Journal Articles

Water-related soil erosion is a major environmental concern for catchments with barren topography in arid and semi-arid regions. With the growing interest in irrigation infrastructure development in arid regions, the current study investigates the runoff and sediment yield for the Gomal River catchment, Pakistan. Data from a precipitation gauge and gridded products (i.e., GPCC, CFSR, and TRMM) were used as input for the SWAT model to simulate runoff and sediment yield. TRMM shows a good agreement with the data of the precipitation gauge (˜1%) during the study period, i.e., 2004–2009. However, model simulations show that the GPCC data predicts runoff better than the other gridded precipitation datasets. Similarly, sediment yield predicted with the GPCC precipitation data was in good agreement with the computed one at the gauging site (only 3% overestimated) for the study period. Moreover, GPCC overestimated the sediment yield during some years despite the underestimation of flows from the catchment. The relationship of sediment yields predicted at the sub-basin level using the gauge and GPCC precipitation datasets revealed a good correlation (R2 = 0.65) and helped identify locations for precipitation gauging sites in the catchment area. The results at the sub-basin level showed that the sub-basin located downstream of the dam site contributes three (3) times more sediment yield (i.e., 4.1%) at the barrage than its corresponding area. The findings of the study show the potential usefulness of the GPCC precipitation data for the computation of sediment yield and its spatial distribution over data-scarce catchments. The computations of sediment yield at a spatial scale provide valuable information for deciding watershed management strategies at the sub-basin level.

The United Nations Food Systems Summit aimed to chart a path toward transforming food systems toward achieving the Sustainable Development Goals. Despite the essentiality of water for food systems, however, the Summit has not sufficiently considered the role of water for food systems transformation. This focus is even more important due to rapidly worsening climate change and its pervasive impacts on food systems that are mediated through water. To avoid that water “breaks” food systems, key food systems actors should 1) Strengthen efforts to retain water-dependent ecosystems, their functions and services; 2) Improve agricultural water management; 3) Reduce water and food losses beyond the farmgate; 4) Coordinate water with nutrition and health interventions; 5) Increase the environmental sustainability of food systems; 6) Explicitly address social inequities; and 7) Improve data quality and monitoring for water-food system linkages.

CONTEXT: Although rice production has increased significantly in the last decade in West Africa, the region is far from being rice self-sufficient. Inland valleys (IVs) with their relatively higher water content and soil fertility compared to the surrounding uplands are the main rice-growing agroecosystem. They are being promoted by governments and development agencies as future food baskets of the region. However, West Africa’s crop production is estimated to be negatively affected by climate change due to the strong dependence of its agriculture on rainfall. OBJECTIVE: The main objective of the study is to apply a set of machine learning models to quantify the extent of climate change impact on land suitability for rice using the presence of rice-only data in IVs along with bioclimatic indicators. METHODS: We used a spatially explicit modeling approach based on correlative Ecological Niche Modeling. We deployed 4 algorithms (Boosted Regression Trees, Generalized Linear Model, Maximum Entropy, and Random Forest) for 4-time periods (the 2030s, 2050s, 2070s, and 2080s) of the 4 Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0, and RCP8) from an ensemble set of 32 spatially downscaled and bias-corrected Global Circulation Models climate data. RESULTS AND CONCLUSIONS: The overall trend showed a decrease in suitable areas compared to the baseline as a function of changes in temperature and precipitation by the order of 22–33% area loss under the lowest reduction scenarios and more than 50% in extreme cases. Isothermality or how large the day to night temperatures oscillate relative to the annual oscillations has a large impact on area losses while precipitation increase accounts for most of the areas with no change in suitability. Strong adaptation measures along with technological advancement and adoption will be needed to cope with the adverse effects of climate change on inland valley rice areas in the sub-region. SIGNIFICANCE: The demand for rice in West Africa is huge. For the rice self-sufficiency agenda of the region, “where” and “how much” land resources are available is key and requires long-term, informed planning. Farmers can only adapt when they switch to improved breeds, providing that they are suited for the new conditions. Our results stress the need for land use planning that considers potential climate change impacts to define the best areas and growing systems to produce rice under multiple future climate change uncertainties.

Fish inhabiting freshwater environments are susceptible to the ingestion of microplastics (MPs). Knowledge regarding MPs in freshwater fish in South Africa is very limited. In this study, the uptake of MPs by common carp (Cyprinus carpio) in the Vaal River in South Africa was assessed. MPs were detected in all of the twenty-six fish examined, 682 particles of MPs were recovered from the gastrointestinal tracts of the fish with an average of 26.23 12.57 particles/fish, and an average abundance of 41.18 52.81 particles/kg. The examination of the physical properties of MPs revealed a predominance on fibers (69%), small-sized particles of less than 0.5 mm (48%), as well as prevelance of coloured MPs (94%), mostly green, blue, and black. Using Raman Spectroscopy, the following plastic polymers were identified: high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE). To the best of our knowledge, this study, is the first to report MPs uptake by freshwater biota in the Vaal River using common carp as a target organism. It provided evidence of MP contamination in the Vaal.

Land policy reform has dominated the development agenda across the Global South over the past two decades. In contrast with earlier distributive land reforms, contemporary policies reflect an amalgamation of neoliberal, state territorial, and social justice agendas. This paper demonstrates how land policy changes reflect the spatially extensive and multi-scalar politics of land contestation and control, employing the cases of Myanmar and Laos. Myanmar’s short-lived democratic transition enabled civil society actors to exert uneven influence on policy reform. In contrast, communist party and state dominance in Laos has constrained, although not wholly obstructed, policy intervention by non-governmental groups.

There are growing calls to adopt more sustainable forms of agriculture that balance the need to increase production with environmental, human health, and wellbeing concerns. Part of this conversation has included a debate on promoting and mainstreaming neglected and underutilized crop species (NUS) because they represent a more ecologically friendly type of agriculture. We conducted a systematic review to determine the ecosystem services derived from NUS and assess their potential to promote functional ecological diversity, food and nutritional security, and transition to more equitable, inclusive, sustainable and resilient agricultural landscapes and food systems in Africa. Our literature search yielded 35 articles for further analysis. The review showed that NUS provide various provisioning, regulating, cultural, and supporting ecosystem services and several environmental and health co-benefits, dietary diversity, income, sustainable livelihood outcomes, and economic empowerment, especially for women. Importantly, NUS address the three pillars of sustainable development- ecological, social, and economic. Thus, NUS may provide a sustainable, fit-for-purpose transformative ecosystem-based adaptation solution for Africa to transition to more sustainable, healthy, equitable, and resilient agricultural landscapes and food systems.

The use of polluted water to irrigate is an increasing problem in the developing world. Lebanon is a case in point, with heavily polluted irrigation waters, particularly in the Litani River Basin. This study evaluated the potential health risks of irrigating vegetables (radishes, parsley, onions, and lettuce) using three water sources (groundwater, river water, and treated wastewater) and three irrigation methods (drip, sprinkler, and surface) over two growing seasons in 2019 and 2020. Water, crop, and soil samples were analyzed for physicochemical parameters, pathogens, and metals (Cu, Cd, Ni, Cr, and Zn). In addition, the bioaccumulation factor, estimated dietary intakes, health risk index, and target hazard quotients were calculated to assess the health risk associated with metal contamination. The study showed that, for water with less than 2 log E. coli CFU/100 mL, no pathogens (Escherichia coli, salmonella, parasite eggs) were detected in irrigated vegetables, irrespective of the irrigation method. With over 2 log E. coli CFU/100 mL in the water, 8.33% of the sprinkler-and surface-irrigated vegetables, and 2.78% of the drip-irrigated root crops (radishes and onions), showed some degree of parasitic contamination. E. coli appeared only on root crops when irrigated with water having over 3 log CFU/100 mL. The concentrations of most metals were significantly lower than the safe limits of the FAO/WHO of the Food Standards Programme Codex, except for zinc and chromium. The trends in the bioaccumulation factor and the estimated dietary intakes of metals were in the order of Cu lt; Cd lt; Ni lt; Cr lt; Zn. The target hazard quotient values for all metals were lower than 1.0. Under trial conditions, the adoption of drip irrigation with water with less than 3 log E. coli CFU/100 mL proved to be safe, even for vegetables consumed raw, except for root crops such as onions and radishes that should not be irrigated with water having over 2 log E. coli CFU/100 mL. Treated wastewater had no adverse effect on vegetable quality compared to vegetables irrigated with other water sources. These results support efforts to update the Lebanese standards for water reuse in agriculture; standards proposed in 2011 by the FAO, and currently being reviewed by the Lebanese Institution of Standards. This research will inform a sustainable water management policy aimed at protecting the Litani River watershed by monitoring water quality.

The food self-sufficiency policy has always featured as an unquestionable policy objective for Egypt. This is understandable when one considers both the high population growth and the social and political vulnerability associated with a dependence on food imports and world market food prices such as wheat. Intensive agriculture has led to a growing subsidy burden for the Egyptian government. In addition, the agricultural fields in Egypt are commonly distributed with relatively small sizes parcels that usually reduce the reliability of the agricultural sector, particularly in the delta region, to meet the national food policy. On top of that, climate change, through changing weather patterns and increased temperatures, is affecting agricultural yields and thus farmers’ livelihoods. A water profitability analysis was conducted for three governorates in the Nile Delta in Egypt to establish a baseline and assess the net return per unit of water of the main crops in each of these governorates; this can act as a reference of the water profitability of different crops before they are affected by climate change and other internal and external factors. The analysis was based on extensive in-person surveys in each governorate in addition to workshop discussions with farmers. The study has highlighted the impact of a lack of extension services, which limits farmers’ ability to increase their land and water productivity. Farmers with more access to subsidized production inputs managed to achieve higher levels of water profitability even on smaller lands. Finally, we drew from our findings key policy actions to improve water profitability and land productivity for farmers in the Nile Delta to achieve higher levels of food security. This will help build resilient food production systems that are reliable in the face of climate change and other drivers. In addition, an integrated nexus strategy and plan for the inter- and intra-country is recommended to address the challenges related to food and climate security.

We proposed a modification of the existing approach for mapping active paddy rice fields in monsoon-dominated areas. In the existing PPPM approach, LSWI higher than EVI at the transplantation stage enables the identification of rice fields. However, it fails to recognize the fields submerged later due to monsoon floods. In the proposed approach (IPPPM), the submerged fields, at the maximum greenness time, were excluded for better estimation. Sentinel–2A/2B time-series images were used for the year 2018 to map paddy rice over the Lower Gangetic Plain (LGP) using Google earth engine (GEE). The overall accuracy (OA) obtained from IPPPM was 85%. Further comparison with the statistical data reveals the IPPPM underestimates (slope (b1) ¼ 0.77) the total reported paddy rice area, though R2 remains close to 0.9. The findings provide a basis for near real-time mapping of active paddy rice areas for addressing the issues of production and food security.

Agriculture in Africa is adversely affected by the loss of soil fertility. Conservation agriculture (CA) was introduced to curb the loss of soil fertility and water shortages and improve crop productivity. However, information on how CA practices enhance soil quality and nutrients is scarce in the sub-Saharan Africa context. The objective of this study was to investigate the effects of CA and conventional tillage (CT) on soil organic matter and nutrients under irrigated and rainfed vegetable on-farm production systems. During the dry and wet monsoon phases in the northern Ethiopian Highlands, a four-year experiment with CA and CT was carried out on ten vegetable farms under rainfed and irrigated conditions. Although the increase in concentration of organic matter in CA was generally slightly greater than in CT, the difference was not significant. The average organic matter content in the top 30 cm for both treatments increased significantly by 0.5% a-1 from 3% to almost 5%. The increase was not significant for the 30–60 cm depth. The total nitrogen and available phosphorus concentrations increased proportionally to the organic matter content. Consequently, the extended growing season, applying fertilizers and livestock manure, and not removing the crop residue increased the nutrient content in both CA and CT. The increase in CA was slightly greater because the soil was not tilled, and hay was applied as a surface cover. Although CA increased soil fertility, widespread adoption will depend on socioeconomic factors that determine hay availability as a soil cover relative to other competitive uses.

The vast majority of farmers in the drylands are resource-poor smallholders, whose livelihoods depend heavily on their farming systems. Therefore, increasing the resilience of these smallholders is vital for their prosperity. This study quantified household resilience and identified livelihoods and their influence on resilience in the semiarid tropics of India by analysing 684 households. A resilience capacity index was devised based on the composition of household food and non-food expenditure, cash savings, and food and feed reserves. The index ranged from 8.4 reflecting highly resilient households with access to irrigation characteristics, to -3.7 for households with highly limited resilience and low household assets. The livelihoods were identified through multivariate analysis on selected socioeconomic and biophysical variables; households were heterogeneous in their livelihoods. Irrigated livestock and rainfed marginal types had the highest and lowest resilience capacity index with the mean score of 0.69 and -1.07, respectively. Finally, we quantified the influence of livelihood strategies on household resilience. Household resilience was strengthened by the possession of livestock, crop diversification and access to irrigation. Low resilience is predominantly caused by low household assets. The resilience capacity index and derived livelihood strategies helps to understand the complexity of household resilience, and will aid in targeting technology interventions for development.

Sub-Saharan Africa faces unprecedented disasters, with climate change expected to exacerbate the frequency and severity of unpredictable and stressful catastrophic events. Unlike developed nations, reconstruction in developing nations is hindered by resource constraints, with certain communities potentially experiencing multiple and enduring effects of disasters. Despite the potential danger of such cumulative community disaster exposure on mental health (e.g. depression), large-scale population-level evidence for the region is limited. We investigated the association between exposure to cumulative disaster and the first onset of depression in a nationally representative survey in South Africa. We used panel data from the South African National Income Dynamics Study (SA-NIDS) from 2008–2017, consisting of 17,255 adult study participants who were depression free at baseline. Risk of first depression onset between individuals exposed and unexposed to community disaster was measured, accounting for multiple disaster exposure over time by fitting generalized estimating equation (GEE) regression models. Data on the geographic location of disasters were obtained from the South African government gazette, and mapped with the government delineated SA-NIDS households’ locations. Of the sampled individuals, 2,986 were exposed to disaster during the study duration (17.3%). Increased cumulative community disaster was significantly associated with the likelihood of depression onset (adjusted relative risk [aRR] = 1.20, plt;0.01, 95% CI: 1.09–1.33), even after controlling for socio-demographic factors. In sub-group analyses, greater likelihood of depression onset was found among females [but not in men] (aRR = 1.23, plt;0.01, 95% CI: 1.09–1.38), Black African [but not in other population group] (aRR = 1.21, plt;0.01, 95% CI: 1.09–1.36), lower education attainment group [but not in tertiary and above educational attainment group] (aRR = 1.20, plt;0.01, 95% CI: 1.08–1.33), and lower income attainment group [but not in the top income quartile group] (aRR = 1.24, plt;0.01, 95% CI: 1.11–1.38), due to cumulative community disaster. Although cumulative community disaster exposure was significantly associated with the first onset of depression, its negative impact may be more pronounced among individuals considered chronically socially vulnerable (i.e. the groups above) in South Africa. Given that many individuals in South Africa rely on social, food parcel relief, and health services from government/public sector, timely access to community-based supportive intervention is needed for disaster survivors, prioritizing socially vulnerable groups to help mitigate problems associated with mental health challenges.

Over the years, South Africa has made significant investments aimed at transforming the agricultural sector to deliver on rural economic development and job creation. These investments have had varying levels of success; still, what is worrying is the high youth unemployment rate which is amongst the highest globally. We conducted a scoping review using the PRISMA-P guidelines to identify the challenges youth face in accessing sustainable employment in the agriculture sector. Peer-reviewed studies were retrieved from online databases (Web of Science, Cab Direct, and Science Direct) for 1994–2021. The findings showed that youth are still facing significant challenges in the demand and supply side of the labour market and lack of inclusivity in policy formulation and implementation, limiting their involvement in agriculture and rural development initiatives. Policies and strategies responding to these challenges exist, and the spectrum of support services provided are primarily focused on entrepreneurship. Yet, the implementation of programs and initiatives has not been successful. This could be attributed to the obstacles persisting in the sociopolitical environment in SA, causing additional barriers to program implementation. Therefore, to enhance youth involvement in agriculture and rural development, there is a need to connect more rural youth to support services, local employment programmes, and youth inclusion in policy formulation processes. Additionally, the focus of policy and programs should be broadened to cater to different youth knowledge and skill profiles.

