PROF. OLAGO DANIEL OCHIENG

To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites across AGL; while at others sites, it is rare or conducted irregularly in response to sporadic funding or short-term projects/studies. Managers and scientists working on the AGL thus often lack critical long-term data to evaluate and gauge ongoing changes. Hence, we propose a multi-lake approach to harmonize data collection modalities for better understanding of regional and global environmental impacts on AGL. Climate variability has had strong impacts on all AGL in the recent past. Although these lakes have specific characteristics, their limnological cycles show many similarities. Because different anthropogenic pressures take place at the different AGL, harmonized multi-lake monitoring will provide comparable data to address the main drivers of concern (climate versus regional anthropogenic impact). To realize harmonized long-term multi-lake monitoring, the approach will need: (1) support of a wide community of researchers and managers; (2) political goodwill towards a common goal for such monitoring; and (3) sufficient capacity (e.g., institutional, financial, human and logistic resources) for its implementation. This paper presents an assessment of the state of monitoring the AGL and possible approaches to realize a long-term, multi-lake harmonized monitoring strategy. Key parameters are proposed. The support of national and regional authorities is necessary as each AGL crosses international boundaries.

Tropical Africa experienced large changes in hydroclimatic conditions since the Last Glacial Maximum (LGM), ∼26.5 to 19 thousand years (ka or kyr) ago. The hydrogen isotopic composition of fossil leaf waxes (δDwax), assumed to record past variations in the hydrogen isotopic composition of precipitation (δDprecip), 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 δDprecip records from tropical Africa, there are few robust δDprecip 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 δDprecip record based on analyses of δDwax 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 δDprecip 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 δDprecip. This revealed that a change in the temperature lapse rate exerts strong control on δDprecip 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 δDprecip record with other leaf-wax based δDprecip 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.

Lodwar Municipality is one of the fastest-growing urban areas of Sub-Saharan Africa that depends mainly on groundwater for its municipal water supply. Most of the groundwater sources are located within the riparian zones of the Turkwel River. With limited understanding of its aquifers, the groundwater of Lodwar may be at risk of natural processes and anthropogenic activities. Statistical techniques and geochemical methods were applied to determine the aquifer hydrogeochemistry. Three distinct aquifers, which we collectively refer to as the Lodwar Alluvial Aquifer System, underlie Lodwar and its environs, the shallow alluvial, intermediate, and deep aquifers which are the main source of fresh water. A fourth, the shallow aquifer of the Turkana grit, is highly saline and with fluoride contamination. Just as the Turkwel River, the shallow alluvial aquifer (SAA) was dominated by Ca–HCO3 water type, while the TGSA was Na–Cl water type and became Na–HCO3 near the Holocene sediments. The intermediate aquifer (IA) was Na–HCO3water type. Pockets of Mg–HCO3 water occurred in the shallow alluvial and intermediate aquifers. The natural processes in the SAA include rock-water interaction, recharge by surface water, and oxidation reactions, while evaporation and dissolution are the major factors controlling the chemistry of the TGSA. Ion exchange, dilution, and dissolution are the major processes in the IA. Elevated levels of NO3− and SO42− during the wet season within the SAA and the IA reflects their vulnerability to pollution. Saline intrusion into the shallow and intermediate aquifers from the Turkana grit aquifers is likely to occur.

The advent of anthropogenic global warming and widespread modification of the climate, landscape and environment has brought humans to the fore as a formidable force of nature. The terrestrial and aquatic environment of the East African region is sensitive to a variety of global, regional and local stresses. The geological materials along East Africa coasts, lakes and peats are excellent archives of environmental and climatic changes. The study of their sedimentary records has contributed to our understanding of global environmental and ecosystem changes induced by anthropogenic activities associated with the “Anthropocene”, the proposed new geological epoch in Earth history. Humans have occupied East Africa for thousands of years, but until about 300 years ago, their impact on the environment was localized and transitory. The impacts intensified during the 19th century due to rapid population growth and extension and intensification of agriculture that was largely driven by colonists; during this period, the overprinting of natural environmental changes by humans is clear, marked by significant changes in sedimentation, sediment properties, and lake water quality as a consequence of land and water degradation and overexploitation of terrestrial and aquatic ecosystem goods and services. Related impacts include changes in terrestrial and aquatic ecosystems and associated biodiversity losses. There have been temporal and spatial lags in the changes, depending on locality, but there is a widespread convergence of these effects from the mid-1900s, support the Anthropocene Working Group's proposed date of 1950 as the start of the Anthropocene.

