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Item Trends in Rainfall and Discharge over Zaaba Sub Catchment, Vihiga County, Kenya(Open Access Library Journal, 2024-10) Aholi, Joel Philip; Makokha, Mary; Obiero, KennedyTemporal variation of rainfall has a direct influence on discharge of a river; however, considerable land cover changes through conversion of natural veg etation to agricultural land, settlement and commercial usage like urbanization have led to encroachment into forested, river riparian and other wetland areas therefore altering runoff generation through variation of rates of vegetal inter ception, infiltration, evapotranspiration and surface detention. This study determined rainfall trends and discharge from 1991 to 2020 and factors de termining response of streamflow to rainfall variability in Zaaba river sub catchment in Vihiga County, Western Kenya. Rainfall data was sourced from Kenya Meteorological Department, discharge data was sourced from Water Resources Authority and land cover data was downloaded from USGS website http://www.earthexplorer.usgs.gov/. Trend analysis was determined by Z-Test, p-value and Sen’s slope estimator. Regression analysis determined the correla tion between rainfall and discharge. Data from Key informant interviews, ques tionnaires and Focus Group Discussions was analysed through SPSS by com puting totals and percentages and drawing charts. Rainfall trend analysis at α = 0.05 revealed rainfall was variable at monthly (p-value = 0.037 and Sen’s slope = 0.182), seasonal (Sen’s slope = −0.030 and p-value = 0.043 for MAM and Sen’s slope = 0.136 and p-value = 0.046 for OND) and annual (Sen’s slope = 1.081 and p-value = 0.010) time steps. Discharge trend analysis at α = 0.05 re vealed existence of trend on seasonal (Sen’s slope = 0.51 and p-value = 0.009 for MAM and Sen’s slope = 0.521 and p-value = 0.008 for OND) and annual (Sen’s slope = 0.085 and p-value = 0.001). Regression analysis revealed insig nificant seasonal correlation (MAM and OND with r = −0.124 and 0.067) and annual correlation (r = 0.051). Statistical analysis revealed that major land cover changes were agricultural area that decreased from 50.05% (2001) to 41.07% (2011) and 32.8% (2020) and increased buildup areas from 5.06% (2001) to 9.29% (2011) to 17.68% (2020) attributed to increased population, expansion of urban areas and encroachment into river riparian that decreased from 5.18% (2001) to 1.18% (2011) and 0.87% (2020). These findings would encourage ca pacity building on increasing rainfall trends and take measures to control floods.Item The impact of land use and cover changes on river flows in Wundanyi Catchment of Taita Hills, Kenya (1970–2030)(2024) Obando, Joy A.; Luwesi, Cush N.; Akombo, Rose AdhiamboTaita hills are one of the most important biodiversity hotspots of Kenya but experiencing a high rate of deforestation due conversion of its original forestland to agriculture and settlement during the last century. These landscape dynamics coupled with rainfall fluctuations in these critical ecosystems may significantly affect water resource distribution and food security in Taita Taveta County and its environs. This study aimed to establish the trends of land use/cover change (LUCC) in Wundanyi catchment from 1970 to 2030 and predict their specific and combined effects on surface runoff and stream flow in the same period. The analysis was based on statistical trend analysis and dynamic landscape modeling using both historical and primary data from Wundanyi catchment, and Landsat TM and ETM+ imagery of Taita Hills for 1990, 2000, and 2010. Results show highly variable mean seasonal and annual values of discharge in Wundanyi catchment probably attributed to environmental changes affecting Taita Hills in general and Wundanyi catchment in particular. Compared to 1990, major land use/cover changes in 2010 were featured by the expansion of built-up area (250%), plantation forest (23.7%), broadleaved forest (17.4%), and thicket (15.9%). Was also notable the decrease in woodland (−30.3%), cropland (−21.6%), and shrubland (−0.8%)...Item Scaling-Up Sustainable Land Management in the Drylands of Sub-Saharan Africa(Frontiers, 2024-06) Shisanya, Chris A.This Research Topic of Frontiers in Environmental Science focuses on different innovation aspects related to sustainable land management (SLM) in sub-Saharan Africa (SSA), within a framework of different but related thematic areas, whose long-term goal is to scale up these promising SLM technologies for impact at the local levels. SLM constitutes an array of activities that sustain land and its given ecosystem functions (Critchley et al., 2023). Considerably, SLM is generally accepted as playing an important function in soil and water conservation (Liniger et al., 2019). Currently, it is acknowledged as a key driver of “land-based solution” in achieving climate change (CC) mitigation through carbon sequestration and reduction of ...Item Modeling of Soil Erosion Risk in a Typical Tropical Savannah Landscape(Elsevier B.V, 2023-12-17) Asempah, Mawuli; Shisanya, Christopher Allan; Schütt, BrigittaTropical savannah landscapes are faced with high soil degradation due to climate