From source to sea, the river keeps the world alive. #Worldriversday

Rivers are critical for the health and functioning of ecosystems on a global scale. As natural waterways, they function as essential freshwater sources, supporting diverse habitats and underpinning many human activities. Moreover, the value of rivers extends far beyond their physical characteristics; they are vital to the ecological equilibrium and cultural values embedded in many communities, from the UK to the Amazon rainforest in Brazil, the sacred Ganges in India and the Mississippi River in the United States.

Comprehending the role and function of rivers is necessary to preserve and sustain them, alongside the considerable challenges they face. The natural and human systems they support require careful preservation, restoration and conservation with multiple knock-on effects; for example, by planting trees alongside their bank (often biodiverse habitats known as riparian zones), we can slow and stabilise the increasing existential threat of flooding in the UK, preserve the culture built up and embedded in meanders and wooded riparian areas through ecosystem services, and create habitats for a wide range of wildlife.

With contributions based on primary research, this article summarises some central findings, focusing on the importance of rivers, the increasing detrimental effects of flooding, and the broad benefits of riparian natural flood management on UK communities.

Ecological Importance of Rivers

Rivers are home to some of the most diverse and endangered wildlife on earth

Rivers function as vital ecological “arteries” for sustaining the health and functioning of biodiversity, providing habitats for a huge scope of different eclectic lifeforms, including fish, amphibians, birds, trees and plants. These dynamic environments underpinned by rivers, such as wetlands and floodplains, are vital supporting ecosystems for the abundant life found within them. They also support consequential ecological processes, including nutrient cycling and sediment transport—vital natural mechanisms for sustaining balanced ecosystems. Beyond those zones, rivers extend their influence to neighbouring landscapes, regulating microclimates and nourishing soil fertility. The ecological benefits of healthy rivers encompass:

Habitat diversity
Biodiversity hotspots
Nutrient cycling
Water filtration
Floodplain fertility
Erosion control
Carbon sequestration
Climate regulation
Groundwater recharge
Support for aquatic food webs

The Human Factor

82% of the global population relies on freshwater sources greatly threatened by pollution, overuse and environmental degradation.

Throughout history, human societies have depended on rivers continuously for innumerable vital resources and functions. Rivers are primary sources of fresh drinking water, which is essential for daily consumption and agricultural activities. They have also supported industrial processes, energy production and transportation. Countless communities are built along the sides of riverbanks, where access to water has dictated settlement patterns and economic development. Finally, rivers provide recreational opportunities and have cultural and spiritual significance in numerous traditions (see section 7 below). The main human benefits include:

Economic development
Urban development
Education and research
Flood control
Waste disposal
Drinking water
Food source (e.g., fish, feeding tens of millions globally).
Irrigation (for crops)
Transportation
Energy production
Producing products - check
Spiritual significance
Cultural significance
Recreation and tourism

Current Challenges

Not a single section of river in England or Northern Ireland is in good overall condition; only 15% of rivers in England, 31% in Northern Ireland and 50% in Ireland meet the standards for good ecological health.

Regardless of their essentiality, rivers are contending with substantial threats that are increasingly jeopardising their overall health and ecological balance. For example, pollution from agricultural runoff, industrial discharge and untreated sewage can undermine water quality and disturb aquatic life. In addition, the over-extraction of water for irrigation purposes and other uses diminishes river flow while detrimentally impacting ecosystems downstream. On top of this, climate change exacerbates these issues by shifting river flow patterns and multiplying the frequency and intensity of extreme weather events. Thus, addressing these challenges necessitates coordinated undertakings to control water resources, protect habitats and mitigate any environmental impacts. Their threats include:

Pollution
Over-extraction
Habitat destruction
Climate change
Invasive species
Dams and barriers
Deforestation
Agricultural runoff
Urbanization
Overfishing

A man looks at a flooded street on September 15, 2024 in Opava, Czech Republic. Source: Michal Cizek, AFP

Flooding: A Rising Threat to Communities

Flooding is the most common natural hazard worldwide, affecting more people than any other disaster; accounting for 44% of all disaster events from 2000-2019, flooding affected 1.6 billion people during this period.

The frequency and severity of flooding have increased over the last 70 years, as global warming drives weather events with cumulatively detrimental outcomes. Flooding detrimentally effects people, assets, and economies and is not limited to one nation or continent. Thus, mitigation of its detrimental effects is relevant to billions of people worldwide. It is a global issue that affects more people worldwide than any other weather hazard. In this context, flooding impact assessments are often restricted to evaluations of economic loss, with a disproportionate focus on engineered structural solutions in the aftermath. Meanwhile, the human “psychosocial” damages are often overlooked and difficult to measure as an intangible consequence of repeat flooding.

