Department of Biological and Environmental Sciences

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Access to water in Kenya’s coast region
(2018) Ignatius, David O.; Hassan, Farida A.; Morara, George N.; Osore, Melckzedeck k.; Mutua, Benedict M.; Kitaka, Nzula K.
Water is considered a basic commodity and essential for life - living on planet earth is dependent on it. However, access to water has been and will continue to be a dilemma for a majority of the residents at the coast of Kenya. A close look at the window on “Coastal Resources and People” reveals that water is a key resource but despite its immense importance, many people especially in the rural areas and among the Vulnerable and Marginalized Groups (VMG’s) do not have adequate access to potable, reliable and convenient sources of water. Lamu, currently considered among water scarce counties in Kenya as per the Lamu County Integrated Development Plan (http://lamu.go.ke/wp-content/uploads/2016/03/LAMU_CIDP-Revised.June_2014-1.pdf), faces serious challenge of provision of potable water to its residents. With the influx of people from other parts of the country as a result of the implementation of the Kenya Vision 2030 flagship project - Lamu Port Southern Sudan Ethiopia Transport (LAPSSET) Corridor, the current water stresses is only expected to worsen. The Lamu County Government plans to address the ever-increasing demand for access to water but resources to actualise these plans are yet to be consolidated. To complement this situation, Kenya Coastal Development Project (KCDP), a World Bank funded project is working with local communities in Lamu in the development and implementation of community-led water projects targeting to increasing access to water at the household level. This paper will focus on community-based approaches to understand the water-web in Lamu East Sub-County to provide an assessment of opportunities, challenges and sustainability implications. Primary data is used on surveys, Social Assessment (SA),Vulnerable and Marginalised Group Plan (VMGP), observations and recommendations from the Lamu CIDP. It further proposes that direct usage of saline water, seawater or brackish water, for sanitation purposes could alleviate the freshwater shortage.
Allelopathic potential of mexican sunflower [tithonia diversifolia (hemsl) a. gray] on germination and growth of cowpea seedlings (vigna sinensis l.)
(2015) Musyimi, D.M.; Okelo, L.O.; Okello, Victor Samuel; Sikuku, P.S.
Invasive plant species when introduced into new environments may result into a number of ecological problems (Howard et al., 2000). They may influence other species through pathways such as allelopathy or phytotoxicity (Samuel et al., 2005; Imeokpara and Okusanya, 1994; Ayeni et al., 1997). Allelopathy is the inhibitory or stimulatory effect of a plant on another by chemicals released from the donor plant to the environment (Taiwo and Makinde, 2005; Bano et al., 2012). Allelopathy is a process by which plants release chemical compounds in their vicinity (Rice, 1984). Studies have shown that different plant parts release toxic metabolites into the soil that affect adversely germination and growth of plants (Kumar et al., 2008).
Analysis of drought and wet-events using SWSI-based severity-duration-frequency (SDF) curves for the upper Tana river basin, Kenya
(Science Publishing Group, 2018-06-12) Raphael Muli Wambua, Raphael Muli; Mutua, Benedict M.; Raude, James Messo
Drought and wet-event patterns in the Upper Tana River basin have significantly been changing due to variation of climatic and human-induced factors. This paper presents the analysis of drought and wet-events using Severity-DurationFrequency (SDF) curves for the Upper Tana River basin, Kenya based on Surface Water Supply Index (SWSI). The extreme value EV1 (Gumbel) frequency distribution function was used to formulate SDF curves. The developed SDF curves were used to develop isoseverity maps for the basin. From the results, the event-probability show that likelihood of drought events increased linearly with increase in magnitude of SWSI while the return period of drought events increased exponentially with decrease in magnitude of SWSI. The findings show that the probability and magnitude, the return period and magnitude of drought have linear and exponential regression coefficients of 0.984 and 0.980 respectively. On the other hand the probability of wet-period events decreased linearly with increase in magnitude of SWSI while the return period of the events increased exponentially with increase in magnitude of SWSI with regression coefficients of the linear and exponential functions of 0.804 and 0.881 respectively. This indicates that both the drought and wet-events probability and magnitude, and the return period and magnitude have a strong correlation. Spatially, it was found that generally the river basin exhibit an increasing pattern in cumulative SWSI in south-eastern areas than the north-eastern and generally a more increase in extreme wet-events than droughts in the basin. The developed (SDF) curves are critical for design of hydrologic, hydraulic and water resources supply systems while the spatial event-patterns can be incorporated in prioritized mitigation of extreme events.