change and variability coupled with anthropogenic factors. However, the spatiotemporal dynamics of this is not sufficiently understood particularly, in the tropical savannah contexts. Using the Wa municipality of Ghana as a case, we applied the Revised Universal Soil Loss Equation (RUSLE) model to predict the potential and actual soil erosion risk for 1990 and 2020. Rainfall, soil, topography and land cover data were used as the input parameters. The rate of predicted potential erosion was in the range of 0–111 t ha− 1 yr− 1 and 0–83 t ha− 1 yr− 1 for the years 1990 and 2020, respectively. The prediction for the rate of potential soil erosion risk was generally higher than the actual estimated soil erosion risk which ranges from 0 to 59 t ha− 1 yr− 1 in 1990 and 0 to 58 t ha− 1 yr− 1 in 2020. The open savannah areas accounted for 75.8 % and 73.2 % of the total soil loss in 1990 and 2020, respectively. The validity of the result was tested using in situ data from a 2 km2 each of closed savannah, open savannah and settlement area. By statistical correlation, the predicted soil erosion risk by the model corresponds to the spatial extent of erosion damages measured in the selected area for the validation. Primarily, areas with steep slopes, particularly within settlement, were identified to have the highest erosion risk. These findings underscore the importance of vegetation cover and effective management practices in preventing soil erosion. The results are useful for inferences towards the development and implementation of sustainable soil conservation practice in landscapes with similar attributes.Item Assessment of Water Supply and Demand in Walatsi Sub-Catchment, Busia County, Kenya(SCIRP, 2024-05) Diang’a, Justus; Obiero, Kennedy; Makokha, MaryOverexploitation of water supplies remains the most serious constraint on its sustainability, and many authorities are confronting serious problems in its management because of growing competition for the ever-dwindling natural resource. The study aims to assess the supply and demand for water in the Walatsi sub-catchment from 2022 to 2030. Data from key informants, experiment, direct observations, and GIS analyses were utilized and analyzed through QGIS software and Microsoft Excel, and a decision support system - WEAP model was adopted for scenario analysis and simulations. Using WEAP’s built-in supply and demand database, available water supply, present and future water demand, and water balance were determined, and a correlation between simulated water balance and demand was established to interpret water balance results further. Results from the study indicated an annual supply between 31.63 and 31.65 Million cubic meters (Mm3 ) and a monthly supply ranging from 0.48 to 6.80 Mm3 . An annual increase in water demand by 27.59% from 6.45 Mm3 in 2022 was observed, which further revealed a declining annual water balance by −7.07% from 25.18 Mm3 in 2022 and an increasing annual monthly water deficit in February from −0.02 to −0.15 Mm3 . The −0.999 coefficient explained the unmet demand gap from 0.24% to 1.85%. Variations in monthly supply annually are due to the bimodal dry and rainy seasons, and annual supply is due to regular and leap years. The positive trend in demand is likely to put pressure on available water supplies. An increasing deficit indicates pressure on water sources and exploitation of the reserve. This study, therefore, indicates a water scarcity sub-catchment.Item Socio-Economic Drivers of Agroforestry Practices in Kaiti Watershed, Makueni County, Kenya(EANSO, 2024-05) Ngila, Vallary Mutave; Kweyu, Raphael Mulaha; Mbuthia, Susan WanjiruForests and trees are essential resources for sustainable provision of goods and services. However, trees have not only been depleted in reserved forests but also on agricultural lands. Several measures have been formulated to improve forest cover in Kenya and one of such strategies is agroforestry. This study aimed to examine agroforestry practices, tree density on farms and determine the relationship between socio-economic characteristics of households and tree density on farms in Kaiti watershed, Makueni County, Kenya. Quadrats were used to determine tree density and tree species diversity on farms while questionnaires were used to record socio-economic characteristics of households. Data files were prepared in the Microsoft Excel and SPSS version 20 software where descriptive and inferential statistics were used. The study found 8 agroforestry practices. The results of One-Way ANOVA for both Shannon Diversity Index and Simpsons’ Index of Diversity showed significant difference in species diversity in Kaiti watershed with p-value of 0.00023 and 0.00012, respectively. The mean of tree density was 104.5 trees per acre where 54% of farms had less than 40 trees per acre while 46% of farms had more than 40 trees per acre. Further, the study found significant relationship between socio-economic characteristics of households and tree density on farms. Household income was the most significant with p-value of 0.000. The study recommends sensitization of farmers about importance of trees and suitable tree species for growing in arid and semi-arid