Riparian Planting as a Flood Mitigation Strategy

Riparian zones are strips of vegetation that border water bodies such as rivers, streams, ephemeral creeks, ponds and lakes, including the land, trees and water-loving animals and plants along the channel.

“Natural Flood Management” is an alternative strategy of river conservation seeking to work with nature to mitigate flooding, often encompassing native riparian woodland planting as part of holistic river catchment management. Riparian planting—a practice of encouraging vegetation along the sides of stream sides and riverbanks—has become a prominent tool in flood mitigation. Meanwhile, vegetated buffers are vital for managing water flow and improving overall ecological health. Reinforcing the edges of waterways with native plants constructs a natural barrier that absorbs and slows water runoff, decreasing the speed and volume of water that inevitably arrives in downstream areas.

Absorption and Filtration

Riparian plants and trees perform a vital function by absorbing excess water through their root systems; the roots penetrate the soil, increasing its ability to retain water and decrease surface runoff. Meanwhile, dense vegetation also acts as a “filter” that captures sediments and pollutants that could otherwise contribute to waterway degradation and elevated flooding risks. This filtration process maintains cleaner waterways and improves overall water quality, further supporting flood mitigation efforts. Trees absorb water through their leaves, roots and bark, creating “grooves” in the ground to slow water flows.

Erosion Control

The root systems of riparian plants effectively stabilise soil along riverbanks and stream sides. Soil binding by these roots prevents erosion, a common issue that can lead to increased sedimentation and altered water flow patterns. Stabilised banks help to reduce the likelihood of watercourse widening and the subsequent risk of flooding. Here, the planting of trees can play a part in binding soil together, which is held in place between the root system. These roots absorb water and slow the flow of water draining off the land into waterways, effectively acting as “sponges”. Therefore, riparian planting contributes to maintaining the integrity of riverbanks and minimising potential flood damage.

Habitat Enhancement

Riparian planting also augments ecological balance by supplying habitats for innumerable diverse species. The resulting increased biodiversity within riparian zones can reinforce natural processes that regulate water flow and quality. With this greater integrity, resilient ecosystems can better withstand extreme weather events on the increase in the UK, such as heavy rainfall events that can exacerbate flooding. Meanwhile, supporting diverse plant and animal life confirms natural flood mitigation processes remain effective and sustainable over time.

Long-Term Benefits

Executing riparian planting necessitates methodical planning and continued monitoring and maintenance to guarantee effective results. For example, planting trees can theoretically release more carbon than they store while lowering biodiversity, depending on what is planted and where. However, if implemented with careful planning (with all trade-offs navigated conscientiously), the longer-term advantages in riparian zones can include mitigated flood risk, enhanced water quality and strengthened biodiversity. In addition, incorporating riparian planting into comprehensive flood management strategies facilitates communities to establish more sustainable and resilient strategies for managing flood risks, ultimately with the goal of safer and more harmonious aquatic and terrestrial landscapes.

Even Small “Interventions” Could Make a Huge Difference

Localised interventions in upland woodlands and riparian zones can produce marked improvements (particularly cumulatively) in flood management and ecological functioning. Actions such as planting native vegetation along riverbanks, restoring wetlands, installing natural barriers to flooding, “re-meandering” rivers into their natural shape, or creating “retention ponds” to hold water (to name but a few) can improve water absorption, slow water flow, reduce erosion and improve water quality. These measures can thus mitigate flood risks, support biodiversity and strengthen ecosystem resilience. Even modest interventions, when integrated into more comprehensive flood management strategies, can result in palpable environmental and community benefits, illustrating how incremental alterations can collectively produce positive outcomes.

Further reading: Creating and managing riparian woodland - UK Forestry Standard Practice Guide

Riverside living, rich with cultural connection.

Cultural Ecosystem Value of Rivers

Freshwater systems significantly shape cultural diversity globally, frequently influencing artistic and literary traditions, architecture, folklore and local or regional identities. Protecting and enhancing riparian areas preserves these cultural values, strengthening community ties and supporting cultural heritage, demonstrating the profound impact of rivers beyond their ecological and economic roles.