Analysis of drought effect on annual stream flows of river Malewa in the lake Naivasha basin, Kenya
(Radiance Research Academy, 2014-09-15) Kyambia, Marshal M.; Mutua, Benedict M.
The main parameters of drought phenomenon are the longest duration and largest severity for a desired return period. These parameters form the basis for designing water storage structures to cope with drought effects. In this study, these drought parameters were estimated using the probability based theory. The sample estimates of the mean, coefficient of variation, skewness, correlation and information on the probability distribution of flow sequence, were used as the basic input parameters. The truncation level was considered at mean level of the annual flow sequences of River Malewa in Lake Naivasha basin. In this basin, 100, 50, 10, 5 and 2-year droughts may persist continuously for 6, 4, 3, 2 and 1 years respectively. From the probabilistic approach for a normal probability distribution function, high values of coefficient of variation resulted in high values of the actual severity. The results show that there is drought severity in Lake Naivasha basin especially in parts experiencing high inter-annual variability in annual flow regimes.
Analysis of manual and centralised supervisory control operations to improve level of service: a case study of pyramid hill no 1 channel, Victoria, Australia
(Kluwer Academic Publishers, 2001-02) Malano, Hector M.; Mutua, Benedict M.
The current challenge facing irrigation inAustralia is tofind ways to improve the operationalperformance of existing systems rather thanconstructing new ones. Unsteady flowsimulation models are often used as keytools to study and test improvedoperational scenarios for existing systems.While these models are generally notrecommended for real-time control, researchhas shown that they are able to simulatecanal response for different test scenariosfor operations planning. This paperpresents the results of two alternativemodes of operation for the Pyramid Hill No.1 Channel in northern Victoria, Australia.The channel is currently under manualoperation. Centralised control is the mostimmediate option considered by theirrigation authority to enable remotesupervision and control of the canal toimprove the channel operation and level ofservice standards. This type of control istermed Supervisory Control and DataAcquisition (SCADA). The two alternativeoperational scenarios were simulated andanalysed using the unsteady flow-simulationmodel DUFLOW. Specific performanceindicators were defined to compare the twomodes of operations based on the simulationresults. The results show that SCADAoperation has considerable potential toclosely match the discharges at thedownstream regulator with those ordered byfarmers while maintaining the water surfaceelevations within allowable fluctuationtolerance throughout the length of thecanal.
Analysis of spatial and temporal drought variability in a tropical river basin using palmer drought severity index (PDSI)
(Academic Journals, 2017-08-31) Wambua, Raphael M.; Mutua, Benedict M.; Raude, James M.
Analysis of spatial and temporal drought variability in the upper Tana River basin using Palmer Drought Severity Index (PDSI) was conducted. The drought is critical for formulation of mitigation measures in the river basin. A monthly temporal and 90-m spatial resolution was applied. This was achieved within ArcGIS environment. Climatic data for 1970 to 2010 was used for computation of the PDSI while the missing data sets were filled using Artificial Neural Networks (ANNs). The results of PDSI for dry and wet seasons at meteorological stations indicate that the time series plots for the PDSI values for dry season are generally lower than those for the wet seasons. The PDSI values for meteorological stations located at the lower elevation of the basin are lower than those located at higher elevation. On the other hand, spatially distributed drought severity based on PDSI show that the ranges of maximum and minimum drought severity values in 1970 are -0.868 to -0.804 and -0.675 to -0.610 respectively. These values of drought severity occur respectively in the north-western and south-eastern areas of the basin. PDSI values increased from the range -0.675 to -0.610 in 1970 and from -1.087 to 0.957 in 2010 for the north-eastern areas of the upper basin. The south eastern areas of the basin are more prone to drought risks than north-western parts. Use of the PDSI reflects the spatial heterogeneity and temporal variability of drought across the basin. The drought assessment offer technical approach for comprehensive understanding of drought for effective drought-induced disaster mitigation and its management, with a view to reducing adverse effects on livelihoods.
Analyzing the Mara river basin behaviour through rainfall-runoff modeling
(Scientific Research Publishing, 2017-09-14) Birundu, Anne M.; Mutua, Benedict M.
