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Item Evaluation of Sediment Generation and Transport: A Case Study of Thwake Dam in Kenya(IWA Publishing, 2024) Maiyo, Gilbert Chumo; Ndiba, Peter Kuria; Odira, Patts M.; Nyangeri, EzekielThe study aimed to evaluate sediment generation, transport, and deposition into the Thwake reservoir. This research sought to assess sediment transport patterns and their potential impact on the reservoir using regional and numerical techniques. The Thwake River basin constitutes 30% of the dam’s catchment area and experiences high soil loss due to its semi-arid climate, steep slopes, and lack of vegetation. The river system in the sub-basin is ephemeral, with the riverbed remaining dry throughout most of the year and experiencing tidal flow only during storm events. Bed material samples were collected from selected reaches, and sediment properties were evaluated. The study involved analyzing datasets on the reservoir, catchment, and sand-bed channel. Numerical models assessed hydrological and sediment transport information by considering interacting variables and predicting deposition patterns and sediment yield estimates. The findings indicated that sufficient bed material from sub-basin 3E would be deposited into the reservoir, resulting in delta formation approximately 5 km downstream of the tail waters at minimum dam operating level. The mass cumulative sediment inflow from 3E into the reservoir was estimated between 14 and 26.3 metric tons per annum, representing reservoir loss and useful life under 50 years.Item Analysis of the Risk of Landslids in Kebomas, Gresik District(Calamity, 2024-01) Setiawan, Romy; Aji, Priatmojo; Arifin, Syahdan; Irmansyah, Rizal; Raenaldy; Kinyua, James GitongaThe landslide disaster occurred during the rainy season in Kebomas District, Gresik Regency, which has topography in the form of hills left over from lime mining in 1960-1990. A field survey conducted from December 2021 to March 2022 stated that landslides occurred during the rainy season in Kebomas District and caused damage to surrounding settlements. Land slope, rainfall, rock type, soil type, and land use are factors that influence the occurrence of landslides. The aim of this research is to map the level of landslide vulnerability in Kebomas District using the Geographic Information System. The research results show that there are three levels of landslide vulnerability in Kebomas District, namely, low, medium and high. The low vulnerability class is found in all villages in Kebomas District, most of which are in six villages or sub-districts in the south, west and north, namely; Dahanrejo, Kedanyang, Pambangan, Kembangan, Randuagung, and Segoromadu. The moderate vulnerability class is found in all villages in Kebomas District, most of which are in six villages in the southeast, northwest and north, namely; Randuagung, Pambangan, Dahanrejo, Kembangan, Sidomoro, and Ngargosari. Areas with a high vulnerability class are in the central part of the sub-districtItem Chromium (VI) Adsorption from Steel Industry Wastewater Using Biomass and Agro-Based Adsorbents: A Review(JAGST, 2024-01) Tinega, N. Joseph; Omosa, B. Isaiah; Letema, C. SammyIn recent years, increased steel production has resulted in an increased release of Cr (VI) effluent from electroplating processes. The current conventional technologies for Cr (VI) removal, for instance, chemical precipitation, ion exchange, membranes, and electrochemical technologies, have proven to be expensive and not eco-friendly. Adsorption using biomass or agro-based adsorbents has been demonstrated to be an eco-friendly method. In this study, the potential of several biomass and agro-based adsorbents for Cr (VI) removal from steel industry wastewater has been reviewed. The application of adsorption parameters, isotherms, and kinetic models has also been reviewed. The study review reveals that the maximum adsorption of Cr (VI) ions from wastewater was dependent on the pH, temperature, contact time, type of adsorbent material, and initial metal concentration. The literature review demonstrated that maximum Cr (VI) adsorption efficiency ranged from 90–100%, with optimum pH, contact time, and temperature ranging from 2–5, 30-180 min, and 25–30 °C, respectively. The equilibrium adsorption data was best described by the Langmuir and Freundlich isotherms and the pseudo- second-order kinetic model. The thermodynamic studies revealed that the adsorption process was spontaneous and endothermic. It has been found that biomass and agro-based adsorbents are potentially eco-friendly alternatives for Cr (VI) removal from industrial wastewater. However, several gaps have been identified to improve the Cr (VI) removal efficiency, spent adsorbent reuse and safe disposal, optimisation, and commercial application of agro-based adsorbents.Item Heavy Metals and Trace Elements Contamination Risks in Peri-Urban Agricultural Soils in Nairobi City Catchment, Kenya(Frontiers, 2023) Agassin Ahogle, Arcadius Martinien; Letema, Sammy; Schaab, Gertrud; Ngure, Veronica; Mwesigye, Abraham R; Korir, Nicholas KIntroduction: With urbanization and