As it has for millennia, human wellbeing continues to depend on rivers for drinking water, irrigation, and fishing livelihoods. According to Chris Dickens, Principal Researcher at the International Water Management Institute and moderator of the CGIAR Initiative on NEXUS Gains webinar "The future of global river health monitoring", river health is increasingly part of the discourse of ecosystem health. However, action to protect and restore rivers is hindered by a dearth of appropriate indicators that can be used to talk about river health on a global scale while remaining relevant at the basin level. The webinar, held on September 24, 2024 provided an overview of and future pathways toward global river health monitoring as part of the sustainable development agenda.

Indicators to shape narratives and drive action

David Tickner, Chief Adviser on Rivers and Water for WWF-UK, began his presentation by emphasizing the utility of effective indicators, likening the WWF Living Planet Index to a "stock market index". WWF's indicator for freshwater wildlife points toward a decline of 83% since 1970 - a fall so precipitous it was recently cited by the UK government in an announcement that it will be supporting a new program of research on nature and water.

Tickner then described the value of connectivity as a key aspect of river health, which has been impaired by the disruption of river flows globally. He is now involved in developing a scalable indicator that helps in the estimation as well as easy visualization of river connectivity at global, basin, and local levels.

The next step, according to Tickner, should be to develop indicators of other key aspects of river health, such as water quality and flow regime. This could support monitoring of progress on the UN Global Biodiversity Framework, and potentially the Sustainable Development Goals. While acknowledging that governments have made commitments to try and restore ecosystems, including rivers, he added, "We need a set of indicators that can help governments and others track their progress," concluding that better communication is key: "You've got to tell stories in a way to emotionally engage people and get people to care about the issue. If we can get better data on what's happening to river health and tell better stories, I think we can be optimistic about the future of our rivers."

A scalable, policy-relevant framework focused on ecosystems

Lauren Kuehne, Environmental Scientist with Omfishient Consulting, continued with a presentation on a global river health monitoring framework that was developed with Dickens and Tickner, among others, with support from NEXUS Gains. The researchers started by reviewing a selection of large-scale river health assessments in order to distil a future framework into 4 components - biology, water quality, physical habitat, and hydrology - and 15 indicators. The study also included an evaluation of the feasibility of implementation by 2030 and 2050.

The indicators had a focus on biophysical conditions, to represent the state of ecosystems. This is a departure from many other evaluations of river health that focus on the pressures or impacts on aquatic ecosystems. Measurements therefore had to be based on direct in-situ data or remote sensing data complemented with estimates provided by modelling. "The first priority," explained Kuehne, "is to address the considerable knowledge gaps and technical barriers to evaluating the biophysical state of rivers at a global scale." The framework aimed to be scalable and relevant to local, regional, and global levels. It sought to blend these approaches through a common geospatial framework that could, for example, link hi-res local hydrographic features to coarser global datasets or modelling results.

However, as Kuehne emphasized, "Data aren't enough. There needs to be, concurrently, work and attention by the entire community on enabling factors." She explained that river health monitoring needs to be adopted as a priority within local, regional, and global initiatives. Researchers need to commit to a common framework in order to appropriately invest their resources into methods development and data synthesis. Finally, there is a need to identify and strongly promote an international organization to coordinate national and regional commitments and initiatives.

Biological and digital perspectives

Abby Lynch, Research Fish Biologist with the United States Geological Survey National Climate Adaptation Research Centers, provided a perspective on freshwater biodiversity. Noting that freshwater ecosystems host 10% of Earth's species, and that they are among the worst-affected ecosystems, she identified logistical and regulatory constraints to prioritizing them: "A lot of programs rely on simple indicators, and water quality is often easier to monitor and measure than biodiversity. Secondly, existing policies are more likely to focus on immediate human needs. So how do we think outside the fishbowl?" Or how do we think about novel approaches to address these major needs?

As an example, Lynch described a project she is involved in that is developing an indicator for inland fisheries at a global scale. The result is a global threat map that can serve as a proxy for monitoring inland fisheries. "Basin report cards" derived from this exercise are being "ground-truthed" so that local data can augment global datasets.

The final presentation, on digital solutions, was by Mpho Sadiki, Earth Observation Data Scientist with Digital Earth Africa. Earth observation is an incredibly powerful tool, as its near-global coverage allows us to go where in-situ monitoring cannot, while also providing visualization of long-term river dynamics. "By integrating Earth observation with in-situ measurements, we gain a more complete and reliable understanding of river systems," Sadiki said. "That allows us to identify trends, predict changes and make informed decisions for their management." She clarified that while the technology cannot measure biodiversity directly, it can use proxy indicators of river health on water quality, physical habitat, and hydrology.

Among a number of advances in hydrological monitoring, Sadiki highlighted GeoMAD, which condenses satellite imagery into a high quality, cloud-free composite image over specific time frames, making it ideal for long term series analysis. The use of open datasets means that Digital Earth Africa can expand and present local data at continental scale - although the spatial and temporal resolutions of available data may be limiting and complicated by cloud cover, particularly in tropical regions.

The best possible portfolio for the future, from local to global

The panelists then fielded participant questions. In response to a query on how climate change might affect the appropriateness of "natural" reference points when measuring river health, David Tickner suggested that we should worry less about what it used to look like in the past, and more about what it should look like in the future. Arguing that it is unrealistic to aim for a natural or even semi-natural state for many of the working rivers of temperate latitudes, he said: "We should come up with the best portfolios of ecosystem services that benefit a range of groups of people."

Panelists also responded to a question on the need to capture improvements in local biodiversity, commenting that a global river health monitoring framework should be able to integrate improvements as well as declines, including by making use of emerging technologies. The moderator concluded: "There are many countries who are doing a wonderful job at a country level. But we need to scale those: it's got to become global."

Didn't catch the webinar? You also listen to the podcast:

View the presentation slides by David Tickner View the presentation slides by Lauren Kuehne View the presentation slides by Abby Lynch View the presentation slides by Mpho Sadiki

Learn more about all the webinars in the series on the NEXUS Gains Talks landing page and subscribe to the NEXUS Gains newsletter to be the first to hear about upcoming webinars.

This work was carried out under the CGIAR Initiative on NEXUS Gains, which is grateful for the support of CGIAR Trust Fund contributors: www.cgiar.org/funders

Header image: Crossing the Kelani river in Sri Lanka. Photo by Hamish John Appleby/IWMI.

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