IWMI Journal Articles

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Implications of changes in water stress and precipitation extremes for cocoa production in Côte D’Ivoire and Ghana
(Journal Article, 2025-04) Obahoundje, Salomon; Akpoti, Komlavi; Zwart, Sander J.; Tilahun, Seifu A.; Cofie, Olufunke
Climate change induces high variability in drought patterns and extreme precipitation indices in rainfed cocoa farming, impacting cocoa production. This study evaluated water stress, meteorological and agricultural drought conditions, and critical extreme precipitation indices in the world's two largest cocoa-producing nations from 1981 to 2022. The results revealed a significant reduction in total annual precipitation (PRCPTOT), in the last three decades, with the greatest decline in the 1991–2000 and 2011–2022 periods. Ghana experienced the most significant reduction up to 15% (200mm/year) in the last decade, attributed to a substantial decrease in wet days number (RR1) up to 25days per year, a reduction in maximum consecutive wet days (CWD) up to 6days per year, and an increase in maximum consecutive dry days (CDD) up to 15days per year. Moreover, there was a notable decline in the Simple Daily Intensity Index (SDII), with reductions of up to 4mm/day in certain areas, contributing to increased drought frequency, severity, and duration. In the most recent decade (2011–2022), particularly during the extremely dry years of 2013 and 2015, cocoa-growing regions in Ghana (GHA) and eastern Côte d'Ivoire (CIV) experienced prolonged agricultural drought expressed by soil moisture deficit, typically extending from May to September. Additionally, large portions of central and eastern Ghana, as well as northeastern Côte d'Ivoire experienced sustained water stress, with over three consecutive months of total monthly precipitation falling below 100mm, negatively impacting cocoa productivity. The decrease in the yield in the range of 2.5% to 37% was noted in the dry years and the following years, varying according to the country depending on the severity of the drought. Sensitivity analysis highlights cocoa yield's responsiveness to drought and water stress, particularly in specific years when water stress occurred, such as 1984,1985, 1989, 1995, 1999, 2000, and 2008. Considering the observed trends in precipitation patterns and their impact on cocoa production, it is crucial to acknowledge the inherent uncertainty of future precipitation patterns due to climate change. To address this challenge effectively, our study underscores the importance of identifying and closely monitoring regions currently facing water stress, as determined by precipitation and drought indicators. Over the analysed period (1981–2022), we have noted shifts in the distribution of water-stressed areas, highlighting the dynamic nature of this issue. Consequently, we advocate for a targeted approach to implement cocoa supplementary irrigation in consistently water-stressed regions.
Bridging scales and borders on water availability and use in the transboundary Volta River Basin: a water accounting approach
(Journal Article, 2025-06) Owusu, Afua; Akpoti, Komlavi; Leh, Mansoor; Perera, Tharindu; Madushanka, Lahiru; Mekonnen, Kirubel; Tinonetsana, Primrose; Tayebi, N.; Escalera-Rodriguez, A. C.; Fofana, R.; Velpuri, Naga Manohar
Study region: Volta Basin Study focus: Water management in transboundary basins is challenging due to the interaction of natural and human factors across political borders. The Volta River Basin, shared by six West African countries, exemplifies this with variable water distribution and socio-economic pressures. This study presents a comprehensive multi-scale water accounting of the basin, assessing water flows and usage at basin-wide, sub-basin, and riparian country scales from 2003 to 2021. New hydrological insights for the region: The results reveal average basin closure is 55 % with room for additional water allocation given that utilizable water in the basin is 20 km3 /year and almost 25 % of the basin’s exploitable water is non-recoverable water (wastewater). Sub-basin analysis showed variations in average annual rainfall, ranging from 940 to 1250 mm/year, and groundwater recharge rates (18–64 mm/year), with southern sub-basins receiving more rainfall and having higher recharge rates. Similarly at the country level, variability in rainfall (630–1220 mm/ year) and recharge rates (20–280 mm/year) were noted, with downstream countries benefiting from higher rainfall and significant inflows from upstream countries. The analysis underscored the interconnectedness of water use across the basin’s riparian countries. The study’s findings give insights for the strategic management of water resources and the crucial need for enhanced cooperation among riparian countries to address shared challenges and opportunities in the Volta Basin.