areas. Further, supply of certified seedlings close to farmers and at affordable prices would improve tree species diversity and tree density on farms. There is also need for private land ownership for households to promote sense of ownership of trees.Item Demographical Factors and their Hindrances to Metropolitan Land Zone Use Policy Adherances(AJGR, 2024-01) Mogire, Dennis Annan; Kweyu, Raphael; Francis, Jane KagendoThe appropriate application of metropolitan land zone use policies and regulations may help in resolving metropolitan land zone use hitches such as undesirable zonal fragmentation, zonal use mix-up and zonal encroachment. This research aims at contributing to acquaintance required to enhance adherence to metropolitan land zone uses in metropolitan land zone use planning. This paper focused on the hindrances to metropolitan land zone use adherence in Nakuru City. Human population in Nakuru city has been on upward trajectory over the past thirty years. Just like any other modern metropolitan area in the world, Nakuru city’s land use is mainly divided into residential, industrial, commercial and agricultural zone. The size of Nakuru city (municipality) has remained unchanged since 1974. However, there is a proposal to expand its size following its upgrading into a city. This has pressurized the already limited metropolitan land use zones. The study adopted Hoyt Theory which says that metropolitan land use zones are swayed by financial factors. Precisely, the study’s main objective was to assess socio-economic aspects of metropolitan demography as hindrances to metropolitan land zone use adherence. This paper employed descriptive survey design. Field data from a sample size of 400 respondents from eleven sample units were collected. All demographical factors (ignorance, political interference, nature of implementation, corruption, availability of capital, and population influx) under study had positively correlated with metropolitan land zone use policy adherences since they had a correlation coefficient of 0.82, 0.90, 1.00, 0.80, 0.92 and 0.98 respectively. The average t-test of all demographical factors under investigation was 0.02. Therefore, the null hypothesis was rejected at p-value of 0.05. Information from Key informants were also incorporated. This research suggested that these hindrances should be minimized through incorporation of all stakeholders, integrity, checked urbanization and proper implementation and adherence to all metropolitan land zone use policies that are in place. This study may be useful to metropolitan land planners, developers and government.Item Assessment of Land Use and Land Cover Change Dynamics and Drivers in Mbagathi River Catchment in Kajiado County, Kenya(Scientific Research Publishing, 2024-02) Munyoki, Faith; Makokha, Mary; Obiero, KennedyLand use and land cover change through human modifications has brought great changes at global, regional and local levels part of which poses a threat to human and environmental systems. Monitoring of these changes is necessary to ensure the sustainability of terrestrial ecosystems such as the Mbagathi River catchment. The study sought to determine the land use and land cover changes and drivers in the Mbagathi River catchment for the period 1990-2020. This was achieved by the classification of multitemporal Landsat imageries of 1990, 2000, 2010 and 2020 using the Google Earth Engine web platform. The study established four main land use/cover classes including forest, grassland, urban and bare ground. The results of the classification and analysis process established that forest cover reduced from 32% to 14%, grassland reduced from 53% to 30%, bare ground increased from 10% to 38% and urban land cover increased from 4% to 17%. This revealed that urban and bare ground land covers increased at the expense of forest and grassland covers. Multitemporal and spatial assessment of settlement observed that more settlements emerged around the key urban centres namely Kiserian, Ongata Rongai, Ngong, Mlolongo and Tuala. Further analysis within a 3 Km radius of the towns revealed that urban area increased by 11% and 19% for Tuala and Kiserian respectively while in Ongata Rongai and Ngong, the urban area increased by 20% and 23% respectivelyItem Assessing the Effects of Land Use/Land Cover Change on Discharge Using SWAT Model in River Ruiru Watershed, Kiambu County, Kenya(IJRIAS, 2019) Waithaka, Ann; Murimi, Shadrack; Obiero, KennedyWatersheds and water resources are highly vulnerable to land use/land cover changes (LULCC) as they directly influence hydrological characteristics in terms of water quantity. This study aimed at assessing the effects of land use/land cover changes (LULCC) on Surface runoff contribution to discharge (SURQ), lateral flow contribution to discharge (LATQ) and groundwater contribution to discharge (GWQ) of River Ruiru watershed, Kiambu County. The study integrated the use of remote sensing, GIS and hydrological modeling to collect and analyze data. Results of the study indicate that built-up areas, annual crops (mixed farming) and perennial crops (Tea and coffee farming) increased by 1.83%, 15.05% and 10.90% from 1984 to 2017 while grassland, shrubland