Abstract
The African Great Lakes (AGL) have rich fisheries and are renowned “biodiversity hotspots”. Consequently the AGLand the ecosystem services they provide, underpin the welfare and livelihoods of over 50 million people across 10 countries. Despite the recognized importance of the AGL, these vital ecosystems and their livelihood support systems are threatened by numerous anthropogenic stressors at local, regional, and global scales. Past and continued efforts to address critical challenges on these lakes are often short-term, parochial, disparate, and uncoordinated resulting in a lack of comprehensive and comparable scientific data and inadequate resources to influence evidence-based policy. Over the past two decades, several international workshops, conferences and scientific publications have identified the need for collaboration, knowledge sharing, and harmonization of research and management as key elements to enhance conservation efforts in the AGL. In this commentary, we introduce the African Center for Aquatic Research and Education (ACARE), which aims to strengthen research and provide the scientific evidence needed to make informed decisions related to sustainable fisheries and aquatic resource management in the AGL. To do this, ACARE will administer a highly collaborative network of experts with three long-term goals: (1) strengthen global and regional research partnerships; (2) establish transboundary and inter-jurisdictional lake advisory groups; and (3) build capacity of freshwater scientists through experiential education and public engagement.

Keywords
African Great Lakes Collaborative networks Transboundary lake advisory groups, educationResearch partnerships

Groundwater is the preferred alternative water source during times of shortages and in areas not served by piped water supplies. Pit latrines are the main sanitation facilities in Kisumu where sewerage extends over less than 20 per cent of the city. Pit latrines contribute to microbial contamination of shallow groundwater in Kisumu.

Kajiado County is predominantly inhabited by the Maasai nomadic pastoralists who rely on natural systems for their provisions and production needs. Traditionally, communal land management has been the norm in the area but that has evolved under the swift development context with the private holding of land becoming prevalent. The land-use transformation has curtailed the traditional seasonal movement of livestock and that has exposed the Maasai community to production risks which have contributed to the widespread food insecurity in the area. To address this gap, the study investigated land-use transformation in the area using Landsat 8, 4 and 5 datasets, where 1987, 2000 and 2015 epochs with a spatial resolution of 30*30m were sourced from www.glovis.usgs.org Remote sensing technology used to evaluate biophysical attributes showed changes in land-use patterns with the bare area, built-up area, cropland, forested land, grassland, riverine, shrubland, waterbody and wetland having undergone significant changes in their respective sizes. These land-use transformations have been compounded with the spread of invasive species to the point of threatening pastoralism. However, the successive governments have shown a marked disdain for resource use patterns. Thus, there is need for an all-inclusive land-use policies to inform adaptation and resilience planning in Kajiado County, Kenya.

Keywords

Natural Resource; Pastoralism; Biophysical Attributes, Land-Use Transformation; Remote Sensing; Masai Pastoralists

Access to water and sanitation remain a challenge in many developing countries, especially in pro-poor
urban informal settlements where socioeconomic livelihoods are generally low. The aim of this study was to characterise the water and sanitation facilities in the informal settlements of Kisumu City and to evaluate their effect on
community hygiene and health. The study focussed on the five urban informal settlements of Nyalenda A, Nyalenda
B, Manyatta A, Manyatta B and Obunga, and the three Peri-urban informal settlements of Kogony, Usoma and
Otonglo. Using descriptive techniques, the researcher surveyed 114 water sources and all sanitation facilities within
0-15m and 15-30m radii of the water sources. The findings revealed dominance of shallow wells and traditional pit
latrines as the primary water sources and sanitation facilities, respectively. Out of the water sources studied, 87.7%
(100) were shallow wells (mean depth 1.5 m), 9.6% (11) springs and 2.6% (3) boreholes. Most of these shallow
wells (83%) were within the urban informal settlements where uses range from washing and cleaning, cooking, and
even drinking (13.5%), despite the majority being unprotected. The analysis of the density of sanitation facilities
near the water points showed that 32.3% existed within a 15m radius of the nearest water sources, in violation of
the recommended safe distance of 30m. With an increased density of toilets near critical water sources and other
sanitary practices, public health is highly compromised.

