Department of Environmental Earth Scienceshttp://41.89.164.27:8080/xmlui/handle/123456789/2002024-03-29T13:26:49Z2024-03-29T13:26:49ZWater quality and ecology of Lake Kanyaboli, Kenya: Current status and historical changesKondowe, Benjamin N.etl.al...http://41.89.164.27:8080/xmlui/handle/123456789/17962023-06-13T07:39:15Z2022-01-01T00:00:00ZWater quality and ecology of Lake Kanyaboli, Kenya: Current status and historical changes
Kondowe, Benjamin N.; etl.al...
Small waterbodies are the most threatened freshwater habitats because of the large ratio between their size and the catchment they drain. The present study assessed the current and historical changes in the physical, chemical and biological variables of Lake Kanyaboli, a satellite lake on the northern shores of Lake Victoria in west -ern Kenya. Primary and secondary data on pH, electrical conductivity (EC), dissolved oxygen (DO) concentration, temperature, Secchi depth (SD), and nitrate (NO−3), nitrite (NO−2), ammonium (NH+4 ), soluble reactive phosphorus (SRP), total nitrogen (TN), and total phosphorus (TP) and chlorophyll-a (Chl- a) concentrations were utilized in the present study. The results indicated Secchi depth and chlorophyll-a were the most erratic of all the analyzed environmental variables studied, exhibiting a range of 0.69± 0.29– 0.87 ± 0.34 m and 9.03 ± 0.81– 34.97 ± 3.36 μg/L respectively. Two- way ANOVA yielded no significant interactions between sampling sites and seasons for all the variables. Except chlorophyll-a, there also were no significant differences among the sampling sites for the studied variables. Seasonality yielded significant differences for Secchi depth, dissolved oxygen and chlorophyll-a. The Carlson Trophic Index for Chl- a and SD indicated Lake Kanyaboli is currently eutrophic, while the TP concentra-tion indicated hypereutrophic conditions. The lake, however, has fluctuated betweeneutrophic and hypereutrophic conditions over the past years. Although historical water quality data for the lake is scanty and infrequent, most physical and chemical variables reflected anthropogenic effects on a temporal scale. Interestingly, despite its eutrophic status, the general lake condition is still relatively good, attributable to the buffering effect from the extensive macrophytes fringing it. The present study identified nutrient loading, wetland reclamation and connectivity with the Yala River through a feeder canal as the management issues of critical concern. Accordingly con -tinuous monitoring of the lake's water quality to detect anthropogenic effects is rec -ommended for management intervention purposes.
2022-01-01T00:00:00ZMapping Landslide Susceptibility Along the Nandi Escarpment in Malava Sub-CountyKakamega County, KenyaChepkosgei, E.Ucakuwun, E. K.Nduru, G. M.http://41.89.164.27:8080/xmlui/handle/123456789/17452023-02-20T07:53:12Z2022-01-01T00:00:00ZMapping Landslide Susceptibility Along the Nandi Escarpment in Malava Sub-CountyKakamega County, Kenya
Chepkosgei, E.; Ucakuwun, E. K.; Nduru, G. M.
Landslidesmay occur in hilly terrain due to a combination of factors like deforestation, heavy precipitation, slope steepness and gravity, land use and cover. Whenever they occur, they may result in disasters such as loss of property and/or life. The frequency of landslidesin any area may be high if all the factors that trigger them are prevalent. The main objective of this study was to determine the factors that influence the occurrence of slope failure over space and time and produce a landslide susceptibility map of the Nandi Escarpment in Kabras area of Malava Sub-County. It also presents the capability of a Remote Sensing and GIS based approach to mapping the susceptibility of hilly terrains, with the Nandi escarpment as a case, to slope failure. A slope failure susceptibility map was used to help in identifying strategic points and geographically critical zones thatare prone to landslide risks. The study involved generation of landuse/ landcover maps extracted from Satellite Images, which were taken in the years 1973, 1995 and 2006. SRTM DEM 90m was used in generating slope and contour maps of the area. Soil maps were obtained as secondary data from Moi University Soil Laboratory and Soil Survey of Kenya, while rainfall maps were obtained from the Kenya Meteorological Department (KMD), Kakamega County. A slope failure risk map of Kabras region was produced by overlaying all thematic maps and analysis using GIS was conducted after assigning appropriate ranks and weights to respective variables. Focused groupsdiscussionswere used in data collection and probing historical information on land use changes in the area. The result is a map showing zones with varying degrees of susceptibility to slope failureandslopes steeper than 54owasmore susceptible to slope failures. It is opined that such a map will enable decision and policy makers to identify and implement suitable mitigation measures, with hopes of forestalling future losses in life and property in the area of study.Settlement should belimited to slopes of less than 24osince, according to this study, slopes higher than this are prone to sliding.There is needfor Kenya ministry of lands and physicalplanning to ensuresustainable land use activities are conducted in the slopes of various degrees.