and forestland decreased by 6.21%, 11.92% and 10.06%. SWAT model results indicate that land use/land cover changes that have occurred in River Ruiru watershed between 1984 and 2017 have had effects on Surface runoff (SURQ), lateral flow (LATQ) and groundwater contribution to discharge (GWQ) which have increased from 30.25 mm/yr, 8.48mm/yr and 9.95mm/yr to 181.25mm/yr, 11.44mm/yr and 10.66mm/yr respectively. The results from this study will help in understanding the effects of LULCC on the quantity of discharge which is one component of the knowledge base required in applying the principles of integrated water resources management (IWRM) thus providing critical input to the decision making on water resources management and planningItem Spatiotemporal Relationship between Variability in Selected Climate Parameters and Malaria Transmission Trends in Different Altitudes of Lower Lake Victoria Basin(IJNRD, 2024-01) Olela, Samwel Odhiambo; Makokha, George L.; Obiero, KennedyPurpose: Consequences of Global Climate Variability and Change are among the biggest environmental threats and challenges the world is facing. Malaria burden is greatest in developing countries of the tropics especially Africa south of the Sahara. In Kenya, it is blamed on high rainfall, temperature and relative humidity. This study investigated spatiotemporal relationship between variability in selected climate parameters and malaria transmission in different altitudes of lower Lake Victoria Basin, Kenya. Methodology: The study used secondary data archived at sampled meteorological stations and health facilities. Flooded sampling of malaria morbidity cases from health facilities within selected sub - counties in three sampled counties was obtained from Kenya Health Information System (KHIS) for ten years (2011 - 2020). Meteorological data was obtained for twenty years (2001 - 2020) except for Kisumu Relative Humidity which was only available for 12 years (2009 - 2020). Pearson’s moment correlation coefficient and regression were used to establish the strength of the relationship between malaria transmission, climate elements and altitude. Findings: Given temperature ranging between 22.520C – 23.770C, RH of 58.77% - 67.74% and a mean annual rainfall of 1844.57, the study area was found to be well within climatic threshold for endemic malaria transmission. When correlated and regressed, none of the climate parameters revealed significant relationship with malaria transmission except monthly temperature and monthly malaria transmission in Migori County. Transmission significantly decreased with increase in altitude. All climate variables were eliminated leaving only altitude as the significant spatial determinant of malaria transmission. Climate therefore remained an insignificant spatiotemporal determinant of variability in malaria transmission in the study area. Unique Contribution to Theory, Policy and Practices: Spatiotemporal Variability of Malaria transmission was significantly defined by altitude and proximity to the lake. This made the study zone LLVB, Kenya into three based on altitude and malaria transmission rates as follows: 1001m to 1200m – high transmission zones; 1201 to 1400 - medium transmission zones; 1401 to 1600 – low transmission zones. Meteorologists and the Medics should combine efforts to put remedial measures in place depending on altitude and time of the year. There is need to find out why some parts should experience upsurge while others like Migori County are experiencing reduction. These recommendations were necessary in the LLVB, Kenya for the realization of Kenya’s vision 2030.Item Sand Harvesting and Its Social, Economic and Environmental Effects on Household’s Livelihoods in Homabay County, Kenya(IAJAH, 2024-01) Buke, Mercy; Musau, Jackson; Muiruri, PhilomenaSand harvesting is an economic activity that has socio-environmental effects on people's lives. The magnitude of the effects varies from place to place based on the prevailing circumstances in such places. This study, therefore, sought to find out the socioenvironmental effects of sand harvesting on residents of Kobala Sub-location in HomaBay County. Subsequently, the key objective of this study was to explore sand harvesting and it’s social-environmental effects on household’s livelihoods in Kobala sublocation in Homabay County. The study adopted a descriptive survey design and used questionnaires and key informant interviews as the instruments of data collection. Using Yamane formula, the study sampled 370 respondents from the residents of the Kobala sub-location. Purposively, 15 key informants were selected; ten residents of Kobala engaging in sand harvesting activities and five NEMA officials of Homabay County. Data from questionnaires were analyzed using descriptive statistics while qualitative content analysis was used to analyze data from key informant interviews. The findings of the study revealed that sand harvesting in Kobala sub-location has had negative social effects on the residents by increasing the rate of education wastage among teens, an increase in domestic violence, an increase in accidents and deaths in the area. Further, the findings have established that the cost of