Water and aquatic foods in revised principles of agroecology can accelerate food systems transformation
(Journal Article, 2025-04) Freed, S.; Lo, M. G. Y.; McCartney, Matthew; Allison, E. H.; Smith, Douglas Mark; Joffre, O. M.; Sinclair, F.
The interaction between climate change and agricultural intensification contributes to biodiversity loss, while widespread degradation of land and water undermine food system productivity. Agroecological principles aim to guide food systems transformation but rarely refer to water or aquatic foods, which are critical elements of nutritious, sustainable and equitable food systems. Here we examine the principles and frameworks presented in agroecological literature and suggest rephrasing of six of the principles to incorporate water, aquatic foods and land- to seascapes. We recommend three cross-sectoral actions that leverage aquatic features in agroecosystems to facilitate more effective transition pathways towards sustainable food systems.
Does social transformation drive out-migration? Perceptions and changes
(Journal Article, 2025-04) Setrana, M. B.; Teye, J. K.; Nikoi, E. G. A.; Asiedu, E.; Osei-Amponsah, Charity; Yakass, E.
Migration and social transformation are major drivers of socio-economic development. Yet, the linkages between social transformation and migration in Ghana are poorly understood. This article seeks to shed light on how social transformation affects or is affected by migration, using mixed methods with transformationalist and social change theoretical lenses. At the same time, there have been retrogressive transformations in the economic conditions, technology and demography have improved and increased, respectively, and political and cultural factors have remained relatively the same over the past decade. Although there is a perceived bi-directional relationship between social transformation and migration, social transformation exerts greater influence on migration than migration has on social transformation except for higher educational attainment and improved household income. Therefore, the relationship between social transformation and migration is not balanced in our study area as the former influences more than the latter.
On the feasibility of an agricultural revolution: Sri Lanka’s ban of chemical fertilizers in 2021
(Journal Article, 2025-04) Drechsel, Pay; Madhuwanthi, Piumi; Nisansala, Duleesha; Ramamoorthi, Dushiya; Bandara, Thilini
Sri Lanka Government’s ambitious decision to ban synthetic agrochemicals, including chemical fertilizers (and pesticides), in April 2021 made it the first nation in the world to embark on a full-scale transition to – as the Government called it—organic farming, and address concerns about human health and the environment. Previous policies had envisioned a gradual shift, but the sudden ban caught agriculture off guard. Declining foreign exchange reserves to import chemical fertilizers and coinciding peak fertilizer prices appeared to support the timing of the move. However, the ensuing rush for organic fertilizers failed to meet the national demand, resulting in severe losses in rice and export-oriented plantation crops. Facing decreasing yields and food insecurity, the government lifted the ban in November 2021. The events raised critical questions about the necessity and feasibility of such a drastic transition and alternative ways. To explore the general feasibility of transitioning toward organic fertilizers, this study considered the actual and potential availability of biomass to “replace” chemical fertilizers at the national scale as was envisioned by the Government. The analysis focused on the four main national crops and showed that in none of the selected scenarios, Sri Lanka’s actual and potentially available organic fertilizer could supply rice- and plantation-based agrosystems with sufficient nitrogen, not to mention other crops or nutrients. The Government will in every scenario, including one that assumes a stepwise transition, remain compelled to spend significantly on importing organic fertilizer to maintain the required crop yields, which would cost the Government more foreign currency than purchasing chemical fertilizer. Even more costly is purchasing rice to close the national production gap, as Sri Lanka eventually did at the end of its nationwide experiment, which resulted in major food security concerns.
Cereal yield and water requirements in response to irrigation and soil fertility management in a changing climate: a case of Tulsipur, western Nepal
(Journal Article, 2025-03) Zuber, Md.; Kalauni, N.; Shrestha, Nirman; Pandey, V. P.; Pokharel, B.