2022-01-01T00:00:00ZOn-Site Runoff Management, Challenges and Prospects in Amalemba, an Urban Informal Settlement in Kakamega Municipality, Kakamega County, KenyaMusonye, P. K.Ucakuwun, E. K.Munyao, T. M.http://41.89.164.27:8080/xmlui/handle/123456789/16522022-08-24T08:34:19Z2022-06-01T00:00:00ZOn-Site Runoff Management, Challenges and Prospects in Amalemba, an Urban Informal Settlement in Kakamega Municipality, Kakamega County, Kenya
Musonye, P. K.; Ucakuwun, E. K.; Munyao, T. M.
This study investigated the challenges and prospects of on-site runoff management in Amalemba informal urban settlement in Kakamega Municipality, Kenya. The study followed a qualitative research design. Visual observations, photography, individual and focus group interviews were used to collect data. The findings indicate that on-site and institutional practices complemented each other in management of runoff. This study therefore affirmed the importance of meaningful participation of residents in runoff management interventions and approaches that sustain ‘socio-human’ capacity for response in relation to impacts of runoff in informal urban settlements. In conclusion, the benefits of catchment-scale model for runoff management, the potential of green infrastructure and the necessity for policy transition to sustainable drainage systems in Amalemba informal urban settlement are of critical importance.
2022-06-01T00:00:00ZANALYSIS OF SPATIAL AND SEASONAL VARIATIONS OF WATER QUALITY USING STATISTICAL, CCME-WQI AND GIS METHODS IN NAKURU MUNICIPALITY, KENYAKELI, MARGARET MWIKALIhttp://41.89.164.27:8080/xmlui/handle/123456789/15962022-03-02T09:30:28Z2022-01-01T00:00:00ZANALYSIS OF SPATIAL AND SEASONAL VARIATIONS OF WATER QUALITY USING STATISTICAL, CCME-WQI AND GIS METHODS IN NAKURU MUNICIPALITY, KENYA
KELI, MARGARET MWIKALI
Nakuru Municipality lies in the larger Lake Nakuru basin where the natural chemistry of its watershed is characterized by high levels of inorganic salts posing a significant problem to water resources. River and ground waters are the primary sources of drinking water for the municipalities’ population but despite their significance, there are limitations to the availability of a robust database that can describe their quality status in a reliable way. Information that can explain spatial and seasonal variations of river and ground water quality is not sufficient. This study targeted to bridge this gap by adopting a quantitative research design. Stratified random sampling was applied in the study of pH, electrical conductivity, and levels of fluoride selenium, chloride and cadmium. Thirty eight sampling points and three sampling periods/seasons were selected for this study. The seasons were put in three groups: group 1: Transition Period (TP), group 2: Short Rain Period (SRP) and group 3: Dry Period (DP). The data were analyzed, processed and interpreted using SPSS software Version 22.0, Microsoft window Excel tool, statistical, Geographical Information Systems (GIS) and Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) methods. Water quality data were presented as mean values and evaluated based on guideline values to assess its suitability for drinking. Spatial and seasonal variations of examined parameters were descriptively analyzed. The results showed significant spatial and seasonal variations in some of the examined water variables (pH, chloride, fluoride, selenium, cadmium and electrical conductivity). Kruskal - Wallis H test was applied to test for seasonal variation in mean concentration values of water parameters where results were reported at 0.05 level of significance. Seasonally, the results indicated a statistically significant difference between the means of pH (P = 0.001) and cadmium (P = 0.000) but no significant difference for electrical conductivity (P = 0.130), selenium (P = 0.981), fluoride (P = 0.293) and chloride (P = 0.228) in ground water. Post hoc results showed significant existence of mean difference in pH between the TP and DP (P = 0.000) and TP and SRP (P= 0.006) while for cadmium there existed significant mean difference existed between TP and SRP (P = 0.001) and TP and DP (P = 0.000). For natural river water samples, Kruskal - Wallis H test results showed existence of significant differences between the means of pH (P = 0.050) and electrical conductivity (P = 0.008). However chloride (P = 0.629), cadmium (P = 