The team’s argument begins with a sober assessment of the global situation. Climate change is placing mounting strain on water and sanitation services, with floods contaminating shallow wells, droughts drying up springs, and erratic rainfall disrupting the piped networks on which growing urban populations depend. Each of these disruptions carries a direct public health cost, because unsafe water is a principal vehicle for cholera and other diarrhoeal diseases. In low-income and fragile contexts, the authors note, the need for increased investment in water and sanitation is urgent, but money alone will not close the gap. Equally important is enhancing the efficiency with which available financial resources are used, so that every dollar spent on pipes, pumps, treatment and household connections delivers the greatest possible reduction in disease risk.

This is where operational research enters the picture. Operational research, in the sense the authors use the term, is the systematic study of programmes as they are actually delivered, asking not only whether an intervention works under ideal conditions but whether it works, for whom, at what cost and with what unintended consequences when rolled out at scale by real institutions under real constraints. Randomised trials of water treatment technologies conducted in stable research settings have produced valuable knowledge, but their findings often translate poorly to the chaotic, rapidly changing environments of complex emergencies, where supply chains break, populations move, and the institutions responsible for maintenance may be weak or contested. The result is a persistent mismatch: the places with the greatest burden of waterborne disease generate the least evidence about how to reduce it.

To illustrate what a different approach looks like, the authors draw on their own experience conducting research embedded within a large-scale water supply infrastructure improvement programme in an urban, cholera-endemic area of South Kivu. The programme, implemented against the backdrop of one of the world’s most protracted humanitarian crises, aimed to upgrade drinking water services for hundreds of thousands of residents. Rather than standing apart from the implementers, the research team worked alongside them, shaping evaluation questions around the decisions that programme managers actually faced: which neighbourhoods to prioritise, how to design connections that households could afford, and how to measure whether improved infrastructure was translating into safer water at the point of consumption and fewer cholera cases at treatment centres.

The technical challenges of doing this well are considerable, and the article is candid about them. Measuring water quality in an urban African setting requires laboratory capacity, cold chains for reagents, and sampling frames that can keep pace with shifting neighbourhood boundaries. Measuring health outcomes such as cholera incidence depends on surveillance systems that may themselves be strained by insecurity and underreporting. Infrastructure programmes unfold over years, while funding cycles and political attention operate on shorter clocks, creating pressure to produce findings before the intervention has had time to take effect. The authors describe how pragmatic methods, including mixed-methods designs that combine quantitative water quality testing and epidemiological analysis with qualitative work on household behaviour and institutional dynamics, allowed the team to generate useful evidence despite these constraints, accepting some trade-offs in precision in exchange for relevance and feasibility.

Central to their argument is the idea that multi-stakeholder research partnerships are not a soft, diplomatic nicety but a methodological necessity in fragile settings. The South Kivu collaboration brought together international academic researchers, Congolese scientists, ministry officials, water utility staff and implementing organisations, each holding pieces of knowledge the others lacked. Local researchers understood the epidemiology of cholera in the region, the politics of water access and the practical realities of fieldwork in insecure areas. International partners contributed methodological expertise, analytical capacity and connections to the global evidence base. Implementers knew the engineering constraints and the programme’s decision points. When these perspectives are integrated from the design stage, the authors contend, studies are more likely to ask questions that matter, collect data that decision-makers will actually use, and survive the inevitable disruptions that complex emergencies inflict on any long-term project.

The partnership model also carries implications for capacity, which the authors treat as a first-class outcome rather than a by-product. Research in crisis-affected settings has too often followed a pattern in which external teams arrive, extract data, publish findings in journals inaccessible to local institutions, and depart, leaving behind little durable capability. By contrast, the South Kivu experience illustrates the role of research in strengthening capacities for both science and practice: Congolese doctoral and masters students gained training in study design, laboratory methods and data analysis; national institutions gained experience with rigorous evaluation; and programme staff gained a clearer understanding of how their interventions were performing on the ground. This reciprocal capacity building, the authors suggest, is what allows evidence generation to become a sustained national capability rather than a series of one-off foreign expeditions.

The cholera context gives the work particular urgency. South Kivu sits within one of the persistent hotspots of the seventh cholera pandemic, and the Great Lakes region has repeatedly seen explosive outbreaks driven by a combination of dense urban settlement, limited sanitation, and populations displaced by conflict. Cholera is exquisitely sensitive to water infrastructure: sustained access to safely managed drinking water and sanitation is the only durable route to eliminating transmission, which is why the global roadmap for cholera control places water and sanitation investment at its core. Yet the evidence on which infrastructure configurations deliver the greatest protection, and how to sequence and target investments in cities where full coverage is years away, remains surprisingly weak. Studies embedded in real programmes, like the one described in South Kivu, are among the few ways to close that gap, because they can observe the transition from inadequate to improved services as it happens, at a scale and in a setting where the findings are directly generalisable to other cholera-endemic cities.