treatment for the residents has risen due to increased mosquitos breeding in open valleys as well as in the management of waterborne diseases. The study has further established that water sources are negatively impacted with increased soil erosion and depletion of vegetation which worsen food insecurity in the area.Item The Extent to Which Rainfall Variability has Affected Small Scale Dairy Farmers in Uasin-Gishu County, Kenya(IJRISS, 2023-09) Nyongesa, Geoffrey Mukhebi; Makokha, George; Mbuthia, SusanDairy farming in Kenya remains among the key wheelers to the Nations GDP contributor at about 6- 8%. Majority of the farmers in this sector, are small scale who mostly have no knowledge and capacity to handle challenges posed by rainfall variability that causes frequent droughts, impacting on water and pasture supply to their animals. Objective of study was: To assess the extent to which rainfall variability had affected small scale dairy farming in Uasin-Gishu County in Kenya between years 2010-2020. Rainfall data was collected from the Kenya Meteorological Department (KMD), Eldoret. While milk produce data was obtained from Ministry of Agriculture Uasin-Gishu County. Structured Questionnaires were used to collect data from farmers with few key respondents interviewed on the same . The questionnaire was administered to small scale dairy farmers who were sampled in a stratified manner based on their sub counties, then randomly within the Sub County. In total about 368 small scale dairy farmers were sampled out of which 300 (82%) of administered questionnaire were fully responded to. Analysis of objective one was done by Pearson correlation to establish the relationship between various rainfall characteristics and milk produce. Total annual rainfall with total annual milk had correlation of r= 0.532, number of rainy days in a year to the amount of milk with Pearson correlation of r =0.375, P>0.05. Onset and cessation periods had Pearson correlation of r=0.305 and r=0,019 respectively. Average monthly rainfall to milk had Pearson correlation indicating a negative relationship of r= -0.424, P= 0.169, meaning months with high rainfall amounts had lower milk produced while dry ones had higher milk produced. The researcher therefore failed to accept the null hypothesis and adopted the alternative one that rainfall variability has had significant impact on small scale dairy farming in Uasin –Gishu County. Research recommended that farmers should keep more of cross breed animals which cope with climate variability unlike exotic ones. There was also need for farmers to join and strengthen cooperative societies to assist them adapt, this is besides use of digital methods of sharing challenges and solutions to rainfall variabilityItem Analysis of Riparian Land Rehabilitation on Water Quality and Macro Invertebrates’ Diversity along Nairobi River, Kenya(IJWR, 2023) Ndichu, NN; Tela, SA; Kweyu, RM; Makokha, M; Okeyo, FAquatic life has been facing a lot of threat from the anthropogenic activities occurring near water bodies. This calls for rehabilitation actions to save the lives. The aim of this study is to analyze the rehabilitation actions that have taken place along Nairobi River and how the remedies have affected water quality as well as diversity of macro invertebrates. Notable rehabilitation activities have taken place at a river section called Michuki Park where garbage collection, fencing, planting of trees (vegetation), offering security among other practices have been undertaken. Comparison was done between the rehabilitated and non-rehabilitated sections of the river. The objectives of this study are: To assess the riparian cover types along Nairobi River, to analyze the relationship between riparian cover types and water quality, to determine the impact of rehabilitation on water quality and to establish the relationship between rehabilitation and diversity of macro invertebrates. The land use cover assessed were forest, shrubs, bare land and settlement (development). These land use cover types were analyzed in order to help in understanding the human activities carried out along the river. Four main sampling points were used to gather data where in each two samples were taken. The process was done both in a dry and a wet period. A total of 16 samples were analyzed. Data collected was analyzed using the satellite image analysis for the period of study. Data presentation was done in maps, tables, and graphs. The study findings revealed significant differences in water quality parameters between rehabilitated and nonrehabilitated zones during dry days (P<0.05), but no significant differences on wet days (P>0.05). The number of macro-invertebrates showed no significant difference. Pearson's correlation analysis revealed a negative relationship between macro-invertebrate diversity and nitrates and phosphate levels (r=-0.863 and -0.603, P<0.05). Although not statistically significant, negative relationships were observed between macro-invertebrate diversity and water temperature, electrical conductivity, total dissolved solids, and turbidity. Dissolved oxygen and pH showed positive correlations with macro-invertebrate diversity. Species evenness was