Primary research for my master's thesis in 2021 showed how sensory experiences were underacknowledged but vital benefits of riparian woodland environments, based on exceptionally positive connections to water. At the same time as mitigating flood risk and adapting towards a changing climate, the cultural potential of these zones and the psychological function they can have is essential for countless diverse cultures on a worldwide scale.

Typically, connections are built to landscapes through sensory engagement enhanced by water-orientated environments, resulting in restorative and therapeutic experiences, inspiration (e.g., spirituality, education and art), and greater physical and mental well-being.

However, repeat flooding was found to threaten these benefits, resulting in the deterioration of vital pathways on riverbanks and causing psychological damage to residents, particularly where their daily lives and homes were also threatened. In this context, their established “sense of place” becoming increasingly at risk from flooding led to detrimental effects for the community as a whole.

This highlighted the need for more interventions to strengthen ecological resilience and community attachment. While a direct link between riparian woodland and flood-related psychosocial recovery was not established, there was evidence that these environments offer mental, physical and spiritual benefits; riparian woodland, the river and the paths along its banks were vital to the restorative and inspirational experiences of locals.

The investigation used a plethora of qualitative research instruments to understand these tangible (and less tangible) benefits people derive from preserved or restored riparian zones. For example, the image below (Figure 1) shows the outcome of a visual exercise where participants were asked to give positive or negative responses to various natural and manmade river elements. Figure 1 clearly shows that respondents favoured naturally formed landscape features over manmade (particularly anti-flooding) aspects.

Figure 1: Visual qualitative mapping exercise. Participants were asked if there were any positive (blue) or negative (red) feelings towards a series of images of rivers, in various states of human involvement or non-involvement.

Meanwhile, Figure 2 below used visual mapping to establish what areas were most important to local residents in the study area. The map clearly shows (in red) that locals favoured areas with healthy riparian zones for their daily activities relating to relaxing, peacefulness, leisure, bonding experiences, and many other activities that were tied to these wooded river environments.

Figure 2. Community value mapped riparian areas. Participants from riverside communities (in a flood prone towns next to rivers) were asked to map their daily movement on maps. The image clearly shows one predominant area (a riparian zone) that was most popular.

This study recommended incorporating notions of “place” into flood risk assessments before interventions to address climate change and complement structural solutions. Natural Flood Management should be adaptive, not “one-size-fits-all”. It should be tailored to different users, incorporating riparian planting and social dynamics.

In the future, research could explore how trees offer shelter, safety, and privacy, maximizing cultural ecosystem services for diverse groups. Ultimately, the construct of “place” means different things to different people, so spaces should be tailored to enhance the cultural potential of riparian planting, as it strengthens a “sense of place” and should be encouraged in flood-affected villages with those suffering from increasingly severe flooding.

A theoretical diagram of how this could be implemented is shown in Figure 3 below.

Figure 3. Theoretical diagram exploring how Natural Flood Management measures can be planned to support cultural aspects, which must encompass participatory methods to maximise value for the community. Source: Own diagram.

World Rivers Day: Honouring and Protecting Our Waterways

World Rivers Day (WRD) is celebrated every fourth Sunday of September, as an international event committed to acknowledging the indispensable contribution of rivers and advocating for their protection. WRD commenced in 2005, inspired by the United Nations “Water for Life Decade,” which attempted to raise awareness about water resources. The initiative was coordinated by Mark Angelo, a respected river conservationist who previously established BC Rivers Day in 1980.

Angelo’s fruitful initiative was endorsed by various UN agencies, resulting in the first World Rivers Day in 2005. The inaugural event generated broad participation, with observances taking place in many countries. Since 2005, WRD has expanded substantially, serving as a means of engaging millions of people in almost 100 countries each year. Its fundamental goal is to elevate levels of consciousness worldwide and promote sustainable management practices for river resources.

Celebrations on WRD include a plethora of diverse activities, including river cleanups, restoration projects and educational programmes. Attendees can link up with existing events or assemble their own and typically range from local cleanups to community festivals. These undertakings stimulate awareness and bring together communities in river conservation efforts that benefit their cultural connection to these vital bodies of water.

However, the worldwide influence of WRD extends beyond individual events; it becomes a platform for heightening recognition of river conservation and establishing stronger international collaboration. Therefore, WRD is a critical occasion in the recognition of the significance of rivers and advocating for their preservation; through greater awareness and more practical involvement, this day supports the health and sustainability of our waterways, securing their benefits for future generations.

By Neil Insh - Researcher

Veins of the world: How rivers drive nature’s pulse and human societies