SoNaRR 2025: Freshwater

Freshwater-based ecosystems occur wherever rainfall, snowmelt or groundwater collects into rivers and streams, standing waters, or associated bogs, fens, grazing marshes, wetlands and floodplains.

Key messages

• Freshwater ecosystems provide important ecosystem services including drinking water, renewable energy production, flood and drought mitigation, waste disposal, fisheries and recreation. However, their ability to do so is increasingly compromised.
• The resilience of freshwater ecosystems has not improved since 2020, and some widespread species are undergoing further declines; salmon is predicted to be locally extinct in some Welsh rivers by 2030. There are huge pressures from climate change, rural and urban pollution, physical modifications, changes to flow, and invasive non-native species.
• More frequent extreme weather events and increasing temperatures are a serious risk to freshwaters with floods and droughts causing degradation of habitat, wash out of species, changes in food availability, shifts in species composition and stranding of species.
• Restoration projects across Wales are showing the positive impact of interventions such as restoring gravels and boulders, putting large wood into rivers, removing bank protection and embankments, re-meandering straightened sections, creating wooded river corridors and addressing barriers. In total 854 km of river has been improved, protected or restored since 2020 and this is set to continue into the future.
• We must take a collaborative approach to landscape scale catchment management, ensuring that the Sustainable Farming Scheme delivers for freshwater and improving our regulation of habitat degradation. Ultimately this relies on society’s awareness of the environment and the impact of our behaviours.
  
  

Assessment of SMNR

This freshwater assessment is one of eight ecosystem and three natural resource assessments that inform the overall SoNaRR2025 report. It builds on the findings of SoNaRR2020, drawing together updated evidence from subject experts, national datasets, and collaborative projects such as Four Rivers for LIFE, DeeLIFE and the Upper Wye Restoration project. This assessment is closely linked to the Water Assessment as well as to evidence in the Climate Change and Land Use Change assessments.

The assessment is structured around four interlinked aims that guide Wales’ progress toward the sustainable management of natural resources (SMNR), helping to communicate the relationship between the environment, well-being, and the economy.

Aim 1: Stocks of natural resources are safeguarded and enhanced

Freshwater ecosystems in Wales face significant pressures from modification, regulation, pollution, invasive species, and climate change. Most freshwater species recently assessed under the Habitats Regulation are in unfavourable condition, with salmon and freshwater pearl mussel in serious decline. Invasive non-native species (INNS) such as Himalayan balsam and signal crayfish continue to threaten native biodiversity and riverbank stability. Pollution from nutrients, chemicals, and metals have historically degraded water quality, though some improvements have occurred. However, emerging contaminants like microplastics and pharmaceuticals pose new risks, and the future outlook remains uncertain.

Efforts to safeguard freshwater resources include habitat restoration, INNS control, and pollution management. Projects like 4 Rivers for LIFE and the Wales Metal Mines Programme are improving river habitats and reducing pollution. Constructed wetlands and weather stations help manage runoff and water quality. Water company investments are addressing storm overflow spills, and research into antimicrobial resistance is advancing understanding of waterborne health risks. These actions support species conservation and enhance ecosystem resilience.

Aim 2: Ecosystems are Resilient to Expected and Unforeseen Change

The resilience of freshwater ecosystems is their capacity to withstand external pressures. The mechanisms of resilience are generally quite well understood in freshwaters, although our understanding of the resilience of freshwaters in Wales is hampered by a lack of national level datasets to measure it.

The assessments of diversity, extent, condition, and connectivity across freshwater habitats reflect the way ecosystem resilience of freshwaters has been significantly compromised by human impacts on habitat structure such as invasive species, the extent of shade, weirs and dams, abstractions, and river-flood plain connectivity. Generally, assessments are lower in lowland freshwaters compared with those in upland areas, with upland lakes and rivers assessed higher for diversity and condition.

The main challenge in delivering SMNR for freshwater habitats and species in Wales is preventing further damage and identifying opportunities to restore natural ecosystem function to build resilience. Restoration projects like DeeLIFE and Salmon for Tomorrow have improved over 850 km of river environment and enhanced fish migration routes between 2020-2025. These efforts, alongside updated River Basin Management Plans and targeted habitat measures, are stabilising measures of extent and connectivity and building resilience against climate change and other pressures.

Aim 3: Healthy Places for people, protected from environmental risk

Freshwater ecosystems support human health by purifying water and regulating extreme flows. In-stream and riparian processes retain significant amounts of sediment and nutrients, improving water quality. Constructed wetlands are being trialled to treat effluents and manage water flow, contributing to safer and cleaner environments.

These ecosystems also enhance well-being through recreation, cultural heritage, and education. Over 28 million visits were made to freshwater sites in 2021/22, offering physical and mental health benefits. Traditional fishing methods hold heritage value, and many freshwater sites support learning and research. However, minority groups remain underrepresented among visitors. Promoting equitable access and cultural services can strengthen the role of freshwater ecosystems in public health and well-being.