Keywords : density, health, informal settlements, water-source, Sanitation technology.

Abstract

Geomorphological and sedimentary records near the confluences of the Tana River and major tributaries draining the eastern slopes of Mt. Kenya and the Nyambeni Range, indicate impacts of Late Quaternary volcanic activity in their fluvial records. The main reconstructed event was triggered by a 366.9 ka basalt flow (40Ar/39Ar dated) which flowed along Kazita River from the Nyambeni Range blocking both Kazita River and Tana River near Kibuka Grand Falls, causing a temporary lake. Consequently, Tana River and Kazita River started to build volcanoclastic Gilbert type deltas. The preserved pro-delta sediments rich in trachytic pumice fragments display a mineralogical and age match with known Ithanguni trachytic tuffs, indicating delta build up right after a contemporary Ithanguni eruption. This trachytic eruption caused the deposition of lahars and fluvial volcaniclastic sediments in all river records draining the Eastern side of Mt. Kenya. The multiple lahars seem to be triggered by eruptions under glacial conditions (basalt age indicates MIS 10). The lava dammed lake was only short lived (estimated to have lasted only a few years to decades) and breached before a complete lake infill could occur. The current Kibuka Grand Falls can be viewed as the delayed incisional response of this lava dam breach, indicating that after >366.9 ka, Tana River is still responding and adjusting to this short-lived disruptive phase. The current Kazita River has re-incised adjacent to a MIS 4 basalt flow down into the crystalline Basement System rocks. The MIS 10 pre-volcanic sedimentary record indicates that more sediments were in the fluvial system during glacial conditions than during the interglacial conditions. An implication of our reconstruction is that the Late Quaternary fluvial record of Tana River is of only limited use to reconstruct uplift rates because reconstructed Quaternary incision rates are reflecting both volcanic disruptions as climate change trends of aridification and decreasing glaciation extents.

The sub-surface is used in most parts of Africa as a repository of human waste and as a source of groundwater through pit latrines and shallow wells respectively. The wells provide freshwater to millions of people in Africa who are either not connected to the piped water or have intermittent supplies. These shallow wells are hand dug and therefore are mostly less than 20 meters in depth. This same sub-surface environment is also used as a repository of human waste through pit latrines. The water points and the sanitation facilities are mostly located close to each other. This study aimed at appraising the groundwater and sanitation challenges based on a rapid survey, sampling, interviews, existing literature review and historical borehole data in Kisumu city, Kenya. Previous studies in the area have shown that the number of shallow wells, city buildings, density of unimproved pit latrines and sanitary risks have increased tremendously between 1999 and 2019. Most of the wells are shallow and therefore prone to contamination by pollutants. Fluoride and chloride content in most boreholes are above the recommended WHO maximum values and the local KEBS standards. The study confirmed that the main water and sanitation challenges in Kisumu are poor and deteriorating water quality, poor waste disposal management systems and poor sanitation services. There is need for the introduction of new and sustainable groundwater approaches supported by scientific models and involving all stakeholders. Current deficiencies in the provision of adequate water and dignified sanitation to the poor in Kisumu can be remedied through improved knowledge on shallow aquifer dynamics and innovative research. It was noted that apart from the donor agencies and multi-national NGOs, the private investors are unwilling to invest in water projects in Kisumu due in part to government legislation that constrains the cost that may be levied on water

Sub-Saharan Africa (SSA; Fig. 1) refers to an area encompassing the countries in Africa that are fully, or partially, located south of the Sahara. The remaining African countries are generally referred to as belonging in North Africa. Although the socio-economic and hydrogeological conditions in SSA are diverse, they are sufficiently distinct (in general) from the conditions in North Africa to warrant being assessed separately—for example, high-yielding, high-storage, sedimentary aquifers are more common in North Africa than in SSA, while low-yielding, low-storage, basement aquifers are more widespread in SSA than in North Africa. The use of fossil groundwater is more typical in North Africa, while the use or renewable groundwater is more typical in SSA. Other hydrological characteristics associated with SSA include: groundwater resources that are generally under-utilized; lack of research and development that often prevents the optimal use of groundwater rather than over-development; and a heavy reliance by the rural and urban poor on shallow unconfined or semi-confined groundwater for potable water supplies, other domestic uses, and subsistence agriculture. Because of distinguishing characteristics such as these, there are good reasons for treating the hydrogeology of SSA as a whole, and separate from North Africa.