This study reports a comprehensive review on drought indices used in monitoring meteorological, agricultural, hydrological, and socio-economic drought. Drought indices have been introduced as an important approach to quantitative and qualitative calculations of drought’s severity and impact. There were 111 drought indices reviewed in this study, which fall into two categories: traditional (location-specific/model) and remote sensing (RS). Out of 111 indices, 44 belong to the traditional indices and 67 belong to the RS section. This study shows that meteorological drought monitoring has the highest number (22) of traditional indices, about 20% overall, while the lowest (7) agricultural drought monitoring is 6.3%. The specialty is that when considering remote sensing-based drought indices, 90% are used for agricultural drought monitoring and 10% for hydrological and meteorological drought monitoring. However, the study found that advances in satellite technology have accelerated the design of new drought indices and that replacing traditional location-specific data with satellite observation makes it easier to calculate more spatial distribution and resolution.

Groundwater is a significant resource that supports almost one-fifth population globally, but has been is diminishing at an alarming rate in recent years. To delve into this objective more thoroughly, we calculated interannual (2002–2020) GWS (per grid) distribution using GRACE amp; GRACE-FO (CSR-M, JPL-M and SH) Level 3 RL06 datasets in seven Indian river basins and found comparatively higher negative trends (-20.10 1.81 to -8.60 1.52 mm/yr) in Basin 1–4 than in Basin 5–7 (-7.11 0.64 to -0.76 0.47 mm/yr). After comparing the Groundwater Storage (GWS) results with the CHIRPS (Climate Hazards Group Infrared Precipitation with Stations) derived SPI (Standardized Precipitation Index) drought index, we found that GWS exhausts analogously in the same period (2005–2020) when SPI values show improvement (~ 1.89–2), indicating towards wet condition. Subsequently, the GWSA time series is decomposed using the STL (Seasonal Trend Decomposition) (LOESS Regression) approach to monitor long-term groundwater fluctuation. The long term GWS rate (mm/yr) derived from three GRACE amp; GRACE-FO solutions vary from -20.3 5.52 to -13.19 3.28 and the GWS mass rate (km3 /yr) lie in range of -15.17 4.18 to -1.67 0.49 for basins 1–3. Simultaneously, in basin 4–7 the GWS rate observed is -8.56 8.03 to -0.58 7.04 mm/yr, and the GWS mass rate differs by -1.71 0.64 to -0.26 3.19 km3 /yr. The deseasonalized GWS estimation (2002–2020) states that Himalayan River basins 1,2,3 exhibit high GWS mass loss (-260 to -35.12 km3 ), with Basin 2 being the highest (-260 km3 ). Whereas the Peninsular River basin 4,6,7 gives moderate mass loss value from -26.72 to -23.58 km3 . And in River basin 5, the GWS mass loss observed is the lowest, with a value of -8 km3 . Accordingly, GPS (Global Positioning System) and SAR (Synthetic Aperture Radar) data are considered to examine the land deformation as an effect due to GWS mass loss. The GPS data acquired from two IGS stations, IISC Bengaluru and LCK3 Lucknow, negatively correlates with GWS change, and the values are ~ -0.90 to ~-0.21 and ~-0.7 to -0.4, respectively. Consequently, correlation between GWS mass rate (km3 /yr) and the SAR (Sentinel-1A, SBAS) data procured from Chandigarh, Delhi, Mehsana, Lucknow, Kolkata and Bengaluru shows ~ 72 – 48% positively correlated area (PCA). The vertical velocity ranges within ~ -94 to -25 mm/yr estimated from PCA. There is an increase in population (estimated 2008–2014) in Basin 1 amp; 2. Likewise, the correlation coefficient ( ) between GWS change and the irrigational area is positive in all seven basins indicating significant depletion in GWS due to an uncalled hike in population or irrigational land use. Similarly, the positive linear regression (R 2 ) in Basins 1–3 also indicates high depletion in GWS. But basins 4–7 observe negative linear regression even after increasing population, which implies a control on the irrigational land use, unable to determine the GWS change at local scale a

July-September rainfall is a key component of Ethiopia’s annual rainfall and is a source of rainfall variability throughout inland Greater Horn of Africa. In this study we investigate the relative influences of the Mascarene (MH) and South Atlantic (AH) highs on July-September rainfall in a covarying region of the Greater Horn of Africa using CHIRPS observed rainfall and the ERA5 reanalysis. We show that a mixed metric using the circulation at 850 hPa of these two subtropical anticyclones (AH-MH), is better correlated with rainfall than individual high circulations. Variations in remote circulation are translated by changes in Central African westerlies and Turkana Jet wind speeds. We apply the AH-MH mixed metric to the CMIP5 and CMIP6 ensembles and show that it is a good indicator of mean July-September rainfall across both ensembles. Biases in circulation are shown to be related to the Hadley circulation in CMIP5 atmosphere-only simulations, while causes of biases in CMIP6 are more varied. Coupled model biases are related to southern ocean warm biases in CMIP5 and western Indian Ocean warm biases in CMIP6. CMIP6 shows an improved relationship between rainfall and Turkana Jet winds and Central African westerlies across the ensemble.

Rice is one of the major staple foods in sub-Saharan Africa (SSA) and is mainly grown in three environments: rainfed upland and rainfed and irrigated lowlands. In all rice-growing environments, the yield gap (the difference between the potential yield in irrigated lowland or water-limited yield in rainfed lowland and upland and the actual yield obtained by farmers) is largely due to a wide range of constraints including water-related issues. This paper aims to review water management research for rice cultivation in SSA. Major water-related constraints to rice production include drought, flooding, iron toxicity, and soil salinity. A wide range of technologies has been tested by Africa Rice Center (AfricaRice) and its partners for their potential to address some of the water-related challenges across SSA. In the irrigated lowlands, the system of rice intensification and alternate wetting and drying significantly reduced water use, while the pre-conditions to maintain grain yield and quality compared to continuous flooding were identified. Salinity problems caused by the standing water layer could be addressed by flushing and leaching. In the rainfed lowlands, water control structures, Sawah rice production system, and the Smart-Valleys approach for land and water development improved water availability and grain yield compared to traditional water management practices. In the rainfed uplands, supplemental irrigation, mulching, and conservation agriculture mitigated the effects of drought on rice yield. The Participatory Learning and Action Research (PLAR) approach was developed to work with and educate communities to help them implement improved water management technologies. Most of the research assessed a few indicators such as rice yield, water use, water productivity at the field level. There has been limited research on the cost-benefit of water management technologies, enabling conditions and business models for their large-scale adoption, as well as their impact on farmers’ livelihoods, particularly on women and youth. Besides, limited research has been conducted on water management design for crop diversification, landscape-level water management, and iron toxicity mitigation, particularly in lowlands. Filling these research gaps could contribute to sustainable water resources management and sustainable intensification of rice-based systems in SSA.

Groundwater is the main available freshwater resource and therefore its use, management and sustainability are closely related to the Sustainable Development Goals (SDGs). However, Land Use Land Cover (LULC) and climate change are among the factors impacting groundwater recharge. The use of land-use and climate data in conjunction with hydrological models are valuable tools for assessing these impacts on river basins. This systematic review aimed at assessing the integrated modeling approach for evaluating hydrological processes and groundwater recharge based on LULC and climate change. The analysis is based on 200 peer-reviewed articles indexed in Scopus, and the Web of Science. Continuous research and the development of context-specific groundwater recharge models are essential to increase the long-term viability of water resources in any basin. The long-term impacts of natural and anthropogenic drivers on river basin interactions require integrating knowledge and modeling capabilities across biophysical responses, environmental problems, policies, economics, social, and data.

While extreme rainfall events may provide rare opportunities for replenishment of surface water and groundwater resources in vulnerable (semi)arid areas, they are typically also associated with widespread flooding. The impacts on contaminant movement associated with spatio-temporally complex relationships between surface water and groundwater during such events in these regions are largely unknown. The catchment area (~4350 km2) upstream of Gaborone Dam on the Notwane River in south-east Botswana and northern South Africa experienced extreme rainfall and major flooding in 2016/17, following a severe 5-year drought. In this generally data-sparce area, we collected a unique data set that combined traditional water quantity observations with stable water isotope, major ion, trace metal and geophysical data. These were analysed to gain insights into water quantity and quality dynamics following flooding, including contaminant movement using trace metals as pollution indicators. Results revealed that the extreme rainfall and flooding was responsible for replenishment of surface water and groundwater resources, but also contaminant mobilisation from the surface. This subsequently resulted in increased concentrations of contaminants during the recession. Overall, hydrogeological heterogeneity dictated spatially variable surface water - groundwater interactions, characterised by poor connectivity in low productivity aquifer areas as opposed to good connectivity in moderate to high productivity aquifers. This in turn affected water quality dynamics and contamination, locally superimposed by land use impacts, primarily from urban landfill and local agricultural practices. Groundwater-connected streams had consistently lower (responses in) contaminants. We also found that Gaborone Reservoir facilitated prolonged conditions for recharge but likely also enhanced contamination of groundwater through maintaining a high water table in urban areas located immediately downstream. Management implications of our findings include a requirement for careful consideration of land use and landfill planning in relation to bedrock geology and presence of surface water reservoirs, conjunctive surface water and groundwater management, but also the need for even higher (space-time) resolution of monitoring in these data sparce environments. This could contribute to enhancing the benefits that extreme rainfall events provide in terms of surface water and groundwater resources replenishment for future dry seasons and periods of drought.

Investments in land management practices, such as stone and soil bunds, are a key strategy to recover degraded lands in Ethiopia. However, the benefits of these practices in relation to ecosystem services are not properly assessed and documented. Therefore, the objective of this study was to assess the benefits of land management practices in relation to provisioning, supporting and regulating ecosystem services. The study was conducted in four watersheds with selected indicators of provisioning, supporting and regulating ecosystem service. Generally, the results show that provisioning services (e.g. yield of crops), regulating services (e.g. organic matter accumulation) and supporting services (e.g. soil nutrient content) were improved with age of stone and soil bunds except in Jawe-gumbura watershed. Accordingly, in Alekit-wonz watershed, the grain yield of barley recorded from 4-year-old stone bunds was higher than the yield recorded from 2-year old soil bund. Similarly, in Borodo watershed, the grain yield of wheat from 5-year-old soil bunds was higher than the yield obtained from the control treatment. The results also showed that highest regulating and supporting ecosystem services were recorded in the accumulation zones in all watersheds compared with erosion zone. Similarly, the highest provisioning services were recorded at the accumulation zone in all watersheds. This shows that land management practices are effective to improve supporting, regulating and provisioning ecosystem services. Hence, more investments in land management are needed to enhance ecosystem services from degraded lands of Ethiopia.

This paper investigates the impact of erratic rainfall and related water problems on agricultural productivity. The paper also aims to shed light on the conceptual importance of understanding the incidence and impacts of rainfall shocks for choosing feasible agricultural water risk management strategies both at household and policy levels. To achieve these goals we develop a conceptual framework, use national representative data from Zambia’s crop estimates survey for 2017/2018 farming season, employ fixed effects regression approach, and find that dry spells, excessive floods, incidence of water logging are all detrimental to crop productivity. The crop-based equations also reveal the differential impacts of the rainfall shocks on different crops. Since the effect of water factors including dry spells, floods and water logging on agricultural productivity is dependent on the crop types, it is important for the Zambian government as well as other countries to take this into account when planning and implementing strategies for agricultural water risk management.

Many communities in South Asia are highly exposed and vulnerable to weather and climate hazards, and climate services play an important role in managing present and future climate risks. Here we take stock of ongoing climate service activities under the Asia Regional Resilience to a Changing Climate (ARRCC) Met Office Partnership programme. ARRCC aims to strengthen climate resilience in South Asia through co-producing weather and climate services, building institutional capacities, and enhancing coordination across the region and in focal countries: Afghanistan, Bangladesh, Nepal and Pakistan. We identify what is working well and challenges that remain in the provision and uptake of climate services, focusing on examples of applying seasonal forecasts, sea-level rise projections, and extreme rainfall information for hydropower decisions. We demonstrate the value of building equitable and sustainable partnerships, enhancing knowledge sharing, strengthening evaluation, and approaches that combine model information within a decision-centred framework. Based on experiences in ARRCC, we find that climate information alone is often insufficient to meet decision-maker needs, and discuss the role for new climate impact services that integrate climate information with knowledge and tools on climate impacts and vulnerabilities.

COVID-19 has changed the permeability of borders in transboundary environmental governance regimes. While borders have always been selectively permeable, the pandemic has reconfigured the nature of cross-border flows of people, natural resources, finances and technologies. This has altered the availability of spaces for enacting sustainability initiatives within and between countries. In Southeast Asia, national governments and businesses seeking to expedite economic recovery from the pandemic-induced recession have selectively re-opened borders by accelerating production and revitalizing agro-export growth. Widening regional inequities have also contributed to increased cross-border flows of illicit commodities, such as trafficked wildlife. At the same time, border restrictions under the exigencies of controlling the pandemic have led to a rolling back and scaling down of transboundary environmental agreements, regulations and programs, with important implications for environmental democracy, socio-ecological justice and sustainability. Drawing on evidence from Southeast Asia, the article assesses the policy challenges and opportunities posed by the shifting permeability of borders for organising and operationalising environmental activities at different scales of transboundary governance.

Using farm animals for their natural capability of “recycling” food waste (FW) that is unfit for direct human consumption can support a circular economy as shown in the case of Sri Lanka’s Western Province. The reuse of organic residues including FW as animal feed is a traditional agricultural practice in Sri Lanka but is less studied within an urban FW context. A survey of piggeries using FW in and around the rapidly urbanizing city of Colombo showed that FW is a major feed source in the farms accounting for on average 82% of total feed. About 40% of the farms collected the FW mainly from hotels, restaurants, and institutional canteens. Urban FW is supplied to farmers free of charge when collected directly from the sources, although 26% of the farmers collected FW via intermediaries against a fee. As FW is collected daily, the restaurants appreciate the reliable service, the farmers the low-cost feed, and the municipality the reduced FW volumes to be collected. However, this triple-win situation encounters challenges such as (tourist related) seasonal low supply, which was exacerbated under the Covid-19 lockdown of food services. Another area of concern refers to biosafety. Although the large majority of interviewed farmers boil FW which contains raw meat or fish, there is a paucity of related guidelines and control. Given the benefits of FW use, it is worthwhile to explore how far these informal partnerships could be scaled without increasing transport costs for farmers, while introducing biosafety monitoring. For now, the regulatory environment is highly siloed and does not support material transitions across sector boundaries towards a circular economy.

Poor availability and accuracy of streamflow data constrains research and operational hydrology. We evaluated the status of forty streamflow stations and data quality in the Omo-Gibe basin, Ethiopia. The method included a 3-week field inspection of the stations. Inspection of stations followed common WMO guidelines for appropriate gauging sites. Feedback of observers was collected, and the streamflow data was analyzed. Most of the stations were installed on rivers at headwater catchments. Only 17% of the stations were fully operational whereas the remaining stations require major maintenance. Common problems of the time series data include short observation period, large number of missing records, and inhomogeneity. Nearly all observers expressed dissatisfaction due to lack of supervision, uncertain salary payments and lack of recognition of their contribution. The findings of this study indicate the need to investigate the institutional barriers that affected the homogeneity, completeness, and timeliness of the stream data.

