The River Wye Catchment

The River Wye is the fourth largest river in the UK, stretching for 155 miles with much of its length forming part of the border between England and Wales. The Wye's main tributaries include the Elan, Ithon, Lugg and Monnow. Much of the lower Wye valley is a National Landscape(External link).


Image: River Wye


The river corridor supports a variety of plants, otters, water voles, several bat species, dippers, sand martins, kingfishers and little ringed plovers. The Wye supports an exceptionally diverse community of river invertebrates, and is home to rare species such as the Yellow Mayfly and Depressed River Mussel. The river is famous for its large salmon that have spent three or more years at sea before returning to spawn.



Image: Bullhead fish (Cottus Gobio)
The river is one of the most important areas of conservation and is a Site of Special Scientific Interest (SSSI)(External link). The River Wye and part of the River Lugg form the ‘River Wye Special Area of Conservation’ (SAC).(External link) This means the river has the highest level of protection in the UK.

Natural England, assesses and reports on protected sites using data and other evidence available. Common Standards Monitoring Guidance(External link) is used to check the health of protected sites.

To protect the river everyone must continue working together to make improvements. The scale and complexity of the challenges in the catchment means solutions will take time, there is no quick fix and interventions must be evidenced based. When positive interventions are identified it will take time before the benefits take effect.


What are the big challenges facing the Wye?

During May 2023 Natural England downgraded the status of the Wye from unfavourable-improving, to unfavourable-declining. The reason for this was because their assessment identified that the River Wye SAC is showing declines in Atlantic Salmon and White-Clawed Crayfish populations, and water quality is declining in the Lugg.

Invasive Signal Crayfish carry the crayfish plague and are responsible for the decline of the native, White-Clawed Crayfish. Salmon declines are due to a number of different factors including adult survival rates at sea. More evidence is needed to fully understand all issues impacting water quality. Some of the problems are due to changing agricultural and industrial practices, climate change, urbanisation and a growing human population over the last decades.

‘There has not been a sudden decline in the health of the river.’

Read Natural England’s Blog(External link)


Phosphorus

Eutrophication is when there are too many nutrients in rivers, lakes/reservoirs, estuaries or the sea, causing excessive growth of algae and plants. This adversely affects the quality of the water and can be damaging the local ecology.

Find out more about eutrophication check out Ecology in the Wye.

Phosphorus and nitrogen are the main nutrients involved in eutrophication, with phosphorus the main cause of eutrophication in freshwaters. Phosphates are the most common cause of water quality failures under the Water Framework Directive(External link) in England.

Read Focus on Phosphorus to learn about the difference between phosphate and phosphorus.

Over 70% of the phosphate load in the Wye catchment is estimated to come from diffuse agricultural pollution from livestock manure and nutrients washing into the river during heavy rain. Other sources of phosphate include wastewater treatment works, highways, industry and intermittent sewage discharging including combined sewer overflows. Currently, phosphate levels in the English River Wye pass for their quality threshold. However, many of the Wye’s tributaries including the River Lugg have excessively high phosphate levels. Source Apportionment Geographical Information System and Simulation of water quality in Catchments models were used by Natural Resources Wales (NRW) and the Environment Agency (EA) to produce the source apportionment data. These are the main water quality catchment modelling tools that are used by all the Regulators in the UK.


Image: Saturated land and run off



The ground-breaking RePhoKUs research project indicated that soils in the Wye catchment as less able to hold onto phosphorus added by fertilisers and manures than other soils. This means there is a greater risk of losing phosphorus to draining streams and into the river. Evidence suggests the Wye catchment has been in phosphorus surplus for the last 150 years. Farming in the catchment generates an annual phosphorus surplus of 2000 tonnes, which is accumulating in the catchment soils. This amount of unused phosphorus is nearly 60% greater than the national average and is driven by the large amounts of livestock manure produced in the catchment.



Climate change

Using the latest science from the Met Office and around the world, the UK Climate Projections 2018(External link) illustrate a range of future climate scenarios until 2100 – showing that increasing summer temperatures, more extreme weather events and rising sea levels are all on the horizon and urgent international action is needed.


Image: Farm land during drought


Climate change is expected to impact the water quality and quantity in our rivers increasing the risk of eutrophication. Changes to phosphate concentration, river flow, temperature and sunlight are all likely to increase the risk of eutrophication.

Severe weather events will increase sediment entering our rivers. More frequent or extreme rainfall events can increase erosion and sediment loading from runoff. Increased sedimentation will impact both Water Crowfoot (Ranunculus), and fish populations. Water Crowfoot is an aquatic member of the buttercup family, with long trailing green foliage and small white flowers, it provides a habitat for aquatic life, provides cover for fish and modifies the river flow. Excessive sediment can reduce the amount of light that reaches Water Crowfoot.

Image: White Water Crowfoot (Ranunculus aquatilis)
Excess nutrient loading from sediment can lead to eutrophication, promoting the growth of algae and other plants which outcompete Water Crowfoot.

Many freshwater species are sensitive to the water thermal regime and often have a limited range of temperature tolerance.

Climate change is expected to impact the water quality in our rivers increasing the risk of eutrophication. Changes to phosphate concentration, river flow, temperature and sunlight are all likely to increase the risk of eutrophication.

Read about the Environment Agency and climate change adaption(External link).

Carbon footprint is the amount of carbon dioxide released into the atmosphere as a result of the activities of a particular individual, organization, or community.