Climate change is projected to notably impact water requirements and crop yield; therefore, it is imperative to quantify climate risk and devise climate-resilient field management practices. This study applied the AquaCrop model to Tulsipur, a sub-metropolitan city located in Western Nepal. The model was calibrated and validated on a field scale, and various scenarios were analysed for baseline (2010–2020) and future (2021–2100) periods to formulate workable management strategies for irrigation and fertilizer applications. Results showed that a deficit irrigation strategy could lead to 81% fewer requirements for irrigation in rice and 24% in wheat at the cost of a minimal (~1%) reduction in yield. Water requirement is projected to decrease and crop yield to increase for both crops for all future scenarios, except wheat water requirement, where water requirement is projected to increase by up to 13% in the future. Rainfed irrigation leads to extremely high variance in crop yields. Deficit irrigation under the nationally recommended fertilizer dose is recommended as a better option to develop climate resiliency in cereal yield in the study area.
System understanding and stakeholder analyses for the vulnerability of small-scale agricultural producers in the Awash River Basin, Ethiopia
(Journal Article, 2025-03) Mekuria, Wolde; Admasu, W.; Abebe, S.; Negash, D.; Getachew, T.; Seid, Abdulkarim Hussein; Haileslassie, Amare
1. As climate change impacts intensify, water-related problems and the vulnerability of small-scale agricultural producers are expected to increase, suggesting the need for an inclusive and integrated management of water resources. This requires understanding the system and mapping the stakeholders, among other things. 2. This study was conducted in the Borkena and Mille catchments of the Awash River basin, Ethiopia. It aimed to improve the understanding of how to improve the effectiveness of agricultural water management practices and water resource planning to address the vulnerability of small-scale agricultural producers and draw implications for future stakeholder participation. 3. Data were collected through key informant interviews, focus group discussions, literature reviews, and observation. The Driver-Pressure-State-Impact-Response framework was used to assess the system's state and its implications for the vulnerability of small-scale agricultural producers. Stakeholder analyses involved mapping the stakeholders, examining their power and power resources, and evaluating their interest, influence, participation, trust levels, and dynamics of exclusion and empowerment. 4. The results suggested that the natural and agricultural systems in both catchments are degrading, though multiple responses are implemented regarding agricultural water management practices. 5. Diverse groups of stakeholders, such as development organizations, academic and research organizations, local administrative bodies, subregional policy and decision-makers, communities and community-based organizations, civil society organizations, donors, and nongovernmental organizations, participate in the planning, design, and implementation of agricultural water management practices. 6. The stakeholder indicated multiple strategies such as promoting community participation and participatory decision-making, aligning plans with communities' priorities and interests, improving collaboration and integration, improving access to resources, providing targeted capacity building and continuous awareness raising, and improving the implementation of policies and strategies to improve the effectiveness of interventions and address the vulnerability of small-scale agricultural producers. 7. Stakeholders have perceived strong legitimacy, but most of them have very little or no access and control over resources and connections with other stakeholder groups. Furthermore, stakeholders showed similarities in strategic options, differences in degree of influence, and demonstrated moderate to considerable trust in others. The alliance or relationship of most stakeholder groups in terms of coordinated action and coproduction using common resources was found to be weak, and most of the stakeholders lack competencies (that is, basic skills to plan, design, and implement interventions). 8. We argue that a relatively weak relationship or alliance in terms of coordinated action and co-production with common resources could affect the successful implementation of interventions. However, there is a high potential for collaboration, as most stakeholders did not vary in their strategic options. Furthermore, interventions related to agricultural water management practices could be implemented with low transaction costs, as the level of trust between the different stakeholders ranged from moderate to considerable.
Impacts of urbanization on land use change and its incidences on the climate: case of Bingerville City (Ivory Coast, West Africa)
(Journal Article, 2025-03) Traore, K. S.; Obahoundje, Salomon; Hauhouot, A. C.; Diedhiou, A.