industrialization in the developing world, urban and peri-urban agriculture is increasingly contributing to urban food systems, employment, and income generation opportunities. However, urbanization and industrialization may release harmful pollutants, including heavy metals and trace elements into agricultural soils, posing ecological, environmental and public health concerns. This paper assessed the potential risks of soil contamination with heavy metals and trace elements in peri-urban farmlands in Nairobi city catchment in Kenya. Methods: A total of 60 soil samples were collected from ten vegetable farming zones (S1-S10) and processed following standard protocols. The concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn were analyzed in the samples using inductively coupled plasma-mass spectrometry (ICP-MS). Results and discussion: Results revealed that the soil samples have elevated concentrations of As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V and Zn, with some elements including As (1.7%), Cd (13.3%), Mn (80%), Pb (1.7%) and Zn (11.7%) exceeding the permissible thresholds for agricultural soils. The spatial distribution of the elements exhibited three similar distribution patterns with slight variations between the hotspot sites of the different elements: (i) Co and Mn, (ii) Cu and Cr and (iii) As, Cd, Fe, Hg, Pb and Zn, while Ni and V exhibited singular spatial distributions compared to other elements. Elements such as As, Cd, Co, Fe, Hg, Mn, Pb and Zn appeared to be of anthropogenic enrichment, while Cr, Cu, Ni and V appeared to originate mainly from lithogenic and natural sources. The elements As, Cd, Hg and Pb exhibited high ecological risks, with Cd contributing about 46-66% of the overall ecological risk. The sampling sites S1, S5, S7, S9 and S10 depicted the highest ecological risks of 145, 103, 146, 121 and 146, respectively. The findings call for proper zoning of suitable agricultural areas and sound waste management protocols in urban and peri-urban landscapes. Further, remediation of contaminated soils and farmers’ sensitization are recommended for ecological and public health risk alleviation.Item A Perspective of Sustainable Livelihood Framework in Analysis of Sustainability Of rural Community Livelihoods: Evidence from Migori River Watershed in Kenya(Taylor \& Francis, 2023) Opiyo, Stephen Balaka; Opinde, Godwin; Letema, SammyEvaluation of livelihood sustainability in ecologically sensitive areas, impoverished regions, and disaster-stricken zones is critical for understanding sustainability challenges and administering poverty-relief interventions. This paper assesses the sustainability of rural households’ livelihoods in the Migori River watershed in Kenya by constructing a livelihood sustainability index (LSI). A cross-sectional survey design was used to collect data from 318 randomly selected households from the upstream, midstream, and downstream watershed zones. The LSI was constructed using the UK Department for International Development (DFID) methodology based on the five livelihood capitals, and one-way ANOVA was used to test for significant differences between watershed zones. The results of the analysis show that although the livelihoods of all the three watershed zones are moderately sustainable with no significant variations (at p < 0.05) between the zones, the livelihoods of midstream households are most sustainable followed by the upstream households and then downstream. The social (ranging from 0.64 to 0.69), physical (ranging from 0.60 to 0.67) and natural (ranging from 0.60 to 0.64) capitals registered relatively high index values across the watershed zones unlike the human (ranging 0.55–0.65) and financial (ranging from 0.44 to 0.57) capitals that recorded relatively low index values; which implies that human and the financial capitals are least possessed assets in the watershed. Therefore this paper recommends increasing the natural capital through sustained conservation of natural resources, increasing human capital by providing skills training to household on alternative livelihood options, and increasing access to financial capital by strengthening rural entrepreneurship. The paper suggests the usage of LSI by policy-makers as a practical tool to quantify the livelihood capital endowment of rural communities to help in prioritizing watershed management programs and the development of interventions aimed at a specific livelihood asset. It may also help policymakers in project monitoring and evaluation, where it provides feedback critical for continual project improvement.Item Assessing Distribution Changes of Selected Native and Alien Invasive Plant Species under Changing Climatic Conditions in Nyeri County, Kenya(Public Library of Science San Francisco, CA USA, 2022) Waititu, Julius Maina; Mundia, Charles Ndegwa; Sichangi, Arthur WThe role of climate change in enhancing bio-invasions in natural environments needs to be assessed to provide baseline information for effective species management and policy formulations. In this study, potential habitat suitability maps were generated through Ecological Niche Modeling for five