Do you recall a particular personal, academic or professional experience that inspired you to pursue a career in environmental science and freshwater research? Tell us where it all began.

For me, it was not one dramatic moment, but a gradual realization that water connects almost everything I was interested in. My earlier training and work around microbiology, aquatic ecology, fisheries, aquaculture, and environmental science increasingly brought me into contact with questions of water quality, freshwater ecosystems, and the people whose livelihoods depend on them.

That became much more concrete during my work in Malawi. When you are in the field collecting water-quality data, observing a river system and speaking with people who depend on that same water for domestic use, agriculture or fishing, environmental science stops being abstract. A change in water quality is not simply a change in a laboratory value; it can affect food production, human health, aquatic organisms, and household livelihoods simultaneously.

That experience pushed me towards a more integrated view of freshwater research. I became interested not only in describing environmental problems, but also in understanding where they come from, how they change across space and time, and how tools such as Geographic Information System (GIS), satellite Earth observation, and field monitoring can help us respond to them.

Your academic journey has taken you across several countries and disciplines. How have these experiences shaped your understanding of water-related challenges?

Working and studying across different academic and geographical settings has taught me that water problems rarely fit neatly within one discipline. My background has taken me through fisheries and aquaculture, water quality, freshwater ecology, environmental management and increasingly spatial approaches such as GIS and remote sensing.

Experiences in Kenya, Malawi and Zambia have been particularly important because they have kept me close to the realities of water management in Southern and Eastern Africa. In many communities, the same river may support domestic water needs, irrigation, fisheries, biodiversity and other economic activities. Therefore, managing one use without considering the others can simply transfer a problem from one sector to another.

International research and professional interactions have also shown me the value of combining approaches. A water-quality sample provides very detailed information at a particular place and time, while satellite data can reveal what is changing across an entire catchment. I increasingly see the strongest environmental science as the combination of those perspectives rather than choosing one over the other.

Your work applies the Water-Energy-Food nexus approach. How can this approach help decision-makers manage competing demands for water while protecting freshwater ecosystems and supporting local livelihoods?

I see the Water-Energy-Food nexus primarily as a way of forcing us to ask what happens outside the sector in which a decision is being made.

For example, allocating more water for irrigation may improve agricultural production, but if it reduces environmental flows or affects downstream water quality, fisheries and ecosystems may carry part of the cost. Likewise, energy development can provide major economic and social benefits while also changing river flows and ecological processes. These are not arguments against agriculture or energy development; they are reasons to plan them together.

For decision-makers, the nexus approach therefore helps reveal trade-offs before they become conflicts. I would also extend the conventional Water-Energy-Food nexus to explicitly recognise ecosystems because functioning freshwater ecosystems underpin all three sectors.

What is especially important to me is bringing livelihoods and climate-smart approaches into this discussion. A theoretically optimal allocation on a planning document may look very different to a farming or fishing household whose daily income depends on that river. Good nexus planning has to combine environmental evidence with those social realities.

Your research also examines hydropower alongside other pressures affecting industrialized river landscapes. Why is it important to consider hydropower, river ecology and other human activities together?

Rivers almost never experience one pressure at a time. A regulated river may simultaneously be affected by altered flows, agriculture, urban development, pollution, sediment changes, water abstraction and climate variability. If we examine hydropower or any other activity in isolation, we risk attributing ecological change to the wrong cause or overlooking interactions among pressures.

This is why cumulative and catchment-scale thinking is so important. River organisms respond to the total environment they experience, not to the institutional boundaries through which humans manage different pressures.

There is also an important role for spatial information here. Field ecological data can show what is happening at particular sites, while satellite observations and GIS can provide the wider landscape context—for example, changes in land cover, vegetation, sediment sources or water extent upstream and downstream. Combining those sources of evidence gives us a much more realistic understanding of why a river is changing and where management interventions might be most effective.

In the challenge you submitted to the Space4Water Portal, you highlighted the degradation of water quality in the Bua River in Malawi. What are the main pressures affecting the river, and how do they influence local communities and aquatic ecosystems? 