In Addis Ababa and its environs, most urban wastewater is discharged into rivers without treatment. This study related urban wastewater characteristics to the prevalence of faecal, antibiotic resistant, and potentially pathogenic bacteria in rivers of the Akaki catchment across six locations, for the dry and wet season. Spatiotemporal variation in bacterial hazards across the catchment was up to 6 log10 units. Cooccurrence of sewage pollution marker gene HF183 in all river samples testing positive for the Vibrio cholerae marker gene ompW, and high levels of these two genes in untreated wastewater, identified human sewage as the likely source of Vibrio cholerae hazards in the catchment. Levels of the marker genes rodA for E. coli, HF183 for human host associated Bacteroides, ciaB for Arcobacter, and ompW for Vibrio cholerae were all higher in the dry season than in the wet season. Marker gene gyrB for Pseudomonas aeruginosa was not detected in the samples. From the sequencing data, notable bacterial genera in the dry season included wastewater pollution indicators Arcobacter and Aeromonas, whereas soil erosion may explain the greater prominence of Legionella, Vicinamibacter, and Sphingomonas during the wet season. Except for the most upstream location, all faecal coliform (FC) counts exceeded WHO standards of 1000 CFU/100 mL for unrestricted irrigation. Concerningly, 0.6–20% of FC had ESBL producing antimicrobial resistance traits. In conclusion, multiple bacterial hazards were of concern for river water users in the Akaki catchment, and elevated in the dry season, when the river water is being used for irrigation of vegetable fields that supply the markets of Addis Ababa. This reflects inadequate treatment and limited dilution of urban wastewater by the natural river flows during periods of low rainfall.

Climate-related hazards can lead to agricultural losses and affect local and wider food supply via food trade. This study estimates the potential for adverse effects of climate hazards on food supply across Indian States and Union Territories (hereafter ‘states’) by quantifying climate hazard risks. Risks were estimated using the most recent data available on hazard presence, vulnerability, and volume of per capita food supply that is exposed to hazards. Historical (2000–2020) climatological and geological data sourced from meteorological stations and satellite imagery were used to estimate the state-level presence of eight climate-related hazards (droughts, forest fires, floods, extreme rainfall, landslides, cyclones, extreme temperatures, sea level rise). For each state and hazard type, we distinguished between risk to food supply produced in the state and the risk to food supply imported from other states. The source of food supply was estimated from a supply and demand balance model for 30 major food items that uses government data from 2011–12. We found that climate hazard risks to food supply vary across states and by hazard type. The largest climate hazard risks to state food supply are in Bihar, Madhya Pradesh, and Assam, where the majority of risk is to locally produced supply. Food supply in each state is at risk to all eight climate hazards via food imports from other Indian states. For 14 states, the climate hazard risk is greater for imported food supply than for locally produced supply. Just five states contribute to more than half of the climate hazard risk in interstate food trade. The findings indicate that climate-related hazards in Indian states could have potentially adverse effects on national food supply, affecting both local production and interstate trade. For policy-makers, these climate hazard risks identify potential priorities for enhancing food system resilience to mitigate impacts on local and national food security.

This paper proposes a reformulation of the Sustainable Livelihoods Framework (SLF) fit for the 21st century. The article explores the rise and usage of the original SLF, highlighting how its popularity among development practitioners emerged both from its practical focus, and its depoliticization of wider shifts in the development landscape at the time. Distilling the various critiques that have emerged around the use of the SLF and sustainable livelihoods approaches, the article highlights problems of theory, method, scale, historical conceptualisation, politics, and debates on decolonising knowledge. It further explores two key shifts in the global development landscape that characterise the 21st century, namely the impacts of climate change on rural livelihoods, and the shifts wrought by globalisation, before highlighting the structural and relational turns in critical development literature. In speaking to both historical critiques and more recent debates, we present a SLF for the 21st century, foregrounding a structural, spatially-disaggregated, dynamic and ecologically-coherent approach to framing rural livelihoods. We offer a framework and not an approach, hoping that that our SLF leaves open the possibility for different theoretical traditions to better work with emerging rural livelihoods.

A comprehensive evaluation of the impacts of climate change on water resources of the West Africa Volta River basin is conducted in this study, as the region is expected to be hardest hit by global warming. A large ensemble of 12 general circulation models (GCMs) from the fifth Coupled Model Intercomparison Project (CMIP5) that are dynamically downscaled by five regional climate models (RCMs) from the Coordinated Regional-climate Downscaling Experiment (CORDEX)-Africa is used. In total, 43 RCM–GCM combinations are considered under three representative concentration pathways (RCP2.6, RCP4.5, and RCP8.5). The reliability of each of the climate datasets is first evaluated with satellite and reanalysis reference datasets. Subsequently, the Rank Resampling for Distributions and Dependences (R2D2) multivariate bias correction method is applied to the climate datasets. The bias-corrected climate projections are then used as input to the mesoscale Hydrologic Model (mHM) for hydrological projections over the 21st century (1991–2100). Results reveal contrasting dynamics in the seasonality of rainfall, depending on the selected greenhouse gas emission scenarios and the future projection periods. Although air temperature and potential evaporation increase under all RCPs, an increase in the magnitude of all hydrological variables (actual evaporation, total runoff, groundwater recharge, soil moisture, and terrestrial water storage) is only projected under RCP8.5. High- and low-flow analysis suggests an increased flood risk under RCP8.5, particularly in the Black Volta, while hydrological droughts would be recurrent under RCP2.6 and RCP4.5, particularly in the White Volta. The evolutions of streamflow indicate a future delay in the date of occurrence of low flows up to 11 d under RCP8.5, while high flows could occur 6 d earlier (RCP2.6) or 5 d later (RCP8.5), as compared to the historical period. Disparities are observed in the spatial patterns of hydroclimatic variables across climatic zones, with higher warming in the Sahelian zone. Therefore, climate change would have severe implications for future water availability with concerns for rain-fed agriculture, thereby weakening the water– energy–food security nexus and amplifying the vulnerability of the local population. The variability between climate models highlights uncertainties in the projections and indicates a need to better represent complex climate features in regional models. These findings could serve as a guideline for both the scientific community to improve climate change projections and for decision-makers to elaborate adaptation and mitigation strategies to cope with the consequences of climate change and strengthen regional socioeconomic development.

Sector-based resource management approaches partly contribute to the insecurities in water, energy and food sectors and resources. These approaches fail to acknowledge and capture the interlinkages between these connected resources, a key strength in the water-energy-food (WEF) nexus approach. However, the multi-centric, multidimensional, and spatiotemporally dynamic WEF nexus is complex and uncertain, thus requiring dedicated tools that can unpack it. Various sources have blamed the slow uptake and practical implementation of the WEF nexus on the unavailability of appropriate tools and models. To confirm those claims with evidence, literature on WEF nexus tools was searched from Scopus and Web of Science and systematically reviewed using the PRISMA protocol. It was found that the WEF nexus tools are being developed increasingly, with a current cumulative number of at least 46 tools and models. However, their majority (61%) is unreachable to the intended users. Some available tools are in code format, which can undermine their applicability by users without programming skills. A good majority (70%) lack key capabilities such as geospatial features and transferability in spatial scale and geographic scope. Only 30% of the tools are applicable at local scales. In contrast, some tools are restricted in geographic scope and scale of application, for example, ANEMI 3 and WEF models for large and household scales, respectively. Most (61%) of the tools lack wide application in actual case studies; this was partly attributed to the tools not being readily available. Thus, efforts should be made to disseminate and ensure end-users’ uptake and application of developed tools. Alternatively, the user-friendly tools should be developed on-demand as requested and inspired by potential clients. Developers should consider utility, transferability and scalability across uses and users when improving existing tools and developing new tools so that they are adaptable, only requiring new, specific location-adapted inputs and data. Where and when it is necessary to capture spatial dynamics of the WEF nexus, tools should be geographic information system (GIS)-enabled for automatic WEF nexus location selection, geospatial mapping, and visualization. Such GIS-enabled WEF nexus tools can provide a bird’s eye view of hotspots and champions of WEF nexus practices.

The global goal to end hunger requires the interpretation of problems and change across multiple domains to create the scope for collaboration, learning, and impactful research. We facilitated a workshop aimed at understanding how stakeholders problematize sustainable diet transition (SDT) among a previously marginalized social group. Using the systems thinking approach, three sub-systems, namely access to dietary diversity, sustainable beneficiation of natural capital, and ‘food choice for well-being’, highlighted the main forces governing the current context, and future interventions of the project. Moreover, when viewed as co-evolving processes within the multi-level perspective, our identified microlevel leverage points—multi-faceted literacy, youth empowerment, deliberative policymaking, and promotion of sustainable diet aspirations—can be linked and developed through existing national macro-level strategies. Thus, co-designing to problematize transformational SDT, centered on an interdisciplinary outlook and informational governance, could streamline research implementation outcomes to re-structure socio-technical sectors and reconnect people to nature-based solutions. Such legitimate aspirations could be relevant in countries bearing complex socio-political legacies and bridge the local–global goals coherently. This work provides a collaborative framework required to develop impact-driven activities needed to inform evidence-based policies on sustainable diets.

Medicinal plants contribute substantially to the well-being of people in large parts of the world, providing traditional medicine and supporting livelihoods from trading plant parts, which is especially significant for women in low-income communities. However, the availability of wild medicinal plants is increasingly threatened; for example, the Natal Lily (Clivia miniata), which is one of the most widely traded plants in informal medicine markets in South Africa, lost over 40% of individuals over the last 90 years. Understanding the species’ response to individual and multiple pressures is essential for prioritizing and planning conservation actions. To gain this understanding, we simulated the future range and abundance of C. miniata by coupling Species Distribution Models with a metapopulation model (RAMAS-GIS). We contrasted scenarios of climate change (RCP2.6 vs. RCP8.5), land cover change (intensification vs. expansion), and harvesting (only juveniles vs. all life stages). All our scenarios pointed to continuing declines in suitable habitat and abundance by the 2050s. When acting independently, climate change, land cover change, and harvesting each reduced the projected abundance substantially, with land cover change causing the most pronounced declines. Harvesting individuals from all life stages affected the projected metapopulation size more negatively than extracting only juveniles. When the three pressures acted together, declines of suitable habitat and abundance accelerated but uncertainties were too large to identify whether pressures acted synergistically, additively, or antagonistically. Our results suggest that conservation should prioritize the protection of suitable habitat and ensure sustainable harvesting to support a viable metapopulation under realistic levels of climate change. Inadequate management of C. miniata populations in the wild will likely have negative consequences for the well-being of people relying on this ecosystem service, and we expect there may be comparable consequences relating to other medicinal plants in different parts of the world.

Climate change and rapid population growth are already putting increasing demand and pressure on the worldapos;s freshwater resources. Irrigated agriculture is responsible for about 70% of global freshwater withdrawals, consuming the most amount of water. However, the diverted water in irrigation systems is often not utilized efficiently because of poor water management at different spatial scales, resulting in a system efficiency of only 30–50% in most Asian countries. Typically, improving water management in irrigated areas requires accurate information on various water balance parameters while also considering a changing climate across different spatial scales. There have been technical limitations in getting accurate and reliable information on various key water balance parameters with the conventional approaches used in the recent past. In the twenty-first century, considerable advances have been made in using satellite imagery, including processing and geospatial algorithms, to estimate hydro-meteorological fluxes and relevant components at different spatial scales. This paper provides a perspective on the application of innovative and non-conventional approaches to water resources management in the Murray Darling basin, Australia, the Indus basin, Pakistan and the Amu Darya basin, Uzbekistan. Examples of the state-of-the-art tools described in this paper include: (i) using geoinformatics to monitor the diagnostic and operational performance of large irrigation schemes; (ii) quantifying groundwater and surface water to better manage these two resources using geoinformatics; (iii) forecasting irrigation supply and demand at high spatial and temporal scales using hydrological modelling based on the nodal network; (iv) forecasting crop yield production by satellite remote sensing. The approaches in this study clearly demonstrate that new monitoring and planning tools and methods are highly effective in improving irrigation water management in the ‘space age’ (for the purposes of this paper, space age refers to a period in which earth observation satellites are available to accurately monitor agricultural practices and water balance parameters such as soil moisture and evapotranspiration). The application of these innovative tools can assist in strategizing, diagnosing, monitoring and improving the performance of irrigation systems to grow more crop per drop of water while minimizing environmental impacts and dealing with climate change impacts.

The projected implications of climate change for water and agriculture to meet diverse and competitive water demands requires smart water management solutions. Science- and evidence-based, agricultural water management (AWM) can significantly contribute to reduce unsustainable water use and help enhance water resilience and adaptation to climate change. This paper presents a brief overview of potential AWM practices focusing on enhancing water resilience, increasing yields, and wherever possible, reducing emissions. This is achieved via increased land and water use efficiency, water and energy savings, and improved water productivity with considerable scope to improve agricultural resilience. In this context, the prioritization of a location-specific portfolio of smart AWM practices to make the right investment decisions is very important. We present two distinct and complementary approaches to prioritize AWM practices in this paper: one follows stakeholder analysis to build a prioritized portfolio of climate-smart AWM practices and the other employs a simple water balance-based approach to prioritize interventions. The way forward in mainstreaming and scaling out context-specific climate-smart AWM interventions is also discussed with a focus on capacity building, water management extension services, and the mobilization of resources through the convergence of institutions and co-financing from relevant development schemes.

Rainfall forecast is useful for farmers to avoid expensive irrigation decisions both in rain-fed and irrigated agricultural areas. In developing countries, farmers have limited knowledge of weather forecast information sources and access to technology such as the internet and smartphones to make use of these forecasts. This paper presents a case of developing Farmers Advisory Service (FAS) in Pakistan that is based on rainfall forecast data. The analysis emphasizes on statistical verification of 16-day rainfall forecast data from a global weather forecast model (Global Forecast System). In-situ data from 15 observatories maintained by Pakistan Meteorological Department in Khyber Pakhtunkhwa province has been considered for verification. Scores of various indicators are calculated for the rainfall forecast ranging from simple forecasts of dichotomous outcomes to forecasts of a continuous variable. A sensitivity analysis is also performed to understand how scores of dichotomous indicators vary by changing the threshold to define a rainfall event and forecast lead time interval. The quality of forecast varies across the stations based on the selected skill scores. The findings of verification, sensitivity analysis, and attributes of FAS provide insight into the process of developing a decision support service for the farmers based on the global weather forecast data.

UAV-based multispectral vegetation indices are often used to assess crop performance and water consumptive use. However, their ability to assess the interaction between water, especially deficit irrigation, and nitrogen application rates in irrigated agriculture has been less explored. Understanding the effect of water-nitrogen interactions on vegetation indices could further support optimal water and N management. Therefore, this study used a split plot design with water being the main factor and N being the sub-factor. African eggplants were drip irrigated at 100% (I100), 80% (I80) or 60% (I60) of the crop water requirements and received 100% (F100), 75% (F75), 50% (F50) or 0% (F0) of the crop N requirements. Results showed that the transformed difference vegetation index (TDVI) was best in distinguishing differences in leaf moisture content (LMC) during the vegetative stage irrespective of the N treatment. The green normalized difference vegetation index (GNDVI) worked well to distinguish leaf N during vegetative and full vegetative stages. However, the detection of the interactive effect of water and N on crop performance required a combination of GNDVI, NDVI and OSAVI across both stages as each of these 3 VI showed an ability to detect some but not all treatments. The fact that a certain amount of irrigation water can optimize the efficiency of N uptake by the plant is an important criterion to consider in developing crop specific VI based decision trees for crop performance assessments and yield prediction.