There is a consensus that current trends in climate change may be due to increasing concentrations of greenhouse gases (predominantly methane and carbon dioxide) from anthropogenic emissions. Among measures proposed for curbing this increase is Carbon Capture and Sequestration (CCS) in geological media. CCS incorporates three technologies comprising; (a) carbon capture, (b) compression and transportation, and (c) injection into geological media. This paper focuses on CO2 injection into geological media and its applicability to the Lamu basin. Sedimentary basins, which host the geological formations suitable for subsurface CO2 storage, are ideal to varied extents determined by such factors as their tectonic settings. A (coarse) basin scale suitability assessment of the Lamu basin was undertaken using the following parameters; size and depth, tectonic and structural settings, seismicity, geothermal-hydrodynamic regimes, basin maturity (based on hydrocarbon well density) and economic resources. The assessed attributes are used to constrain GIS data, delineating possible CCS trap areas with the production of a preliminary map of potential trap areas. Also, a suitability matrix table is generated in comparison with analogous basins such as the Alberta basin in Canada. Following this assessment, the Lamu basin can be considered geologically suitable for geosequestration given its stable tectonic settings, good depth and size. However, the western flanks of the basin and the coastal strip are unsuitable due to shallowness, population and protected zones respectively.

Abstract

This study presents past and projected temporal changes in mean temperature and rainfall around the Marsabit Forest Reserve (MFR), a sub-humid montane forest in Kenya. Rainfall data for the period 1961–2014 and temperature data for the period 1972–2011 were acquired from the Marsabit meteorological station. Future projections (2006–2100) were based on data from five models that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5) under Representative Concentration Pathways (RCPs) 4.5 and 8.5. Climate simulations for the 2071–2100 period were compared to the 1961–1990 IPCC baseline period to establish significant change. The MFR recorded a mean rainfall of 784 mm which declined annually at a rate of 6 mm over the period of the study. The long rains (March–May) recorded a mean of 379 mm and decreased annually by 10 mm while the short rains (October–December) recorded a mean of 269 mm and decreased annually by 2 mm between 1961 and 2014, with no statistically significant trend (p > 0.05).

The model ensemble reproduced the MFR bimodal rainfall pattern, but overestimated the short rains at 333 mm, compared to the actual mean of 269 mm, and underestimated the long rains at 331 mm, compared to the actual mean of 379 mm. The model ensemble simulated a historical mean rainfall of 651 mm compared to the actual mean of 784 mm. Annual rainfall is projected to increase under both scenarios with higher increases during the OND season compared to the MAM season and under RCP8.5 than under RCP4.5. The mean rainfall in the baseline year was 859 mm while the mean rainfall in the projection period for the RCP4.5 and RCP8.5 scenarios is expected to be 1022 (+19%) and 1105 (+28.7%) mm, respectively; significant enough to be characterized as climate change.

Temperatures are projected to increase at a rate of 0.2 °C and 0.5 °C per decade under RCP4.5 and RCP8.5, respectively. Between 2071 and 2100, the MFR is projected to have warmed by between 1.2–1.7 °C and 3.2–4.8 °C under RCP4.5 and RCP8.5, respectively. Extreme rainfall events are projected to increase under the RCP4.5 scenario (severe wetting 13.1%, severe drying 3%) and the RCP8.5 scenario (severe wetting 20.1%, severe drying 3%) compared to the baseline period (severe wetting 6.1%). Our results conform to the ‘East African climate paradox’, where the observed rainfall trends were declining compared to the scenario simulations projecting a wetting anomaly as local temperatures rise. Further studies to better understand the cause of the poor rainfall simulation in the general circulation models (GCMs) in the MFR and the larger East African region will be necessary.