The authors are careful not to oversell the model. Embedded research requires funders to accept longer timelines and greater uncertainty than conventional studies, and it requires implementing agencies to tolerate independent scrutiny of their work, which not all are willing to do. It demands genuine power-sharing, since partnerships in which local institutions are consulted but not empowered tend to reproduce the extractive patterns of the past. Ethical questions also intensify in complex emergencies, where participants may be vulnerable in multiple overlapping ways and where the research itself must never delay or distort the delivery of services that people’s survival may depend on. Navigating these tensions, the article suggests, is as much a part of the method as any statistical technique, and the learnings the authors distil are intended as practical guidance for the next team attempting something similar.

The way forward the authors sketch is one in which operational research becomes a standard component of water and sanitation investment in fragile and low-income countries, funded and planned alongside the infrastructure itself rather than bolted on afterwards or omitted entirely. As climate change intensifies pressure on water systems worldwide and urbanisation concentrates more people in underserved neighbourhoods of fragile states, the cost of flying blind grows each year. The South Kivu experience offers a concrete demonstration that rigorous, decision-relevant evidence can be produced even in one of the world’s most difficult operating environments, provided that research is treated as a partner to practice rather than its judge, and that the institutions closest to the problem are given the resources and authority to lead. If that lesson travels, the authors argue, the next generation of water investments in crisis-affected cities can be built on a far firmer evidentiary foundation than the last.

Subject of Research: Embedded operational research on water supply infrastructure and cholera risk in a complex emergency in South Kivu, Democratic Republic of the Congo

Article Title: Pragmatic water and health research in a complex emergency: Learnings and way forward

Article References: Gallandat, K., Saidi, J. M., Rumedeka, B. B., Machuel, D., Seon, A., Malembaka, E. B., Bugeme, P. M., German, E., Bompangue, D., Hutchins, C., Knee, J., Azman, A., & Cumming, O. (2026). Pragmatic water and health research in a complex emergency: Learnings and way forward. PLOS Water, 5(10), e0000646. https://doi.org/10.1371/journal.pwat.0000646

Image Credits: AI Generated

DOI: 10.1371/journal.pwat.0000646

Keywords: water and sanitation, cholera, operational research, complex emergency, Democratic Republic of the Congo, South Kivu, public health, research partnerships, capacity building, climate change, drinking water infrastructure, PLOS Water

The study area covers roughly 2,400 square kilometers of mountainous terrain in the Albertine Rift, where altitudes climb from about 810 meters to nearly 3,470 meters from west to east. The climate is tropical with a bimodal rainfall regime: a long rainy season from October to February, a shorter one from March to June, and a dry spell from July to September. Annual rainfall totals between 1,000 and 1,300 millimeters, delivered both by convective storms associated with the Intertropical Convergence Zone and by orographic rain forced upward over the rugged relief. That combination of steep slopes, weathered soils, and intense precipitation makes the landscape inherently unstable, but the researchers emphasize that human activity has dramatically amplified the problem.

Decades of population growth, deforestation for agriculture and fuelwood, artisanal mining, and unregulated rural road construction have stripped hillslopes of their natural protection. Earlier regional studies had already suggested that anthropogenic disturbance interacts with natural controls such as slope gradient, elevation, and rainfall to drive slope failure, but no one had systematically tracked how landslide-affected land actually changed year by year in this part of the rift. The new inventory fills that gap by building a multi-temporal record rather than the single-snapshot surveys that have dominated previous mapping efforts in the eastern Congo.

The team’s primary tool was Google Earth Pro, whose free multi-temporal imagery allowed the researchers to digitize landslide scars as polygons and to distinguish newly initiated failures from the progressive widening of older ones. Because dense vegetation can hide landslide morphology from orbit, the satellite interpretation was cross-checked against archival records from local organizations, including the Action de Développement pour les Milieux Ruraux and the Mission Antiérosive, as well as student theses and field reports from the Institut Supérieur Pédagogique de Walungu. Finally, the researchers validated a representative sample of 904 landslide sites in the field, selected to span the full range of altitude, slope, soil type, land cover, and slope aspect across the study area, within the sectors accessible despite security constraints.

The validation exercise produced strikingly strong results. Of 870 landslides confirmed on the ground, 823 had been correctly identified in Google Earth imagery, while 47 were missed and 34 features were falsely flagged as landslides. That translates into a precision of 96 percent and a recall of 95 percent, figures that held almost identically for both shallow and deep-seated failures. The findings demonstrate that freely available virtual globe imagery, when systematically checked against ground truth, can support reliable landslide inventories in regions that cannot afford commercial very-high-resolution satellite data, although the authors caution that small, partially vegetated failures remain the weakest link in any image-based approach.

