Water availability analysis of multiple source groundwater supply systems in water stressed urban centers: case of Lodwar municipality, Kenya

Ensuring water security to urban population in fragile environments through interlinked systems of groundwater abstraction, storage and distribution of sufficient quantity is challenging especially to urban utilities situated in arid and semi arid regions. The purpose of this research was to evaluate water delivery challenges for water utilities in fragile environment in Kenya. A systematic analysis of availability from each supply sub-components from source to consumer was carried out through water audit and network analysis by employing water flow measurement equipments and through pump performance analysis and by employing continuity equation and Bernoulli’s principle to sections of the network. Results showed that water availability within a utility in such environments is contributed by seasonal variations between wet and dry affecting quantity at source, optimal design of supply infrastructure in this case better matching of solar power with the pump, using standard pipes and on optimal operational strategies employed to reduce losses within the network. Based on these findings, we conclude that with clear understanding of each subcomponent’s contributions to entire water supply system and optimizing their design and operations, more people will be made water secure in all seasons in the fragile environments

Assessing the underlying drivers of change over two decades of land use and land cover dynamics along the Standard Gauge Railway corridor, Kenya

We acknowledge funding from the UK Research and Innovation’s Global Challenges Research Fund (UKRI GCRF) through the Development Corridors Partnership project (project number: ES/P011500/1).Land cover has been modified by anthropogenic activities for thousands of years, although the speed of change has increased in recent decades, particularly driven by socio-economic development. The development of transport infrastructure can accelerate land use land cover change, resulting in impacts on natural resources such as water, biodiversity, and food production. To understand the interaction between land cover and social–ecological drivers, changing land cover patterns and drivers of change must be identified and quantified. This study documents land cover dynamics along the Standard Gauge Railway (SGR) corridor in Kenya and evaluates the underlying drivers of this change from 2000 to 2019. The study utilised GIS and remote sensing techniques to assess the land use and land cover changes along the SGR corridor, while correlational and regression analyses were used to evaluate various drivers of the changes. Results showed that built-up areas, bare lands, water bodies, croplands and forests increased by 144.39%, 74.73%, 74.42%, 9.32% and 4.85%, respectively, while wetlands, grasslands and shrub lands reduced by 98.54%, 67.00% and 33.86%, respectively. The underlying drivers responsible for these land use and land cover dynamics are population growth, urbanisation, economic growth and agro-ecological factors. Such land cover changes affect environmental sustainability, and we stress the need to adequately identify and address the cumulative social and environmental impacts of mega-infrastructure projects and their interacting investments. The findings of this study provide an evidence base for the evaluation of the social–ecological impacts of the SGR and the implementation of best practices that will lead to enhanced sustainability in the development corridors in Kenya and beyond.Publisher PDFPeer reviewe

Effects of Shallow Water Table on the Construction of Pit Latrines and Shallow Wells in the Informal Settlements of Kisumu City

Kisumu city, like many cities in the developing world, has increased burden of urban informal settlements where access to basic sanitation and water remain a challenge. Despite several studies focussing on sanitation and water situation within Kisumu environment, elaborate research on the influence of shallow water table on the construction of facilities and quality of structures has however not been extensively reported. In order to discuss potential implications of sanitation facility quality on public health in the informal settlements, this study characterised sanitation facilities by depth and quality of superstructure, analysed association between depth of pit latrines and types, and between depth of pit latrines and shallow wells (SWs). The study targeted five urban informal settlements in Kisumu city namely Nyalenda A, Nyalenda B, Manyatta B, Manyatta A and Obunga, and two peri-urban informal settlements of Korando and Kogony. The study involved physical ground surveys on all SWs in the study area and convenience sampling of toilet facilities within 30 m radius to the water points. Analysis was carried descriptively and with the help of GIS spatial analysis tool. A total of 100 SWs and 400 pit latrines were studied. Our findings revealed some evidence of the influence of shallow water table on the construction quality and depth of pit latrines and SWs both in the urban informal settlements and those of the peri-urban. The mean depth of pit latrines and SWs in the urban informal settlements ranged from 0.25 m–3.8 m and 0.0 m–4 m, respectively, while peri-urban areas ranged from 3.5 m–8.1 m and 7.6 m–14.4 m. The study also established that most pit latrines were raised to a mean height of 0.25 m–0.5 m above ground. Analysis of depth revealed that the depth of pit latrines and shallow wells in the urban informal settlements were overlapped while those of the peri-urban were not overlapped. Moreover, majority of pit latrines in the urban informal settlements were raised by an average 0.25 m–0.5 m above mean ground level, a strategy, identified by residents, to overcoming the double challenge of flooding and cross contamination. Overall, the study established that, where construction depth of both pit latrines and shallow wells is limited, the incentive to construct quality pit latrines or SWs lessens, the possible reason for the prevalence of low quality and less durable facilities in the urban informal settlements as opposed to peri-urban areas where deeper and improved pit latrines and wells exist. In conclusion, the high prevalence of poor-quality pit latrines and SWs in the informal settlement predisposes residents in these settlements to public hygiene challenges with potential escalation during floods. Creation of awareness on improved toilet facilities with potential of withstanding the challenges of raised water table and frequent flood risks is recommended in the short term while development of specific toilet construction guidelines concerning depth and superstructure recommended on the long term