This study aimed to assess the impact of urbanization on land use dynamics and its consequences on the local climate of the town of Bingerville for the period from 1990 to 2020. Land cover classification was based on Landsat data for the years 1990, 2000, 2015, and 2020 in order to perform a diachronic analysis of surface conditions. Precipitation and temperature data were used to assess local climate trends. A number of extreme precipitation indices (PRCPTOT, RR1, SDII, CWD, CDD, R95p, and R99p) and temperature indices (TN10p, TN90p, TX10p, TX90p, and WSDI) were calculated. The results show a sharp increase in the built-up area from 1990 to 2020, with 32.11 km² (29.68% per year), compared with forest or crops, i.e., 19.09 km² (0.62% per year), and scrubland or fallow land, i.e., 13.21 km²(1.39% per year). However, extreme precipitation indices such as annual precipitation (PRCPTOT), rainy days (RR1), consecutive rainy days (CWD), and extremely rainy days (R99p) have increased from 2011 to 2020. In addition, buildings are correlated with RR1 and CWD. This could be one of the key factors contributing to the occurrence of flooding in the town of Bingerville, which is probably linked to urbanization. As for extreme temperature indices, most show a statistically insignificant trend, except for cold days (TX10p) and hot days (TX90p), which have a statistically significant trend of 0.004 and 0.018, respectively. This means that there have been changes in these two indices. Consecutive hot days (WSDI) and TX90p increased from 2010 to 2016, and buildings also correlated with these two indices. Consequently, changes in land use could have an influence on local temperature through the urban heat island (UHI) phenomenon. However, uncontrolled urbanization has an impact on the local climate. The town authorities need to be aware of this, and be rigorous in this area, to avoid future disasters in Bingerville.
Responses of surface runoff and soil water-erosion to changes in seasonal land cover and rainfall intensity; the case of Shilansha Watershed, Rift Valley Basin of Ethiopia
(Journal Article, 2025-04) Gedle, Assefa; Rientjes, T.; Haile, Alemseged Tamiru; Mekuria, Wolde; Hallett, P.; Smith, J.
Study Region: Shilansha is a watershed located in the Upper Bilate River of the Rift Valley Lake Basin in southern Ethiopia. The region experiences extreme soil water-erosion among the greatest rates globally at 498 tons ha- 1 yr- 1 leading to large quantities of sediment accumulation in Lake Abaya. Study Focus: Surface runoff, soil water-erosion, and sediment loads in the region vary with agricultural seasons and rainfall intensities but are often poorly quantified in modeling studies. This study assessed these effects using the event-based physically based distributed open-source Limburg Soil Water Erosion Model (OpenLISEM), incorporating local field data and multi-sensor satellite data processed with machine learning techniques. New Hydrological Insights: During the fallow season, simulated surface runoff and total soil loss were 9.7 % and 47 % larger than the growing season and 0.9 % and 42 % larger than the harvest season, respectively. Compared to moderate intensity, an 87 % increase in high rainfall intensity increased surface runoff by 159 % and soil loss by 295 %, while a 45 % decrease in low rainfall intensity reduced surface runoff by 49 % and soil loss by 85 %. High rainfall intensity had a greater impact when combined with fallow season land cover, while effects were smallest when low rainfall intensity combined with growing season land cover. A calibrated model parameter set for a particular season resulted in deteriorated model performance when applied to other seasons. These findings offer insights on the importance of considering seasonal changes in land cover and rainfall intensity when developing soil and water conservation strategies.
Assessment of land degradation neutrality to guide sustainable land management practices in Ethiopia
(Journal Article, 2025-06) Mekuria, Wolde; Girma, R.