problematic alien and native species in current and future climate simulations for the periods 2050s and 2070s under RCP2.6, RCP4.5, and RCP8.5 emission scenarios. Projected current binary suitability maps showed that 67%, 40%, 28%, 68%, and 54% of the total study area ~ 3318 Km2 is suitable for C. decapetala, L. camara, O. stricta, S. didymobotrya and S. campylacanthum species, respectively. Assuming unlimited species dispersal, two of these species, C. decapetala and S. didymobotrya, were observed to have consistent gradual increase in potential habitats and no habitat losses under the three RCPs by the end of the 2050 and 2070 future periods. The highest recorded relative potential habitat increase was observed for O. stricta at ~205% under RCP2.6 and ~223% under RCP8.5. Although L. camara and O. stricta were observed to have habitat losses, the losses will be very low as compared to that of S. campylacanthum. L. camara and O. stricta relative habitat losses were predicted to be between ~1% under RCP2.6 to ~4.5% under RCP8.5 by 2070 while that of S. campylacanthum was between ~50% under RCP2.6 to ~68% under RCP8.5 by the year 2070. From this study we conclude that the target study species are expected to remain a big threat to inhabited areas as well as biodiversity hotspot areas especially in the Mt. Kenya and the Aberdare forest and national park reserves under climate change. The information generated through this study can be used to inform policy on prioritizing management of these species and subsequent determination of their absolute distributions within the area.Item Customary System as ‘Constraint’ or ‘Enabler’ To Periurban Land Development: Case of Kisumu City, Kenya(The UFS, 2019) Wamukaya, Edwin; Mbathi, MusyimiScholarly research on land delivery processes and land tenure dynamics in the context of accelerated urbanization and massive rural-urban land use conversion in sub-Saharan African cities remains limited, especially in Kenya. Kisumu city, Kenya’s third largest urban agglomeration, is currently experiencing spontaneous growth and uncontrolled outward expansions of urban development from the urban centre. This is taking place in the peri-urban areas and rural hinterland, where urban-based actors, under the pressure and anticipation of urbanization, undertake land transactions, land tenure conversions, and land development. Making use of three case studies that represent contrasting phases of settlement formation (incipient, intermediate, and consolidated), this article attempts to provide knowledge, particularly on the relationship between the land delivery processes, land tenure dynamics, and the role of various actors involved in the context of land development. The results indicate that the current trend with regard to landholding in the case study areas was a gradual shift from community control to individualisation. There is a need to integrate both customary and public authority’s efforts towards orderly urban development. This study thus advocates for partnerships between the municipal authority and neocustomary/customary actors and, where appropriate, uses their creativity in solving problems to adapt municipal by-laws and procedures.Item Evaluation and Application of Alternative Rainfall Data Sources for Forcing Hydrologic Models in the Mara Basin(IWA, 2018) Alemayehu, Tadesse; Kilonzo, Fidelis; Griensven, Ann Van; Bauwens, WillyAccurate and spatially distributed rainfall data are crucial for a realistic simulation of the hydrological processes in a watershed. However, limited availability of observed hydro-meteorological data often challenges the rainfall–runoff modelling efforts. The main goal of this study is to evaluate the Climate Forecast System Reanalysis (CFSR) and Water and Global Change (WATCH) rainfall by comparing them with gauge observations for different rainfall regimes in the Mara Basin (Kenya/Tanzania). Additionally, the skill of these rainfall datasets to simulate the observed streamflow is assessed using the Soil and Water Assessment Tool (SWAT). The daily CFSR and WATCH rainfall show a poor performance (up to 52% bias and less than 0.3 correlation) when compared with gauge rainfall at grid and basin scale, regardless of the rainfall regime. However, the correlations for both CFSR and WATCH substantially improve at monthly scale. The 95% prediction uncertainty (95PPU) of the simulated daily streamflow, as forced by CFSR and WATCH rainfall, bracketed more than 60% of the observed streamflows. We however note high uncertainty for the high flow regime. Yet, the monthly and annual aggregated CFSR and WATCH rainfall can be a useful surrogate for gauge rainfall data for hydrologic application in the study area.Item Proposed Catchment Conservation Plan in Community Water Supply in Kenya: The Case of Mbumbuni Water Scheme(Internet Archive, 2020) Omosa, Isaiah Bosire; Oonge, Zablon Isaboke; Kirui, Wesley KipkemoiMbumbuni community water scheme is served by surface runoff and ephemeral streams which is harnessed in an earth dam. The dam has been in existence for decades, and was facing a big problem of reservoir sedimentation from the heavily loaded