positively influenced by nitrate levels (r=0.360, P=0.043). Other factors such as water turbidity, phosphates, and electrical conductivity also had positive relationships with species evenness. The comparison between the rehabilitated and non-rehabilitated areas showed no significant difference in macro-invertebrate diversity (t=0.478, P=0.636), but a significant difference in species evenness (t=2.35, P=0.0255). The rehabilitated area had higher pH and dissolved oxygen levels, while the nonrehabilitated areas had higher electrical conductivity, total dissolved solids, and turbidity. Nitrates and phosphates were significantly higher in the non-rehabilitated area. Interview responses indicated that 25% of the participants reported benefiting from Nairobi River water despite its deteriorating quality, while 75% did not report any benefits. The diversity and abundance of macro-invertebrates were significantly influenced by key parameters. Oxygen showed a positive correlation, while phosphates and nitrates exhibited a negative correlation with macro-invertebrate diversity and abundance. The study emphasized the positive impact of rehabilitation on aquatic life, as rehabilitated areas had higher diversity. To prevent pollution, measures such as proper waste disposal and penalties for polluters should be enhanced. Further research is recommended to explore the distribution and adaptability of other species in the river, as well as identify extinct species. Public education on the detrimental effects of pollution on aquatic life is crucial. Expanding rehabilitation efforts to cover larger sections or the entire river is suggested. The study's findings raise awareness among residents living along the river about the harm caused to water biodiversity.Item Improved Crop Productivity and Soil Properties under Varying Planting Densities of Pentaclethra Macrophylla Benth. and Acacia Auriculiformis A. Cunn. In Congo Basin(Springer Link, 2023-09) Mapenzi, Neville; Katayi, Alain L.; Bauters, Marijn; Masimane, Jules; Schure, Jolien; Kweyu, RaphaelSoil fertility depletion is a major constraint to agricultural production in the Congo Basin and is aggravated by climate change. Therefore, agroforestry systems (AFS) are used to improve soil fertility and crop productivity. Indeed, Pentaclethra macrophylla and Acacia auriculiformis are among the most agroforestry species used in this basin. However, smallholders are limited in their choice of agroforestry species and the spacing. Hence, this study comparatively evaluated the efects of P. macrophylla (native) and A. auriculiformis (exotic) legume tree species on soil macronutrients and food crops’ yield during four cropping seasons. To do this, a multifactor trial design was implemented in Lobilo catchment, Congo Basin, with two tree species, four tree planting densities (T1: 2500 trees× ha−1, T2: 625 trees× ha−1, T3: 278 trees× ha−1; and T0: crop monoculture), and three intercrops (cassava, maize, and peanut). The results revealed that both agroforestry species did not signifcantly difer regarding their impact on soil macronutrients. The total nitrogen and the pH in soil have increased with the cropping seasons. With regard to the food crops, cassava and maize yield were greater under P. macrophylla than under A. auriculiformis. However, the 2500 trees× ha−1 density negatively afected food crops’ yield and did not allow food crop production after the second cropping season. To maximize the positive efects of these AFS, it is essential to plant or co-plant these two agroforestry species at 625 trees× ha−1 density Future research could investigate other native species and include water and light interactions.Item Analysis of Spatial and Temporal Distribution of Aquatic Macroinvertebrates in Relation to Selected Environmental Parameters along Nairobi River, Kenya(JGEESI, 2023) Ndichu, Naomi Nyambura; Tela, Samuel Abuyeka; Fred, Okeyo; Makokha, Mary; Kweyu, RaphaelAquatic diversity in riverine ecosystems is threatened by the intensification of unsustainable human actions in the river catchment areas. Nairobi River is one of the global wetlands that is experiencing high levels of degradation and this has a detrimental effect on the community's livelihood. The study aimed to analyze the spatial and temporal distribution of aquatic macro invertebrates in relation to some environmental parameters in the Nairobi River watershed in Kenya. The study objectives were: to find out macroinvertebrates' diversity in the Nairobi River; to investigate selected water quality parameters in rainy and dry periods along the river; and to analyze the spatial distribution of macroinvertebrates in relation to selected water quality parameters. During the dry days, temperature, electrical conductivity, total dissolved solids, turbidity nitrates, and phosphates had significant differences (P ˂0.05 and F˃1). In the same period, macroinvertebrates were higher in the middle course 1 section of the river (mean 657.00) and in the middle course 2 section (mean 588.00) to upper and lower sections. However, there was no significant difference (P > .05) in the sites. Similarly, during the wet days, macroinvertebrates were noted to be higher in the