems. This study aimed at assessing the effects of incorporating biochar by power tiller and ox-plough on soil water retention, maize growth and yield. A 2 x 3 factorial experiment was conducted in a split-plot design with biochar incorporating method as a main plot factor and biochar level as subplot factor, on ferralsols of central Uganda. Incorporation methods were by power tiller and ox-plough with hand mixing in planting basins as a control, while levels of biochar were 0 and 10 t ha-1 application rates. Data was analysed using two-way ANOVAs in Minitab for significant differences among incorporation methods. Results showed that incorporating biochar by power tiller significantly increased water retention effect of biochar by 27.5% (p < 0.05), while no significant effect was observed (p ≥ 0.05) when incorporated by ox-plough, compared to hand mixing. No significant difference on growth and yield was observed (p ≥ 0.05) as a result of incorporating biochar by power tiller and ox-plough instead of hands in planting basins. These findings suggest that biochar incorporation can be scaled-up, to commercial levels, through the use of power tiller and ox-plough, without negative effects on biochar performance. It is recommended that promotion of biochar technology encompasses the use of power tillers and ox-ploughs to enhance scalability.
Freshwater lake inundation monitoring using Sentinel-1 SAR imagery in Eastern Uganda
(Annals of GIS, 2020) Barasa, Bernard; Wanyama, Joshua
In flood hazard assessment, little attention has been given to the seasonal observation of freshwater inundation using Sentinel-1 Synthetic-Aperture Radar (SAR) images in the tropics. To assess these spatial variations, this study examined the inundation magnitudes and reflectance of riparian flora in the raining seasons (February-April and September-November) and dry-periods (May-August and December-January). The inundation areas were determined using an object-oriented classification algorithm, whilst the merits concerning the lake, riparian vegetation and shoreline were well-defined using backscatter-coefficient values. Findings indicated that the SAR images are practical to monitor inundation coverages and discern lake basin specific features such as highland areas, shoreline, water and riparian-vegetation. Seasonally, inundated sizes were comparatively higher in February (902 sq. km) and October (700 sq.km). Backscatter values of inundated parts varied from −16 dB to −19 dB, whereas those of riparian vegetation were higher in the months of May and August. This study hence displays a clear-cut correlation between riparian-vegetation, hydrology and climate variables.
Greenhouse gas emissions from Uganda's cattle corridor farming systems
(Agricultural systems, 2019) Kiggundu, Nicholas; Ddungu, Stanley Peter; Wanyama, Joshua; Cherotich, Sam; Mpairwe, Denis; Zziwa, Emmanuel; Mutebi, Faizal; Falcucci, Alessandra
The objective of this study was to estimate the greenhouse gas (GHG) emissions from practised cattle farming systems (Stall, Semi-Intensive, Grazing, Tethering and Scavenging) and identify potential areas for GHG mitigation. Using the Global Livestock Environmental Assessment Model (GLEAM-i), GHG emissions in 2016 were 2009 Gg CO2-eq/yr of which the Grazing system contributed 88.5%. Enteric fermentation produced about 75.8% of the total GHG emissions. At an annual growth rate of 3%, the projected GHG for 2020 and 2025 would increase by 12.6% and 30.7% respectively. The milk and meat emission intensities were far higher than the global averages. A reduction in grazing by 10% and a 10% increase in use of anaerobic digesters to handle manure resulted in a 4.4% reduction in annual GHG emission.
Hydraulic performance evaluation of the water conveyance system of Doho Rice Irrigation Scheme in Uganda
(Journal of Sustainable Research in Engineering, 2019) Bwambale, Erion; Home, Patrick G.; Raude, James M.; Wanyama, Joshua
Poor water distribution is a major problem in many surface irrigation schemes in Uganda, especially at the tail reaches. This has led to reduced crop yield from these water-stressed fields. This study reports the results of evaluating the hydraulic performance of the water conveyance system of Doho Rice Irrigation Scheme for one cropping season for the first quarter of 2019. For the main canal, the conveyance efficiency indicator was used while for the lateral canals indicators of adequacy, efficiency, dependability, equity, and the equity ratio of head to tail were used to evaluate the hydraulic performance. Performance indicators were computed at the head and tail ends of the canals thus comparing the inlet and distribution processes. Field measurements coupled with simulation techniques were used to obtain the delivered and required flows. It was found that the acceptable average hydraulic performance indicators of the scheme were 0.84, 0.79, 0.07 and 0.26 for adequacy, efficiency, dependability, and equity respectively, the tail reaches suffer in performance with the adequacy, dependability, and equity ratio at 0.68, 0.12, and 3.13 respectively. Improving hydraulic performance of the scheme necessitates reduction of water conveyance losses, adherence to distribution plans and monitoring of diversions to the canals
The impact of papyrus wetland encroachment on the spatial and temporal variability of stream flow and sediment export in the upper Rwizi catchment, Southwest Uganda
(EGU General Assembly, 2014) Ryken, Nick; Vanmaercke, Matthias; Wanyama, Joshua; Deckers, Jozef; Isabirye, Moses; Poesen, Jean
During the past 30 years, human activities in the Lake Victoria basin are responsible for eutrophication of Lake Victoria via sediment-bound nutrients. This affects food security for millions on people. Addressing this problem in this densely populated region will require adequate catchment management strategies. However, sediment yield and runoff data to develop such a strategy are currently unavailable. Also in general, sediment yields for catchments in tropical environments are very scarce, especially in East-Africa. Therefore, runoff discharge and sediment export measurements were conducted in the upper Rwizi, a representative catchment for the Lake Victoria basin which is located in Southwest Uganda. Land use in this catchment is characterized by grazing area on the high plateaus, banana cropping on the slopes and Cyperus papyrus L. wetlands in the river valleys. These papyrus wetlands are currently encroached and transformed into cropland. Eight subcatchments (99 km2 - 2120 km2), with different degrees of wetland encroachment, were monitored during the hydrological year June 2009 - May 2010.
Irrigation Development in Uganda: Constraints, Lessons Learned, and Future Perspectives
(Journal of Irrigation and Drainage Engineering, 2017) Wanyama, Joshua; Ssegane, Herbert; Kisekka, Isaya; Komakech, Allan John; Banadda, Noble; Zziwa, Ahamada; Ebong, Tobias Oker; Mutumba, Charles; Kiggundu, Nicholas; Kayizi, Ronald Kato; Mucunguzi, Dominic Banaga; Kiyimba, Florence Lubwama
Policy makers in sub-Saharan African (SSA) countries have identified irrigation as a key ingredient to boosting food security and income as well as a precursor for agricultural development. However, most SSA countries have hardly exploited their irrigation potential. The overarching aim of this paper is to critically examine factors constraining exploitation of irrigation potential in Uganda. Lessons learned from previous interventions and successes elsewhere from countries comparable to Uganda are drawn and future perspectives to guide effective irrigation planning and development are recommended. From this paper, it is evident that there is no single blanket solution to constraints of irrigation development in SSA. All strategies should be implemented in a holistic manner dictated by specific local conditions. The key to successful adoption of irrigation lies in building the national irrigation capacity, improving access to reliable water for irrigation in proximity of the farms, streamlining extension services for farmers, addressing economic aspects of irrigation, and streamlining land tenure systems and management. It is recommended to operationalize government policy on irrigation by developing national guidelines on irrigated agriculture.

Browsing by Author "Wanyama, Joshua"

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