runoff water. De-silting the reservoir or increasing the dam height would not be long-term solutions without a proper system in place to protect the dam by reducing future siltation through conservation works in the catchment area. An urgent need for protection of the catchment area of the dam arose, not only for conserving or improving the water source and the storage capacity, but also to enhance agriculture and the livelihood of the inhabitants. The conservation plan was develop using project approach method. This article describes a proposed conservation plan for the study area. Implementation of the conservation plan will improve water supply and increase the Dam lifespan through reduction in siltation.Item Application of Unmanned Aerial Vehicles in Improving Land Registration in Kenya(International Journal of Research in Engineering and Science (IJRES), 2017-05) Wayumba, Robert; Mwangi, Patricia; Chege, PatrickThis paper explains why and how Unmanned Aerial vehicles (UAVs), also known as drones, can be used to improve land registration in Kenya. According to a World Bank report that was released in 2003, only about ten percent of land in Sub-Sahara Africa has been formally registered. A more optimistic figure for developing countries in the whole World was released in 2013, which shows that only about thirty percent of land is registered. Thus, a majority of the people are unable to gain from the benefits of registration. An effective land registration system can contribute towards improving: tenure security, real estate markets, access to credit, taxation, dispute resolutions and urban planning among others. A key requirement for improving the extent of registration is to map property boundaries. A means of rapidly mapping the boundaries is to use UAVs. However, it is not clear how UAVs can be used in a county like Kenya. This paper employs case study methodology to explain why and how the UAVs can be used in Kenya. The results section explains different types of UAVs that may be used, legal regulations for using the UAVs and techniques that are required for land registration. The hope of this paper is that it might contribute towards the use of UAVs for improving land registration not only in Kenya but also in other developing countries.Item Evaluation of Potential Physico-Chemical Ground Water Pollution: a Case Study of Kiwanja Market, Kenya(IDOSI Publications, 2019) Macharia, Agnes W.; Kirui, Wesley K.; Omosa, IsaiahGround water is a large source of water for utilisation in the world. This resource is not easily accessible to monitor its changes and its deterioration is not easy to reverse. In the current study, physico-chemical parameters for groundwater for Kiwanja Market (KM) were analysed and compared to the Kenya Bureau of Standards (KEBs) water quality. The pH, DO, temperature, turbidity, chlorine, iron, water hardness, potassium and calcium were analysed. All the parameters studied were within the stipulated levels except iron, chlorine and for samples from point C (Ebenezer Hostel). Turbidity for points A and C were above the permissible levels of KEBs standards. The water from point A and C may require further treatment to allow for domestic use. This analysis revealed to some extent a healthier system, though further analysis is needed to support this assertion. Continuous monitoring of the groundwater source within KM should be taken on regular basis to detect any changes and to sustainably maintain the quality of water within the required KEBs water quality standards.Item The heavy metal content of crops irrigated with untreated wastewater: a case study of Nairobi, Kenya(Jomo Kenyatta University of Agriculture and Technology, 2014) Kaluli, J. W.; Home, P. G.; Githuku, C.Use of untreated wastewater for irrigation could have devastating effects on crop quality. A study was conducted to determine the content of lead, cadmium and chromium in food crops irrigated with untreated wastewater at Kibera and Maili Saba, in Nairobi, Kenya. Crop samples were collected from farms irrigated with untreated wastewater during the dry and wet seasons. While the safe limits of lead and cadmium in food crops are 0.3 and 0.2 ppm, the concentration of lead and cadmium, at Maili Saba downstream ofthe industrial area, in the edible crops during the dry season was 48.4 and 26.5 ppm, respectively. Enrichment factor (EF)was used as a measure of the risk and hazard sustained when crops are irrigated with water that is contaminated heavy metals. Plots planted with black nightshade (BNS) and Kales at Maili Saba, downstream of Nairobi's industrial area, had the highest EF values. Lead in BNS at Maili Saba during the dry season had the highest EFvalue of about 2200, suggesting that irrigating BNS with contaminated sewage could be hazardous. This study has confirmed that irrigation of food crops increases the concentration of heavy metals such as lead and cadmium to unsafe levels.Item Assessment of the Biological Treatability of Black Tea Processing Effluent(2007) Omosa, I.B.; Oonge, Z.N. I.The anaerobic degradability of tea beverage processing effluent was assessed using a stationary upflow