0.122), fluoride (P = 0.105) and selenium (P = 0.472) did not show any significant difference. Post hoc results showed existence of significant mean difference in electrical conductivity between TP and DP (P = 0.004) and SRP and DP (P= 0.016) while for pH significant mean difference existed between TP and DP (P = 0.034) and SRP and DP (P = 0.34). Spatial distribution maps gave a pictorial representation of the spread of water quality parameters at different sampling points. Based on the CCME-WQI, index values for drinking water quality of river and ground water samples were calculated in a range of 20.94-39.69 and ranked as poor. Selenium, cadmium and fluoride were taken as important parameters impacting water quality as their concentrations were elevated. Aquifer geological formations and water quality characteristics showed spatial variation among the boreholes. Considering all examined variables, correlation results showed that correlation coefficient (r) values ranged from -0.85 to 0.70 in river water and -0.87 to 0.56 in ground water. The study concluded that the quality of river and ground water of the study area was mainly influenced by geological hydrogeological settings of the area, not potable and need proper treatment before consumption.
2022-01-01T00:00:00ZRUNOFF GENERATION, IMPACTS AND MANAGEMENT PRACTICES IN AMALEMBA URBAN INFORMAL SETTLEMENT, KAKAMEGA MUNICIPALITY, KENYAMUSONYE, PATRICK, K.http://41.89.164.27:8080/xmlui/handle/123456789/15392021-12-02T11:28:55Z2021-01-01T00:00:00ZRUNOFF GENERATION, IMPACTS AND MANAGEMENT PRACTICES IN AMALEMBA URBAN INFORMAL SETTLEMENT, KAKAMEGA MUNICIPALITY, KENYA
MUSONYE, PATRICK, K.
The study was carried out in Amalemba informal urban settlement within Kakamega municipality, Kenya. It concerned environmental impacts of uncontrolled runoff in the environmentally vulnerable low income settlement. Management of runoff is a significant component towards the sustainability of a sound urban environment infrastructure. Runoff management is imperative in urban informal settlements since it enhances a healthy surrounding. This study identified human and physical features that influence runoff generation, determined influence of rainfall on runoff discharge, influence of slope and ground cover on runoff discharge, effects of runoff; and investigated runoff management measures in Amalemba informal urban settlement. The study followed a quasi-experimental research design. Runoff discharge measurements, visual observations, photography, individual and focus group interviews were used to collect data. Runoff from bare ground, 50% grass cover and 100% grass cover were compared using thirty rainfall events during long rains in April/May 2020. Runoff volume was collected using the Gerlach trough setup, the precise volume of discharge was measured using a graduated one litre measuring cylinder. Data from interviews with respondents was analyzed according to themes while data from the Gerlach trough setup was analyzed using inferential statistics. The rainfall-runoff relationship for Amalemba informal urban settlement indicates a statistically positive significant correlation between daily rainfall and runoff volume with r = 0.9822 for 100% grass cover, for 50% grass cover r = 0.9672 and r= 0.9934 for bare ground respectively with p-value <0.0000001 for all the three surfaces. Bare ground coupled with steeper slope produced the highest runoff while the surface with 100% grass cover yielded the lowest runoff. The results show that vegetation cover is better at protection of the soil against erosion and reduction of runoff than bare ground. Runoff produced adverse effects such as flooding, mini landslides, soil erosion, and blockage of drains as a result of bad solid waste disposal mechanisms and destruction of shacks, farmland and roads. On-site and institutional practices complemented each other in management of runoff. This study emphasizes meaningful involvement and participation in management of runoff; adopting methodologies which withstand both social and human capabilities ranging from controlling and managing runoff to the effects of runoff in informal urban settlements. Runoff management at the catchment level, appropriate use of green infrastructure and the formulation of policies aimed at development of sustainable drainage systems in Amalemba informal urban settlement is of critical importance.