middle course 2 areas (mean 168) and middle course 1 (mean 155). However, the number of macroinvertebrates was not significantly different (P > .05). Animals such as midge larvae and pupa, aquatic earthworms and mosquito larvae were highly tolerant to pollution due to adaptations to survival while others such as water penny, gilled snails, fingernail clam were sensitive to pollution thus they survived in very few sections of the river and in small numbers. The study recommends the need to conserve the river watershed as well as restore degraded river sections to guarantee the continued future provision of ecosystem services to the adjacent urban river communities and improve the river's biological integrity.Item Allometry and Aboveground Biomass of Acacia auriculiformis A. Cunn.ex Benth Based Agroforestry Systems in Yangambi Landscape, Democratic Republic of Congo(EANSO, 2023) Ndimubenchi, Innocent Amani; Assani, Neville Mapenzi; Mugisho, Gérard Imani; Mukirania, John KatemboMost of the population living near the Yangambi Biosphere Reserve lives mainly from slash-and-burn agriculture which causes deforestation. The agroforestry system (AFS) is reputed to stabilise agriculture, store carbon in plant biomass and in the soil, and improve soil fertility. Acacia auriculiformis is a fast-growing leguminous tree that has been planted in AFS in the Yangambi landscape, but few or no studies assessed its aboveground biomass storage. This study aims to determine the aboveground biomass storage of AFS-based Acacia auriculiformis when intercropped with cassava, maise, and peanut food crops at different tree planting densities in the Yangambi landscape. The experimental device is a multifactorial trial of 36 plots of 400 m2 each one; with 4 treatments and 3 repetitions for each of these tree species in association with maise, groundnut, and cassava. Therefore, for assessing the aboveground biomass, the stem circumference and tree height were taken in each plot. Moreover, to study the A. auriculiformis allometry, 30 trees were cut and the aboveground biomass was estimated from the local allometric model set up in this study. Through this work, we have developed the three best allometric models for estimating the aboveground biomass of A. auriculiformis. The result showed that the aboveground biomass of A. auriculiformis varies between 0.49 and 10.54 t/ha (0.25 to 5.27 t/ha of carbon) depending on tree planting density and food crops. By comparing the results of the current study with those of others who worked on A. auriculiformis biomass, it was noted that the local models developed in this study contribute to increasing the precision of carbon estimation in the Congo basin. This is important for the implementation of REDD+ projects (Reducing emissions from deforestation and forest degradation) in the DRC. In conclusion, agroforestry plantations contribute to storing carbon in plant biomass.Item Effects of Rapid Population Growth on Waste Disposal in Thika Town, Kiambu County, Kenya(IRJP, 2023) Mugure, Lucy; Kibutu, Thomas N.The purpose of the study was to establish the effects of rapid population growth on waste disposal in Thika town, Kiambu County, Kenya. The study was based on the Driving ForcePressure-State-Effect-Response (DPSER) model (OECD, 1994), and adopted a survey research design. The target population for the study was town physical planners, local officials of NEMA, members of the public and community groups who engaged in environmental conservation in the municipality. Stratified random sampling was used to select community group members, officials from NEMA, the Physical Planning Department and District Environment Officers. Data for the study was collected by use of questionnaires and interview guides. Quantitative data collected was analyzed using descriptive statistics such as frequency counts and percentages. On the other hand, qualitative data was analyzed thematically in line with the study objectives. The results of the analysis were presented using tables, pie charts and bar graphs. The study established that the rapid population growth in Thika Town has led to environmental problems such as water pollution, air pollution, poor disposal of waste, formation of slums, poor maintenance of water supply, sewerage and sanitation systems and congestion in the transport system. The study recommends that environmental education should be incorporated into the school curriculum at all levels to build a generation of environmentally conscious citizens; the government should provide adequate funding for agencies concerned with environmental management and ensure proper implementation of programs and policies; the government should also install a recycling plant within Thika Town to curb environmental degradation; among other actions.Item Changes in Water Quality Parameters along Thika River Sub-Catchment, Upper Tana, Kenya(JARWW, 2023) Odero, Joanes Ooko; Makokha, George Lukoye; Mati, Bancy; Okoth, Nathan OduorSurface water pollution is a challenge due to effluent discharge from land-based factors like agro-based sectors, settlements, and poor sanitation. The research investigated the spatial and seasonal variation of physico-chemical and