anaerobic filter. The filter, with an active column of 1.2m height, inner diameter of 100 mm and filled with rock as the attachment medium was operated at room temperature ranging between 20-250C throughout the study period in both batch and continuous modes. It was seeded with an anaerobic sewage sludge inoculum from an anaerobic pond of a Municipal Sewage Treatment Plant of the City of Nairobi at Ruai. The tea beverage processing effluent obtained from factory washing after processing operations at Kambaa Tea Factory was used as substrate The start-up took over three months for the anaerobic colonies to develop and to start digesting the factory effluent. The long period was for acclimation of the organisms to the new substrate. During this period the filter was operated in a batch mode at a hydraulic retention time (HRT) of 7 days. The operation lasted for 105 days. Immediately after introduction of the black tea effluent (substrate) from Kambaa Tea Factory, the system was in a shock for 28 days. However, it recovered from the shock from day 29 and by day 105 while maintaining the HRT of 7 days a chemical oxygen demand (COD) removal efficiency of 74% was achieved. From day 106 to day 162, the filter was operated on a continuous mode at a HRT of 36 hours with the substrate being fed at an organic loading rate (OLR) of 0.67 kg COD/m3-day. A COD removal efficiency of about 90% was achieved by the end of the period. Removal of suspended solids was 100% in this operation. Removal of colour was more than 85%Item Application of water demand management strategies in Kenya journal of civil engineering research and practice under review.(Kenya journal of civil engineering research and practice, 2013) Omosa, I.B.; Nyangeri, E.N.This study set out to examine the policy position in Kenyan health care financing, with regard to implementation of the proposed social health scheme (NSHIF) and its performance potential. The specific objectives were to: examine the existing social scheme (NHIF), its role and challenges in health care financing; establish whether or not Kenya has the key pre-requisites for introduction and sustainability of a social health scheme and to provide recommendations on the way forward. This was largely a desk study, supplemented with limited primary data from key informants. The analysis indicates that: i) For a universal social health plan to be sustainable, favorable economic indicators and availability of essential infrastructures are critical prerequisites. Resources must be available, government must be in a position to afford high subsidies, the population must be ready to pay high premiums and the supply of health services must be adequate to cater for the expected increase in demand; ii) Countries that have successfully embraced social health plans introduced their schemes carefully and gradually (overtime) in terms of coverage; iii) Kenya compares unfavorably with these countries in terms of prerequisites for sustainability of a social health scheme, due largely to a poor economy, high poverty levels and shortfalls in facilities and services. The study concludes that Kenya lacks the key prerequisites for introducing and sustaining a universal social health scheme. The scheme can hardly be supported by the current status of the economy and healthcare infrastructures. The study recommends: i) Expansion and development of health care infrastructural capacities through subsidies and tax concessions for those investing in health care and providing subsidized services, particularly to the poor and rehabilitation of the GoK facilities; ii) Increasing the health budget from 7 per cent of government expenditure to above 10 per cent and directing more resources and efforts towards preventive/promotive and primary health care (P&PH); and iii) Other recommendations include subjecting the proposed scheme to an actuarial evaluation and comprehensive policy plan in order to determine the attendant and corresponding premium and benefit levels and pursuing a phased approach in the implementation of the scheme.Item Water and Wastewater Treatment in Africa–Current Practices and Challenges(Wiley, 2014) Omosa, I.B.; Wang, Hongtao; Wang, Tao; Zhang, Bingru; Li, Fengting; Toure, Brahima; Chiramba, Thomas; Abdel-Monem, Mohamed; Pradhan, MaheshSustainable access to safe drinking water and basic sanitation is an important part of the millennium development goals (MDGs). For most African countries, an extensive effort is needed for the last three remaining years for the achievement of the MDGs, especially in Sub-Saharan Africa. Current practices for water and wastewater treatment in Africa are insufficient to ensure safe water and basic sanitation. To address this challenge, joint efforts are needed, including transforming to green economy, innovating technologies, improving operation and maintenance, harvesting energy, improving governance and management, promoting public participation, and establishing water quality standards.Item Assessment of environmental and public health hazards in wastewater used for urban agriculture in Nairobi, Kenya(Universidad Autonoma de Yucatan, 