What concerned me about the Bua River is that its water-quality problem cannot be reduced to one pollution source. It is a catchment problem.

Crop agricultural expansion, deforestation, domestic waste disposal and broader land-use changes can influence erosion, sediment delivery and nutrient inputs into the river. These pressures vary spatially and seasonally, which makes water quality itself highly dynamic. In the work surrounding the Bua catchment, parameters such as water transparency, nutrients, pH and temperature became particularly useful for thinking about how human activities in the landscape eventually appear as changes in the river.

The consequences are both ecological and social. The Bua supports aquatic biodiversity and eventually connects with Lake Malawi, while communities use river water directly and indirectly for agriculture, domestic needs and livelihoods. Degradation therefore has several meanings at once: poorer habitat for aquatic organisms, reduced suitability of water for different uses, possible health concerns and increasing vulnerability for communities dependent on the system.

That interconnectedness is exactly why I felt the Bua was a suitable challenge to bring to Space4Water.

How could satellite remote sensing, Earth observation data and GIS be combined with field-based water-quality monitoring to identify pollution hotspots and support better management of the Bua River catchment? 

I would not use satellite data as a replacement for field water-quality monitoring. I see the two as complementary.

Field measurements tell us what is actually occurring in the water at a particular location: parameters such as temperature, pH, nutrients, conductivity, dissolved oxygen or turbidity can be measured directly. Satellite Earth observation gives us something different—the ability to step back and examine the whole catchment repeatedly through time.

For the Bua, we can use historical and current satellite imagery to map land-use and land-cover change, vegetation loss, exposed soil, changes in surface-water extent and potential sediment-producing areas. High resolution optical satellite observations can also support assessment of some water characteristics, such as suspended material or turbidity-related patterns, where conditions permit. GIS can then bring these layers together with river networks, settlements, agricultural areas and field-sampling locations.

The most useful approach is iterative. Satellite data can help identify locations where change appears strongest and therefore where additional sampling should occur. Field results can then help validate and interpret what we see from space. Over several seasons, that combination can reveal persistent hotspots rather than relying on isolated measurements.

For me, this is one of the most exciting applications of Earth observation in African catchments: using space-based information to make limited field-monitoring resources more strategic.

What role should local communities, government agencies, researchers and civil society organizations play in developing and sustaining solutions for the Bua River catchment?

Each group has a different role, and a solution will probably fail if one of them is missing.

Researchers can generate and interpret evidence, but we should not assume that producing a scientific paper automatically produces environmental change. Government agencies are essential because water, land use, agriculture and environmental protection ultimately involve policy, regulation, planning and enforcement.

Local communities are equally important because they interact with the catchment continuously. They often observe changes long before a research project begins, and they also understand the practical reasons behind particular land- or water-use practices. Their knowledge should therefore contribute to problem definition and monitoring rather than communities being consulted only after a solution has already been designed.

Civil society organizations can help connect these groups, strengthen environmental awareness and maintain continuity after individual research projects end.

I would like to see catchment management move towards genuine co-production: scientific measurements, Earth-observation evidence and local knowledge informing one another rather than operating as separate systems.

Your research also covers fisheries and small-scale aquaculture. How can sustainable aquaculture contribute to food security, climate resilience and livelihoods without placing additional pressure on water resources?

My multi-disciplinary research background in water, sanitation, aquaculture and fisheries makes me very aware that aquaculture is both dependent on water and capable of affecting water if poorly managed, especially when in commercialized settings.

Its major opportunity in Sub-Saharan Africa is that relatively smallholder and medium production systems can contribute fish, income and employment close to the communities where these benefits are needed. Fish is also nutritionally important, so sustainable aquaculture contributes not only economically but also to food and nutrition security.

However, increasing production alone is not enough. Sustainable systems have to consider water availability, stocking densities, feed efficiency, waste and nutrient management, suitable species and the carrying capacity of receiving environments. Where appropriate, integrated production approaches can also make better use of nutrients and resources rather than treating effluent simply as waste.

