Status: No overall trend discernible with few or no concerns

(Baxter et al, 2011)

Status of eutrophication: Stable situation since 2012

(United Kingdom Marine Monitoring & Assessment Strategy, n.d)

Marine environments require nutrients, however when there is the input of nutrients (such as nitrogen and phosphorus), or other plant nutrients, in larger amounts than necessary water bodies become overly enriched. Eutrophication is the term used to describe the increase in nutrients in coastal and aquatic environments. Excessive algae growth, plant growth and plankton blooms are the result of eutrophic waters. In turn, these impacts can cause oxygen depletion harming marine organisms, reduction in sunlight entering marine environments, and aesthetic issues with visual impacts from excessive algal growth on the water surface. There is also danger to people taking part in recreational activities and to other socio-economic sectors such as fishing and aquaculture.

A potential side effect of eutrophication is sea foam. Sea foam can be caused simply by ocean agitation but can also be an impact of the breakdown of algal blooms.


Image; Sea foam at Port Logan © G. Reid/ Solway Firth Partnership


Excess Nutrients

The input of excessive nutrients into marine environments can occur in several ways  upstream of coastal environments through increased run-off or pollution from a variety of sources such as urban pollution, but often significantly through agriculture. It can also occur directly into the coastal environment through socio-economic activities such as aquaculture, atmospheric deposition or from sewage outfalls.

In Scotland, many of the activities which can cause eutrophication of coastal and upstream waters are licensed through the The Water Environment (Controlled Activities) (Scotland) Regulations 2011 (as amended) which minimises excess nutrients entering the system. Scottish Environment Protection Agency (SEPA) can authorise the carrying out of a controlled activity in accordance with the respective regulations. There is a practical guide to The Water Environment (Controlled Activities) (Scotland) Regulations 2011 (as amended) available from SEPA which outlines whether an activity requires authorisation from SEPA, and the level of authorisation needed. The guide is available here. In England environmental permitting is managed through the Environmental Permitting (England and Wales) Regulations 2016 (as amended). Among other environmental permitting requirements, these regulations outline that a person must not ’cause or knowingly permit a water discharge activity or groundwater activity’ unless they have an environmental permit (there are exceptions).

A publication from the Environment Agency (EA) in 2019, ‘Climate change and eutrophication risk thresholds in English rivers‘, looked at projected phytoplankton growth, response and signs of eutrophication, in light of climate change (with previous work indicating climate change would increase the phosphorus concentrations in the future) in England. The River Eden (testing site near Carlisle, upstream of the Solway and the only site in North West Cumbria) was identified as a site with no current or future projection of eutrophication risk, being a site with low phosphorous concentrations.

SEPA and the EA work to help prevent excess nitrates entering and polluting waters through working with the agricultural sector.



Directives and Monitoring

Eutrophication is a marine pressure which is sought to be minimised from all sources through European Union Directives, such as the Marine Strategy Framework Directive (08/56/EC) (MSFD) and the Water Framework Directive (2000/60/EC) (WFD). In addition, the Nitrates Directive (91/676/EEC), and the Urban Waste Water Treatment Directive (91/271/EEC) combat eutrophication from agricultural and waste water sources respectively. The OSPAR eutrophication Strategy also seeks to combat eutrophication more generally from all sources rather than targeting specific inputs.


Marine Strategy Framework Directive

Eutrophication is assessed as a ‘descriptor’ for achieving ‘Good Environmental Status’ (GEnvS). Achieving GEnvS in the marine environment is required in all European Union member states as per the Marine Strategy Framework Directive in order to provide more effective marine environment protection and sustainable use. Council Decision 2017/848 lays out the criteria and methodological standards on GEnvS of marine waters and specifications and standardised methods for monitoring and assessment. No additional monitoring is required over and above that already prescribed through the Water Framework Directive (WFD) (only covers coastal waters out to 3 nautical miles in Scotland and 1 nautical mile in England) for coastal waters.

In terms of defining what GEnvS is and how to reach it, there are 11 qualitative ‘descriptors’ included in Annex I of the MSFD to help each member state interpret GEnvS and illustrate what a marine environment which has GEnvS looks like. Descriptor 5 concerns eutrophication, with the UK high-level objective for reaching GEnvS for eutrophication being; “Human-induced eutrophication is minimised in UK marine waters” (Department for Environment, Food, and Rural Affairs, 2019).

The United Kingdom Marine Monitoring & Assessment Strategy, Marine Online Assessment Tool, details progress towards GEnvS in terms of eutrophication. Only 0.41% of the UK’s coastal and transitional waters have an issue with eutrophication (United Kingdom Marine Monitoring & Assessment Strategy, n.d.). According to the 2019 updated Part 1 Assessment GEnvS for eutrophication around the UK had been ‘largely achieved’ through assessing nutrient and Chlorophyll a concentrations, and the content of dissolved oxygen as well as nutrient input.