2010) Githuku, C.; Karanja, N.; Njenga, M.; Prain, G.; Kang’ethe, E.; Kironchi, G.; Kinyari, P.; Mutua, G.K.Thirty percent of residents in Nairobi practise urban agriculture (UA) with a majority of the farmers using untreated sewage to irrigate crop and fodder. Due to the environmental and health risks associated with wastewater irrigation, a study was carried out in partnership with farmers in Kibera and Maili Saba which are informal settlements along the Ngong River, a tributary of the Nairobi River Basin. Soil, water, crops and human faecal samples from the farming and non-farming households were analysed to elucidate sources, types and level of heavy metal pollutants in the wastewater and the pathogen loads in humans and vegetable crops. Heavy metal accumulation in soils collected from Kibera and Maili Saba were Cd (14.3 mg kg-1), Cr (9.7 mg kg-1) and Pb (1.7 mg kg-1) and Cd (98.7 mg kg-1), Cr (4.0 mg kg-1) and Pb (74.3 mg kg-1), respectively. This led to high phytoaccumulation of Cd, Cr and Pb in the crops that exceeded the maximum permissible limits. No parasitic eggs were detected in the vegetables but coliform count in the wastewater was 4.8 x108±2.2 x1011/100ml. Soils irrigated with this water had parasitic eggs and non-parasitic larvae counts of 54.62 and 27.5/kg respectively. Faecal coliform and parasitic eggs of common intestinal parasites increased in leafy vegetable sampled from the informal markets along the value chain.Item Spatial–temporal variability in water quality and macro-invertebrate assemblages in the Upper Mara River basin, Kenya(Elsevier, 2014) Kilonzo, Fidelis; Obando, Joy Apiyo; Masesea, Frank O.; Griensven, Ann Van; Bauwens, Willy; Lens, Piet N.L.Tropical rivers display profound temporal and spatial heterogeneity in terms of environmental conditions. This aspect needs to be considered when designing a monitoring program for water quality in rivers. Therefore, the physico-chemical composition and the nutrient loading of the Upper Mara River and its two main tributaries, the Amala and Nyangores were monitored. Initial daily, and later a weekly monitoring schedule for 4 months spanning through the wet and dry seasons was adopted. Benthic macro-invertebrates were also collected during the initial sampling to be used as indicators of water quality. The aim of the current study was to investigate the physico-chemical status and biological integrity of the Upper Mara River basin. This was achieved by examining trends in nutrient concentrations and analyzing the structure, diversity and abundance of benthic macro-invertebrates in relation to varying land use patterns. Sampling sites were selected based on catchment land use and the level of human disturbance, and using historical records of previous water quality studies. River water pH, dissolved oxygen, electrical conductivity (EC), temperature, and turbidity were determined in situ. All investigated parameters except iron and manganese had concentration values within allowable limits according to Kenyan and international standards for drinking water. The Amala tributary is more mineralized and also shows higher levels of pH and EC than water from the Nyangores tributary. The latter, however, has a higher variability in both the total phosphorus (TP) and total nitrogen (TN) concentrations. The variability in TP and TN concentrations increases downstream for both tributaries and is more pronounced for TN than for TP. Macro-invertebrate assemblages responded to the changes in land use and water quality in terms of community composition and diversity. The study recommends detailed continuous monitoring of the water quality at shorter time intervals and to identify key macro-invertebrate taxa that can be used to monitor changes of the water quality in rivers of the Mara basin as a result of anthropogenic changes.Item Critical review of SWAT applications in the upper Nile basin countries(European Geosciences Union (EGU) [Society Publisher], 2012) Kilonzo, Fidelis; Griensven, A. van; Ndomba, P.; Yalew, S.The Soil and Water Assessment Tool (SWAT) is an integrated river basin model that is widely applied within the Nile basin. Up to date, more than 20 peer-reviewed papers describe the use of SWAT for a variety of problems in the upper Nile basin countries, such as erosion modelling, land use and climate change impact modelling and water resources management. The majority of the studies are focused on locations in the tropical highlands in Ethiopia and around Lake Victoria. The popularity of SWAT is attributed to the fact that the tool is freely available and that it is readily applicable through the development of geographic information system (GIS) based interfaces and its easy linkage to sensitivity, calibration and uncertainty analysis tools. The online and free availability of basic GIS data that are required for SWAT made its applicability more straightforward even in data-scarce areas. However, the easy use of SWAT may not always lead to appropriate models which is also a consequence of the quality of the available free databases in these regions. In this paper, we aim at critically reviewing the use of SWAT in the context of the