The COVID-19 pandemic has underlined the importance of safe access to sufficient clean water in vulnerable communities, renewing interest in water, sanitation and hygiene (WASH) programs and related targets under Sustainable Development Goal 6 (SDG 6). The purpose of this study was to better understand the obstacles to water access in vulnerable communities and identify ways they might be addressed in five countries in the Mekong Region (Cambodia, Laos, Myanmar, Thailand, Vietnam). To this end, qualitative interviews with 50 government officials and development or health experts were complimented with a quantitative survey of the experiences and views of individuals in 15 vulnerable communities. There were several key findings. First, difficulties in accessing sufficient clean water for drinking and hygiene persist in certain vulnerable communities, including informal urban settlements, remote minority villages, and migrant worker camps. Second, limited rights, high prices, and remote locations were common obstacles to household access to improved water sources. Third, seasonal differences in the availability of clean water, alongside other disruptions to supply such as restrictions on movement in COVID-19 responses, drove households towards lower quality sources. Fourth, there are multiple threats to water quality from source to consumption that should be addressed by monitoring, treatment, and watershed protection. Fifth, stakeholder groups differ from each other and residents of vulnerable communities regarding the significance of water access, supply and quality difficulties, and how they should be addressed. The paper ends with a set of program suggestions addressing these water-related difficulties.

Globally, the use of untreated, often diluted, or partly treated wastewater in agriculture covers about 30 million ha, far exceeding the area under the planned use of well-treated (reclaimed) wastewater which has been estimated in this paper at around 1.0 million ha. This gap has likely increased over the last decade despite significant investments in treatment capacities, due to the even larger increases in population, water consumption, and wastewater generation. To minimize the human health risks from unsafe wastewater irrigation, the WHO’s related 2006 guidelines suggest a broader concept than the previous (1989) edition by emphasizing, especially for low-income countries, the importance of risk-reducing practices from ‘farm to fork’. This shift from relying on technical solutions to facilitating and monitoring human behaviour change is, however, challenging. Another challenge concerns local capacities for quantitative risk assessment and the determination of a risk reduction target. Being aware of these challenges, the WHO has invested in a sanitation safety planning manual which has helped to operationalize the rather academic 2006 guidelines, but without addressing key questions, e.g., on how to trigger, support, and sustain the expected behaviour change, as training alone is unlikely to increase the adoption of health-related practices. This review summarizes the perceived challenges and suggests several considerations for further editions or national adaptations of the WHO guidelines.

This paper follows the transition from ethnobotany to a deeper scientific understanding of the food and medicinal properties of African agroforestry tree products as inputs into the start of domestication activities. It progresses on to the integration of these indigenous trees as new crops within diversified farming systems for multiple social, economic and environmental benefits. From its advent in the 1990s, the domestication of indigenous food and non-food tree species has become a global programme with a strong African focus. This review of progress in the third decade is restricted to progress in Africa, where multi-disciplinary research on over 59 species has been reported in 759 research papers in 318 science publications by scientists from over 833 research teams in 70 countries around the world (532 in Africa). The review spans 23 research topics presenting the recent research literature for tree species of high priority across the continent, as well as that in each of the four main ecological regions: the humid zone of West and Central Africa; the Sahel and North Africa; the East African highlands and drylands; and the woody savannas of Southern Africa. The main areas of growth have been the nutritional/medicinal value of non-timber forest products; the evaluation of the state of natural resources and their importance to local people; and the characterization of useful traits. However, the testing of putative cultivars; the implementation of participatory principles; the protection of traditional knowledge and intellectual property rights; and the selection of elite trees and ideotypes remain under-researched. To the probable detriment of the upscaling and impact in tropical agriculture, there has been, at the international level, a move away from decentralized, community-based tree domestication towards a laboratory-based, centralized approach. However, the rapid uptake of research by university departments and national agricultural research centres in Africa indicates a recognition of the importance of the indigenous crops for both the livelihoods of rural communities and the revitalization and enhanced outputs from agriculture in Africa, especially in West Africa. Thus, on a continental scale, there has been an uptake of research with policy relevance for the integration of indigenous trees in agroecosystems and their importance for the attainment of the UN Sustainable Development Goals. To progress this in the fourth decade, there will need to be a dedicated Centre in Africa to test and develop cultivars of indigenous crops. Finally, this review underpins a holistic approach to mitigating climate change, as well as other big global issues such as hunger, poverty and loss of wildlife habitat by reaping the benefits, or ‘profits’, from investment in the five forms of Capital, described as ‘land maxing’. However, policy and decision makers are not yet recognizing the potential for holistic and transformational adoption of these new in

We developed an empirical soil wetting geometry model for silty clay loam and coarse sand soils under a semi-permeable porous wall line source Moistube Irrigation (MTI) lateral irrigation. The model was developed to simulate vertical and lateral soil water movement using the Buckingham pi (p) theorem. This study was premised on a hypothesis that soil hydraulic properties influence soil water movement under MTI. Two independent, but similar experiments, were conducted to calibrate and validate the model using MTI lateral placed at a depth of 0.2 m below the soil surface in a soil bin with a continuous water supply (150 kPa). Soil water content was measured every 5 min for 100 h using MPS-2 sensors. Model calibration showed that soil texture influenced water movement (plt; 0.05) and showed a good ft for wetted widths and depths for both soils (nRMSE = 0.5–10%; NSE = 0.50; and d-index = 0.50. The percentage bias (PBIAS) statistic revealed that the models’ under-estimated wetted depth after 24 h by 21.9% and 3.9% for silty clay loam and sandy soil, respectively. Sensitivity analysis revealed agreeable models’ performance values. This implies the model’s applicability for estimating wetted distances for an MTI lateral placed at 0.2 m and MTI operating pressure of 150 kPa. We concluded that the models are prescriptive and should be used to estimate wetting geometries for conditions under which they were developed. Further experimentation under varying scenarios for which MTI would be used, including feld conditions, is needed to further validate the model and establish robustness. MTI wetting geometry informs placement depth for optimal irrigation water usage.

The COVID-19 pandemic brought unprecedented socio-economic changes, ushering in a “new (ab)normal” way of living and human interaction. The water sector was not spared from the effects of the pandemic, a period in which the sector had to adapt rapidly and continue providing innovative water and sanitation solutions. This study unpacks and interrogates approaches, products, and services adopted by the water sector in response to the unprecedented lockdowns, heralding novel terrains, and fundamental paradigm shifts, both at the community and the workplace. The study highlights the wider societal perspective regarding the water and sanitation challenges that grappled society before, during, after, and beyond the pandemic. The premise is to provide plausible transitional pathways towards a new (ab)normal in adopting new models, as evidenced by the dismantling of the normal way of conducting business at the workplace and human interaction in an era inundated with social media, virtual communication, and disruptive technologies, which have transitioned absolutely everything into a virtual way of life. As such, the novel approaches have fast-tracked a transition into the 4th Industrial Revolution (4IR), with significant trade-offs to traditional business models and human interactions.

Participatory Geographic Information Systems (PGIS) is an empowering tool for the enhancement of local communities’ participation in the planning and management of natural resources. The inadequate involvement of local stakeholders in rangeland planning and management has been of great concern. Discussions on the role of PGIS and collaborative management approaches in promoting local involvement in rangeland management has not been clearly understood due to the scarcity of literature. This paper assessed how local participation in rangeland management can be enhanced using a combined collaborative management framework and PGIS approach. The objective was achieved through a focus group discussion, local ecological knowledge mapping and key informant interviews. The combined PGIS and collaborative management approach enabled the empowerment of local actors through knowledge enhancement, encouraged the practice of rangeland governance and the transfer of responsibility to local actors. This study provides a conceptual contribution toward the improvement of local actors’ participation in rangeland management.

Africa has a long history of novel and re-emerging infectious disease outbreaks. This reality has attracted the attention of researchers interested in the general research theme of predicting infectious diseases. However, a knowledge mapping analysis of literature to reveal the research trends, gaps, and hotspots in predicting Africa’s infectious diseases using bibliometric tools has not been conducted. A bibliometric analysis of 247 published papers on predicting infectious diseases in Africa, published in the Web of Science core collection databases, is presented in this study. The results indicate that the severe outbreaks of infectious diseases in Africa have increased scientific publications during the past decade. The results also reveal that African researchers are highly underrepresented in these publications and that the United States of America (USA) is the most productive and collaborative country. The relevant hotspots in this research field include malaria, models, classification, associations, COVID-19, and cost-effectiveness. Furthermore, weather-based prediction using meteorological factors is an emerging theme, and very few studies have used the fourth industrial revolution (4IR) technologies. Therefore, there is a need to explore 4IR predicting tools such as machine learning and consider integrated approaches that are pivotal to developing robust prediction systems for infectious diseases, especially in Africa. This review paper provides a useful resource for researchers, practitioners, and research funding agencies interested in the research theme—the prediction of infectious diseases in Africa—by capturing the current research hotspots and trends.

A large proportion of the rural population in Ethiopia depends on community-managed forests for food security and livelihoods. However, the government and development partners have paid little attention to the governance challenges which limit the contributions of community-managed forests to food security and livelihoods. Also lacking is a synthesis of evidence relating to the requirements for improved governance to support the efforts of decision makers and practitioners. This paper attempts to review and synthesize the available evidence with the aim of identifying the requirements to achieve improved governance in community-managed forests. The results revealed that failure to devise benefit-sharing mechanisms which consider the heterogeneity of rural communities was prevalent. Interference of local authorities and elite capture in decision-making processes of forest and landscape restoration also compromised the willingness of rural communities to engage in collective action. Requirements such as the identification of the needs of specific categories of communities and enabling of the negotiation of diverse interests in the design and implementation of interventions could improve the governance of community-managed forests. Developing management plans and business model scenarios which balance the ecological and socio-economic goals at a local level in collaboration with rural communities is important to improve the governance of community-managed forests. There is also a need to revisit the practice of evaluating the performance of community-managed forests almost exclusively based on the goals of climate change adaptation and mitigation and biodiversity conservation.

Community-led watershed development activities, including the establishment of exclosures (areas where both livestock and farming activities are excluded) on degraded communal grazing land, have become a common practice in Ethiopia since the 1990s. However, it is not yet fully understood how these exclosures change soil organic carbon and total soil nitrogen in different soil types and under different agroecologies. A meta-analysis using data gathered from the most relevant peer reviewed articles from Ethiopian exclosure systems was conducted to assess the variation in the effects of exclosures on soil carbon and nitrogen and to investigate the factors controlling change. The results demonstrate that after 16 years, exclosures can increase soil organic carbon and total soil nitrogen up to an effect size greater than two. This is moderated by soil type, exclosure age, landscape position and agroecology. More effective restoration of soil carbon was observed in less developed Leptosols and Cambisols than in more developed Luvisols, and in drier than more humid agroecologies. The results suggest that soil type and agroecology should be taken into consideration when planning and implementing exclosures on degraded communal grazing land. The findings of this study provide base line information for the future expansion of exclosures, and guide where to focus implementation. They also provide criteria to be used when planning and establishing exclosures to restore soil carbon and nitrogen. In addition, the results generated through this meta-analysis provide better understanding of the spatial and temporal variation of the effectiveness of exclosures to restore soil carbon and nitrogen.

Access to sufficient clean water is important for reducing the risks from COVID-19. It is unclear, however, what influence COVID-19 has had on water insecurities. The objective of this study was to assess the associations between COVID-19 control measures and household water insecurities. A survey of 1559 individuals living in vulnerable communities in five countries (Cambodia, Laos, Myanmar, Thailand, Vietnam) showed that increased needs for clean water to wash hands or facemasks made it more likely a person was water insecure along those dimensions. Water insecurities with respect to handwashing and drinking, in turn, made adoption of the corresponding good practices less likely, whereas in the case of washing facemasks there was no association. Water system infrastructure, environmental conditions such as foods and droughts, as well as gender norms and knowledge, were also important for water insecurities and the adoption of good practices. As domestic water insecurities and COVID-19 control measures are associated with each other, efforts should therefore be directed at identifying and assisting the water insecure at high risk when COVID-19 reaches their communities.

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world’s rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals.

Eighty percent of wastewater is left untreated or not reused, exacerbating the water quality challenge, especially in vulnerable communities. This Voices asks: how can we improve wastewater management and convert wastewater into a resource?

The impact of climate change on the availability of water affects all types of land use and sectors. This complexity calls for integrated water resources management and negotiations between sectors on the most important, cost-effective, and productive allocation of water where it is a limited resource. This reflection paper shows examples of adaptation efforts to water scarcity at a scale where gains in water productivity can be derived from intersectoral water reuse and wastewater–freshwater swaps, complementing other water scarcity coping strategies (water savings, long-distance transfer, and desalination). Wastewater treatment for reuse offers opportunities across scales as it allows, for example, donor regions to be compensated with reclaimed water for the release of freshwater for higher-value use, increasing overall economic water productivity in this way. In such water swaps, farmers are compensated with higher water volumes in exchange for higher quality. The reuse of water between sectors offers opportunities to (i) expand the traditional (agricultural) water productivity concept and (ii) significantly increase water productivity at the system level. While rural–urban water reallocation can help mitigate the impacts of climate change, compensating farmers with reclaimed water remains limited for the reasons discussed in the paper.

The African continent harbours many native species with nutraceutical and pharmaceutical potential. This study reviewed underutilised crops in South Africa to determine their potential as food and herbal medicinal crops. Over 5,000 species have been identified and earmarked for their medical attributes in formal and informal setups. Researchers, plant breeders and policymakers have mostly ignored the development potential of these crops. Consequently, their value chains are poorly developed. In South Africa, there is a wide range of neglected and underutilised crops, which were historically popular and used by communities; however, over the years, they have lost their status within farming systems and been relegated to the status of neglected and underutilised. Recently, driven by the need to transition to more sustainable and resilient food systems, there has been renewed interest in their potential as food and herbal medicinal crops to establish new value chains that include vulnerable groups. They are now gaining global attention, and their conservation and sustainable utilisation are now being prioritized. The review confirmed that several of these crops possess nutraceutical and pharmaceutical properties, highlighting their potential for development as food and herbal medicines. However, current production levels are too low to meet the requirements for industrial development; research and development should focus on all aspects of their value chain, from crop improvement to utilisation. A transdisciplinary approach involving a wide range of actors is needed to develop the identified neglected and underutilised crops’ potential as food and herbal medicinal crops and support the development of new and inclusive value chains.

Smallholder farmers depend on healthy and productive crop yields to sustain their socio-economic status and ensure livelihood security. Advances in South African precision agriculture in the form of unmanned aerial vehicles (UAVs) provide spatially explicit near-real-time information that can be used to assess crop dynamics and inform smallholder farmers. The use of UAVs with remote-sensing techniques allows for the acquisition of high spatial resolution data at various spatio-temporal planes, which is particularly useful at the scale of fields and farms. Specifically, crop chlorophyll content is assessed as it is one of the best known and reliable indicators of crop health, due to its biophysical pigment and biochemical processes that indicate plant productivity. In this regard, the study evaluated the utility of multispectral UAV imagery using the random forest machine learning algorithm to estimate the chlorophyll content of maize through the various growth stages. The results showed that the near-infrared and red-edge wavelength bands and vegetation indices derived from these wavelengths were essential for estimating chlorophyll content during the phenotyping of maize. Furthermore, the random forest model optimally estimated the chlorophyll content of maize over the various phenological stages. Particularly, maize chlorophyll was best predicted during the early reproductive, late vegetative, and early vegetative growth stages to RMSE accuracies of 40.4 mol/m-2 , 39 mol/m-2 , and 61.6 mol/m-2 , respectively. The least accurate chlorophyll content results were predicted during the mid-reproductive and late reproductive growth stages to RMSE accuracies of 66.6 mol/m-2 and 69.6 mol/m-2 , respectively, as a consequence of a hailstorm. A resultant chlorophyll variation map of the maize growth stages captured the spatial heterogeneity of chlorophyll within the maize field. Therefore, the study’s findings demonstrate that the use of remotely sensed UAV imagery with a robust machine algorithm is a critical tool to support the decision-making and management in smallholder farms.