Hydrological models are considered as necessary tools for water and environmental resource management. However, modelling poorly gauged watersheds has been a challenge to hydrologists and hydraulic engineers. Research done recently has shown the potential to overcome this challenge through incorporating satellite based hydrological and meteorological data in the measured data. This paper presents results for a study that used the semi-distributed conceptual HBV Light Model to model the rainfall-runoff in the Mara River Basin, Kenya. The model simulates runoff as a function of rainfall. It is built on the basis established between satellite observed and in-situ rainfall, evaporation, temperature and the measured runoff. The model’s performance and reliability were evaluated over two sub-catchments namely: Nyangores and Amala in the Mara River Basin using the Nash-Sutcliffe Efficiency which the model referred to as Reff and the coefficient of determination (R2 ). The Reff for Nyangores and Amala during the calibration and (validation) period were 0.65 (0.68) and 0.59 (0.62) respectively. The model showed good flow simulations particularly during the recession flows, in the Nyangores sub-catchment whereas it simulated poorly the short term fluctuations of the high-flow for Amala sub-catchment. Results from this study can be used by water resources managers to
Antimicrobial Coumarins from the Oyster Culinary-Medicinal Mushroom, Pleurotus ostreatus (Agaricomycetes), from Kenya
(International Journal of Medicinal Mushrooms, 2016-01-01) Baraza, Lilechi D.; Wekesa, Wekesa; Korir, Cheruiyot Jackson; Juma, Fredrick B.; Ochieno, Dennis; Wairimu, Kamau R.; Osogo, Aggrey; Heydenreich, Matthias
Pleurotus ostreatus has been widely used as food because of its nutritional and medicinal properties. These have been attributed to the presence of macronutrients, minerals, vitamins, and amino acids, among other secondary metabolites. There are, however, few reports on the antimicrobial activities of different classes of purified compounds from P. ostreatus. This led to the current study, the objective of which was to chemically characterize the antibiotic activities of P. ostreatus against selected human pathogenic bacteria and endophytic fungi. Chemical structures were determined using spectroscopic methods and by comparison with values of related structures reported in the literature. Pure compounds from P. ostreatus were tested in vitro against pathogenic bacteria (Staphylococcus aureus and Escherichia coli) and endophytic fungi (Pencillium digitatum and Fusarium proliferatum). A new compound, (E)-5,7-dimethoxy-6-(3-methylbuta-1,3-dienyl)-2H-chromen-2-one (5-methoxy-(E)-suberodiene) (compound 2), along with ergosterol (compound 1) and 5,7-dimethoxy-6-(3-methylbut-2-enyl)-2H-chromen-2-one (toddaculin; compound 3), were isolated from the fruiting bodies of P. ostreatus. The growth of S. aureus, F. proliferatum, and P. digitatum colonies was inhibited in media containing compound 2, with minimum inhibitory concentrations closely comparable to those of conventional antibiotics.
Assessment of water flow and sedimentation processes in irrigation schemes for decision-support tool development: a case review for the Chókwè irrigation scheme, Mozambique
(Multidisciplinary Digital Publishing Institute, 2019-02-28) Salvador de Sousa, Lateiro; Wambua, Raphael M.; Raude, James Messo; Mutua, Benedict M.
Water flow and sedimentation processes have been significantly erratic at the Chókwè Irrigation Scheme (CIS) and have affected its hydraulic performance. Given its expansion there is need to understand these processes taking place on-site and along the channels of the scheme. CIS being the biggest project of its kind in Mozambique requires proper management of water flow and sedimentation processes. Therefore, the effect of water flow, sediment transport and deposition parameters on the performance of the CIS is needed. In order to determine the effect of spatial and temporal water flow and sediment distribution trends along the irrigation canals, there is need to establish a correlation between these parameters. Determining the influence of water flow velocity on sediment settling rate at different depths along the canal reaches is important in managing the CIS. In addition, a developed decision-support tool to predict sediment deposition is required. For this reason, it is therefore crucial to carry out a timely assessment of water flow and sedimentation processes in CIS in a review concept. From the current review, some gaps that exist for more focused research on Chókwè Irrigation Scheme have been identified. In this regard therefore, there is need to develop an effective support tool for managing water flow and sediment deposition along the canal reaches with a view to increasing crop production in CIS
Autoregulation of ccl26 synthesis and secretion in a549 cells: a possible mechanism by which alveolar epithelial cells modulate airway inflammation
(2005) Abonyo, B. O.; Alexander, M. S. Alexander; Heiman, A. S.
