Department of Environmental Studies
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Item Causal Factors Responsible for Changes in the Attributes of Urban Green Spaces in Nairobi City County, Kenya(2024-07-26) Mbugua, Martin Wandie; Kamiri, Hellen; Kamau, PeterUrban green spaces are an important part of public open spaces and a common service provided by a city, town, or municipal council. In Nairobi City County, green spaces have been increasingly threatened by overcrowding, poor planning, weak management structures, and illegal alienation thus denying city residents access to the much-needed recreation and leisure facilities. As the population increases in urban areas, their activities impact the environment and therefore the ecosystem services. This study was done with the Principle of Intelligent Urbanism in mind, as the most prolific urban development theory developed by the International Congress of Modern Architecture. Quantitative and qualitative methods were used to collect data while a cross-sectional survey designs and stratified random sampling of the green spaces was employed, based on the location within the urban core and peri-urban of Nairobi County. Four green spaces (Karura Forest, Ngong Road Forest, Nairobi Arboretum, and City Park) with diverse characteristics and attributes were selected. A sample population of 384 visitors to the green spaces was surveyed for their perceptions of the functions, uses, and benefits of the green spaces. Our findings showed that management structures and population growth are the main causal factors responsible for changes in the attributes of urban green spaces.Item Temporal changes in Rainfall and Temperature influence on Solid Waste Generation in Bungoma County Urban Centres, Kenya(2024-07-28) Wafula, Godfrey Wekesa; Ouna, Tom; Kamiri, HellenGlobally, temperature and rainfall play an integral role in the management of solid waste in urban areas. This is because many countries especially, the developing countries conventionally rely on both variables in the management of waste. However, the urban environment faces many threats as a result of challenged waste management practices due to these climate stressors. This research aimed to assess how temporal changes in temperature and rainfall influence solid waste generation. The study was carried out in Bungoma county urban centres, specifically Bungoma town, Webuye, Kimilili, Kapsokwony, Chwele, and Sirisia townships. The study applied a stratified sampling technique to select the urban and peri-urban centres while random sampling was used to select respondents in residential dwellings, business people, urban residents, and officers from government institutions including public health and environment, water, and natural resources were interviewed. Ancillary data was collected using questionnaires and interview schedules while historical data was obtained to validate observed data. Data was analysed using descriptive and inferential statistics and summarized using tables, charts, and graphs. The findings of the study indicated that rainfall and temperature significantly influenced the generation of solid waste.Item Assessment of Solid waste generation and composition in Bungoma County Urban Centres for appropriate waste management approaches(2024-08-02) Wafula, Godfrey Wekesa; Kamiri, Hellen; Ouna, TomThe quantity and characteristics of urban solid waste are a result of the interconnectedness of diverse factors at play including social, economic, and environmental factors. These directly influence the choice of management practice at the household or community level. Understanding these relationships can help policymakers and urban planners develop more effective waste management strategies. This study aimed at assessing solid waste generation and composition in Bungoma county urban centers to inform on strategies for effective management of urban waste. The study was carried out in Bungoma County urban centers, specifically Bungoma town, Webuye, Kimilili, Kapsokwony, Chwele, and Sirisia townships. The study applied a stratified sampling technique to select the urban and peri-urban centers while random sampling was used to select respondents in residential dwellings, business people, urban residents, and officers from government institutions including public health and environment, water, and natural resources were interviewed. Ancillary data was collected using questionnaires and interview schedules while historical data was obtained from the Bungoma County Department of Environment and used to validate observed data. Data was analysed using descriptive and inferential statistics and summarized using tables, charts, and graphs. Our findings show that the highest waste was generated from residential homes, commercial, and municipal services. In terms of composition, biodegradable waste had the highest proportion, followed by plastics and glass waste. Population growth could be a key factor in the increased generation of the waste.Item Attributes of Urban Greenspaces and their Influence on Visitors’ Preferences in Nairobi City County, Kenya(Eastern African Journal of Humanities and Social Sciences Vol. 3 No. 1, 2024-07-07) Mbugua, Martin Wandie; Kamiri, Hellen; Kamau, PeterUrban green spaces refer to land covered with vegetation such as forests, street trees, parks, gardens, and water bodies in an urban setup. In this study, we sought to investigate the attributes of urban green spaces in Nairobi County and their relationships to visitor preferences. The Garden City Model advanced by Howard (1898) guided the study. Quantitative and qualitative methods were used to collect data while a cross sectional survey designs and stratified random sampling of the green spaces was employed, based on the location within the urban core and peri-urban of Nairobi County. Four green