2021-01-01T00:00:00ZEFFECTS OF GEOLOGICAL VARIABILITY AND SELECTED PHYSICAL PARAMETERS OF WATER QUALITY ON FLUORIDE LEVELS IN RIVER NJORO CATCHMENT, KENYAOntumbi, George Morarahttp://41.89.164.27:8080/xmlui/handle/123456789/14922021-11-12T12:58:30Z2020-01-01T00:00:00ZEFFECTS OF GEOLOGICAL VARIABILITY AND SELECTED PHYSICAL PARAMETERS OF WATER QUALITY ON FLUORIDE LEVELS IN RIVER NJORO CATCHMENT, KENYA
Ontumbi, George Morara
Fluoride levels higher than the World Health Organization (WHO) recommended levels of 1.5 mg/l have to raise serious health issues. Therefore fluoride contamination is a pertinent matter that calls for concern by all people and government especially in countries where the phenomenon of volcanicity has been experienced. The study sought to analyse the effects of geological variability and selected physical parameters of water quality on fluoride levels in River Njoro catchment. The study was guided by the following objectives: to determine the relationship between fluoride levels and surface geology in River Njoro catchment, to determine the relationship between borehole stratigraphy formation matrices and fluoride levels in borehole water in River Njoro catchment, determine the relationship between pH, temperature and Electrical conductivity and fluoride levels in groundwater in River Njoro catchment and finally model spatial variation and distribution of fluoride levels in ground water in the River Njoro catchment. The study sought to highlight the levels of fluoride and give recommendations on identification and delineation of potential sites for safe groundwater for the local population and advice on the water treatment and de fluoridation strategies. Past researches on River Njoro catchment gave much emphasis on land use/cover changes and strong condemnation on elevated fluoride levels in the Njoro catchment and therefore the gap in this research was based on the integration of geological variations and geological stratigraphy of River Njoro catchment and ultimately produce a predictive trend. This study adopted purposive longitudinal survey and quasi experimental research designs. In this research borehole and river water, soil and rock samples from designated points along the River Njoro and its tributaries were collected for laboratory analysis of fluoride levels. The research adopted descriptive and correlation statistical analysis. The sources of data included: field surveys which were used to collect data about the fluoride levels, the remotely sensed, GIS and Geostatistical interpolation, content analysis of the literature on the geology of the Njoro catchment and the hydro-meteorological and geological characteristics data. From the results of the study it was observed that: the fluoride levels in River Njoro catchment varied with the geology of the catchment and fluoride levels in groundwater depended on the borehole stratigraphy matrix, the selected physical parameters of water quality (pH, Electrical Conductivity and temperature) had a significant statistical relationship with fluoride levels in River Njoro catchment and land use/cover changes and variations in the borehole depths. The results through Geostatistical interpolation also observed that there is varied distribution and variation of fluoride levels in River Njoro catchment. Therefore geological variations, borehole depths and lithological formations were manifested in the fluoride level variations in the water and rock sampling points that were located either upstream, midstream and downstream of the River Njoro catchment. Finally the study recommends isotopic analysis of water samples from the sources of water in River Njoro catchment to assist in tracing their origin, contamination of fluoride and fluoride enrichment pathways and water quality alteration within the catchment.
