Background: At the centre of smallholders' adaptation is a need to understand their perceptions on key climatic scenarios so as to glean helpful information for key decision-making processes. In Kenya at the moment, downstream information regarding these circumstances remain scanty, with many smallholders being 'on their own', in spite of the imminent threats from shifting precipitation patterns, rising temperatures, and intensifying droughts. At the sub-national levels, potential impacts of these situations are likely to deepen due to extensive cases of land use transformations, habitat degradation, plummeting water resources capacity and common inter-ethnic conflicts, among other negative externalities. The study examined current climatic situations in Trans-Mara East sub-County, to the south-western part of Kenya, as well as the smallholders' perceptions about the situations, their adaptation levels and constraints thereof. Results: Pearson correlation coefficient, indicated a weak positive association between smallholder's perceptions and either their age, marital status, level of education, or livelihood streams (r ≤ 0.1; p ≥ 0.05, for all), unlike their climatic perceptions and farm sizes which showed a strong positive association (r = 0.430; p ≤ 0.01). Key desired adaptation options, improving crop varieties, livestock feeding techniques and crop diversification, topped their options, with destocking being least desired. Education levels (r = 0.229; p ≤ 0.05) and farm sizes (r = 0.534; p ≤ 0.01) had a positively significant association with adaptive capacity, in addition to a significantly weak, association between their adaptive capacity and both their individual's marital status (r = 0.154; p ≥ 0.05) and diversity of livelihood streams (r = 0.034; p ≥ 0.05). The analysis also showed a weak negative association between their adaptive capacity and age (r = − 0.026; p ≥ 0.05). Amid the key constraints which emerged include high cost of farm inputs, limited access to credit and market uncertainties, among others. Pearson correlation coefficient showed a significantly strong negative association between smallholders' constraints and both (r ≥ − 0.3; p ≤ 0.01) their level of education, and diversity of livelihood streams. A significantly strong positive association (r = 0.280; p ≤ 0.01) was identified between smallholder's age and constraints, while marital status and farm sizes both (r ≤ − 0.01; p ≥ 0.05) revealed weak non-significant negative association with the constraints.

No abstract

This study was to determine the spatiotemporal characteristics of historical and projected drought events throughout Isiolo County, Kenya, through using self-calibrating Palmer drought severity index (scPDSI). The scPDSI is a complex and robust drought index that applies the water balance model by incorporating the role played by evapotranspiration and soil properties on drought analysis therefore making it appropriate to identify the linkages between meteorological, agricultural and hydrological droughts. The historical scPDSI was computed at a monthly timescale using a 39-year long monthly mean precipitation data from Climate Hazard Group Infrared Precipitation with Station (CHIRPS) and monthly average temperature data from the Climate Research Unit (CRU). The climatological (1950-1996) available water holding capacity (AWHC) of the soil was obtained from Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) for biochemical dynamics at a spatial resolution of 1o x 1o. The projected scPDSI under Representative Concentration Pathways (RCPs) was computed using bias corrected monthly temperature and precipitation model output data from Coordinated Regional Climate Downscaling Experiment (CORDEX). The datasets were extracted for ten grid points in the County. The scPDSI was used to assess the historical and projected duration, severity, and intensity of droughts. The major significant historical and projected drought events and their characteristics were clearly identified using the run theory. ScPDSI runs have shown that more severe drought events dominated the period between 1980 and 2000. ScPDSI had the longest dry event duration of 61 months and a severity of 126.412 with adverse effects on the eastern locations. The projected drought events identified Mar 2046 –Mar 2048 under RCP4.5 to be the most severe drought lasting for 25 months with severity of 59.292 while under RCP8.5 run Nov 2042 – Nov 2046 is identified as the most severe, 114.362 with the duration of water stress anticipated to last for 49 months. To examine the spatial variability of the drought events in the County, the Empirical Orthogonal Analysis (EOF) was applied to the historical and projected scPDSI time series. The EOF results indicated that the two leading eigen vectors accounted for over 85% of the spatial variability for both historical and projected droughts under the RCPs. Subsequently, the Mann-Kendall (MK) test was applied to the projected scPDSI, temperature and precipitation timeseries in order to determine the local expected drought trends. The MK test of the identified significant increase in trend for temperatures under RCP8.5 and precipitation under RCP4.5 towards the end of the last decade under the study period considered. Both scenarios showed a decline in trends of drought events in Isiolo County from 2020-2050.

Temporal changes of sediment dynamics within the Nairobi River sub-basins between 1998-2006 time scale, Kenya The city of Nairobi is the heart of both industrial production and the economic hub in Kenya and the Eastern Africa region. The city of Nairobi and its environs are drained by three streams, namely: Nairobi, Mathare and Ngong rivers. These streams drain areas of diverse land use activities. The land use changes in a spatial manner from the rich agricultural system through residential cum urban to industrial. The significance of these various land use systems to pollutants generation, pollution, sediment generation and hence water pollution and quality degradation is quite enormous and worth investigation. The land use changes in a spatial manner making the basin ideal for a temporal variation of sediments yields along the river profile and their impacts on the water quality status. This paper examines the results of study carried out within the basins in the years 1998-2006. The method of study involved water sampling and laboratory analysis to reveal the trends in sediment load increases downstream the investigated streams. Soil samples were also investigated to determine their relationship to soil erosion rates and sediment fluxes. The study attempts further to find the best sediment management strategies in reversing their increasing trends and restoring water quality within the basin.