spaces (Karura Forest, Ngong Road Forest, Nairobi Arboretum, and City Park) with diverse characteristics and attributes was selected. A sample population of 384 visitors to the green spaces were surveyed for their perceptions of the functions, use, and benefits of the green spaces. Our findings showed that attributes of green spaces including location, accessibility, security, hygiene, and infrastructure could explain the interaction between green space provision factors and the frequency of visits, time spent in the green spaces and overall satisfaction of the visitors. Green space provision should be equitable in regard to distance to residents, quality of spaces, facilities and services and should be designed to meet the needs of diverse residents. Further, they should provide services and benefits such as shade, recreation, and health which are the main attractions to the green spaces. To achieve maximum benefits for visitors, green spaces need to be safe and physically accessible to all.Item Analysis of Short-Term Drought Episodes Using Sentinel-3 SLSTR Data under a Semi-Arid Climate in Lower Eastern Kenya.(2023-06) Musyimi, Peter K.; Sahbeni, Ghada; Timár, Gábor; Weidinger, TamasThis study uses Sentinel-3 SLSTR data to analyze short-term drought events between 2019 and 2021. It investigates the crucial role of vegetation cover, land surface temperature, and water vapor amount associated with drought over Kenya’s lower eastern counties. Therefore, three essential climate variables (ECVs) of interest were derived, namely Land Surface Temperature (LST), Fractional Vegetation Cover (FVC), and Total Column Water Vapor (TCWV). These features were analyzed for four counties between the wettest and driest episodes in 2019 and 2021. The study showed that Makueni and Taita Taveta counties had the highest density of FVC values (60–80%) in April 2019 and 2021. Machakos and Kitui counties had the lowest FVC estimates of 0% to 20% in September for both periods and between 40% and 60% during wet seasons. As FVC is a crucial land parameter for sequestering carbon and detecting soil moisture and vegetation density losses, its variation is strongly related to drought magnitude. The land surface temperature has drastically changed over time, with Kitui and Taita Taveta counties having the highest estimates above 20 ◦C in 2019. A significant spatial variation of TCWV was observed across different counties, with values less than 26 mm in Machakos county during the dry season of 2019, while Kitui and Taita Taveta counties had the highest estimates, greater than 36 mm during the wet season in 2021. Land surface temperature variation is negatively proportional to vegetation density and soil moisture content, as non-vegetated areas are expected to have lower moisture content. Overall, Sentinel-3 SLSTR products provide an efficient and promising data source for short-term drought monitoring, especially in cases where in situ measurement data are scarce. ECVs-produced maps will assist decision-makers with a better understanding of short-term drought events as well as soil moisture loss episodes that influence agriculture under arid and semi-arid climates. Furthermore, Sentinel-3 data can be used to interpret hydrological, ecological, and environmental changes and their implications under different environmental conditions.Item Hourly reference evapotranspiration analysis using synoptic meteorological measurements and ERA5 reanalysis data from Kenyan Counties(2023-09) Musyimi, Peter K.; Mendyl, Abderrahmane; Agustiyara, Agustiyara; Székely, BalázsKenya has had five failed rain seasons for the last three years. In this context, there was a mass recurrent crop failure, death of livestock and wildlife, persistent water scarcity, and droughts of varying intensities. There have been a lot of challenges in assessing climate change and variability impacts in Kenya due to limited data sources. Further, assessing the local and regional effects on the hydrological cycle, food security, and available water resources remains a great regional threat. Reference evapotranspiration, is the evaporative power climatic parameter of the atmosphere, vital for water budgets on the land surface. The study’s main goal was to analyze hourly reference evapotranspiration, from two climatic regions using single levels ERA5 hourly dataset from 2000 to 2022. The dataset was sought from three stations from, arid, and semi-arid savannah tropical conditions regions (Voi Garissa, and Mombasa) with elevations between 57 m to 579 m, and three (Trans-Nzoia, Nyeri, and Embu) sought from humid Kenya highlands (>1350 m). Reference Evapotranspiration was calculated using Penman-Monteith (FAO56), the standard methodology developed by Food and Agriculture Organization. Results from 5 years (2018 to 2022) in Taita-Taveta County indicated that ranged from 0.17±0.2 mm/hour in 2020 to 0.22±0.2 mm/hour in 2022. Daily averages were 4.17±1.2 mm./day to 5.2±1.1 mm/day in 2020 and 2022 respectively. The mean monthly and was highest in March with an estimated value of 159.7±53.7 mm/month while the lowest was 120±15 mm/month in December. This is because March falls at the onset of the long rainy season in Kenya where precipitation is high while December is the last month of the short rainy season when precipitation reduces significantly. These results are vital because they enhance comparisons of the spatial climatological patterns and variability of seasonal precipitation about the evaporative power and demand variation across regions. Further, it will necessitate investigations of uncertainties from the datasets for better decision-making after comparisons with analysis from field meteorological datasets and soil moisture data measurements currently being carried out in Kenya. Further comparison of the results with reference evapotranspiration