The inventory itself catalogued 2,088 landslides covering a total of 528 hectares. Shallow failures, predominantly earth flows, utterly dominate the record: 2,051 events, or 98.2 percent of the total, accounting for just over 79 percent of the affected area, with a mean individual footprint of only 0.20 hectares. Deep-seated landslides are rare, just 37 events, but disproportionately destructive, covering 109 hectares thanks to mean areas of nearly 3 hectares and a maximum of almost 24 hectares. Notably, 81 shallow failures occurred along roads and 46 within active artisanal mining perimeters, underscoring the imprint of infrastructure and extraction on slope stability.

To understand why landslides occur where they do, the team applied a Bayesian Weight of Evidence analysis within a geographic information system, testing seven conditioning factors: slope gradient, slope aspect, curvature, elevation, drainage density, land use and land cover, and soil type. A Chi-square test confirmed that every factor is statistically significantly associated with landslide occurrence, with slope degree showing the strongest dependence. The centered weight values reveal a clear threshold: slopes gentler than 20 degrees are consistently stable, with strongly negative weights, while susceptibility jumps sharply between 25 and 30 degrees, where the positive weight peaks at 3.14. Convex and planar curvatures, higher elevations above 1,800 meters, and positions 400 to 600 meters from stream channels, where fluvial incision undercuts steep valley sides, all show strong positive associations with failure.

The land cover results carry perhaps the most consequential message for policy. Forested and woodland terrain shows a strongly negative weight of minus 3.26, reflecting the protective role of dense root networks, rainfall interception, and evapotranspiration in binding soils together. Cropland and herbaceous cover, by contrast, shows a positive weight of 3.15, and built-up or bare soil surfaces a weight of 2.75. Soil type reinforces the pattern, with shallow Leptosols and deeply weathered Ferralsols both highly susceptible. Together, these relationships describe a coupled natural and human system in which terrain establishes the gravitational framework, drainage controls water movement, soils govern material strength, and vegetation removal dismantles the last line of defense.

The temporal record is equally sobering. The number of mapped landslides grew from 967 in 2015 to 2,088 in 2024, with 1,121 newly initiated failures over the decade and a cumulative net land loss of 278 hectares. The affected proportion of the study area rose from 0.104 percent to 0.220 percent. Activity was strikingly episodic rather than steady: quiet years such as 2017 and 2022 saw only about 3 and 2 hectares of new land loss respectively, while 2019, 2021, and 2024 delivered major pulses of 40, 76, and 100 hectares, the last corresponding to annual area growth of more than 23 percent. Importantly, part of the expansion reflects the progressive widening of existing failures, particularly deep-seated ones that continue deforming long after initial failure, meaning the inventory captures ongoing geomorphic adjustment rather than simply counting isolated new events.

The authors are careful to frame their conclusions as a baseline rather than a definitive predictive model. The Weight of Evidence approach quantifies spatial associations but cannot fully resolve interactions among factors, and the study did not quantitatively analyze rainfall triggers, a task the researchers say will require daily rainfall data and the derivation of local triggering thresholds to support early-warning systems. Armed conflict also prevented exhaustive field validation in some sectors, and the results cannot be directly generalized across the whole of eastern Congo. Still, the study delivers something the region has never had: a field-validated, decade-long, annually resolved account of how a tropical rift landscape is unraveling, and a demonstration that with free imagery, local archives, and determined fieldwork, even the world’s most data-scarce mountains can be brought into the scientific record. As populations keep growing and forests keep receding across the Albertine Rift, that record may prove essential for planning where people can safely build, farm, and live.

Subject of Research: Landslide inventory, dynamics, and predisposing factors in the tropical highlands of eastern Democratic Republic of Congo

Article Title: Landslide inventory and dynamics in the tropical highlands of eastern Democratic Republic of Congo

Article References: Richard, B. C., Jean-Claude, M. M., Léonard, M. K., & Karume, K. (2026). Landslide inventory and dynamics in the tropical highlands of eastern Democratic Republic of Congo. Environmental Challenges, 25, Article 101662. https://doi.org/10.1016/j.envc.2026.101662

Image Credits: AI Generated

DOI: 10.1016/j.envc.2026.101662

Keywords: landslides, Democratic Republic of Congo, South Kivu, Albertine Rift, Google Earth Pro, remote sensing, landslide susceptibility, Weight of Evidence, deforestation, land cover, shallow landslides, deep-seated landslides