Plastic usage increases year by year, and the growing trend is projected to continue. However as of 2017, only 9% of the 9 billion tons of plastic ever produced had been recycled leaving large amounts of plastics to contaminate the environment, resulting in important negative health and economic impacts. Curbing this trend is a major challenge that requires urgent and multifaceted action. Based on scientific and gray literature mainly published during the last 10 years, this review summarizes key solutions currently in use globally that have the potential to address at scale the plastic and microplastic contaminations from source to sea. They include technologies to control plastics in solid wastes (i.e. mechanical and chemical plastic recycling or incineration), in-stream (i.e. booms and clean-up boats, trash racks, and sea bins), and microplastics (i.e. stormwater, municipal wastewater and drinking water treatment), as well as general policy measures (i.e. measures to support the informal sector, bans, enforcement of levies, voluntary measures, extended producer responsibility, measures to enhance recycling and guidelines, standards and protocols to guide activities and interventions) to reduce use, reuse, and recycle plastics and microplastics in support of the technological options. The review discusses the effectiveness, capital expenditure, and operation and maintenance costs of the different technologies, the cost of implementation of policy measures, and the suitability of each solution under various conditions. This guidance is expected to help policymakers and practitioners address, in a sustainable and cost-efficient way, the plastic and microplastic management problem using technologies and policy instruments suitable in their local context.

This paper illustrates an approach to measuring economic benefits and ecological and social impacts of various configurations of reservoir systems for basin-wide planning. It suggests indicators and examines their behavior under several reservoir arrangement scenarios using two river basins in Sri Lanka as examples. A river regulation index is modified to take into account the volume of flow captured by reservoirs and their placement and type. Indices of connectivity illustrate that the lowest river connectivity in a basin results from a single new reservoir placed on the main stem of a previously unregulated river between the two locations that command 50% and 75% of the basin area. The ratio of the total affected population to the total number of beneficiaries is shown to increase as the cumulative reservoir capacity in a river basin increases. An integrated index comparing the performance of different reservoir system configurations shows that while results differ from basin to basin, the cumulative effects of a large number of small reservoirs may be comparable to those with a few large reservoirs, especially at higher storage capacities.

This study reveals rainfall variability and trends in the African continent using TAMSAT data from 1983 to 2020. In the study, a Mann–Kendall (MK) test and Sen’s slope estimator were used to analyze rainfall trends and their magnitude, respectively, under monthly, seasonal, and annual timeframes as an indication of climate change using different natural and geographical contexts (i.e., sub-regions, climate zones, major river basins, and countries). The study finds that the highest annual rainfall trends were recorded in Rwanda (11.97 mm/year), the Gulf of Guinea (river basin 8.71 mm/year), the tropical rainforest climate zone (8.21 mm/year), and the Central African region (6.84 mm/year), while Mozambique (-0.437 mm/year), the subtropical northern desert (0.80 mm/year), the west coast river basin of South Africa (-0.360 mm/year), and the Northern Africa region (1.07 mm/year) show the lowest annual rainfall trends. There is a statistically significant increase in the rainfall in the countries of Africa’s northern and central regions, while there is no statistically significant change in the countries of the southern and eastern regions. In terms of climate zones, in the tropical northern desert climates, tropical northern peninsulas, and tropical grasslands, there is a significant increase in rainfall over the entire timeframe of the month, season, and year. This implies that increased rainfall will have a positive effect on the food security of the countries in those climatic zones. Since a large percentage of Africa’s agriculture is based only on rainfall (i.e., rain-fed agriculture), increasing trends in rainfall can assist climate resilience and adaptation, while declining rainfall trends can badly affect it. This information can be crucial for decision-makers concerned with effective crop planning and water resource management. The rainfall variability and trend analysis of this study provide important information to decision-makers that need to effectively mitigate drought and flood risk.

The Gravity Recovery and Climate Experiment (GRACE) has recently been identified as a useful tool for monitoring changes in groundwater storage (GWS), especially in areas with sparse groundwater monitoring networks. However, GRACE’s performance has not been evaluated in the highly heterogeneous Indus Basin (IB) to date. The objective of this study was thus (i) to evaluate GRACE’s performance in two distinctively different agroecological zones of the IB, and (ii) to quantify the trend of groundwater abstraction over 15 years (i.e., from 2002 to 2017). To capture this heterogeneity at the IB, the two different agro-ecological zones were selected: i) the Kabul River Basin (KRB), Afghanistan, and ii) the Lower Bari Doab Canal (LBDC) command area in Pakistan. The groundwater storage anomalies (GWSA) for both regions were extracted from random pixels. The results show a correlation (R2 ) of 0.46 for LBDC and 0.32 for the KRB, between the GWSA and in-situ measurements. The results further reveal a mean annual depletion in GWSA of - 304.2 749 and - 301 527 mm at the LBDC and the KRB, respectively. Overall, a net GWS depletion during 2002–2017 at the LBDC and KRB was 4.87 and 4.82 m, respectively. The GWSA’s response to precipitation analyzed through cross-correlation shows a lag of 4 and 3 months at the KRB and the LBDC, respectively. The GWSA’s poor correlation with the in-situ measurements particularly in the mountainous region of the KRB is driven by the 4 months lag time unlike in the LBDC (i.e. 3 months); besides, the observations wells are sparse and limited. The complex geomorphology and slope of the landscape also cause discrepancies in the correlation of the in-situ measurements and the GRACE-derived changes in GWS at the two different agroecological zones of the IB. The spatially averaged GWSA in monthly time steps is another reason for the lower correlation between GRACE-based GWSA estimates and point-based in-situ measurements. Therefore, care must be taken while using GRACE’s output in regions with heterogeneous geomorphologic features.

Sustainable and resilient food systems depend on sustainable and resilient water management. Resilience is characterised by overlapping decision spaces and scales and interdependencies among water users and competing sectors. Increasing water scarcity, due to climate change and other environmental and societal changes, makes putting caps on the consumption of water resources indispensable. Implementation requires an understanding of different domains, actors, and their objectives, and drivers and barriers to transformational change. We suggest a scale-specific approach, in which agricultural water use is embedded in a larger systems approach (including natural and human systems). This approach is the basis for policy coherence and the design of effective incentive schemes to change agricultural water use behaviour and, therefore, optimise the water we eat.

Kitchen gardening is considered a way to reconnect with agriculture and complement the cereal-based relief food offered to refugees in East Africa. This work aimed at profiling mineral content of okra in four refugee camps and settlements located in Ethiopia and Uganda and its contribution to adequate intake (AIs) or recommended dietary allowances (RDAs) for young children and pregnant and lactating women (PLW). The study also evaluated the applicability of portable X-ray fluorescence (PXRF) as compared with inductively coupled plasma mass spectrometry (ICP-MS) for mineral profiling of okra powder samples. The contents of minerals (mg kg-1) from the ICP-MS readings were in the following ranges: K (14,385–33,294), Ca (2610–14,090), P (3178–13,248), Mg (3896–7986), Cu (3.81–19.3), Fe (75.7–1243), Zn (33–141) and Mn (23.1–261). Regardless of geographic origin, at low-end consumption probability (17 g day-1 for young children and 68 g day-1 for PLW), okra could contribute 15% (2.7–12.9%) AI for macro-minerals (K and Ca). In addition, the contributions to RDA values for Fe and Zn, elements of known public health interest, ranged from 4.5 to 34.7% for young children. Interestingly, regression lines revealed strong agreement between ICP-MS and PXRF readings for Mn and Zn, with R2 valuesgt;0.91. This information is useful in support of nutrition-sensitive kitchen gardening programs through scaling culturally important crops in refugee settings.

Small reservoirs are one of the most important sources of water for irrigation, domestic and livestock uses in the Upper East Region (UER) of Ghana. Despite various studies on small reservoirs in the region, information on their spatial-temporal variations is minimal. Therefore, this study performed a binary Random Forest classification on Sentinel-2 images for five consecutive dry seasons between 2015 and 2020. The small reservoirs were then categorized according to landscape positions (upstream, midstream, and downstream) using a flow accumulation process. The classification produced an average overall accuracy of 98% and a root mean square error of 0.087 ha. It also indicated that there are currently 384 small reservoirs in the UER (of surface area between 0.09 and 37 ha), with 20% of them newly constructed between the 2016-17 and 2019-20 seasons. The study revealed that upstream reservoirs have smaller sizes and are likely to dry out during the dry season while downstream reservoirs have larger sizes and retain substantial amounts of water even at the end of the dry season. The results further indicated that about 78% of small reservoirs will maintain an average of 54% of their water surface area by the end of the dry season. This indicates significant water availability which can be effectively utilized to expand dry season irrigation. Overall, we demonstrate that landscape positions have significant impact on the spatial-temporal variations of small reservoirs in the UER. The study also showed the effectiveness of remote sensing and machine learning algorithms as tools for monitoring small reservoirs.

Globally, collection of tipping fees is being promoted as a solution to sustain the operation of fecal sludge treatment plants (FSTPs). Currently, there are six large-scale FSTPs in Ghana, of which five were in operation in June 2017. In Kumasi, Sekondi-Takoradi and Tamale, fecal sludge (FS) is co-treated with landfill leachate using waste stabilization ponds (WSPs). In Tema and Accra, FS is treated using WSPs and a mechanical dewatering system coupled with an upflow anaerobic sludge blanket (UASB). The focus of this study is FSTPs and to assess how, and if, the tipping fees set by the municipalities could enable cost recovery to sustain their long-term operation. Using a questionnaire survey to interview plant managers from the public and private sectors, and directors of waste management departments, we found that the overall average operation, maintenance and management (OMamp;M) costs per 1000 m3 of treated waste (FS or FS + leachate) in 2017 were USD89 in Kumasi, USD150 in Tamale, USD179 in Tema, USD244 in Sekondi-Takoradi and USD1,743 in Accra. There were important disparities between FSTPs due to their scale, age, and level of treatment and monitoring. Currently, most FSTPs charge tipping fees that range between USD310 and USD530/1000 m3 of FS, averaging USD421 98/1000 m3 of FS discharged at FSTPs. Our study also showed that the OMamp;M costs of large-scale intensive FSTPs cannot be sustained by relying solely on tipping fees. However, there could be potential to cover the routine expenditures associated with operating smaller FSTPs that relying on WSP technologies.

Closing the yield gap and enhancing efficiency in rainfed maize production systems in Ethiopia requires urgent action in increasing the productivity of degraded agricultural land. The degradation of land through continuous compaction and decline in the organic matter has resulted in a wide-spread formation of a hardpan that restricts deep percolation, prevents plant root development, and, ultimately can lead to increased erosion. Studies exploring practical low-cost solutions to break the hardpan are limited in Ethiopia. The main objective was to evaluate soil mechanical (i.e. modified plow or Berken plow) or biological intervention (i.e. intercropping with pigeon pea) effectiveness to enhance soil water management and crop yield of rainfed maize systems whilst reducing soil erosion and runoff. Five farm fields, each including four plots with different tillage treatments, were monitored during two rainy seasons in 2016 and 2017. The treatments were: (i) farmers practice under conventional (CT) tillage; plots tilled three times using an oxen driven local plow Maresha, (ii) no-till (NT), (iii) Berken tillage (BT), plots tilled three times using an oxen pulled Berken plow, and (iv) biological (CT + Bio), taprooted pigeon pea intercropped with maize on plots conventionally tilled. Results showed that mean tillage depth was significantly deeper in the BT (28 cm) treatment compared to CT and CT + Bio (18 cm) treatments. Measured soil penetration resistance significantly decreased up to 40 cm depth under BT and maize roots reached 1.5 times deeper compared to roots measured in the CT treatment. Under BT, the estimated water storage in the root zone was estimated at 556 mm, 1.86 times higher compared to CT, 3.11 times higher compared to NT and 0.89 times higher compared to CT + Bio. The positive effects on increased water storage and root development resulted in an average increase in maize grain (i.e. 15%, 0.95 t ha- 1 ) and residual above ground biomass (0.3%, 6.4 t ha- 1 ) leading to a positive net benefit of 138 USD ha- 1 for the BT treatment compared to the CT treatment. The negative net benefit obtained under CT and CT+Bio was mainly related to the high labor cost related to plowing, weeding, planting, and fertilizer application whilst in the NT this was related to the significantly lower maize yields. The positive effects in the BT treatment, and to some extent the CT+Bio treatment show great potential for smallholder rainfed maize systems where degraded soils with hardpans and high variability in rainfall prevail.

The use of improved technologies has been encouraged to improve irrigation on farms, especially in drought-prone areas. However, farmersapos; irrigation decisions may be rather motivated by a desire to reduce risk of crop loss than to reduce water use. Using the case of Jordan, we contribute to the water-saving debate by examining whether current irrigation frequency is influenced by past experiences of losses due to water shortage and whether preferences for technologies and irrigation advisory services are mediated by water shortage experiences. Our data are based on a survey of 304 fruit farms in the highlands that were all using drip irrigation, a popular way to “save” water globally. We find that farms that faced losses due to water shortages in the past are more likely to irrigate more frequently. More frequent irrigators who have such shortages are more likely to prefer receiving irrigation advisory information rather than upgrading technologies, while more frequent irrigators who have not faced such shortages are more likely to prefer upgrading irrigation technologies. Results suggest that irrigation management is motivated by risk reduction, not just by water conservation. Irrigation advisory services, hitherto neglected, may be an important component of agricultural water management in Jordan.

Exposure to metals has been hypothesized as possible cause of chronic kidney disease of unknown cause (CKDu) in Sri Lanka; however, evidence is inconclusive. We measured the concentrations of nephrotoxic metals (As, Pb, and Cd), as well as Se in rice (a staple grain in Sri Lanka) and other grains consumed in CKDu endemic and non-endemic regions using Inductively Coupled Mass Spectrometry (ICP-MS). Our results showed comparable mean concentrations (in g/kg) of 24.518, 7.36.4, and 14.215 for As, Pb, and Cd, respectively, in rice from endemic regions and 17.74.7, 12.76.8, and 17.816 in rice from non-endemic regions. Selenium concentrations (in mg/kg) were 0.050.02 in rice cultivated in both endemic and non-endemic regions. Arsenic and Cd concentrations were significantly higher in rice compared to other grains, which themselves had higher Se than rice. All samples were below the Codex standards established for Cd (400 g/kg for rice; 100 g/kg for cereal grains), Pb (200 g/kg) and inorganic As (200 g/kg) for white rice. Our findings show that dietary exposure to low levels of As, Pb, Cd, and inadequate Se in staple grains cannot be clearly linked to CKDu, suggesting that the disease could be multifactorial. Additional research is needed to determine the contribution of other risk factors such as lifestyle habits and heat stress to plan preventive strategies for reducing CKDu health cases in Sri Lanka.

Small-scale irrigation has gained momentum in recent years as one of the development priorities in Sub-Saharan Africa. However, farmer-led irrigation is often informal with little support from extension services and a paucity of data on land suitability for irrigation. To map the spatial explicit suitability for dry season small-scale irrigation, we developed a method using an ensemble of boosted regression trees, random forest, and maximum entropy machine learning models for the Upper East Region of Ghana. Both biophysical predictors including surface and groundwater availability, climate, topography and soil properties, and socio-economic predictors which represent demography and infrastructure development such as accessibility to cities and proximity to roads were considered. We assessed that 179,584 49,853 ha is suitable for dry-season small-scale irrigation development when only biophysical variables are considered, and 158,470 27,222 ha when socio-economic variables are included alongside the biophysical predictors, representing 77-89% of the current rainfed-croplands. Travel time to cities, accessibility to small reservoirs, exchangeable sodium percentage, surface runoff that can be potentially stored in reservoirs, population density, proximity to roads, and elevation percentile were the top predictors of small-scale irrigation suitability. These results suggested that the availability of water alone is not a sufficient indicator for area suitability for small-scale irrigation. This calls for strategic road infrastructure development and an improvement in the support to farmers for market accessibility. The suitability for small-scale irrigation should be put in the local context of market availability, demographic indicators, and infrastructure development.