2020-01-01T00:00:00ZVariation of Fluoride Levels in Surface Geology: A Study of River Njoro Catchment, KenyaOntumbi, George. M.Ucakuwun, Elias. K.Munyao, Thomas, M.http://41.89.164.27:8080/xmlui/handle/123456789/14352021-11-03T08:20:40Z2020-01-01T00:00:00ZVariation of Fluoride Levels in Surface Geology: A Study of River Njoro Catchment, Kenya
Ontumbi, George. M.; Ucakuwun, Elias. K.; Munyao, Thomas, M.
Fluoride levels in water that is higher than the World Health Organization (WHO)
recommended levels of 1.5mg/l have raised concerns to the health of human.
Subsequently fluoride contamination in water is a pertinent matter that calls for
concern by all people and government. This study sought to investigate variation of
fluoride levels in surface geology in river Njoro catchment. This study adopted
purposive longitudinal survey research designs. In this research, rock samples were
collected from 11 purposively selected points along the river Njoro and its tributaries
to analyse fluoride levels in the laboratory. The research adopted descriptive data
analysis in evaluating fluoride changes as contained in the rocks. The study observed
that despite different types of volcanic rock outcrops along Njoro River, there were
minimal variations in the levels of fluoride in the river Njoro. The study identified
Superficial Deposits of Volcanic Soils with highest fluoride levels (1.575 mg/l) while
eutracite Welded Tuffs had the lowest fluoride levels (0.678 mg/l). In Conclusion the
rocks within the River Njoro catchment have insignificant contribution to the known
elevated fluoride levels contained in sub surface and water in the ground in Njoro
River catchment.
2020-01-01T00:00:00ZStratigraphy and Fluoride Levels Variation in Borehole Water: A Case of River Njoro CatchmentOntumbi, George M.Munyao, Thomas M.Ucakuwun, Elias K.http://41.89.164.27:8080/xmlui/handle/123456789/12922021-08-23T09:52:37Z2020-01-01T00:00:00ZStratigraphy and Fluoride Levels Variation in Borehole Water: A Case of River Njoro Catchment
Ontumbi, George M.; Munyao, Thomas M.; Ucakuwun, Elias K.
Boreholes are main sources of water for human use in the Rift Valley. How ever these boreholes have fluoride levels higher than the World Health Or ganization (WHO) recommended levels of 1.5 mg/l and consequently have
raised serious health issues. This study sought to determine the relationship
between borehole stratigraphy and fluoride levels in ground water in river
Njoro catchment. This study adopted purposive longitudinal survey. The
study adopted descriptive analysis of the borehole stratigraphy characteristics
and fluoride levels recorded. The sources of data included; field surveys
which were used to collect data on the borehole fluoride levels data and
qualitative analysis of the stratigraphy data. From the results of the study, it
was observed that the fluoride levels in boreholes in river Njoro catchment
were dependent on the stratigraphy matrix of the boreholes. Therefore
lithological formations have an influence on fluoride level River Njoro
catchment. This study will form a pool of knowledge to other researchers who
have an interest in the study of fluoride occurrence in ground water in the
Rift Valley. Further the study will help in assisting the drillers in decision
making after geological surveys of where to locate the boreholes.
2020-01-01T00:00:00ZSOIL EROSION PROCESSES AND CONTROL ON RURAL ROADS IN MT. ELGON SUB-COUNTY, TRANS NZOIA AND WEST POKOT COUNTIES, KENYAMANYARA, JAMES M. O.http://41.89.164.27:8080/xmlui/handle/123456789/10022021-06-07T12:08:15Z2015-01-01T00:00:00ZSOIL EROSION PROCESSES AND CONTROL ON RURAL ROADS IN MT. ELGON SUB-COUNTY, TRANS NZOIA AND WEST POKOT COUNTIES, KENYA
MANYARA, JAMES M. O.