Since its introduction at the 2015 UN Convention to Combat Desertification Conference, the concept of land degradation neutrality (LDN) has guided countries’ efforts to restore land for sustainable socio-economic and environmental benefits. LDN aims to balance reductions in land quality with initiatives to rehabilitate degraded land. However, due to budget constraints, it is not feasible to address all degraded land, necessitating strategic decisions about where to invest resources. This study, using Ethiopia as a case study, aimed to: (i) assess the long-term (1995 - 2024) land degradation trends, (ii) identify areas of net land loss or gain, (iii) prioritize regions and actions for addressing LDN, and (iv) evaluate the impact of Ethiopia’s landscape management initiatives on LDN. The analysis of LULC changes and the observed landscape transformation across diverse agroecological zones yielded mixed results. While some areas, such as the dry Kolla and dry Weyna Dega regions, showed improvement, others, including the dry Dega and der Berha zones, experienced continued degradation. These variations affected the three main objectives of LDN: healthy ecosystems, food security, and human well-being. The ongoing landscape transformation, driven by LULC changes, underscores the need for more comprehensive strategies to mitigate further degradation and restore affected lands. Our findings regarding LDN trajectories, such as a 6 % reduction in degraded land between 2010 and 2024, suggest that national LDN implementation, through diverse Sustainable Land Management (SLM) practices, is essential for achieving the country’s LDN goals. However, LDN outcomes varied across Ethiopia’s agroecological zones, influenced by differences in environmental conditions, land use practices, and socio-economic factors. This highlights the necessity for tailored solutions, an understanding of varying restoration potentials, targeted resource allocations, and a focus on prioritizing the most vulnerable areas. Additionally, documenting both the successes and challenges of Ethiopia’s restoration efforts, enhancing the effectiveness of its landscape management initiatives, and ensuring the long-term sustainability of its SLM practices are critical for achieving LDN.
Pathway from water-conflict to water-peace in the Middle East and North Africa
(Journal Article, 2025-03) Khalifa, Muhammad; Al-Zu’bi, Maha; Brouziyne, Youssef
The Middle East and North Africa (MENA) region, with its arid and semi-arid climate, faces profound challenges in managing limited water resources. These challenges are further intensified by political tensions and socioeconomic inequalities, often resulting in water being an essential element in conflicts and tensions. Particularly during the last decade, the number of conflicts involving water has increased dramatically in MENA. This research explores the dynamics of water’s role in conflicts, actors and scales of conflict across five fragile MENA countries, where it serves as a weapon, a catalyst, and a casualty. The analysis revealed a significant increase in the number of water-related incidents during the last two decades in these countries, with devastating implications on multiple social, economic, and security dimensions. The study suggests a concentric circle transformation (CCT) framework with three tiers of strategies: foundational, supportive, and expansive to help move from water-conflict to water-peace in MENA. These strategies, with examples of interventions, support transformation to water-peace by integrating soft interventions like empowering local communities, raising awareness, with hard interventions such as building resilient infrastructures and leveraging the power of innovative technological solutions. The framework offers scalable and adaptable solutions for regions facing similar challenges globally.
Making water pivotal in the design of food systems
(Journal Article, 2024-12) Hellegers, P.; Schmitter, Petra; Talbi, A.; van Iwaarden, C.
Water plays a crucial role in our food systems and food security. However, the essential role of water for a functioning food system and the impacts of food systems on water availability and quality have not yet been adequately recognized. Due to a lack of coordination among water and food systems actors, there are siloed water, food security, and nutrition strategies. This paper presents the case to make water pivotal in designing food systems, laying out action perspectives for different actors to move toward what we call “water-responsible food systems”. This paper is based on input from many participants during workshops and existing literature. A food systems approach provides an excellent entry point to link food with water considering climate change and energy. Moreover, collective and cross-cutting actions between actors in food systems are essential to make decisive progress, as well as a common language and insight into the trade-offs of the multiple values of water for a clear prioritization of water use and allocation.
Methodological challenges in assessing the viability of agroecological practices: lessons from a multi-case study in Africa
(Journal Article, 2025-04) Andrieu, N.; Dedieu, B.; Girard, P.; Scopel, E.; Magaju, C.; Dembele, C.; Mekuria, Wolde; Coe, R.