Abonyo, B. O., M. S. Alexander, and A. S. Heiman. Autoregulation of CCL26 synthesis and secretion in A549 cells: a possible mechanism by which alveolar epithelial cells modulate airway inflammation. Am J Physiol Lung Cell Mol Physiol 289: L478 –L488, 2005. First published April 29, 2005; doi:10.1152/ajplung.00032.2005.— Eotaxins (CCL11, CCL24, CCL26) originating from airway epithelial cells and leukocytes have been detected in bronchoalveolar lavage of asthmatics. Although the alveolar epithelium is the destination of uncleared allergens and other inflammatory products, scanty information exists on their contribution to the generation and regulation of the eotaxins. We envisioned a state whereby alveolar type II cells, a known source of other inflammatory proteins, could be involved in both the production and regulation of CCL24 and CCL26. Herein, we demonstrated that all three eotaxins are constitutively expressed in A549 cells. IL-4 and IL-13 stimulated a concentration-dependent secretion of CCL24 and CCL26. The cytokines did not act synergistically. Cycloheximide and actinomycin D abrogated IL-4- and IL13-dependent CCL26 but not CCL24 secretion. Both IL-13 and IL-4 stimulated CCL26 synthesis that was inhibited in a concentrationdependent manner by CCL26 but not CCL24. Only CCL26 reduced expression of CCR3 receptors by 30 – 40%. On the other hand, anti-CCR3 pretreatment reduced IL-4 IL-13-dependent CCL26 secretion, implying autoregulation. A CCR3-specific antagonist (SB328437) significantly decreased IL-4-dependent synthesis and release of CCL26. Eosinophils treated with medium from IL-4-stimulated A549 cells preincubated with anti-CCL26 showed a marked decrease of superoxide anion production compared with anti-CCL24 treated. These results suggest that CCL26 is a major eotaxin synthesized and released by alveolar epithelial cells and is involved in autoregulation of CCR3 receptors and other eotaxins. This CCL26-CCR3 ligandreceptor system may be an attractive target for development of therapeutics that limits progress of inflammation in airway disease
Bathymetric survey of lake Naivasha and its satellite lake Oloiden in Kenya; using acoustic profiling system
(wileyonlinelibrary.com/journal/lre, 2018-10-23) Raude, James M.; Maina, Caroline W.; Sang, Joseph K.; Mutua, Benedict M.
Lakes and reservoirs play important roles as freshwater sources for domestic, indus-trial, agricultural, fisheries and recreational purposes. However, for the lakes to be sustainably exploited, there is need to understand their bathymetric characteristics by conducting bathymetric surveys. This aids in generating information that can guide lakes stakeholders and managers in establishing the volume of available water. It is recommended, therefore, that bathymetric surveys be conducted at ten-year intervals. Such continuous bathymetric information is lacking in many lakes, espe-cially in developing countries. One example is Lake Naivasha in Kenya, which is largely exploited for various socio-economic purposes. Despite its importance, its most recent published bathymetric data were collected in 1991. The goal of the pre-sent study, therefore, was to conduct a bathymetric survey of Lake Naivasha and its satellite Lake Oloiden, using an Acoustic Profiling System (APS) to generate Depth–Area–Volume relationships for the lakes. The survey results indicate the in the year 2016 mean depth, volume and surface area of the lake were 4.68 m, 722 × 106 m3and 154.17 × 106 m2, respectively. Because of limited information from the 1991 sur-vey, the 2016 survey results were comparable with those of 1983. The difference in the lakes mean, and maximum depth for the 1983 and 2016 survey was less by 0.23 and 2 m, respectively. This could be an indicator the lake is being affected by anthro-pogenic activities or environmental changes. The established Depth–Area–Volume relationships are crucial since they provide invaluable information to lake and water resources managers for making informed decisions regarding management of the lake’s water resources.