Sustainable agriculture focuses using agricultural resources with minimum possible negative environmental externality to produce more food. The present study reports the environmental and health risks associated with the use, management and handling of agrochemical in the Central Rift Valley, Ethiopia. Six Woredas (or districts) covering both upstream and downstream areas and major ecosystems were selected. Data were collected using focus group discussion, key informant interviews, field observation and literature review. Pesticide Risks in the Tropics for Man, Environment and Trade tool was used to analyse data. Results indicated that local community’s awareness on use, handling and management of pesticides was low. Applications of insecticides, fungicides and herbicides polluted surface water systems and affected aquatic animals and plants with different level of risk (i.e. from no or insignificant risk to acute and chronic levels). The level of risks of using agrochemical on aquatic animals, human and the environment increased when the agricultural practices changed from good to non-good practices (i.e. increasing frequency of application). The types of agrochemicals determined the levels of risks on aquatic animals, human and the environment. For example, copper hydroxide and Lambda pose high risk, whereas Chlorpyrifos poses possible risk on fish under good agricultural practices. Also, the results indicated that the level of risks of using agrochemicals on fish and aquatic vertebrates was high for few pesticides (e.g. Chlorpyrifos) under both good and bad agricultural practices. The results of the present study support decision makers, practitioners and farmers to put corrective measures when importing agrochemicals, provide targeted risk management schemes including training on safety measures and screen agrochemicals on the market, respectively.

In recent years, farmer-led irrigation development has gained the interest of development partners and governments in the Global South following its success in enhancing agricultural production and livelihoods in South Asia. However, little is known about the socio-economic situation of farmers who receive public support for its expansion. Considering its rapid expansion in sub-Saharan Africa, we take the case of Ethiopia and explore the relationship between irrigation suitability and farmers’ socio-economic status. We find that high-value crop producers and wealthier farmers are most likely to make private investments and also benefit from public support in farmer-led irrigation expansion if investments are directed to land areas highly suitable for irrigation. Cultivation of high-value crops (fruit, vegetables) was common in areas more suitable for irrigation but staple crop cultivation (cereals, legumes) was negatively associated with irrigation suitability. Wealth status (consumption expenditure, asset index, and land size) was also positively correlated with irrigation suitability. A 10 per cent increase in groundwater irrigation suitability score was associated with a 2 per cent increase in per-capita consumption expenditure. Results imply that policies aiming to facilitate farmer-led irrigation development should combine biophysical information on land and water suitability for irrigation with household socio-economic characteristics and existing agricultural systems.

Drought-related risk is among the major global challenges of our time. It negatively impacts food security and ecosystem health. It is becoming a persistent problem in many parts of sub-Saharan Africa and specifically in Ethiopia. Information on its intensity and spatiotemporal distribution is critical to contextualize interventions and build agroecosystem and community resilience. This study aims at analyzing spatiotemporal characteristics of meteorological drought over eight Agroecological Zones (AEZs) of the Awash Basin, Ethiopia. Annual gridded temperature and precipitation dataset obtained from the National Meteorological Agency of Ethiopia for the period 1983–2016, covering 1655 grid points, were used. The study applied the Standard Precipitation and Evapotranspiration Index (SPEI) and Standard Precipitation Index (SPI) methods to characterize the meteorological droughts. The study applied Arc GIS 10.5 to map the drought hotspots. From the result, the value of SPEI and SPI methods was divergent in characterizing the magnitude and spatial occurrence of drought episodes. SPEI has more advantages in detecting dry months and a small advantage in detecting dry seasons compared to the SPI. Temporally, wet and dry years dominated the 1990s and 2010s, respectively. Drought dominated 1980s and normal years dominated the 2000s. The spatial context of drought hotspot showed that AEZs in the upper and lower parts of the Awash Basin were hit by severe to extreme drought while the escarpments and middle parts of the basin experienced mild to moderate drought. This contrasts with the common perception that the hot to warm arid lowlands AEZs are the only hotspot areas to drought. Moreover, previously none frequent drought AEZs, such as tepid to cool humid mid-highlands were identified as drought hotspots in the basin. This information could help policymakers to target AEZs and implement context-specific and informed drought risk management decisions and adaptation measures.

Groundwater depletion in India is a result of water, energy, and food policies that have given rise to a nexus where growth in agriculture has been supported by unsustainable trends in water and energy use. This nexus emanates from India’s policy of providing affordable calories to its large population. This requires that input prices are kept low, leading to perverse incentives that encourage groundwater overexploitation. The paper argues that solutions to India’s groundwater problems need to be embedded within the current context of its water-energy-food nexus. Examples are provided of changes underway in some water-energy-food policies that may halt further groundwater depletion.

This paper highlights how farmers in a northern Lao village transformed their customary land rights – in the face of incoherent overlapping state territorialization attempts – into a territorial strategy to secure their land tenure. By planting rubber, some villagers have engaged in a crop boom to lay claim to land which has recently been zoned for upland rice cultivation (and conservation) as part of a state-led land use planning initiative. We show how internal resettlement, ethnic division and the influx of commercial agriculture in the Lao uplands intersect in a novel land use planning process and predetermine the plan’s actual significance.

This study was conducted in Lake Hawassa catchment, Ethiopia where policy programs are aiming to restore degraded lands with participation of local stakeholders. We assessed the system in relation to natural resource management and degradation using the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) conceptual framework and conducted a stakeholder analysis to understand stakeholder interest, influence and interactions amongst the different categories of stakeholders. Data were collected using key informant interviews, field observation and a literature review. Results indicate that the degradation of natural resources in the catchment is attributed to several interlinked socio-economic and biophysical factors. Identified stakeholders include government and non-governmental organizations, local administrative bodies, civil society, the private sector and farmers. Most of the stakeholders have a role in landscape restoration, have similar interests and strategic options, and are flexible and innovative. Moderate to pronounced trust exists among identified stakeholders and could provide an opportunity to achieve better coordination and collective action amongst the different stakeholders. However, considerable differences between stakeholders in power, power resources and influence were detected due to differences in access to information, communication and negotiation skills, practical relevance, and social relations. The costs for empowerment measures could be low, as many of the stakeholders have access to and control of resources and high level of basic competencies. Our findings could guide practitioners and policy makers on whom and how to engage when planning and implementing natural resources management and landscape restoration interventions at catchment level.

Cotton yields in Uzbekistan are significantly lower than those in similar agro-climatic regions, requiring the estimation of crop potential and baseline yield to track progress of production enhancement efforts. The current study estimated potential cotton development and baseline yield (maximum given no production constraints) using total heat units (THU) and potential cotton yield (PCY), respectively. Calculations were based on heat units (HU) for a 30-year (1984-2013) period. Long-term average THU and PCY, as well as PCY at three different exceedance probabilities (p=0.99, p=0.80, and p=0.75), were calculated for 21 selected weather stations across cotton-growing areas of Uzbekistan. After confirmation that the current planting date (April 15) is optimal, a comparison of THU with the accepted cotton production cutoff threshold (1444C) suggested that areas with lower elevations and latitudes are more appropriate for cotton production. Yield gap analysis (relative difference between long-term average PCY and actual yields) confirmed that Uzbekistan cotton production is below potential, while the spatial distribution of yield gaps outlined where efforts should be targeted. Areas near the stations of Nukus, Kungrad, Chimbay, and Syrdarya should be further investigated as benefit/cost ratio is highest in these areas. A comparison between state-set yield targets and PCY values, taking into account climatic variability, suggested that all areas except Jaslyk, Nurata, and Samarkand have safe, appropriate targets. These results present a starting-point to aid in strategic actions for Uzbekistan cotton production improvement.

Investigating the effects of optimized fertilizer and irrigation levels on water use efficiency and productivity of wheat crop at small farms is of great importance for precise and sustainable agriculture in Pakistan’s irrigated areas. However, traditional farmer practices for wheat production are inefficient and unsustainable. This study aimed to investigate the effects of deficit irrigation and nitrophos fertilizer levels on bread wheat grain yield, yield parameters, nutrient use and water use efficiencies in bed planting wheat compared to traditional farmers’ practices in the flat sowing method. The two-year field experiment followed a randomized complete block design of three replications, taking three irrigation treatments according to the requirement of crop estimated by CROPWAT model (100% of ETC), deficit irrigation (80% of ETC), and deficit irrigation 60% of ETC and three nitrophos fertilizer treatments (farmer practice 120 kg N ha-1, optimized 96 kg N ha-1, and 84 kg N ha-1) at different growth stages. Crop ETC was calculated using the FAO CROPWAT 8.0 model from the last ten years (2003-2013) average climate data of the experimental station. The traditional farmer practice treatment was included as a control treatment with a flat sowing method compared with other sown-by-bed planter treatments. All treatments were provided with an equivalent amount of fertilizer at the basal dose. Before the first and second irrigation, top-dressing fertilizer was used in traditional farmers’ treatment at the third leaf and tillering stages. It was applied in optimized treatments before the first, second, and third irrigation at the third leaf, tillering and shooting stages, respectively, under the bed planting method. The deficit level of irrigation (80% of ETc) and optimized fertilizer (96 kg N ha-1) showed the optimum grain yield, nutrient use, and water use efficiencies, with 20% reduced irrigation water and fertilizer levels than traditional farming practice. The results suggest that bread wheat should be irrigated with 80% of ETC and applied 96 kg N ha-1 nitrophos fertilizer at the third leaf, tillering, and shooting stages to achieve higher grain yield and water and nutrient use efficiencies under bed planting.

While drinking water is known to create significant health risk in arsenic hazard areas, the role of exposure to arsenic through food intake is less well understood, including the impact of food trade. Using the best available datasets on crop production, irrigation, groundwater arsenic hazard, and international crop trade flows, we estimate that globally 17.2% of irrigated harvested area (or 45.2 million hectares) of 42 main crops are grown in arsenic hazard areas, contributing 19.7% of total irrigated crop production, or 418 million metric tons (MMT) per year of these crops by mass. Two-thirds of this area is dedicated to the major staple crops of rice, wheat, and maize (RWM) and produces 158 MMT per year of RWM, which is 8.0% of the total RWM production and 18% of irrigated production. More than 25% of RWM consumed in the South Asian countries of India, Pakistan, and Bangladesh, where both arsenic hazard and degree of groundwater irrigation are high, originate from arsenic hazard areas. Exposure to arsenic risk from crops also comes from international trade, with 10.6% of rice, 2.4% of wheat, and 4.1% of maize trade flows coming from production in hazard areas. Trade plays a critical role in redistributing risk, with the greatest exposure risk borne by countries with a high dependence on food imports, particularly in the Middle East and small island nations for which all arsenic risk in crops is imported. Intensifying climate variability and population growth may increase reliance on groundwater irrigation, including in arsenic hazard areas. Results show that RWM harvested area could increase by 54.1 million hectares (179% increase over current risk area), predominantly in South and Southeast Asia. This calls for the need to better understand the relative risk of arsenic exposure through food intake, considering the influence of growing trade and increased groundwater reliance for crop production.

Changes in land use and land cover (LULC) are the leading contributors to the decline and loss of ecosystem services in the world. The present study covered the Central Rift Valley lakes basin in Ethiopia, focusing on the valley floor and the East and West escarpments, to analyze changes in LULC and to estimate associated losses in ecosystem service values (ESVs). Covering both upstream and downstream areas in the basin, the study addressed major gaps in existing studies by connecting the sources and sinks of material (e.g., sediment and water) in source-to-lake systems. Additionally, the study facilitated the identification of critical areas for conserving natural resources and reversing the decline of associated ESVs in the Central Rift Valley. A post-classification comparison approach was used to detect LULC changes between 1973 and 2020 using four Landsat images from 1973, 1990, 2005 and 2020. The value transfer valuation method was used to estimate the changes in ESVs due to LULC changes. Among the seven major identified LULC classes, farmlands, settlements, and bare lands showed positive changes, while forestlands, grasslands, shrublands and waterbodies showed negative changes over the last 47 years. The expansion of farmlands, for example, has occurred at the expense of grasslands, forestlands and shrublands. The changes in LULC over a period of 47 years resulted in a total loss of US $62,110.4 × 106 in ESVs. The contributors to the overall loss of ESVs in decreasing order are provisioning services (US $33,795.1 × 106 ), cultural services (US $28,981.5 × 106 ) and regulating services (US $652.9 × 106 ). The results imply that addressing the degradation of land and water resources is crucial to reversing the loss of ecosystem services and achieving the national Sustainable Development Goals (SDGs) related to food and water security (SDGs 2 and 6) and life on land (SDG 15).

For Sri Lanka, as an agricultural country, a methodical drought monitoring mechanism, including spatial and temporal variations, may significantly contribute to its agricultural sustainability. Investigating long-term meteorological and agricultural drought occurrences in Sri Lanka and assessing drought hazard at the district level are the main objectives of the study. Standardized Precipitation Index (SPI), Rainfall Anomaly Index (RAI), and Vegetation Health Index (VHI) were used as drought indicators to investigate the spatial and temporal distribution of agriculture and meteorological droughts. Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) data from 1989 to 2019 was used to calculate SPI and RAI. MOD13A1 and MOD11A2 data from Moderate Resolution Imaging Spectroradiometer (MODIS) from 2001 to 2019, were used to generate the Vegetation Condition Index (VCI) and Temperature Condition Index (TCI). Agricultural drought monitoring was done using VHI and generated using the spatial integration of VCI and TCI. Thus, various spatial data analysis techniques were extensively employed for vector and raster data integration and analysis. A methodology has been developed for the drought declaration of the country using the VHI-derived drought area percentage. Accordingly, for a particular year, if the country-wide annual extreme and severe drought area percentage based on VHI drought classes is =30%, it can be declared as a drought year. Moreover, administrative districts of Sri Lanka were classified into four hazard classes, No drought, Low drought, Moderate drought, and High drought, using the natural-beak classification scheme for both agricultural and meteorological droughts. The findings of this study can be used effectively by the relevant decision-makers for drought risk management (DRM), resilience, sustainable agriculture, and policymaking.

Accurate information on irrigated areas’ spatial distribution and extent are crucial in enhancing agricultural water productivity, water resources management, and formulating strategic policies that enhance water and food security and ecologically sustainable development. However, data are typically limited for smallholder irrigated areas, which is key to achieving social equity and equal distribution of financial resources. This study addressed this gap by delineating disaggregated smallholder and commercial irrigated areas through the random forest algorithm, a non-parametric machine learning classifier. Location within or outside former apartheid “homelands” was taken as a proxy for smallholder, and commercial irrigation. Being in a medium rainfall area, the huge irrigation potential of the Inkomati-Usuthu Water Management Area (UWMA) is already well developed for commercial crop production outside former homelands. However, information about the spatial distribution and extent of irrigated areas within former homelands, which is largely informal, was missing. Therefore, we first classified cultivated lands in 2019 and 2020 as a baseline, from where the Normalised Difference Vegetation Index (NDVI) was used to distinguish irrigated from rainfed, focusing on the dry winter period when crops are predominately irrigated. The mapping accuracy of 84.9% improved the efficacy in defining the actual spatial extent of current irrigated areas at both smallholder and commercial spatial scales. The proportion of irrigated areas was high for both commercial (92.5%) and smallholder (96.2%) irrigation. Moreover, smallholder irrigation increased by over 19% between 2019 and 2020, compared to slightly over 7% in the commercial sector. Such information is critical for policy formulation regarding equitable and inclusive water allocation, irrigation expansion, land reform, and food and water security in smallholder farming systems.