Water Framework Directive

The Water Framework Directive (WFD) aims for water bodies to reach ‘Good Ecological Status’ (GEcS) for groundwaters, surface water, transitional, and coastal waters (out to 1 nautical mile in England and out to 3 nautical miles in Scotland) (see Transitional and Coastal waters). The WFD created an integrated framework for water protection throughout the EU with set standards. Among other requirements, the WFD also dictates that all Member States must produce River Basin Management Plans

SEPA and the EA collect data for the assessment of water bodies under the WFD (data also used for OSPAR monitoring is discussed below). The biological and chemical parameters which give an indication as to whether or not a water body is at risk of eutrophication are: dissolved oxygen, dissolved inorganic nitrogen, macroalgae and phytoplankton.

The Inner Solway (transitional) had a classification of ‘Moderate’ in 2016. This was likely due to factors associated with the overall ecology, phytoplankton, physico-chemical quality, dissolved inorganic nitrogen and biological elements from poor nutrient management from agricultural and rural land management. The Solway Outer South had a ‘Moderate’ classification in 2016, largely due to diffuse pollution from poor soil management from agricultural and rural land management.

Anecdotal evidence from local people suggests there have been some algal blooms in summer months at Sandhead, Dumfries and Galloway. The Dumfries and Galloway Local Biodiversity Action Plan (2009) suggested that eutrophication from agriculture was a factor which may affect maritime cliff habitat, especially at Almorness and the Murray Isles. 

Water body classifications can be examined in more detail using SEPA’s interactive tool ‘Water Environment Hub’ and the EA’s Catchment Data Explorer.


Nitrates Directive

As mentioned above, run-off from the agricultural sector is a significant contributor to eutrophication. The Nitrates Directive (1991/676/EEC) seeks to prevent nitrates from agricultural sources from polluting ground and surface water. An important aspect of the WFD is to assist with protecting waters against agricultural pollution. Member States are required to designate Nitrate Vulnerable Zones (NVZs) under the Nitrates Directive. These are areas draining into waters already exceeding the nitrate concentrations limit set out in the Directive, or at risk of agricultural nitrate pollution (about 55% of land in England is designated as NVZ). NVZs are designated under the Designation of Nitrate Vulnerable Zones (Scotland) Regulations 2014, and the Nitrate Pollution Prevention Regulations 2015 in England. Monitoring, the need to establish codes of good practices for farmers (which are voluntarily implemented) and compulsory Action Programmes for farmers to reduce pollution within NVZs are all required under the Directive. The Directive also requires a limit of 170kg nitrogen per hectare per year from livestock manure. Scotland and England have obligations, legal and environmental, as a result of this Directive. Scotland meets these requirements through the Action Programme for Nitrate Vulnerable Zones (Scotland) Regulations 2008 (as amended) and England does so through the Nitrate Pollution Prevention Regulations 2015.

NVZs along the Solway coast:

  • Lower Nithsdale (Dumfries and Galloway) (designated 2016)
  • Stranraer lowlands (Dumfries and Galloway) (designated 2016)
  • Great Gutter (Cumbria) (2021-2024)
  • Brunsow Beck (Cumbria) (2021-2024)
  • Scad Beck (Cumbria) (2021-2024)
  • St Bees (Cumbria) (2021-2024)

Both Scottish and English NVZs are reviewed every 4 years in line with the Directive’s requirement for Member States to; “review the eutrophic state of their fresh surface waters, estuarial and coastal waters every four years”.

For the newest NVZs, and to see a map of the areas currently designated in England explore the Environment Agency (EA) interactive map available here. A map of each of the five NVZs currently designated within Scotland are available here. The Scottish NVZs are also due to be updated, but it is likely that the five NVZs already designated will continue as NVZs.

In England there is a scheme to provide financial incentives to farmers and land managers to improve the environment. This is called the Countryside Stewardship scheme, and areas where there is the potential through Agreements under the scheme to help the water quality (towards WFD standards) are called ‘Water Quality Priority Areas’. Within these areas there are sites of High and Medium priority for ‘Surface Water Nitrate Issues’ around the English Solway coast. Water quality data can be accessed and explored through Magic Map from the Department for Environment, Food and Rural Affairs.


Urban Waste Water Treatment Directive

The Urban Waste Water Treatment Directive sets standards for the collection and treatment of wastewater from homes and certain industrial sectors, and regulates the nutrient inputs from those waste waters.

Waste water collection and treatment mandated by this Directive are for ‘Urban agglomerations’ in areas where the population is over 2,000, and thereafter more stringent based on how large the population is. The Directive also requires the designation of ‘sensitive areas’, which include ‘natural freshwater lakes, other freshwater bodies, estuaries and coastal waters which are found to be eutrophic or which in the near future may become eutrophic if protective action is not taken’ (Annex II of the Urban Waste Water Treatment Directive). ‘Sensitive areas’ also include areas where further treatment is required in order to comply with other Directives, such as bathing waters and shellfish water protected areas. Sensitive areas also determine if more stringent waste water treatment will be required. According to the European Commission website, of the types of ‘sensitive areas’ which can be designated, eutrophic is the most common. They are areas ‘in which removal of phosphorus and/or nitrogen in the treatment plants of large cities must be applied’ (European Commission, n.d.). Unlike some other member states which applied more stringent treatment requirements to the whole country, the UK identifies individual ‘sensitive areas’.

