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What is Diffuse Pollution?

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

Read more about how soil particles and nutrients reach watercourses in the 2022 CREW report “A state of knowledge overview of identified pathways of diffuse pollutants to the water environment”

What’s the Problem?

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

What can land managers do?

Practical ways to identify and reduce diffuse pollution risks.

Learn more

How can this benefit your farm?

From better management of water around the steading, to compliance with the regulations there are plenty of additional benefits from reducing pollution risks.

Learn more