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The 2015/2016 El Niño has been classified as one of the three most severe on record. El Niño teleconnections are commonly associated with droughts in southern Africa and high precipitation in eastern Africa. Despite their relatively frequent occurrence, evidence for their hydrological effects and impacts beyond agriculture is limited. We examine the hydrological response and impact pathways of the 2015/2016 El Niño in eastern and southern Africa, focusing on Botswana, Kenya, and Zambia. We use in situ and remotely sensed time series of precipitation, river flow, and lake levels complemented by qualitative insights from interviews with key organizations in each country about awareness, impacts, and responses. Our results show that drought conditions prevailed in large parts of southern Africa, reducing runoff and contributing to unusually low lake levels in Botswana and Zambia. Key informants characterized this El Niño through record high temperatures and water supply disruption in Botswana and through hydroelectric load shedding in Zambia. Warnings of flood risk in Kenya were pronounced, but the El Niño teleconnection did not materialize as expected in 2015/2016. Extreme precipitation was limited and caused localized impacts. The hydrological impacts in southern Africa were severe and complex, strongly exacerbated by dry antecedent conditions, recent changes in exposure and sensitivity and management decisions. Improved understanding of hydrological responses and the complexity of differing impact pathways can support design of more adaptive, region‐specific management strategies. Plain Language Summary The 2015/2016 El Niño was one of the three most severe on record. El Niño is commonly linked to droughts in southern Africa and extreme rainfall in eastern Africa but no two El Niño's are the same. We present an analysis of the impact of the 2015/2016 El Niño in eastern and southern Africa, focusing on Botswana, Kenya, and Zambia. We use field measurements and observations from satellites of rainfall, river flow, and lake levels in combination with insights from experts in each country about awareness, impacts, and responses. Our results show that drought conditions prevailed in large parts of southern Africa, reducing river runoff and contributing to unusually low lake levels in Botswana and Zambia. This led to water supply disruption in Botswana and hydroelectric load shedding in Zambia. Warnings of flood risk in Kenya were pronounced, but the El Niño did not materialize as expected in 2015/2016. Extreme rainfall was limited and caused only localized impacts. Improved understanding of the regional impact of El Niño will help to be better prepared for the next El Niño. Key Points Quantitative and qualitative data provide insights into hydrological impact pathways of precipitation anomalies associated with the El Niño of 2015/2016 Variable teleconnection patterns, antecedent hydrological conditions and changing socioeconomic boundary conditions led to complex impact pathways of this El Niño event Our findings show the need for diverse management responses, with adaptive reservoir management required and diversification of energy and water sources essential

The fourth assessment report of the IPCC highlights that the global average surface temperature is projected to increase by 1.8 to 4.0℃ by the year 2100 compared to current climate. Given that climate is the most important driver of the hydrological cycle, the rise in temperature could cause changes in occurrence patterns of extreme hydrologic events like streamflow droughts. An increase in frequency and severity of these events could pose serious challenges for sustainable management of water resources particular in arid regions. However, the understanding of water resources dynamics and the possible impacts of climate change on these dynamics is hindered by uncertainties in climate change models and complex hydrological responses of streams and catchments to climatic changes. Therefore observational evidence of streamflow dynamics at the local scale could play a crucial role in addressing these uncertainties and achieving a fuller reconciliation between model-based scenarios and ground truth. This paper determines spatial and temporal changes in stream- flow volumes and their association with climatic factors based on the non-parametric Mann-Kendall test and ANOVA to determine possible changes in streamflow over the years and their relation to climatic factors. Streamflow is generally stochastic highlighting the importance of factoring in temporal flow variability in water resources planning. There is no clear evidence that changes in climatic variables are related to streamflow behaviour.

The effects of different seed treatment methods and durations of exposure on germination of wild okra (Corchorus olitorius), a traditional leafy vegetable consumed in many parts of Africa, were investigated. Seeds were exposed to seven treatments (hot water at 80 °C, hot water at 100 °C, dry heat at 80 °C, dry heat at 100 °C, concentrated sulphuric acid, 10% hydrogen peroxide and water at room temperature) for periods of up to 30 minutes. Exposure for five to 15 minutes in hot water at 80 °C was the most effective treatment for enhancing germination (>90%), followed by five minutes in hot water at 100 °C (80%) and 30 minutes in sulphuric acid (57%). Other treatments were less effective. Soaking seeds in hot water at approximately 80 °C for about 10 minutes can be recommended, therefore, to farmers as a simple, cheap and very effective way of germinating wild okra.

Groundwater is one of the major sources of exploitation in arid and semi -arid regions. To protect this scarce resource information on its quality status over time is important. This paper examines the quality of groundwater from domestic water supply boreholes across rural Botswana. Ionic concentrations of K+, Na+, Ca2+, Mg2+, F-, Cl-, SO4 2-, HCO3 -, Fe3+, Mn-, and N. Parameters such as pH, total dissolved solids (TDS), and electrical conductance (EC) were correlated and their levels compared to international standards. Levels of various physico-chemical parameters were also analyzed for temporal trends for in the various districts across the country and those with significant trends were then contoured to determine areas at risk of groundwater contamination. Groundwater in rural Botswana is generally suitable for human consumption despite high levels of cations. Nevertheless, levels of Na+, Ca2+, EC and TDS are showing increasing trends in some parts of the country highlighting the need for periodic monitoring of groundwater quality to isolate and possibly advise on discontinuation of polluted boreholes.

IntroductionThe study aim was to determine if rapid enteric diagnostics followed by the provision of targeted antibiotic therapy (‘test-and-treat’) and/or Lactobacillus reuteri DSM 17938 would improve outcomes in children hospitalised in Botswana with acute gastroenteritis.MethodsThis was a multicentre, randomised, factorial, controlled, trial. Children aged 2–60 months admitted for acute non-bloody diarrhoea to four hospitals in southern Botswana were eligible. Participants were assigned to treatment groups by web-based block randomisation. Test-and-treat results were not blinded, but participants and research staff were blinded to L. reuteri/placebo assignment; this was dosed as 1×108 cfu/mL by mouth daily and continued for 60 days. The primary outcome was 60-day age-standardised height (HAZ) adjusted for baseline HAZ. All analyses were by intention to treat. The trial was registered at Clinicaltrials.gov.ResultsRecruitment began on 12 June 2016 and continued until 24 October 2018. There were 66 participants randomised to the test-and-treat plus L. reuteri group, 68 randomised to the test-and-treat plus placebo group, 69 to the standard care plus L. reuteri group and 69 to the standard care plus placebo group. There was no demonstrable impact of the test-and-treat intervention (mean increase of 0.01 SD, 95% CI −0.14 to 0.16 SD) or the L. reuteri intervention (mean decrease of 0.07 SD, 95% CI −0.22 to 0.08 SD) on adjusted HAZ at 60 days.ConclusionsIn children hospitalised for acute gastroenteritis in Botswana, neither a test-and-treat algorithm targeting enteropathogens, nor a 60-day course of L. reuteri DSM 17938, were found to markedly impact linear growth or other important outcomes. We cannot exclude the possibility that test-and-treat will improve the care of children with significant enteropathogens (such as Shigella) in their stool.Trial registration numberNCT02803827.