from the original station and the Global Land Evaporation Amsterdam Model dataset will also be investigated.Item Fine‐scale variation in soil and topography influences herbaceous vegetation and the distribution of large mammalian herbivores(Wiley, 2023-04) Ang'ila, Robert O.; Kimuyu, Duncan M.; Wambugu, Geoffrey M.; Kenfack, David; Musil, Paul M.; Kartzinel, Tyler R.Current understanding of the distribution of vegetation and large mammalian herbivores (LMH) is based on a combination of biogeographic studies and highly controlled field experiments, but a more complete understanding of these patterns requires study of their natural co-occurrence patterns at intermediate spatial scales. The study was conducted in the 120-ha Mpala Forest Global Earth Observatory (ForestGEO) plot, Kenya. We examined differences in herbaceous plant communities and habitat use by LMH among three topographic habitats with distinct soil types, namely steep slopes, valley and plateau. Each pair of habitats differed in plant and animal com position. The steep slopes and plateau respectively had ≥1-fold higher percentage herbaceous cover than the valley, whereas the steep slopes and valley had >1.5-fold greater grass species richness and diversity than the plateau. The activity of LMH was ≥1.7-fold higher in the valley than the steep slopes and plateau, reflecting a positive relationship between LMH activity index and richness and diversity of grass species. Results indicate that fine-scale variation in topography and soil are associated with both the distribution of herbaceous vegetation and LMH, suggesting a need to account for local habitat characteristics when examining the distributions of plants, animals, and plant-herbivore interactions in natural systemsItem 5. Absentee owners and overlapping home ranges in a territorial species(2021-01-07) Isbell, Lynne A.; Bidner, Laura R.; Loftus, Carter; Kimuyu, Duncan M.; Young, Truman P.Abstract Understanding animals’ use of space can shed valuable light on multiple other aspects of behavioral ecology, including social organization, dispersal, and foraging efficiency. Home ranges, territories, core areas, and home range overlaps have been widely studied, but unless animals are directly observed or are tracked remotely on a fine temporal scale, how they actually use the space available to them and how they share (or partition) this space with a community of conspecifics over time cannot be fully understood. Using GPS technology, we tracked three adjacent groups of vervet monkeys (Chlorocebus pygerythrus) in Laikipia, Kenya, for 1 year to better understand the processes involved in territoriality and home range overlaps. Home ranges overlapped with any one neighboring group by 12.7–34.7%, but intergroup encounters only occurred in restricted areas within these zones, which defined territorial boundaries. The resources closest to the territorial boundaries were nocturnal core areas with preferred sleeping sites adjacent to shortgrass areas offering fewer hiding places for ambush predators and greater visibility for predator detection. Home range overlaps were not neutral zones, the result of shifting home range boundaries over time, or based on intergroup encounters at boundaries, but resulted when groups made incursions beyond their territorial boundaries while the neighbor was far away and likely unaware of the intruders. Thus, territories can be non-exclusive but may still be perceived by the animals themselves as sole-owned, as neighbors only intrude when territory owners are absent from that area.Item Faecal Bacterial and Parasitic Contamination of Drinking Water in Eldoret Municipality, Kenya(2012) Olunga, Maureen StellaFaecal contamination of water can introduce a variety of pathogens into water ways, including bacteria, viruses, protozoans and parasitic worms. Poor excreta disposal is often associated with lack of adequate water supplies, poor sanitation facilities and low economic status populations. In this study water samples were collected from wells, taps and harvested rain water containers in Kimumu area of Eldoret municipality in Kenya and analyzed using standard bacteriological and parasitological methods. The quality of tap and rain water was found to be acceptable. The presence of Escherichia coli in well water was an obvious indication of faecal contamination. Faecal parasites observed were Entamoeba histolytica, Ascaris lumbricoides, Giardia lamblia, Necator americanus, Ancyclostoma duodenale, Fasiola hepatica, Taenia saginata and Taenia solium. To control infestations with faecal intestinal parasites, provision of treated piped water to all homesteads, consultation of water engineers and/or health inspectors before well construction and creation of public awareness are recommended. Scholars of microbiology and parasitology and parasitologists will find this book resourceful.Item Radiometric survey of the Tyaa river sand mine in Kitui, Kenya(2020-07-02) Matsitsi, S M; Linturi, J. M.; Kebwaro, J. M.; Kirago, L. M.Gamma spectroscopic analyses of sand and rock samples from Tyaa River report an average activity concentration of 33 ± 1, 55 ± 2.8 and 812 ± 40.46 Bqkg-1 for 226Ra, 232Th and 40K, respectively in the sand. A similar analysis of rock samples reveals a mean of 21 ± 2.47, 49 ± 2.47 and 782 ± 39.13 Bqkg-1 for 226Ra, 232Th and 40K, respectively. The absorbed dose rate in rocks averaged 75 ± 3.78 nGyh-1, while in the sand was 86.2 ± 4.31 nGyh-1. The ranges and mean radiological hazard indices (radium equivalent, internal and external) were within the permissible limits and the use of sand and rocks from this mine as construction material pose no health risks. Correlation analysis between the radioactivity in the sand and rocks reveals weak non-linear positive relationships suggesting that they might be from different bedrocks.