Biodegradation of carbofuran in soils within Nzoia River Basin, Kenya
(Journal of Environmental Science and Health, 2015-04-06) Onunga, Daniel O.; Owino, Isaac; Ngigi, Anastacia; Osogo, Aggrey; Orata, Francis; Getenga, Zachary; were, Hassan
Carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) has been used within the Nzoia River Basin (NRB), especially in Bunyala Rice Irrigation Schemes, in Kenya for the control of pests. In this study, the capacity of native bacteria to degrade carbofuran in soils from NRB was investigated. A gram positive, rod-shaped bacteria capable of degrading carbofuran was isolated through liquid cultures with carbofuran as the only carbon and nitrogen source. The isolate degraded 98% of 100-μg mL−1 carbofuran within 10 days with the formation of carbofuran phenol as the only detectable metabolite. The degradation of carbofuran was followed by measuring its residues in liquid cultures using high performance liquid chromatography (HPLC). Physical and morphological characteristics as well as molecular characterization confirmed the bacterial isolate to be a member of Bacillus species. The results indicate that this strain of Bacillus sp. could be considered as Bacillus cereus or Bacillus thuringiensis with a bootstrap value of 100% similar to the 16S rRNA gene sequences. The biodegradation capability of the native strains in this study indicates that they have great potential for application in bioremediation of carbofuran-contaminated soil sites.
CCL26-targeted siRNA treatment of alveolar type II cells decreases expression of CCR3-binding chemokines and reduces eosinophil migration: implications in asthma therapy
(2009) Errahali, Younes J.; Taka, Equar; Abonyo, B. O.; Heiman, Ann S.
The underlying infl ammation present in chronic airway diseases is orchestrated by increased expression of CC chemokines that selectively recruit leukocyte populations into the pulmonary system. Human CCL26 signals through CC chemokine receptor 3 (CCR3), is dramatically upregulated in challenged asthmatics, and stimulates recruitment of eosinophils (EOSs) and other leukocytes. CCL26 participates in regulation of its receptor CCR3 and modulates expression of a variety of chemokines in alveolar type II cells. Utilizing the A549 alveolar type II epithelial cell culture model, we carried out studies to test the hypothesis that CCL26-siRNA treatment of these cells would ameliorate Th2-driven release of the eotaxins and other CCR3 ligands that would, in turn, decrease recruitment and activation of EOSs. Results demonstrate that CCL26-siRNA treatments decreased interleukin4-induced CCL26 and CCL24 expression by > 70%. CCL26-directed small-interfering RNA (siRNA) treatments signifi cantly decreased release of CCL5 (RANTES), CCL15 (MIP-1δ), CCL8 (MCP-2), and CCL13 (MCP-4). In bioactivity assays it was shown that EOS migration and activation were reduced up to 80% and 90%, respectively, when exposed to supernatants of CCL26-siRNA-treated cells. These results provide evidence that CCL26 may be an appropriate target for development of new therapeutic agents designed to alleviate the underlying infl ammation associated with chronic diseases of the airways.
Challenges of sustainable financing of sanitation in Nakuru municipality, Kenya
(WEDC, Loughborough University, 2009-05-22) Ojwando, K.O.; Mutua, Benedict M.
Adequate sanitation is of great importance in addressing public health and plays an important role with respect to poverty alleviation. A large proportion of population in Nakuru is not served with adequate sanitation facilities. Worldwide experiences on financing of sanitation are widely scattered, and influenced by very dif erent local circumstances. Little, if any, real linkage and upscaling has taken place, to draw conclusions that would fit all circumstances. A study was conducted in Nakuru municipality using structured questionnaires. Results from the data analysis indicated that majority of the households interviewed had low monthly incomes ranging between Kshs. 500010000. Sanitation therefore was not a priority with this meager income. The finding indicated that the only way these residents were willing to contribute to sanitation would be in kind labour, 44%. Majority of Nakuru residents, 65% admitted that they don’t pay for garbage collection services, reason being that of poverty and the notion that this is the responsibility of the municipal council. On household improvement priority, many respondents, 35% would prefer to have water in their residence followed closely with sanitation. They argue that with water availability, sanitation is guaranteed. Potential financial constraints were identified as unwillingness and inability to pay due to poverty, lack of political will and poor governance and low priority for sanitation in public sector spending due to competing interest with other sectors such as health and education.