Aim 4: Contributing to a Regenerative Economy, Achieving Sustainable Levels of Production and Consumption

Freshwater ecosystems contribute to the economy through water purification, hydropower, and recreation. In 2023, hydropower generated 332 GWh, supporting Wales’ renewable energy goals. Clean water reduces treatment costs for industries and utilities, and nature-based solutions like wetlands offer cost-effective alternatives to built infrastructure. Recreational activities linked to freshwater ecosystems support local economies, with tourism spending reaching £90 million in 2022.

Economic pressures leading to agricultural intensification, built development and water abstraction remain a concern, especially in the face of the changing climate. However, nature-based solutions, restoration interventions and improved land management are promoting sustainable land use and enhancing the regenerative potential of freshwater ecosystems. In addition, planning controls are reducing nutrient inputs into key freshwater protected sites and rod/net licence exploitation controls have reduced pressure on salmon and sea trout.

Key changes since SoNaRR2020

Since SoNaRR 2020, new evidence has provided more confidence in the assessment of key freshwater species and a better understanding of the key pressures notably water pollution. A high proportion of water bodies are failing targets for nutrients and salmon are at risk of localised extinction.

The impacts of climate change are becoming more evident and increasing; new evidence shows complex interactions with salmonid spawning and survival as well as long term reductions in cool water stoneflies in response to warming temperatures.

The improved evidence base combined with high levels of public interest and awareness in the health of freshwaters is enabling a variety of regulatory and restoration responses. In particular, planning controls on nutrients are in place across riverine protected sites and we have several large-scale projects working to restore freshwater processes and features. Moving forwards, finding sustainable funding sources and working collaboratively across catchments are priorities to deliver long term solutions for nature and communities.

Read the full assessment of the Freshwater ecosystem in our State of Natural Resources Report 2025.

Underlying evidence

In writing our assessments and to better identify opportunities for action we have gathered evidence that helps us understand these key aspects:

• the drivers of change and pressures on freshwater in Wales.
• the ecosystem resilience of freshwater in Wales.
• the benefits, or services, we get from freshwater and how changes in the state of coastal margins impact on well-being.

Access the detailed evidence through our SoNaRR 2025 Evidence portal.

View full screen version

Evidence needs

There is a critical need to assess the current extent, condition and trends in freshwater ecosystems in Wales. Evidence gaps include the extent of physical modifications, the impacts of climate change and the vulnerability of freshwater-dependent species. Tools for measuring ecosystem health and the benefits of restoration interventions are also needed, alongside improved monitoring of species such as lamprey, frogs, and toads. These insights are essential for informing sustainable management and enhancing the resilience of freshwater ecosystems under increasing environmental pressures.

A significant number of evidence needs relate to understanding the sources and effects of water pollution, including fine sediments, emerging contaminants, and agricultural runoff. There is a call for reliable source-apportionment methods and tools to quantify the ecological effects of pollutants on species like salmon and freshwater pearl mussels. Additionally, the role of regulatory practices, abstraction pressures, and water efficiency in shaping ecosystem health requires further investigation.

Read SoNaRR 2025 Evidence needs.

Key evidence sources

Explore some of the evidence we have used to inform our assessment:

• SoNaRR 2020 Freshwater assessment
• Energy generation in Wales
• ERAMMP Report-105: Wales National Trends and Glastir Evaluation
• First Habitats Regulations 9A Report for Wales 2025 [in prep]
• Measuring and Valuing Ecosystem Contribution of Water Quality in the UK
• NRW water quality reports
• Salmon Stocks and Fisheries in England and Wales
• UK Natural Capital Accounts
  
  

Case studies

Upper Wye Catchment Restoration Project

The Upper Wye Catchment Restoration Project is an NRW project funded by Welsh Government to restore the health of the upper reaches of the River Wye.

It is home to several important species including Atlantic salmon, otter, shad, white clawed crayfish and the plant, water crowfoot.

Upper Wye Catchment Restoration Project - Natural Resources Wales Citizen Space - Citizen Space

LIFE Dee River

The Dee is the largest river in North Wales with a catchment area of more than 1,800 km². LIFE Dee River is a £6.8m project to transform the River Dee and its catchment by restoring the river and its surroundings back to their natural state. This will bring many benefits to the environment, most notably improving the numbers of salmon, lamprey and freshwater pearl mussels to help them become more sustainable in future.

Natural Resources Wales / LIFE Dee River

Four Rivers for LIFE

Four Rivers for LIFE is an ambitious, large-scale river restoration project to improve the condition of four major rivers in Wales: Teifi, Cleddau, Tywi and Usk. these four rivers are classed as Special Areas of Conservation (SAC) which means they are of international importance for their wildlife and plants such as Atlantic salmon, lamprey, shad, otter and water crowfoot. All four rivers are currently in an unfavourable condition as a result of multiple pressures.

Natural Resources Wales / Four Rivers for LIFE