Calculate your carbon footprint(External link)

(External link)

The River Wye is the fourth largest river in the UK, stretching for 155 miles with much of its length forming part of the border between England and Wales. The Wye's main tributaries include the Elan, Ithon, Lugg and Monnow. Much of the lower Wye valley is a National Landscape(External link).


Image: River Wye


The river corridor supports a variety of plants, otters, water voles, several bat species, dippers, sand martins, kingfishers and little ringed plovers. The Wye supports an exceptionally diverse community of river invertebrates, and is home to rare species such as the Yellow Mayfly and Depressed River Mussel. The river is famous for its large salmon that have spent three or more years at sea before returning to spawn.



Image: Bullhead fish (Cottus Gobio)
The river is one of the most important areas of conservation and is a Site of Special Scientific Interest (SSSI)(External link). The River Wye and part of the River Lugg form the ‘River Wye Special Area of Conservation’ (SAC).(External link) This means the river has the highest level of protection in the UK.

Natural England, assesses and reports on protected sites using data and other evidence available. Common Standards Monitoring Guidance(External link) is used to check the health of protected sites.

To protect the river everyone must continue working together to make improvements. The scale and complexity of the challenges in the catchment means solutions will take time, there is no quick fix and interventions must be evidenced based. When positive interventions are identified it will take time before the benefits take effect.


What are the big challenges facing the Wye?

During May 2023 Natural England downgraded the status of the Wye from unfavourable-improving, to unfavourable-declining. The reason for this was because their assessment identified that the River Wye SAC is showing declines in Atlantic Salmon and White-Clawed Crayfish populations, and water quality is declining in the Lugg.

Invasive Signal Crayfish carry the crayfish plague and are responsible for the decline of the native, White-Clawed Crayfish. Salmon declines are due to a number of different factors including adult survival rates at sea. More evidence is needed to fully understand all issues impacting water quality. Some of the problems are due to changing agricultural and industrial practices, climate change, urbanisation and a growing human population over the last decades.

‘There has not been a sudden decline in the health of the river.’

Read Natural England’s Blog(External link)


Phosphorus

Eutrophication is when there are too many nutrients in rivers, lakes/reservoirs, estuaries or the sea, causing excessive growth of algae and plants. This adversely affects the quality of the water and can be damaging the local ecology.

Find out more about eutrophication check out Ecology in the Wye.

Phosphorus and nitrogen are the main nutrients involved in eutrophication, with phosphorus the main cause of eutrophication in freshwaters. Phosphates are the most common cause of water quality failures under the Water Framework Directive(External link) in England.

Read Focus on Phosphorus to learn about the difference between phosphate and phosphorus.

Over 70% of the phosphate load in the Wye catchment is estimated to come from diffuse agricultural pollution from livestock manure and nutrients washing into the river during heavy rain. Other sources of phosphate include wastewater treatment works, highways, industry and intermittent sewage discharging including combined sewer overflows. Currently, phosphate levels in the English River Wye pass for their quality threshold. However, many of the Wye’s tributaries including the River Lugg have excessively high phosphate levels. Source Apportionment Geographical Information System and Simulation of water quality in Catchments models were used by Natural Resources Wales (NRW) and the Environment Agency (EA) to produce the source apportionment data. These are the main water quality catchment modelling tools that are used by all the Regulators in the UK.


Image: Saturated land and run off



The ground-breaking RePhoKUs research project indicated that soils in the Wye catchment as less able to hold onto phosphorus added by fertilisers and manures than other soils. This means there is a greater risk of losing phosphorus to draining streams and into the river. Evidence suggests the Wye catchment has been in phosphorus surplus for the last 150 years. Farming in the catchment generates an annual phosphorus surplus of 2000 tonnes, which is accumulating in the catchment soils. This amount of unused phosphorus is nearly 60% greater than the national average and is driven by the large amounts of livestock manure produced in the catchment.



Climate change

Using the latest science from the Met Office and around the world, the UK Climate Projections 2018(External link) illustrate a range of future climate scenarios until 2100 – showing that increasing summer temperatures, more extreme weather events and rising sea levels are all on the horizon and urgent international action is needed.


Image: Farm land during drought


Climate change is expected to impact the water quality and quantity in our rivers increasing the risk of eutrophication. Changes to phosphate concentration, river flow, temperature and sunlight are all likely to increase the risk of eutrophication.

Severe weather events will increase sediment entering our rivers. More frequent or extreme rainfall events can increase erosion and sediment loading from runoff. Increased sedimentation will impact both Water Crowfoot (Ranunculus), and fish populations. Water Crowfoot is an aquatic member of the buttercup family, with long trailing green foliage and small white flowers, it provides a habitat for aquatic life, provides cover for fish and modifies the river flow. Excessive sediment can reduce the amount of light that reaches Water Crowfoot.

Image: White Water Crowfoot (Ranunculus aquatilis)
Excess nutrient loading from sediment can lead to eutrophication, promoting the growth of algae and other plants which outcompete Water Crowfoot.

Many freshwater species are sensitive to the water thermal regime and often have a limited range of temperature tolerance.

Climate change is expected to impact the water quality in our rivers increasing the risk of eutrophication. Changes to phosphate concentration, river flow, temperature and sunlight are all likely to increase the risk of eutrophication.

Read about the Environment Agency and climate change adaption(External link).

Carbon footprint is the amount of carbon dioxide released into the atmosphere as a result of the activities of a particular individual, organization, or community.



Calculate your carbon footprint(External link)

(External link)

Page last updated: 02 Feb 2024, 10:49 AM