Despite a growing literature highlighting the benefits of agroecology in Africa, policy makers, donors, and scientists are still debating the “viability” of agroecological practices. However, assessing the viability of agroecological practices poses challenges, and so far, no studies have clearly documented them and options for addressing them. The aim of this paper is to describe the main methodological challenges we faced in assessing the viability of agroecology in 11 case studies in Africa so that others planning assessments can benefit from what we learned. Seven methodological challenges discussed are (i) defining an object of study through a list of practices or agroecological principles, (ii) having a practice-based assessment versus a systemic assessment at field or farm scales, (iii) having a subjective assessment of the viability of agroecological practices based on farmers’ perspective or an “objective” assessment, (iv) having a qualitative or quantitative assessment, (v) having a diachronic versus synchronic assessment, (vi) having a multisite approach versus a single-site study, and (vii) having a context-specific assessment method or a unitary assessment method. We conclude that the assessment of the viability of agroecological practices needs to be multicriteria, systemic, and based on farmers’ perspectives and not practice-based using a single simple metric. This is a change from the conventional way such systems are evaluated based on quantitative metrics. We recommend using a mixture of quantitative and qualitative assessments that highlight farmers’ perceptions of practices embedded into their farming systems, using transversal and context-specific data.
Integrated water storage assessment in the Tana-Beles Sub-basin, Ethiopia
(Journal Article, 2025-04) Taye, Meron Teferi; Assefa, T. T.; Ebrahim, Girma Yimer; Lautze, Jonathan; Seid, Abdulkarim Hussein
In river basins with strong seasonal river fluctuation, water storage of various types is required to meet water demands. Water is stored in man-made reservoirs, groundwater aquifers, the soil, natural lakes and wetlands. Ideally, to meet any water demand, these water storage options could be used in an integrated manner. However, integrating suites of water storage options in the management for water, food, energy, and the environment is limited in practice. One of the reasons for this is the lack of knowledge on the volume and temporal dynamics of the different storage types. This study therefore assessed water storage in different storage types and their temporal dynamics using remote sensing and secondary data in the Tana-Beles sub-basin of Ethiopia. The results show that the active total storage volume in the sub-basin varies from 7.3 BCM to 16.2 BCM in dry and wet months, respectively. Lake Tana storage is the largest with 50% of total storage while built reservoirs only account for 2% of the same. Given different competing needs and constraints from each storage options not all the water in the storages can be utilized. Optimizing natural and built storage options in an integrated system can maximize water security gains.
Gendered transformations: rethinking climate resilience building in northwest Ghana
(Journal Article, 2025-03) Osei-Amponsah, Charity; Okem, Andrew; Wahabu, E.; Quarmine, William; Hyde, Sandra N. T.
The transformation of gender roles and responsibilities have implications for how men and women and other social groups are impacted by and cope differently with the changing climate. However, such dynamics are often not considered in formulating and implementing climate resilience interventions. Through a case study in rural communities of the northwestern part of Ghana, Africa, using a mixed-methods approach, this paper investigates the gendered nature of transformations and the implications for climate resilience building. The study found that compared to ten years ago, women have increase access to farmland, participate more in agricultural development decision-making, better access to credit, and more diverse livelihood pathways. Nevertheless, women’s ability to adapt to climate change impacts like droughts is worsening because of cultural norms that restrict women’s control over land resources and their limited adaptive capacities. To achieve positive gendered transformation outcomes while minimising negative social transformation trade-offs, policy makers must rethink the strategies for building climate resilience. There is the need to focus on strategies that support the formulation and implementation of well-funded and targeted interventions with a perspective on gender realities and dynamics that provide women with real resources and agency, enabling institutional support and transformative opportunities.
Estimating crop coefficients for vegetable production and agricultural water management under climate change in sub-humid tropics
(Journal Article, 2025-03-06) Tegegne, Desalegn; Schmitter, Petra; Worqlul, A. W.; Lefore, N.