Roads are essential component to the counties’ economy; they are key agents of economies to thrive, good and well maintained roads imply great and successful economies. Low volume rural roads are facing great challenge and highly deteriorating due to anthropogenic and climatic factors. Low volume rural roads were studied in three varied climatic zones in three counties of western Kenya. The study was carried out to assess the management and the current state of rural roads (Class D and E) in Mt. Elgon Sub County (in Bungoma County), Trans Nzoia and West Pokot counties. Soil loss and deposition on the rural roads, surface runoff rates were determined and the state of soil erosion control works were assessed. Potential areas vulnerable to soil erosion were identified. Catchment characteristics were calculated using Cooks method and the runoff rates coefficient obtained to determine the runoff rates in m3/s. Classification of soils’ drainage potential and soil types in the study areas was determined by using soil data obtained from International Livestock Research Institute. Terrain data was obtained from Shuttle Relief Topography Mission which was used to determine gradients using ARCGIS. Soil movement and deposition was analysed and it was observed that a greater change occurred in the months of November and December 2013 with a deposition change of 11.1 cm compared to 8.80cm for the month of January and February 2014. Highest rate of erosion was recorded at -10.1cm in the rainy months and -6.64 cm in dry months. Total soil volume movement in three months was 8309.75 cm3 where Mt. Elgon Sub County exhibited the highest change of 3284 cm3 .Terrain (gentle/flat and undulating) for West Pokot and Trans Nzoia (Sibanga) roads had a negative correlation while Mt. Elgon (hilly, mountainous and gentle) and Tans Nzoia-Sikulu (gentle/flat) roads had a positive correlation of r=0.530 and r=0.032, respectively. The runoff rates at Mt. Elgon were the highest at 3.7 m3/s, while the mean runoff rate was 1m3/s .Rainfall on the roads catchment ranged between 800-1600 mm3 of rain annually, and this contributed to the most likelihood of roads in upper Mt. Elgon and North of Sibanga getting more eroded than roads in the south and other roads. It was found out that 54.3% of the total road network was made up of gravel and 18.6% of it had been encroached by vegetation which distorted the camber. Culverts’ efficiency was rated at a mean of 40%. Areas most vulnerable to erosion were found to be in Mt. Elgon from 10 km -22 km stretch of the road and Sikulu-Kinyoro road bordering Kapsara tea factory. The research therefore draws recommendations to improve and enhance the management of roads by discouraging road reserve cultivation and creation of cut off drains on upper Mt. Elgon and Sibanga roads, the use of GIS in soil modelling is critical for engineers to avoid vulnerable and unstable areas of the roads.
2015-01-01T00:00:00ZEnviron. Res. Commun.1(2019)125003https://doi.org/10.1088/2515-7620/ab50f6PAPERComputational and experimental study of a hydro-dynamicallandslide model based on laboratoryflume testsKanule, JNg’etich, W.Rotich, Shttp://41.89.164.27:8080/xmlui/handle/123456789/8872021-03-24T07:21:34Z2019-01-01T00:00:00ZEnviron. Res. Commun.1(2019)125003https://doi.org/10.1088/2515-7620/ab50f6PAPERComputational and experimental study of a hydro-dynamicallandslide model based on laboratoryflume tests
Kanule, J; Ng’etich, W.; Rotich, S
Hydrological factors such as volumetric water content(VWC)and pore-water content(PWC)havebeen cited widely as significant factors that trigger slope failures especially shallow landslides anddebrisflows. Over the years, researchers have studied these processes using a range of physically-basedmodels which in many occasions are either too complex incorporating very many parameters or fail tomimic realfield conditions. The principal objective of this study was to derive and incorporate a set ofphysically-based equations that describe the dependence of slope failures at laboratory scale on VWCinto a factor of safety expression herein referred to as the hydro-dynamical landslide model. Themodel was validated by a series of physical tests on soil samples in the laboratory using the Chep-flume. Results showed a close agreement between computational and experimental data, confirmingthe hypothesis that cohesion, internal friction angle and pore-water pressure are modulated by VWCespecially for slopes with sandy-loam soils. More so, rapid change of soil water content was observedto accelerate build-up of negative pore-water pressures(PWP)which triggers slope failure. Apart fromgiving a simplified expression for the factor of safety, the proposed model circumvents the difficultiesassociated with tedious procedures employed in the measurement of cohesive stress by limiting thetests to only three sets of parameters i.e. VWC, PWP and displacement.
2019-01-01T00:00:00Z