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Often driven by rainfall and how we manage land, diffuse pollution occurs when nutrients, pesticides, faecal bacteria, chemicals and fine sediments are lost from the land into local burns, rivers, lochs and groundwater.  This represents a cost to the farm business.

Diffuse pollution is often from a range of sources but the effect is cumulative.  So what appears to be small amounts of runoff from one field, when added to all the other sources that also feed into that burn or river, it can have a big overall effect on water quality.

Examples of diffuse pollution risks include:

  • Fertilisers and pesticides spread at the wrong time or too close to a ditch, burn, river, loch, wetland or coastal water
  • Cultivating too close to a watercourse. This can remove the buffer strip and increase the risk of soil loss or field runoff getting straight into watercourses
  • Erosion and poaching. Soil loss around watercourses or regular traffic through rivers and burns can further increase erosion risk.
  • Soils lost to any ditch, burn, river, loch, wetland or coastal water represents a loss from your farm
  • Slurry or dung.  Applying too much, or spreading too close to a watercourse, risks creating polluting runoff, wastes valuable nutrients and cost you money



It is not just an issue at a local level; the effects of diffuse pollution on water quality can often be seen miles away from the source, for example beaches designated as ‘bathing waters’ can be affected by runoff coming from further up the catchment.

The effects of diffuse pollution include:

  • Increased risk to farm biosecurity and livestock health
  • Toxic substances in drinking water (E.coli, metaldehyde)
  • Health impacts such as stomach upsets, throat and eye infections experienced by people using bathing waters
  • Excess nutrients causing algal problems in rivers, lochs and estuaries (toxic blue green algae growth, aided by phosphorus from waste water and fertiliser)
  • Damage to wildlife including protected species such as salmon, fresh water pearl mussels and water voles (e.g. eroded soils smothering river beds which are important for fish and invertebrates)
  • Economic impacts for the farm, the wider agricultural sector, tourism and recreation

Reducing diffuse pollution risk doesn’t just benefit water quality and the environment; it can also help to improve farm business efficiency, profitability and can lower your farm carbon footprint.

It also keeps you on the right side of the regulations, protecting farm payments.

3 key ways to tackle diffuse pollution:

  • Reduce the source of the pollution – where is it coming from? Can the pollution source be minimised?
  • Block the pathway – assess how the pollution source is getting from the source to the problem site
  • Prevent it getting to areas where it will become a problem – divert or collect the pollution before it reaches the watercourse


Reducing diffuse pollution risks could benefit the farm business by:

  • Improving farm profitability – identifying and removing compaction could improve crop yield or increase the window for stock turnout
  • Improving livestock profitability – keeping livestock out of watercourses and providing clean water for drinking, could improve livestock health by reducing disease transfer risk from other animals drinking upstream
  • Making better use of resources – testing soils and working to a nutrient budget could improve nutrient use on the farm and lower the farm carbon footprint, saving you money
  • Keeping you on the right side of the regulations
  • Knowing what activities pose a diffuse pollution risk and how they are covered in the rules could help you to prioritise diffuse pollution reduction on your farm.  Some topics, for example, nutrient management could lead to financial benefits for the business.

How is Scotland Reducing Diffuse Pollution Risks?

Water quality improvements are being driven by European Legislation, namely the Water Framework Directive (WFD), which has resulted in the Water Environment and Water Services (Scotland) Act 2003 (WEWS Act).

Through the WEWS Act, Scottish Ministers have powers to introduce regulatory controls over water activities, in order to protect, improve and promote sustainable use of Scotland’s water environment. This includes wetlands, rivers, lochs, transitional waters (estuaries), coastal waters and groundwater.

A national coordinated approach is underway to work with farmers, forestry and recreational businesses to improve and protect water quality by reducing diffuse pollution risks.

Legislation is in place to reduce pollution risks from rural land use; forestry operations, golf courses and amenity land all have rules they have to follow when working near any ditch, burn, river, loch, wetland or coastal water. If voluntary actions and current legislation don’t have a positive impact on water quality, it is likely that more rules will follow.

The Diffuse Pollution Management Advisory Group (DPMAG) is focusing on improving Scotland's water environment by taking a partnership approach to reducing rural diffuse pollution risks. This will help to protect and improve the water environment and deliver the targets set in the river basin management plans for the Scotland and Solway Tweed river basin districts.

Part of the DPMAG strategy includes:

  • A national campaign to prevent water bodies from deterioration in status and make improvement where they are not far from a status boundary.
  • A targeted approach in identified ‘Priority Catchments’ where the extent of diffuse pollution problems on the water environment, requires a more focused approach.

For more information visit the DPMAG website.

As part of Scotland’s targeted approach to reduce pollution risk, work is underway in a number of ‘priority catchments’. The priority catchments contain some of Scotland’s most important waters for conservation, drinking water, bathing and fishing, but they are also at heightened risk from diffuse pollution pressures which will lead to poor water quality.

Find out more