The Hominin Sites and Paleolakes Drilling Project:High-Resolution Paleoclimate Records from the East African Rift System and Their Implications for Understanding the Environmental Context of Hominin Evolution

The possibility of a causal relationship between Earth history processes and hominin evolution in Africa has been the subject of intensive paleoanthropological research for the last 25 years. One fundamental question is: can any geohistorical processes, in particular, climatic ones, be characterized with sufficient precision to enable temporal correlation with events in hominin evolution and provide support for a possible causal mechanism for evolutionary changes? Previous attempts to link paleoclimate and hominin evolution have centered on evidence from the outcrops where the hominin fossils are found, as understanding whether and how hominin populations responded to habitat change must be examined at the local basinal scale. However, these outcrop records typically provide incomplete, low-resolution climate and environmental histories, and surface weathering often precludes the application of highly sensitive, state-of-the-art paleoenvironmental methods. Continuous and well-preserved deep-sea drill core records have provided an alternative approach to reconstructing the context of hominin evolution, but have been collected at great distances from hominin sites and typically integrate information over vast spatial scales. The goal of the Hominin Sites and Paleolakes Drilling Project (HSPDP) is to analyze climate and other Earth system dynamics using detailed paleoenvironmental data acquired through scientific drilling of lacustrine depocenters at or near six key paleoanthropological sites in Kenya and Ethiopia. This review provides an overview of a unique collaboration of paleoanthropologists and earth scientists who have joined together to explicitly explore key hypotheses linking environmental history and mammalian (including hominin) evolution and potentially develop new testable hypotheses. With a focus on continuous, high-resolution proxies at timescales relevant to both biological and cultural evolution, the HSPDP aims to dramatically expand our understanding of the environmental history of eastern Africa during a significant portion of the Late Neogene and Quaternary, and to generate useful models of long-term environmental dynamics in the regionpublishersversionPeer reviewe

Atmospheric controls on precipitation isotopes and hydroclimate in high-elevation regions in Eastern Africa since the Last Glacial Maximum

Tropical Africa experienced large changes in hydroclimatic conditions since the Last Glacial Maximum (LGM), similar to 826.5 to 19 thousand years (ka or kyr) ago. The hydrogen isotopic composition of fossil leaf waxes (delta D-wax), assumed to record past variations in the hydrogen isotopic composition of precipitation (delta D-precip), is increasingly being used to study past hydroclimatic change in Africa, and are commonly interpreted to reflect variation in the amount of precipitation through time (i.e., the amount effect). Although there are now many such delta D-precip records from tropical Africa, there are few robust delta D-precip records from easternmost equatorial Africa of sufficient length and resolution to evaluate the mechanisms governing hydroclimate variation during and since the LGM. We produced a new delta D-precip record based on analyses of delta D-wax in sediment cores collected from Lake Rutundu, situated at an elevation of 3,078 meters above sea level (m asl) on Mt. Kenya. This record displays large variations in delta D-precip corresponding with known climate events over the past 25 kyr, including D-enrichment during the Heinrich 1 stadial (H1) and the Younger Dryas (YD), and D-depletion during the Holocene portion of the African Humid Period (AHP). We also observe D-depletion during the LGM relative to the late Holocene, which, considering the amount effect, could be interpreted to imply that LGM climate conditions were wetter than today. However, because other hydroclimate proxies at this site indicate a drier LGM climate at Lake Rutundu, and since precipitation isotopes at this high-elevation site are likely influenced by different processes than at low elevations, we used a single-column Rayleigh distillation model to evaluate temperature and altitude-related effects on high-elevation dDprecip. This revealed that a change in the temperature lapse rate exerts strong control on delta D-precip in this high-elevation setting, and that a steeper lapse rate could explain the observed D-depletion during the LGM at our site. Comparison of the Lake Rutundu delta D-precip record with other leaf-wax based delta D-precip records from East Africa indicates that changes in the meridional precipitation gradient associated with the mean annual position and intensity of the tropical rain belt, in turn driven by precessional insolation forcing, were likely a primary control on East African hydroclimate over the past 25 kyr, thereby contributing to overall regional drying during the LGM. (C) 2021 Elsevier B.V. All rights reserved

Finding sustainable water futures in data-sparse regions under climate change: Insights from the Turkwel River basin, Kenya

Study region: the Turkwel river basin, Kenya experiences a high level of water scarcity due to its arid climate, high rainfall variability and rapidly growing water demand. Study focus: Climate change, variability and rapid growth in water demand pose significant challenges to current and future water resources planning and allocation worldwide. In this paper a novel decision-scaling approach was applied to model the response of the Turkwel river basin’s water resources system to growing demand and climate stressors. A climate response surface was constructed by combining a water resource system model, climate data, and a range of water demand scenarios. New hydrological insights: The results show that climate variability and increased water demand are each important drivers of water scarcity in the basin. Increases in water demand due to expanded irrigation strongly influences on the resilience of the basin’s water resource system to droughts caused by the global climate variability. The climate response surface offers a visual and flexible tool for decision-makers to understand the ways in which the system responds to climate variability and development scenarios. Policy decisions to accelerate water-dependent development and poverty reduction in arid and semi-arid lands that are characterised by rapid demographic, political and economic change in the short- to medium term have to promote low-regrets approaches that incorporate longer-term climate uncertainty. Keywords: Water scarcity, Drought, Water allocation, Climate change, Data-sparse region