Characterization of -soluble n-ethylmaleimide–sensitive fusion attachment protein in alveolar type ii cells implications in lung surfactant secretion
(2002) Abonyo, B. O.; Wang, Pengcheng; Narasaraju, Telugu A.; Rowan III, William H.; Zimmerman, Un-Jin; Lin Liu
N-ethylmaleimide–sensitive fusion protein (NSF) and soluble NSF attachment protein (α-SNAP) are thought to be soluble factors that transiently bind and disassemble SNAP receptor complex during exocytosis in neuronal and endocrine cells. Lung surfactant is secreted via exocytosis of lamellar bodies from alveolar epithelial type II cells. However, the secretion of lung surfactant is a relatively slow process, and involvement of SNAP receptor and its cofactors (NSF and α-SNAP) in this process has not been demonstrated. In this study, we investigated a possible role of α-SNAP in surfactant secretion. α-SNAP was predominantly associated with the membranes in alveolar type II cells as determined by Western blot and immunocytochemical analysis using confocal microscope. Membrane-associated α-SNAP was not released from the membrane fraction when the cells were lyzed in the presence of Ca2+ or Mg2+ATP. The alkaline condition (0.1 M Na2CO3, pH 12), known to extract peripheral membrane proteins also failed to release it from the membrane. Phase separation using Triton X-114 showed that α-SNAP partitioned into both aqueous and detergent phases. NSF had membrane-bound characteristics similar to α-SNAP in type II cells. Permeabilization of type II cells with β-escin resulted in a partial loss of α-SNAP from the cells, but cellular NSF was relatively unchanged. Addition of exogenous α-SNAP to the permeabilized cells increased surfactant secretion in a dose-dependent manner, whereas exogenous NSF has much less effects. An α-SNAP antisense oligonucleotide decreased its protein level and inhibited surfactant secretion. Our results suggest a role of α-SNAP in lung surfactant secretion.
Characterization of greywater from urban and peri-urban areas of Nakuru municipality, Kenya
(Loughborough University, 2009) Raude, James M.; Mutua, Benedict M.; Chemelil, Mathew C.; Sleytr, Kirsten
Kenya faces serious challenges regarding water and sanitation services. Despite many years of government investment, existing facilities continue to deteriorate and have also failed to meet the demand of increasing population. These challenges are particularly severe in rapidly growing settlements of urban poor. One such settlement is Nakuru municipality which has an average annual population growth of about 8%. The municipality’s sewerage connection is inadequate (11% coverage) and only serves middle and high income areas. This study used a semi-structured questionnaire aiming at characterizing and determining the composition of greywater, besides identifying existing water supply and lifestyle characteristics. The total suspended solids range in greywater was 200-3500 mg/l and faecal coliform (FC) count 105 -106 100mL-1. High values of FC concentration in greywater can be associated with life style characteristics and the settlement patterns. These results were used to develop site specific greywater treatment systems ideal for peri-urban areas.
Classification of catchment risk areas using spatially distributed event-based soil erosion: a case of upper Njoro river catchment, Kenya
(WIT Press, 2008-12-19) Wambua, R.M.; Mutua, Benedict M.; Nyaanga, D.M.; Kundu, P.M.
Human-induced soil erosion and drastic change in land use practices have adversely infl uenced the land degradation and surface runoff response in upper Njoro River catchment. The drainage area is approximately 127 km2. Due to human activities, the land has been exposed to accelerated erosion and low land productivity, water scarcity, decline in ground water recharge, siltation of Lake Nakuru and other sediment sinks. This study was conducted to establish event-based risk areas for prioritized conservation within the catchment. Spatially distributed soil erosion map was created as a ratio of sediment yield to sediment delivery ratio (SDR). Modifi ed Universal Soil Loss Equation (MUSLE) integrated within a Geographical Information Systems environment was used to create the sediment yield map. Spatial data layers for the MUSLE were derived from a 20-m resolution Digital Elevation Model, soil property, land use maps and climatic data of the catchment. Land use map was derived from Landsat imagery via its processing using Integrated Land and Water Information Systems software. The results show that the spatially distributed soil erosion ranged from 0.06 to 0.51 t/ha for a 43.2-mm rainfall event. Spatially distributed SDR ranged from 0.09 to 0.82, while the average SDR for the whole catchment was 0.72. These values were derived using an empirical equation. A new contribution was made by developing spatially distributed slope length factor, SDR, runoff volumes, MUSLE parameters and classifi ed erosion risk areas for prioritized catchment conservation. This means that the event-based soil erosion classifi cation can be adopted for prioritized soil and water conservation within Njoro catchment.