biological water quality due to land use changes along the Thika River sub-catchment, Upper Tana, Kenya. The study applied purposive sampling technique from the different zones within the catchment during the dry and wet season of 2021. The samples were tested for physico-chemical and microbial contaminants. R-studio was used to calculate the mean values and t-test performed at a 95% confidence interval to determine variation of the parameters in the two seasons and mean levels compared to the Kenya Bureau of Standards (KEBS) 2010 and the World Health Organization (WHO) acceptable quality for drinking water. There was significant variation in sulphate and nitrate concentration, total coliform and fecal coliform and no significant variations in physical parameters throughout the seasons. The total coliform and fecal coliform exceeded KEBS and WHO limits.Item Identification of Critical Sub-Watersheds Prone to Soil Erosion using Remote Sensing Data and Geospatial Techniques in Thiririka Watershed, Kenya(IOSR, 2023) Inyele, Juliet; Murimi, Shadrack; Kweyu, RaphaelMorphometric Studies And Land Use/Land Cover Analysis Play A Key Role In Integrated Watershed Management. Sustainable Resource Utilization At A Watershed Level Requires An In-Depth Understanding Of Land Use, Drainage, And Hydrological Patterns Of The Watershed. In Developing Countries, Poverty Has Led To Unsuitable Land Management Practices (E.G. Deforestation, Continuous Tillage), Contributing To Increased Soil Erosion In Watersheds. To Reduce Soil Erosion At The Watershed Level, Watershed Managers Need To Make Informed Decisions Such As Developing Vegetative Cover And Agroforestry. However, This Is Limited Due To A Lack Of Readily Available Data To Guide The Process. This Study Explores The Potential Use Of Basin Morphometry And Land Use /Land Cover Parameters With Geographic Information Systems (GIS) And Remote Sensing (RS) Tools To Identify Areas Susceptible To Soil Erosion In Thiririka Watershed In Kenya. Five SubWatersheds Were Delineated And Assigned A Code From SW1 To SW5 Using The Shuttle Radar Topographic Mission (SRTM) 30-Meter Resolution Digital Elevation Model (DEM) In Arcgis Software, Followed By Morphometric Analysis Of Linear, Aerial, And Relief Aspects Of The Watershed. Land Use/Land Cover Classes Were Generated From A Median Composite Of Sentinel-2 2020 Image. A Supervised Classification Scheme Was Used To Develop A Random Forest Classifier To Perform The Classification. Finally, The Effects Of Each Morphometric And Land Use/Land Cover Parameters On Soil Erosion Were Assessed And Assigned Ranks 1 To 5. These Ranks Were Averaged To Get The Compound Priority (CP) In GIS Tabular Database. Results Showed That Sub-Watershed 5 Is Highly Susceptible To Soil Erosion Needing Immediate Management Actions, While Sub-Watershed 4 (SW4) Shows Less Susceptibility To Soil Erosion. The Study Recommends The Use Of Remote Sensing And GIS In Watershed Prioritization ManagementItem Devolution of Agriculture and its Effects on Mango Marketing by Small-Scale Farmers in Makueni County, Kenya(EANSO, 2023) Vamba, Mary Kaluki; Kibutu, Thomas; Musau, JacksonThe study aimed to evaluate the devolution of agriculture and its effects on mango marketing by small-scale mango farmers in Makueni County, Kenya. It utilised a descriptive research design and collected data in narrative and numerical formats from mango farmers in the county. The study used a semi-structured questionnaire and interviews; data was collected using a stratified random sampling technique. Quantitative data was analysed using frequencies, percentages, and correlation analysis in the SPSS (V27) package, while qualitative data from interviews was analysed using thematic analysis. The findings hold significant implications for policymakers, farmers, and researchers. Furthermore, the study informs small-scale farmers about the benefits of adopting good agricultural practices to improve the quality of their mangoes. Key indicators of devolution identified in the study include improved marketing guidelines, farm cooperatives, processing of farm produce, infrastructure development, improved bargaining power, provision of farm inputs, funding/soft loans, and training and capacity building. The benefits of devolution for mango farmers encompass increased decision-making authority, subsidies for farm inputs, and overall improvement in their lives. Some of the challenges faced by mango farmers are limited marketing options, restricted credit availability, and low prices for their produce. Based on the findings, there is a significant positive relationship between agricultural devolution and mango marketing. The correlation analysis indicates a positive relationship between devolution and the marketing of mangoes (r = 0.572, p = 0.000). The study concluded that although mango marketing cooperatives helped farmers, the Makueni County government lacked sufficient marketing options for mango producers. This resulted in limited market access, restricted credit availability, and low prices for their produce. The study recommends collaboration between the county government and mango farmers to increase demand and marketing approaches for mangoes.