modelling purpose and problem descriptions in the tropical highlands of the Nile basin countries. To evaluate the models that are described in journal papers, a number of criteria are used to evaluate the model set-up, model performances, physical representation of the model parameters, and the correctness of the hydrological model balance. On the basis of performance indicators, the majority of the SWAT models were classified as giving satisfactory to very good results. Nevertheless, the hydrological mass balances as reported in several papers contained losses that might not be justified. Several papers also reported the use of unrealistic parameter values. More worrying is that many papers lack this information. For this reason, most of the reported SWAT models have to be evaluated critically. An important gap is the lack of attention that is given to the vegetation and crop processes. None of the papers reported any adaptation to the crop parameters, or any crop-related output such as leaf area index, biomass or crop yields. A proper simulation of the land cover is important for obtaining correct runoff generation, evapotranspiration and erosion computations. It is also found that a comparison of SWAT applications on the same or similar case study but by different research teams and/or model versions resulted in very different results. It is therefore recommended to find better methods to evaluate the representativeness of the distributed processes and parameters (especially when land use studies are envisaged) or predictions of the future through environmental changes. The main recommendation is that more details on the model set-up, the parameters and outputs should be provided in the journal papers or supplementary materials in order to allow for a more stringent evaluation of these models.Item A Drought Monitoring and Forecasting System for Sub-Sahara African Water Resources and Food Security.(American Meteorological Society, 2013-09) Olang, L. O.; Sheffield, Justin; Wood, E. F.; Chaney, Nathaniel; Guan, Kaiyu; Sadri, Sara; Yuan, Xing; Amani, Abou; Ali, Abdou; Demuth, Siegfried; Ogallo, LabanDrought is one of the leading impediments to development in Africa. Much of the continent is dependent on rain-fed agriculture, which makes it particularly susceptible to climate variability. Monitoring drought and providing timely seasonal forecasts are essential for integrated drought risk reduction. Current approaches in developing regions have generally been limited, however, in part because of unreliable monitoring networks. Operational seasonal climate forecasts are also deficient, often reliant on statistical regressions, which are unable to provide detailed information relevant for drought assessment. However, the wealth of data from satellites and recent advancements in large scale hydrological modeling and seasonal climate model predictions have enabled the development of state-of-the-art monitoring and prediction systems that can help address many of the problems inherent to developing regions. An experimental drought monitoring and forecast system for sub-Saharan Africa is described that is based on advanced land surface modeling driven by satellite and atmospheric model data. Key elements of the system are the provision of near real-time evaluations of the terrestrial water cycle and an assessment of drought conditions. The predictive element takes downscaled ensemble dynamical climate forecasts and provides, when merged with the hydrological modeling, ensemble hydrological forecasts. We evaluate the overall skill of the system for monitoring and predicting the development of drought, and illustrate the use of the system for the 2010/11 Horn of Africa drought. A key element is the transition and testing of the technology for operational usage by African collaborators and we discuss this for two implementations in West and East Africa.Item Integrating MDGs in the Formulation of Strategies for Solid Waste Management – A Life Cycle Approach(UNESCO, 2008) Mwai, Marclus; Siebel, Maarten A.; Susanne, Rotter; Piet, LensThe state of solid wastes in most of the developing countries is a major threat to both human and environmental resources. One of the reasons why there is little progress being made is a lack of clear objectives, coupled with a lack of information and of a strong analytical base in which various policies and strategies can be formulated or aligned during the decision making processes. This study, a case study for Nairobi, Kenya aimed at bridging this gap by providing a methodological approach in which Millennium Development Goals (MDGs) can be aligned with SWM strategies. Performance indicators were used to relate SWM to MDGs and to compile impacts data of the ten identified SWM options. The Baseline showed a low contribution towards achievement of MDGs while Option 10 (17% recycling, 63% composting and 20% landfilling) showed the highest contribution. Option 5 (15% recycling, 15% composting and 70% landfilling) provided the most feasible approach for meeting the MDGs, given the present social-economic, legal, political and administrative conditions of the study area.