Community participation in afforestation and agroforestry programmes in kenya: the influence of biophysical environmental in the case of Teso district
(2000) Ekisa, Tom George
On global scale, community participation in various activities is the core in the quest for sustainable development and environmental protection related issues. Community involvement in tree planting in Kenya is as old as modern agroforestry that started in 1971. However, certain biophysical environmental factors have not worked against the concept of community participation in tree planting. Although deforestation and resultant problems such as woodfuel shortage and reduced other forest based products, climate change, and soil erosion, have occurred world-wide, the worst hit areas are in developing countries of the Sub-Saharan Africa. Teso District falls in this region and therefore not an exception; the district inhabitants encounter these environmental problems. The study revealed that both biophysical environmental factors were major disincentives to community participation in tree planting. Among the biophysical aspects, soil and landscape characteristics, and entomological incidences were quite significant. However, the study also discovered that water availability and pathological factors were not significant obstacles to tree planting in the district
Comparative assessment of the effect of climate change and human activities on streamflow regimes in central rift valley basin, Ethiopia
(Science and Education Publishing, 2019) Gadissa, Takele; Nyadawa, Maurice; Mutua, Benedict M.; Behulu, Fiseha
Climate change and anthropogenic activities are the main driving factors for changes in hydrological processes of a given watershed. This research was conducted to assess the relative contribution of climate change and human activities to streamflow change. The ensemble mean of five regional climate models (RCMs) in the coordinated regional climate downscaling experiment (CORDEX)-Africa was considered for the purpose of this study. Two emission scenarios, the Representative Concentration Pathways, RCP4.5 and RCP8.5, were considered for the future scenario period (2041–2070). Streamflow change due to climate change and human activities was assessed using coefficient of elasticity method and SWAT hydrological model. A change due to climate change was further split into change due to precipitation and evapotranspiration. Climate change contributed 46.7% while human activities contributed 53.3% to changes in streamflow. It was found that a 10% decrease in precipitation caused a reduction of 25.1% in streamflow, while 10% increase in potential evapotranspiration caused a reduction of 15.5% in streamflow. The results from ensemble mean of Regional Climate Models (RCMs) show that the average projected precipitation will decrease by 7.97% and 2.55% under RCP4.5 and RCP8.5 respectively. On average, temperature will increase by 1.9°C and 2.7°C under RCP4.5 and RCP8.5 respectively. This corresponds to 4.89% and 6.59% increase in potential evapotranspiration under RCP4.5 and RCP8.5 respectively. Using coefficient of elasticity method, the estimated values of streamflow change were – 26.9% and – 15.8% under RCP4.5 and RCP8.5 respectively. The results of this study show that the reduction in streamflow due to human activities was higher than the reduction due to climate change. The streamflow change induced by anthropogenic factors can be associated with factors such as water abstraction, land use change, ground water abstraction, and the other catchment properties. Hence, further research is recommended to separate changes from these factors.
Contextualized science teaching and student performance: The case of a kenyan girls science class
(Instituto de relaciones internacionales daza de valdes, 2017) Ooko, Selline.; Beru, Festus K.; Nashon, Samson M.; Anderson, David.; Namazzi, Elizabeth.
This paper is about a case study that investigated the impact of contextualized science teaching and learning onperformance of a Form three (Grade 11) class in one of Kenya’s girls high schools. The class experienced nine weeks ofcontextualized science learning. This involved a full day visit toJua Kaliwhere they interacted with artisans. ‘‘Jua Kali’’ is asmall-scale manufacturing and technology-based service sector where artisans manufacture equipment and otherhousehold items that are ubiquitous in everyday Kenyan culture. The visit was followed by organized classroom-basedgroup discussions about what they had learnt and considered most relevant and meaningful. Following this highlyengaging student learning discourse, their creativity and innovative abilities in science improved tremendously as reflectedin the quality of class presentations and participation in the National Science Congress. Moreover, the school’sperformance in the Kenya Certificate of Secondary Education (KCSE): a final national exam at the end of Form 4(Grade 12) improved from a mean of 9.3 in the previous year to 10.4 in the intervention year (p = 0.022). This was furtherattributable to significant improvement in all science subjects: biology, chemistry, physics and mathematics. Besides thecritical insights about theJua Kali’srichness in scientific phenomena, there is also great potential for contextualized scienceexperience to enhance students’ deeper understanding of science.

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