All of the waste water agglomerations of more than 2,000 people in the UK, compliance details, and more information is available through the European Commission urban waste water website here.

Scotland and England each implement the Directive through separate regulations. There are several ‘sensitive areas’ around both sides of the Solway, with designations such as bathing waters and shellfish water protected areas around the Firth. Sensitive areas in England are outlined here, and in Scotland are outlined here.



OSPAR (named ‘OSPAR’ from the unified convention of the Oslo Convention ‘OS’ and Paris Convention ‘PAR’) is the mechanism by which cooperation occurs for protecting the North-East Atlantic marine environment. OSPAR has a Eutrophication Strategy listing requirements for assessing eutrophication, with the objective of reducing eutrophication within the North-East Atlantic marine environment.

A eutrophication assessment framework (‘Common Procedure‘) has been developed by OSPAR which provides a common approach across all Contracting Parties to identify areas where nutrient inputs may cause pollution. The Common Procedure periodically assesses the progress towards the OSPAR eutrophication strategy to reduce eutrophication. According to the Third Integrated Report on the Eutrophication Status of the OSPAR Maritime Area (2017) (available here under the ‘eutrophication assessments’ tab) there are no ‘problem areas’ or ‘potential problem areas’ for eutrophication in the Solway Firth.

Data for the OSPAR eutrophication monitoring programme is collected by SEPA and the EA to assess waterbodies seeking to achieve ‘Good Ecological Status’ (GEcS) under the Water Framework Directive (see Transitional and Coastal Waters).


Image; Scotland’s National Marine Plan Interactive, with layers (links will provide usage licence, data provider, etc); ‘Solway Region (mask)‘ © Crown Copyright, All rights reserved, ‘Chlorophyll in Transitional and Coastal Waters (surface Chl-a concentrations, June – Aug 2008) (µg/l)‘ © Crown Copyright, All rights reserved, data provided by SEPA, ‘Dissolved Inorganic Nitrogen in Transitional and Coastal Waters (depth averaged DIN, 2008) (µM)‘, © Crown Copyright, All rights reserved, data provided by SEPA, ‘Limits and Boundaries – NE and NW Marine Plan Areas for England (MMO) – August 2016‘ © Crown Copyright, All rights reserved

Note; many data points in the ‘Dissolved Inorganic Nitrogen in Transitional and Coastal Waters (depth averaged DIN, 2008) (µM) layer overlay data points in the ‘Chlorophyll in Transitional and Coastal Waters (surface Chl-a concentrations, June – Aug 2008) (µg/l)‘ layer, therefore it is best to interact with the map layers seperately to fully explore the data.



Department for Environment, Food and Rural Affairs (2018). Defra magic map. Available here (Accessed: 03.10.18)

European Commission (2016). Environment. Marine Strategy Framework Directive Descriptor 5: Eutrophication. Available here (Accessed: 04.09.18)

Marine Management Organisation. (n.d). Marine Planning Evidence Base. Available here. (Accessed: 14.05.18)

Mills, F., Sheridan, S. and Brown S., (2017). Clyde Marine Region Assessment. Clyde Marine Planning Partnership. pp 231, Available here. (Accessed: 14.05.18)

Scottish Environmental Protection Agency (2015). Water Environment Hub. Available here (Accessed: 03.10.18)

Solway Firth Partnership (1996). The Solway Firth Review, Solway Firth Partnership, Dumfries. Available here. (Accessed 23.07.19)

United Kingdom Marine Monitoring & Assessment Strategy (n.d). Eutrophication. Available here. (Accessed: 15.12.20)

UK National Ecosystem Assessment (2011). The UK National Ecosystem Assessment Technical Report. UNEP-WCMC, Cambridge. Available here. (Accessed: 28.05.18)


In-Text References;

Baxter, J.M., Boyd, I.L., Cox, M., Donald, A.E., Malcolm, S.J., Miles, H., Miller, B., Moffat, C.F., (Editors), (2011). Scotland’s Marine Atlas: Information for the National Marine Plan. Marine Scotland, Edinburgh. pp 191. Available here. (Accessed: 22.07.19)

Department for Environment, Food and Rural Affairs (2019). Marine strategy part one: UK updated assessment and Good Environmental Status. Available here (Accessed: 02.02.21)

Environment Agency (2019). Climate change and eutrophication risk thresholds in English rivers. Available here. (Accessed: 29.01.21)

European Commission (n.d.) Facts and Figures about Urban Waste Water Treatment. Available here. (Accessed: 15.12.20).

Marine Scotland (n.d.). Scotland’s National Marine Plan Interactive. Available here. (Accessed: 06.08.19)

South West of Scotland Environmental Information Centre (2009). Dumfries and Galloway Local Biodiversity Action Plan – Part 2. Available here. (Accessed: 22.07.19)

United Kingdom Marine Monitoring & Assessment Strategy (n.d). Summary of Progress towards Good Environmental Status. Available here. (Accessed: 15.12.20)


Image; Harrington. © Solway Firth Partnership.