Understanding current and future crop water demand is crucial for improving agricultural productivity and managing long-term water resources in a changing climate. This study aimed to estimate how the crop water demand will change under different water management practices and climate change scenarios. The field experiment using irrigation decision-making tools was carried out in 2016 and 2017 in Lemo, Ethiopia. Crop and water management data were collected on cabbage and carrot production. The field data were used to estimate the crop coefficient (Kc), and the results were compared with the simulated Kc with the Agricultural Policy Environmental eXtender (APEX) model. Predicted future climate data were used in APEX to evaluate the effect of climate change on future crop water requirements and Kc. The field data analysis indicated that, on average, farmer traditional practice (FTP) treatments used more water than wetting front detector (WFD) treatments. Using the soil water balance method, the average of the two treatments’ Kc values at the initial, mid, and late stages was 0.71, 1.21, and 0.8 for cabbage and 0.69, 1.27, and 0.86 for carrot, respectively. The APEXsimulated Kc has captured the FAO Kc pattern very well with the coefficient of determination (R-square) ranging between 0.5 and 0.74. The APEX simulation and the soil water balance estimated Kc also indicated a strong association with R-square ranging between 0.5 and 0.75 for cabbage and 0.66 and 0.96 for carrot. The projected climate change analysis indicated that the crop water demand is expected to increase in the future due to increasing temperatures. Under climate change scenarios, the growing season potential evapotranspiration will increase by 2.5, 5.1, and 6.0% in 2025, 2055, and 2085 compared to the baseline period, respectively. The simulated Kc indicated a higher coefficient of variation in 2085 with 19% for cabbage and 24% for carrot, while the 2025 period simulated Kc indicated the least coefficient of variation (16 and 21% for cabbage and carrot, respectively). The study shows that current irrigation planning with the available water resources should take into account higher crop water requirements in the region to reduce water scarcity risks.
Estimating elements susceptible to urban flooding using multisource data and machine learning
(Journal Article, 2025-01) Asfaw, Wegayehu; Rientjes, T.; Bekele, Tilaye Worku; Haile, Alemseged Tamiru
The accuracy of flood susceptibility prediction (FSP) could be affected by inadequate representation of flood conditioning factors (FCFs) and the approaches used to identify the most relevant FCFs. This study analyzed twenty-eight FCFs derived from open-access earth observation datasets to develop FSP model for a highly urbanized Akaki catchment, which hosts and surrounds the capital city of Ethiopia, Addis Ababa. In the study, relevant FCFs were first identified using different collinearity-based and model-integrated feature selection methods, and sequentially introduced into a machine learning model. Simulated FSPs were compared against a reference flood inventory dataset to determine the most effective selection method. Findings show that: (i) using extreme rainfall indices improved the accuracy of FSP, (ii) Mean Decrease Impurity (MDI) was found to be the most effective feature selection method, (iii) geomorphological and physiographic FCFs showed the highest and the lowest predictive power, respectively, and (iv) the quantile method outperformed other approaches in classifying the flood susceptibility map. Findings indicate that an area of 217 km2 , 43000 buildings, 163 km of paved roads and 0.54 million inhabitants are highly susceptible to flooding in the catchment. In particular, Addis Ababa contains almost 75 % of the estimated susceptible elements in only one-third of the catchment area. The results of this study provide valuable insights for urban planning and flood management, helping to reduce the socio-economic impacts of flooding and enhance urban resilience.
Designing a monitoring plan for microbial water quality and waterborne antimicrobial resistance in the Akaki Catchment, Ethiopia
(Journal Article, 2025-03) Haile, Alemseged Tamiru; Kibret, M.; Haileselassie, M. M.; Anley, K. A.; Bekele, T. W.; Kassa, J. M.; Demissie, Kirubel; Werner, D.; Graham, D.; Mateo-Sagasta, Javier
The Akaki River, in Ethiopia, becomes a source of antimicrobial-resistant (AMR) pathogens and genes that are spreading to receiving water. Water quality monitoring (WQM) is limited in Akaki, and the available evidence is based on short-term monitoring of inconsistent sampling sites and water quality parameters. Therefore, we designed a suitable WQM plan for the Big Akaki River receiving wastewater from rural, urban, and peri-urban areas. WQM plan was designed by employing multiple approaches including literature review, field observations, spatial analysis, and pollutant “hotspot” identification. Information was extracted through a systematic review of 48 articles, selected through a screening process, to guide the selection of suitable monitoring sites. Field observation was used to inspect previously sampled sites and identify pollution sources and exposure routes to antibiotic-resistant bacteria and zoonotic pathogens. For validation, water samples were collected from 40 sites identified from the literature review and field observation, and results were refined during a stakeholder consultation workshop. Hotspots were identified based on chemical oxygen demand, dissolved oxygen, ammonia, and extended-spectrum ßeta-lactamase (ESßL)-producing Escherichia coli and Salmonella enteritidis/Shigella flexneri data. Cluster analysis of the water quality data categorized the 40 sites into three groups, and the number of sites for future monitoring to 20, including possible pollutant hotspots, reference sites, known pollution sources, exposure routes, and availability of river discharge data. The WQM plan will help AMR and zoonotic pathogens monitoring and mitigation in the study sites. Our approach can be replicated to design WQM plans for other rivers.
