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
You can 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”