Climate resilience is another reason to improve, rather than simply expand, aquaculture. Producers need systems that can cope with changing temperature, rainfall and water availability.

For me, sustainable smallholder aquaculture enterprises should therefore be judged by how efficiently they produce food and livelihoods while maintaining the quality and availability of the water on which both people and ecosystems depend.

Across Sub-Saharan Africa, where do you see the greatest potential for using space-based data to address gaps in water-quality and freshwater-ecosystem monitoring?

I think the greatest potential is in places where environmental change is occurring faster than conventional monitoring networks can document it.

Many African river catchments have relatively few long-term monitoring stations, and field campaigns can be expensive. Satellite Earth observation cannot measure every water-quality parameter directly, but it can provide consistent spatial and historical information over areas where ground observations are sparse.

I see particular opportunities in mapping land-use change around rivers and reservoirs, sediment and turbidity patterns, changes in surface-water extent, wetland loss, catchment erosion, algal or chlorophyll-related signals where sensor conditions allow, and the effects of floods and droughts.

The historical archive is also extremely valuable. We can sometimes reconstruct decades of landscape change even in places where systematic field monitoring began only recently.

The important point is not to present satellite data as a substitute for African monitoring infrastructure. Instead, we can use it to decide where limited field resources should be concentrated, identify emerging hotspots and provide spatial context to measurements taken on the ground.

What are the main challenges involved in translating scientific evidence about water quality and environmental degradation into practical action and effective water governance?

One major challenge is that scientific evidence and management decisions often operate on different timelines and in different languages.

Researchers may spend years generating detailed datasets, while a local authority may need to make a decision within weeks and may not have the technical staff or resources to interpret a complex model or satellite product. We therefore need to make evidence usable, not only scientifically correct.

Another challenge is institutional fragmentation. The sources of degradation may involve agriculture, forestry, settlements, water management and environmental regulation, while responsibility is distributed among different institutions. A river, of course, does not recognise those administrative boundaries.

Data continuity is another problem. A single research campaign can identify an issue, but effective governance requires monitoring after the project ends.

I have increasingly come to believe that communication is part of the science. A technically excellent map or model has limited impact if the people responsible for acting on it cannot understand what it means, trust the evidence or translate it into a feasible intervention.

What emerging technologies or research approaches do you believe could make the greatest contribution to sustainable water management in the coming years?

I am particularly interested in the convergence of technologies rather than one technology by itself.

Satellite Earth observation is becoming more accessible, cloud-computing platforms allow us to analyse very large spatial datasets without requiring extremely powerful local computers, and low-cost field sensors can generate more frequent observations on the ground. Artificial intelligence and machine learning can help detect patterns across those datasets, provided they are used carefully and validated against real environmental observations.

For water-quality research, the most promising direction for me is data fusion: combining satellite observations, conventional laboratory and field measurements, low-cost sensors, hydrological information and local knowledge within the same analytical framework.

Platforms such as Google Earth Engine have also changed what is practical for researchers working with long satellite time series.

But I would place one condition on all of this: technology should respond to a clearly defined water-management problem. We should not begin with a satellite or an algorithm and then look for a problem to apply it to. The environmental question must come first.

What advice would you give to young professionals who want to work at the intersection of water, climate, ecosystems and space-based technologies?

I would tell them to learn both the river and the technology.

It is tempting to become very specialised in GIS, remote sensing, coding or artificial intelligence, and those are valuable skills. But a technically impressive analysis is much more useful when you understand the ecological and social system behind the pixels.

Spend time in the field. Learn how water-quality measurements are collected and what their limitations are. Speak with the communities and institutions that use the resource. At the same time, develop quantitative and spatial skills because environmental science is becoming increasingly data-intensive.

I would also encourage young professionals not to be intimidated by interdisciplinarity. My own path has crossed fisheries, aquaculture, water quality, freshwater ecology, environmental management and spatial data. Initially, those can appear to be separate areas, but water connects them.

Most importantly, start with a real problem. Technology changes quickly, but the ability to ask a meaningful environmental question, work across disciplines and communicate evidence clearly will remain valuable.