Future land use simulation modeling for sustainable urban development under the shared socioeconomic pathways in West African megacities: insights from Greater Accra Region
(Journal Article, 2025-03) Siabi, E. K.; Kabo-bah, A. T.; Anornu, G.; Akpoti, Komlavi; Mortey, E. M.; Incoom, A. B. M.; Yeboah, K. A.
The study explores the evolving land use patterns and their implications for sustainable development in Ghana and neighboring megacities. Using 15 years of historical Land Use and Land Cover (LULC) data combined with Land-Use Harmonization datasets, the study applies the Future Land Use Simulation (FLUS) model to project future LULC dynamics under Shared Socioeconomic Pathway (SSP) scenarios in the densely urbanized Greater Accra Region (GAR) of West Africa. Analyzing historical and current land use dynamics in the GAR revealed notable shifts, notably a decrease in Rangeland and an increase in Built-up areas. Future projections of LULC under SSP scenarios show continuous expansion of Built-up areas, particularly under SSP245 (middle of the road scenario) and SSP370 (Regional Rivalry scenario). This is consistent with results from the urban growth analysis using Urban Expansion Intensity Index (UEII), indicating high-speed expansion in baseline periods and shifts towards medium to high-speed expansion under SSP245 and SSP370 with low-speed expansion under the SSP126 (Sustainability scenario). Shannon entropy analysis shows dispersed urban sprawl, especially under SSP245 and SSP370, with rapid increases in Built-up areas and declines in green areas. For instance, the analysis of the landscape metrics reveal that built-up and green areas are projected to increase and decrease up to 87% and 12% respectively, under these scenarios. The decline in urban green areas was significantly influenced by proximity to the central business district (CBD), with green spaces diminishing more as distance to the CBD decreased. Therefore, relevant local legislation, such as the 2016 Land Use and Spatial Planning Act (Act 925) must be enforced, along with integrating urban initiatives and policies that promote green areas, is essential for ensuring the sustainability of urban ecosystems for the well-being of both humans and the environment. This enables West Africa to achieve its Global commitments as reflected in the UN SDGs, towards the New Urban Agenda (NUA) and the Africa Urban Agenda 2063.
Performance of four wastewater treatment plants serving Ethiopia’s capital city, Addis Ababa
(Journal Article, 2025-02-01) Haileselassie, M. M.; Mohamed, J.; Haile, Alemseged Tamiru; Hiruy, A. M.; Acharya, K.; Werner, D.
There is an urgent need to expand wastewater treatment on the African continent. To help choose appropriate technologies for this task, we evaluated the efficiency, energy and chemical demands, and costs of four wastewater treatment plants (WWTPs). These plants represent the main wastewater treatment technologies operated by the Addis Ababa Water and Sewerage Authority (AAWSA): waste stabilization pond (WSP), anaerobic baffled reactor (ABR), up-flow anaerobic sludge blanket with trickling filter (UASB-TF), and membrane bioreactor (MBR) technologies. Principal component analysis revealed that season significantly impacts the raw and treated wastewater quality (ANOSIM, R ¼ 0.3126, p ¼ 0.001), while the type of treatment plant did not significantly affect the measured effluent characteristics (ANOSIM, R ¼ 0.1235, p ¼ 0.2000). In contrast, construction and operational costs, as well as energy and chemical demands per m3 of treated wastewater, varied starkly between the WWTPs. Total costs of wastewater treatment in 2022 ranged from $0.045 to 0.546 per m3 of wastewater treated, being 6–12 times higher for MBR compared with the other WWTP technologies. Real-world performance data as reported in this study are essential for choosing appropriate technologies that meet Africa’s wastewater treatment needs.

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