Establishing worldwide sustainable and phosphorus efficient cropping systems is urgently needed because the supply of suitable phosphate rock is limited, and excess phosphorus in streams causes eutrophication. One of the impediments in the developing world for sustainable P practices is the lack of studies on P transport and its eventual disposition in the environment. One of these regions with few studies is the Ethiopian Highlands, with permeable volcanic soils. The objective was to establish baseline data on P watershed export in the (sub)humid highlands. Two contrasting watersheds were selected near Lake Tana. For 2 years, stream discharge and sediment, total P, dissolved P, and bioavailable particulate P concentrations were determined at the watershed outlet. The first watershed is the 57 km2 Dangishta, with lava intrusion dikes, forcing subsurface flow through faults to the surface and preventing gully formation. Subsurface flow was half of the 1745 mm annual precipitation, and surface runoff and erosion were minimal. The second watershed is the 9 km2 Robit Bata with 1,420 mm precipitation. The banks of several river banks were slumping. The upper part of the watershed generates saturation excess runoff. A hillslope aquifer in the lower part provided interflow. The average sediment concentrations of 10.5 g L-1 in the stream in Robit Bata (11 times that in Dangishta) reflected the sediments from banks slipping in the stream. The hydrology and the soil loss directly affected the phosphorus export. In Dangishta, the total P concentration averaged 0.5 mg L-1 at the outlet. In Robit Bata, the average total P concentration was 2 mg L-1 . The bioavailable particulate P concentration was only twice the concentration in the runoff water. The low phosphorus content of the subsoil slipping in Robit Bata moderated biologically available particulate P at the outlet. Average dissolved P concentrations for both watersheds were around 0.1 mg L-1 in the low range found in temperate climates. It reflects the difference in length of time that phosphorus fertilizers have been applied. Our research concludes that commonly implemented practices such as strengthening river banks and stabilizing gully might not lead to improved water quality in Lake Tana.

Hydropower development in the lower Mekong Basin is being rapidly developed. Taking the Pak Beng hydropower project in Laos as a case study, this paper looks at participation and politics in transboundary hydropower development, how the latter is revealed by multiple, parallel institutional architectures in hydropower decision-making across scales, and its implications for transboundary environmental governance. We look at the institutional disjuncture in hydropower decision-making, how it is (re)produced by powerful, albeit conflicting narratives at respectively national and transboundary levels, power relations shaping these narratives, and how these translate into local communityapos;s limited ability to convey their voices and represent their development needs. Conceptually, the paper sheds light on the underlying politics in transboundary environmental governance by bringing to light the structural factors that prevent participation, including how these factors are justified, sustained and to a certain extent reproduced as an integral part of legal, policy, and institutional landscapes that govern hydropower decision-making across scales (e.g., local to transboundary).

Study region: Central Rift Valley Lakes sub-basin, Ethiopia. Study focus: The competition for water is rapidly increasing in Central Rift Valley lakes sub-basin due to the combined effect of various water resources developments. However, the impacts of recent and future water resources development pathways on the water balance of the three interconnected lakes (i.e. Lake Ziway, Langano and Abiyata) are unknown. The Water Evaluation And Planning (WEAP) model was used to assess the development impacts on water resources of the interconnected lakes. We considered three development pathways that are, recent (2009–2018), short-term (2019–2028) and long-term development (2029–2038). Lake Ziway water inflows from six catchments were estimated using the Hydrologiska Byrns Vattenbalansavdelning (HBV) rainfall-runoff model. Crop water requirements for irrigation schemes were estimated by the CROPWAT model. New hydrological insights for the region: WEAP simulations show a total water demand of 102.3 Mm3 under the recent development pathway that increases by 46% and 118% for short-term and long-term development pathways, respectively. This will notably affect the water balance of the interconnected lakes and cause an unmet water demand of 47.9 Mm3 for the long-term (2028–2038). For Lake Ziway and Abiyata, water levels will decrease substantially to cause water scarcity in the long-term, and developments in Lake Ziway will significantly affect water storage in Lake Abiyata storages in Lake Abiyata. Overall, future developments will threaten the water resource of the interconnected lake system.

Improving water security is critical to delivering the best outcomes for development. In Ethiopia, the upper Awash sub-basin supports expanding urban and industrial areas, with increasing water demands. Studies have preferentially focused either on surface water hydrology or on groundwater characterization. However, novel tools are required to support the conjunctive use of surface and groundwater for competing users under potential climate change impacts. In this paper, we present research based on a WEAPMODFLOW link configured for four catchments in the upper Awash sub-basin (Akaki, Melka Kunture, Mojo, and Koka). The Akaki catchment supplies water for Addis Ababa city. Unlike most surface water hydrological models, both supply (surface water and groundwater) and demand (domestic, industrial, and livestock) are modeled. The tool was used to evaluate the impacts of population growth, leakage, expansion of surface and groundwater supply schemes, and climate change scenarios up to the year 2030. Considering the high population growth rate scenario for Addis Ababa city, the unmet domestic water demand may increase to 760 MCM in 2030. Water leakage through poor water supply distribution networks contributed about 23% of the unmet water demand. Though not significant compared with population and water loss stresses, climate change also affect the supply demand condition in the basin. Planning for more groundwater abstraction without considering additional surface water reservoir schemes will noticeably impact the groundwater resource, with groundwater levels projected to decline by more than 20 m. Even more groundwater level decline is observed In the Akaki catchment, where Addis Ababa city is located. Conjunctive use of surface and groundwater not only boosts the supply demand situation in the basin but will lift off some of the stresses from the groundwater resources. Even under the likely increase in temperature and low precipitation climate scenarios, the conjunctive use resulted in a significant increase in domestic water demand coverage from 26% for the reference condition to 90% in 2030, with minimum effect on the groundwater resources. To improve water security conditions through sustainable utilization of both surface and groundwater resources, policy responses need to consider surface and groundwater conjunctive use. Minimizing water leakage should also be given the highest priority.

Study region: Awash River Basin, Ethiopia Study focus: Many river basins in sub-Saharan Africa have become vulnerable due to the impact from climate change, weak governance and high levels of poverty. One of the primary concerns is the elevated salinity and the degradation of water quality in the Awash River. Located in the Great Rift Valley in Ethiopia, the Awash River has unique hydrochemistry due to water-rock interactions. However, in recent years, increasing anthropogenic activities including the discharge from saline Lake Beseka into the Awash River has caused some concern. This study used an Integrated Catchment Model to simulate chloride concentration in the Awash River Basin by taking both natural and anthropogenic sources of salinity into consideration. Future scenarios of climate change and Lake Beseka discharge were examined to assess the impact to the river water quality. New hydrologic insights: Results show that Lake Beseka has made significant contribution to the rise of the salinity in the Awash River. If the trend of human interference (e.g. increased irrigation and unregulated water transfer) continues, the river downstream of Lake Beseka could see Cl increases up to 200 % in the near future (2006–2030). The modeling results are essential for generating long term plans for proper utilization of water resources especially in the region where the resources and the economic capacity to meet the water demand is lacking.

Solar-powered irrigation has expanded in India at an unprecedented pace—the number of solar irrigation pumps—from less than 4,000 in 2012 to more than 2,50,000 by 2019. It has been argued that besides giving farmers an additional and reliable source of income, grid-connected SIPs also incentivise efficient energy and water use—critical for sustaining groundwater irrigation. The Surya Raitha scheme was the country’s first, state-driven initiative for solarisation of agriculture feeders by replacing subsidy-guzzling, inefficient electric pumps with energy-efficient, net-metered SIPs. An early appraisal of Surya Raitha lauded the scheme as a smart initiative and argued that it could set an example for promoting solar power as a remunerative crop. However, the scheme was eventually executed as a single feeder pilot with some design changes in Nalahalli panchayat from 2015–18. The authors visited the pilot in 2017–18 and 2018–19 to assess if it had delivered the promises of Surya Raitha scheme. The results are a mixed bag and offer important lessons for implementation and scaling out of component C of the Government of India’s Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan policy.

Sustainable management of municipal solid waste (MSW) is a critical issue around the world, especially in South Asia where waste generation is expected to double by 2050. Closing the food-nutrient cycle through composting biodegradable MSW has the potential to meet human needs, including sanitation and food security, while protecting the environment. We use an interdisciplinary case study approach including systems thinking to assess Sri Lanka’s national MSW composting system, which primarily receives residential and commercial food waste. We embed quantitative compost quality analysis and interviews at 20 composting facilities within a broader qualitative assessment informed by ~60 stakeholders in total. This approach yields insights on how institutional, economic, social, and biophysical aspects of the system are interrelated, and how challenges and solutions can create undesirable and desirable cascading effects, respectively. Such dynamics can create risks of composting facility failure and unintended consequences, diminishing the chances of achieving a sustainable circular food–nutrient system. Compost quality, which was variable, plays a pivotal role within the system—a function of program design and implementation, as well as a determinant of value capture in a circular economy. We make several recommendations to inform future efforts to sustainably manage biodegradable MSW using composting, drawing on our case study of Sri Lanka and prior case studies from other nations. Key among these is the need for increased emphasis on compost product quality and markets in policy and program design and implementation. Targeted measures are needed to improve waste separation, boost compost quality, effectively use compost standards, encourage compost market development, ringfence the revenues generated at municipal compost plants, and identify efficient modes of compost distribution. Such measures require adequate space and infrastructure for composting, resource investment, local expertise to guide effective system management, strong links with the agriculture sector, and continued political support.

Most of the part of India is already under water-stressed condition. In this regard, the continuous monitoring of the water levels (WL) and storage capacity of reservoirs, lakes, and rivers is very important for the estimation and utilization of water resources effectively. The long term ground observed WL of many of the water bodies is not easily available, which may be very critical for proper water resources management. Satellite radar altimetry is the remote sensing technique, which is being used to study sea surface height for the last three decades. The advancement in radar technology with time has provided the opportunity to exploit the technique to retrieve the WL of inland water bodies. In the current study, an attempt has been made to generate long term time series on WL of around 29 geometrically complicated inland water bodies in India. These water bodies are mainly large reservoirs namely Ban Sagar, Balimela, Bargi, Bhakra, Gandhi Sagar, Hasdeo, Indravati, Jalaput, Kadana, Kolab, Mahi Bajaj, Maithon, Massanjore, Pong, Ramganga, Ranapratap Sagar, Rihand, Sardar Sarovar, Shivaji Sagar, Tilaiya, Ujjani, and Ukai. The WL of these water bodies was retrieved for around two decades using the European Remote-Sensing Satellite – 2 (ERS-2), ENVISAT Radar Altimeter – 2 (ENVISAT RA-2), and Saral-AltiKa altimeters data through Ice-1 retracking algorithm. Further, an attempt has also been made to estimate the WL of gauged/ungauged lakes namely Mansarovar, Pangong, Chilika, Bhopal, and Rann of Kutch over which Saral-AltiKa pass was there. As after July 2016, the SARAL-AltiKa is operating in the drifting orbit, systematic repeated observation of WL data of all reservoirs was not possible. The data of drifted tracks of Saral-AltiKa were tested for WL estimation of Ban Sagar reservoir. As the ERS-2, ENVISAT RA-2 and Saral-AltiKa all were having almost the same passing tracks, a long term WL series of these lakes could be generated from 1997 to 2016. However, at present only Sentinel – 3 is in orbit, the continuous altimeter based WL monitoring of some of these reservoirs (Gandhi Sagar, Nathsagar, Ranapratap, Ujjani, and Ukai) was attempted through Sentinel-3A satellite data from 2016 to 2018. The accuracy of the retrieved WL was than validated against the observed WL. In most of the reservoirs, a systematic bias was found due to the different characteristics and geoid height of each reservoir. The coefficient of determination, R2 , value for a majority of reser voirs was as good as 0.9. In the case of ERS-2, the values of R2 varied for 0.44–0.97 with root mean square error (RMSE) in the range of 0.63–2.72 m. These statistics improved with the ENVISAT RA-2 data analysis, the R2 value reached more than 0.90 for around 11 reservoirs. The highest, 0.99, for Hasdeo and Shivaji Sagar Reservoirs with RMSE of 0.44 and 0.56, respectively. Further, the accuracy improved with the analysis of Saral-AltiKa data. The R2 was always more than 0.9 for each reservoir a

The countries around the world are dealing with air quality issues for decades due to their mode of production and energy usages. The outbreak of COVID-19 as a pandemic and consequent global economic shutdown, for the first time, provided a base for the real-time experiment of the effect of reduced emissions across the globe in abetting the air pollution issue. The present study dealt with the changes in Aerosol Optical Depth (AOD), a marker of air pollution, because of global economic shutdown due to the coronavirus pandemic. The study considered the countries in south and south-east Asia (SSEA), Europe and the USA for their extended period of lockdown due to coronavirus pandemic. Daily Aerosol Optical Depth (AOD) from Moderate-resolution imaging spectroradiometer (MODIS) and tropospheric column density of NO2 and SO2 from Ozone monitoring instrument (OMI) sensors, including meteorological data such as wind speed (WS) and relative humidity (RH) were analyzed during the pre-lockdown (2017–2019) and lockdown periods (2020). The average AOD, NO2 and SO2 during the lockdown period were statistically compared with their pre-lockdown average using Wilcoxon-signed-paired-rank test. The accuracy of the MODIS-derived AOD, including the changing pattern of AOD due to lockdown was estimated using AERONET data. The weekly anomaly of AOD, NO2 and SO2 was used for analyzing the space-time variation of aerosol load as restrictions were imposed by the concerned countries at the different points of time. Additionally, a random forest-based regression (RF) model was used to examine the effects of meteorological and emission parameters on the spatial variation of AOD. A significant reduction of AOD (- 20%) was obtained for majority of the areas in SSEA, Europe and USA during the lockdown period. Yet, the clusters of increased AOD (30–60%) was obtained in the south-east part of SSEA, the western part of Europe and US regions. NO2 reductions were measured up to 20–40%, while SO2 emission increased up to 30% for a majority of areas in these regions. A notable space-time variation was observed in weekly anomaly. We found the evidence of the formation of new particles for causing high AOD under high RH and low WS, aided by the downward vertical wind flow. The RF model showed a distinguishable relative importance of emission and meteorological factors among these regions to account for the spatial variability of AOD. Our findings suggest that the continued lockdown might provide a temporary solution to air pollution; however, to combat persistent air quality issues, it needs switching over to the cleaner mode of production and energy. The findings of this study, thus, advocated for alternative energy policy at the global scale.

The terrestrial biosphere plays an active role in governing the climate system by regulating carbon exchange between the land and the atmosphere. Analysis of vegetation biophysical parameters and gross primary production (GPP) makes it convenient to monitor vegetationapos;s health. A light use efficiency (LUE) model was employed to estimate daily GPP from satellite-driven data and environmental factors. The LUE model is driven by four major variables, namely normalized difference vegetation index (NDVI), photosynthetically active radiation (PAR), air temperature, and moisture for which both satellite-based and ERA5-Land data were applied. In this study, the vegetation health of Dibru Saikhowa National Park (DSNP) in Assam has been analyzed through vegetation biophysical and biochemical parameters (i.e., NDVI, EVI, LAI, and chlorophyll content) using Sentinel-2 data. Leaf area index (LAI) varied between 1 and 5.2, with healthy forests depicted LAI more than 2.5. Daily GPP was estimated for January (winter) and August (monsoon) 2019 for tropical evergreen and deciduous forest types. A comparative analysis of GPP for two seasons has been performed. In January, GPP was found to be 3.6 gC m-2 day-1, while in August, GPP was 5 gC m-2 day-1. The outcome of this study may be constructive to forest planners to manage the National Park so that net carbon sink may be attained in DSNP.

Remote sensing-based observation provides an opportunity to study the spatiotemporal variations of plant phenology across the landscapes. This study aims to examine the phenological variations of different types of sal (Shorea robusta) forests in India and also to explore the relationship between phenology metrics and climatic parameters. Sal, one of the main timber-producing species of India, can be categorized into dry, moist, and very moist sal. The phenological metrics of different types of sal forests were extracted from Moderate Resolution Imaging Spectroradiometer (MODIS)-derived Enhanced Vegetation Index (EVI) time series data (2002–2015). During the study period, the average start of season (SOS) was found to be 16 May, 17 July, and 29 June for very moist, moist, and dry sal forests, respectively. The spatial distribution of mean SOS was mapped as well as the impact of climatic variables (temperature and rainfall) on SOS was investigated during the study period. In relation to the rainfall, values of the coefficient of determination (R2) for very moist, moist, and dry sal forests were 0.69, 0.68, and 0.76, respectively. However, with temperature, R2 values were found higher (R2 = 0.97, 0.81, and 0.97 for very moist, moist, and dry sal, respectively). The present study concluded that MODIS EVI is well capable of capturing the phenological metrics of different types of sal forests across different biogeographic provinces of India. SOS and length of season (LOS) were found to be the key phenology metrics to distinguish the different types of sal forests in India and temperature has a greater influence on SOS than rainfall in sal forests of India.

Study region: The Lake Tana sub-basin, upper Blue Nile, Ethiopia. Study focus: The Lake Tana sub-basin is one of the agricultural growth corridors for Ethiopia’s ambitious plan to expand irrigation. Despite the booming irrigation activities in the sub-basin, limited information exists on the rate of irrigation expansion and its impact on the water balance of the sub-basin. This study collected and organized smallholder irrigation data in the subbasin to identify the actual irrigated area, the abstracted irrigation water, and its implications on seasonal water availability. The area under small-scale irrigation was estimated through data obtained from ’woredas’ (districts) databases. Crop patterns were obtained through field surveys. Irrigation water abstracted at daily timescale was measured. New hydrological insights for the Region: In the sub-basin, 38,694 ha was under small-scale irrigation in 2020/21. Surface water is the dominant water source, and it supplies about 80% of irrigation withdrawal. Water abstraction for small-scale irrigation is about 430 MCM per dry season (~50% of dry season flow). The eastern side of the sub-basin faces water shortages as the dry season flow is not sufficient for irrigation. With the prospects of more irrigation expansion, small-scale irrigation water withdrawals pose concerns of water scarcity at local level and to the water balance of the sub-basin. Hence, there is urgent need for adaptive management of the small-scale irrigation effect on the sub-basin’s hydrology.

Maintaining healthy, productive ecosystems in the face of pervasive and accelerating human impacts including climate change requires globally coordinated and sustained observations of marine biodiversity. Global coordination is predicated on an understanding of the scope and capacity of existing monitoring programs, and the extent to which they use standardized, interoperable practices for data management. Global coordination also requires identification of gaps in spatial and ecosystem coverage, and how these gaps correspond to management priorities and information needs. We undertook such an assessment by conducting an audit and gap analysis from global databases and structured surveys of experts. Of 371 survey respondents, 203 active, long-term (gt;5 years) observing programs systematically sampled marine life. These programs spanned about 7% of the ocean surface area, mostly concentrated in coastal regions of the United States, Canada, Europe, and Australia. Seagrasses, mangroves, hard corals, and macroalgae were sampled in 6% of the entire global coastal zone. Two-thirds of all observing programs offered accessible data, but methods and conditions for access were highly variable. Our assessment indicates that the global observing system is largely uncoordinated which results in a failure to deliver critical information required for informed decision-making such as, status and trends, for the conservation and sustainability of marine ecosystems and provision of ecosystem services. Based on our study, we suggest four key steps that can increase the sustainability, connectivity and spatial coverage of biological Essential Ocean Variables in the global ocean: (1) sustaining existing observing programs and encouraging coordination among these; (2) continuing to strive for data strategies that follow FAIR principles (findable, accessible, interoperable, and reusable); (3) utilizing existing ocean observing platforms and enhancing support to expand observing along coasts of developing countries, in deep ocean basins, and near the poles; and (4) targeting capacity building efforts. Following these suggestions could help create a coordinated marine biodiversity observing system enabling ecological forecasting and better planning for a sustainable use of ocean resources.

The Kabul River Basin (KRB) in Afghanistan is densely inhabited and heterogenic. The basin’s water resources are limited, and climate change is anticipated to worsen this problem. Unfortunately, there is a scarcity of data to measure the impacts of climate change on the KRB’s current water resources. The objective of the current study is to introduce a methodology that couples remote sensing and the Soil and Water Assessment Tool (SWAT) for simulating the impact of climate change on the existing water resources of the KRB. Most of the biophysical parameters required for the SWAT model were derived from remote sensing-based algorithms. The SUFI-2 technique was used for calibrating and validating the SWAT model with streamflow data. The stream-gauge stations for monitoring the streamflow are not only sparse, but the streamflow data are also scarce and limited. Therefore, we selected only the stations that are properly being monitored. During the calibration period, the coefficient of determination (R2) and Nash–Sutcliffe Efficiency (NSE) were 0.75–0.86 and 0.62–0.81, respectively. During the validation period (2011–2013), the NSE and R2 values were 0.52–0.73 and 0.65–0.86, respectively. The validated SWAT model was then used to evaluate the potential impacts of climate change on streamflow. Regional Climate Model (RegCM4-4) was used to extract the data for the climate change scenarios (RCP 4.5 and 8.5) from the CORDEX domain. The results show that streamflow in most tributaries of the KRB would decrease by a maximum of 5% and 8.5% under the RCP 4.5 and 8.5 scenarios, respectively. However, streamflow for the Nawabad tributary would increase by 2.4% and 3.3% under the RCP 4.5 and 8.5 scenarios, respectively. To mitigate the impact of climate change on reduced/increased surface water availability, the SWAT model, when combined with remote sensing data, can be an effective tool to support the sustainable management and strategic planning of water resources. Furthermore, the methodological approach used in this study can be applied in any of the data-scarce regions around the world.

Rice is the most important food crop. With the largest rain-fed lowland area in the world, flooding is considered as the most important abiotic stress to rice production in India. With climate change, it is expected that the frequency and severity of the floods will increase over the years. These changes will have a severe impact on the rain-fed agriculture production and livelihoods of millions of farmers in the flood affected region. There are numerous flood risk adaptation and mitigation options available for rain-fed agriculture in India. Procuring, maintaining and distributing the newly developed submergence-tolerant rice variety called Swarna-Sub1 could play an important role in minimizing the effect of flood on rice production. This paper assesses the quantity and cost of a flood-tolerant rice seed variety- Swarna-Sub1, that would be required during the main cropping season of rice i.e., kharif at a district level for 17 major Indian states. The need for SS1 seeds for rice production was assessed by developing a geospatial framework using remote sensing to map the suitability of SS1, to help stakeholders prepare better in managing the flood risks. Results indicate that districts of Bihar, West Bengal and Uttar Pradesh will require the highest amount of SS1 seeds for flood adaptation strategies. The total estimated seed requirement for these 17 states would cost around 370 crores INR, less than 0.01 percent of Indian central government’s budget allocation for agriculture sector.

Little is known about the occurrence of emerging pollutants (EPs) in waters in the Middle East and North Africa (MENA) region despite the extensive use of low-quality water there. Available data dealing with the sources, occurrence and removal of EPs within the MENA region in different categories of water is collected, presented and analyzed in this literature review. According to the collected database, the occurrence and removal efficiency of EPs in the water matrix in the MENA region is available, respectively, for 13 and six countries of the 18 in total; no available data is registered for the rest. Altogether, 290 EPs have been observed in different water matrices across the MENA countries, stemming mainly from industrial effluents, agricultural practices, and discharge or reuse of treated wastewater (TWW). Pharmaceutical compounds figure among the most frequently reported compounds in wastewater, TWW, surface water, and drinking water. Nevertheless, pesticides are the most frequently detected pollutants in groundwater. Worryingly, 57 cases of EPs have been reported in different fresh and drinking waters, exceeding World Health Organization (WHO) and European Commission (EC) thresholds. Overall, pharmaceuticals, organic compounds, and pesticides are the most concerning EP groups. The review revealed the ineffectiveness of treatment processes used in the region to remove EPs. Negative removals of some EPs such as carbamazepine, erythromycin, and sulfamethoxazole were recorded, suggesting their possible accumulation or release during treatment. This underlines the need to set in place and strengthen control measures, treatment procedures, standards, and policies for such pollutants in the region.

The COVID-19 pandemic has significantly changed the context of global migration. From a migration perspective, the pandemic is a source of insecurities that challenge migrants, their livelihoods and migration governance. Meanwhile, curtailment in movement has led to economic decline affecting labour markets. For migrant origin and hosting countries, this poses multidimensional development challenges. Analysis from March to August 2020 of China, Ethiopia, Kyrgyzstan, Moldova, Morocco, Nepal and Thailand highlights the varying ways in which they are all severely affected by the disruptions in migration, suggesting a potentially emerging complex situation in migration patterns and pathways. The disruptions in migration and remittances have had a profound impact on migrants and migrant-sending households. The uncertainty of migration returning to pre-pandemic levels and the potential of lasting consequences on migrants and migration patterns and pathways, suggests a future of greater risk and exploitation, and a wider gap between formal and informal migration. This paper calls for greater mobility cooperation between countries and suggests strengthening mobility migration frameworks and policies for safer migration and for the rights of migrants.

The purpose of this study is to investigate the preferences of people in the Bale Eco-Region (BER) for better ecosystem services and to calculate their mean Willingness to Pay (WTP) for selected attributes of conservation practices to maintain watershedapos;s ecosystem functions, using a choice modeling approach. Results from reforestation attributes revealed that the average WTP for reforestation characteristics were 3,053 ($145.38), 2,516 ($119.83), and 1,827 ($87) Ethiopian Birr (ETB)/year for higher, medium, and low impact improvement scenarios respectively, to midland communities. Lowland respondentsapos; mean WTP for exclosure attributes were estimated at 882 ($42), 1,558 ($74.19), and 2,383 ($113) ETB yearly for low, medium, and high impact improvement scenarios respectively. This indicates that respondents from both lowland and midland communities are willing to spend a substantial amount of resource and time (measured in terms of money) on to improve ES in the BER. The study provides valuable input to carry out a cost-benefit analysis of possible interventions conserving natural resources in the BER. Moreover, using this study was an important step for initiating the process of Payment for Ecosystem Services in the BER where local communities, in Ethiopia and beyond could contribute to rehabilitating Ecosystem Services.

New dams impact downstream ecosystems and water infrastructure; without cooperative and adaptive management, negative impacts can manifest. In large complex transboundary river basins without well codified operating rules and extensive historical data, it can be difficult to assess the benefits of cooperating, in particular in relation to new dams. This constitutes a barrier to harmonious development of river basins and could contribute to water conflict. This study proposes a generalised framework to assess the benefits of cooperation on the management of new dams in water resource systems that do not have formal sharing arrangements. Benefits are estimated via multi-criteria comparison of historical reservoir operations (usually relatively uncooperative) vs. adopting new cooperative rules which would achieve the best results for riparian countries as evaluated by a water resources simulator and its performance metrics. The approach is applied to the Pwalugu Multipurpose Dam (PMD), which is being built in Ghana in the Volta river basin. The PMD could impact downstream ecosystems and infrastructure in Ghana and could itself be impacted by how the existing upstream Bagre Dam is managed in Burkina Faso. Results show that with cooperation Ghana and Burkina Faso could both increase energy production although some ecosystem services loss would need to be mitigated. The study confirms that cooperative rules achieve higher overall benefits compared to seeking benefits only for individual dams or countries.

Study Region: The Ethiopian Rift Valley Lakes basin is found in the main Ethiopian Rift Valley system. Study Focus: Understanding the hydrological impact of El Nio-Southern Oscillation (ENSO) is of a paramount importance for society since it substantially affects the environmental and socio-economic conditions. The relation between ENSO indicators (SOI, MEI and Nio3.4) and streamflow magnitude was statistically evaluated with partial correlation, cross correlation, extreme streamflow indices and streamflow deficits to provide empirical evidence on how ENSO phases (La Nia and El Nio) affect streamflow variability. Trends of streamflow and ENSO indicators were tested using the non-parametric Mann-Kendall test. New Hydrological Insights for the Region: Our findings indicate that the partial correlation between the catchment area and ENSO effect on streamflow were not statistically significant at p lt; 0.05 after removing the south-north gradient. The direction of the ENSO effect is spatially inconsistent since El Nio (La Nia) causes positive deviation in some catchments and negative deviation for other catchments. Though statistically insignificant, reduced flow is detected for many catchments during El Nio years. For most catchment, the extreme high flow has a larger magnitude during La Nia than El Nio whereas the extreme low flow has a larger magnitude during El Nio than La Nia years. Overall, the relationship between ENSO and streamflow of the study area is found spatially inconsistent and statistically insignificant for most catchments.

Lake Ziway is providing water for a wide variety of sectors in the central rift valley of Ethiopia. However, there is a lack of systematic study that informs the effect of water abstraction on the lake water balance. In the present study, we conducted a Water Abstraction Survey (WAS) to estimate actual water withdrawal from the lake and developed a water balance model of the lake to evaluate the associated impact on the lake water storage and outflow for three development plans. The mean error and root mean square error of the simulated lake water level as compared with observed counterparts were estimated as 0.1 and 0.2 m, respectively, which is smaller than the range of the observed fluctuation of the lake water level under natural condition. Our findings indicate that the actual storage and outflow of Lake Ziway are significantly impacted by the existing water withdrawal. When the future development plans are fully implemented, the annual amount of irrigation and domestic water withdrawal from the lake will reach 95 Mm3 . This will cause the lake water level to drop by 0.94 m, which translates to 38 km2 reductions in the lake surface area. Consequently, the lake will lose 26.5% of its actual storage volume when the future development plan (2029–2038) is implemented as compared to the observed storage between 1986 and 2000. Hence, the current impact of water resources development around the lake is substantially large and will exacerbate in the future. This indicates the need for urgent actions to monitor and manage water abstraction from the lake.

The frequency and intensity of extreme climate events such as heavy rainfall and droughts are expected to increase with climate change and are predicted to severely affect the agriculture sector. However, drought vulnerability of rural communities in sub-Saharan Africa is not well documented, despite these communities being composed of mainly smallholder farmers whose livelihoods depend on rainfed agriculture. In this study, we evaluated the vulnerability of a rural community in Ethiopia to drought using both primary and secondary data. The primary data was generated from a household survey, whereas the secondary data was obtained from the National Meteorology Agency of Ethiopia and Climate Hazards Group Infrared Precipitation (CHIRP) product. We decomposed vulnerability in to three components which are exposure, sensitivity, and adaptive capacity to drought based on indices derived from the primary and secondary data. Results show that the average score for exposure, sensitivity, and adaptive capacity is nearly equal. High seasonal water variability coupled with severe, frequent, and long drought status increases exposure to drought in the study area. The main factor which affects sensitivity to drought in this community is the land cover. For adaptive capacity, the social capital of the community is low while their physical capital is high. The overall estimated drought vulnerability shows that the community is moderately vulnerable. The community’s exposure and sensitivity analyses show the need to increase the amount of moisture stored within the soil with the adoption of appropriate soil and water conservation techniques. Results also show that the head of the household’s educational level, the number of livestock owned, and annual income affect the community’s adaptive capacity.

The hydrological impact of many expensive investments on watershed interventions remains unquantified due to lack of time series data. In this study, remote sensing imagery is utilized to quantify and detect vegetation cover change in Magera micro-watershed, Ethiopia, where sustainable land management interventions have been implemented. Normalized difference vegetation index (NDVI) values were retrieved for the period 2010 to 2019, which encompasses before, during and after the interventions. Mann-Kendal trend test was used to detect temporal trends in the monthly NDVI values. In addition, multiple change-point analyses were carried out using Pettitt’s, Buishand’s and Standard Normal Homogeneity (SNH) tests to detect any abrupt changes due to the watershed interventions. The possible influence of rainfall on changes in vegetation cover was investigated. A significant increasing trend (from 1.5% to 33%) was detected for dense vegetation at the expense of a significant reduction in bare land from 40.9% to 0.6% over the analysis period. An abrupt change in vegetation cover was detected in 2015 in response to the interventions. A weak and decreasing correlation was obtained between monthly rainfall magnitude and NDVI values, which indicates that the increase in vegetation cover is not from rainfall influences. The study shows that the sustainable land management has an overall positive impact on the study area. The findings of this research support the applicability of remote sensing approaches to provide useful information on the impacts of watershed intervention investments.