• About us
• Air
• Climate change
• Flooding
• Land
• Planning
• Radioactive substances
• Waste
• Water
• Bathing waters
• Diffuse pollution
• Hydropower
• Marine Science
• Monitoring and classification
• Protected areas
• Restoration fund
• River basin planning
• Scotland
• Solway Tweed
• National Advisory Group
• Area Advisory Groups
• Fish and Fisheries AG
• How we work with others
• DP Priority catchments
• Significant issues
• Waterbody Data Sheets
• Diffuse pollution MAG
• Introduction
• Background
• Environmental objectives
• Overview of the strategy
• The national campaign
• Priority catchments
• Monitoring and reporting
• River levels
• Water regulation
• Water publications
• External links
• Science and research
• Customer information...
• SEPA Kids

Background

What is diffuse pollution?

Diffuse pollution is pollution arising from urban and rural land-use activities spread across a catchment or sub-catchment. The sources are heavily influenced by rainfall and can be individually minor but collectively significant.

What impact is rural diffuse pollution having in Scotland?

While management of the water environment has led to huge improvements in water quality over the last 50 years, pollution remains one of the most common causes of water bodies not reaching good status. In the Scotland river basin district, 18% of all water bodies are less than good status due to impacts on water quality.

Much of the pollution affecting the water environment is from diffuse sources. The main diffuse pollutants are phosphorus, faecal pathogens, nitrates and pesticides principally affecting rivers, bathing waters and groundwaters respectively.

Diffuse pollution from rural sources also has a major impact upon protected areas such as those supporting economically important shellfish, designated as bathing waters, providing water for human consumption or supporting species or habitats identified as requiring special protection under European legislation.

Where does diffuse pollution come from?

Diffuse pollution in the rural environment comes from a range of land use activities including agriculture, forestry and mining, and areas maintained for recreational purposes such as parks, green spaces and golf courses. Septic tanks from individual dwellings or small clusters of properties can also contribute.

Individual sources include run-off from ploughed fields or bare soil, farm yard drainage or pesticides or fertilisers washed or draining into the water environment. Each source may only have a small effect on the life in the water environment or water quality, but the impacts of a large number of sources can be significant.

What is required to tackle diffuse pollution?

Experience of managing rural diffuse pollution controls suggests the following key principles are likely to be successful:

• a catchment approach;
  
• a sound evidence base to assess sources, transport, target measures and get stakeholder buy-in;
  
• one to one advice and rural site visits to identify hotspots, target measures and cost-effectively change management practices;
  
• partnership approaches and stakeholder involvement/led;
  
• a combination of regulatory, economic and voluntary measures.

The catchment approach has been successfully implemented at a range of scales in Scotland and elsewhere in the UK. Lessons learnt from such projects have been incorporated into the approach described in this document. Examples include full catchment management plans, such as the Loch Leven catchment management plan, and projects focusing more specifically on diffuse pollution, such as the Lunan Lochs natural care scheme and the Brighouse Bay project. In addition, SEPA has implemented catchment approaches to mitigating rural diffuse pollution via Environmental Improvement Action Plans, including for bathing waters. However, it is worth noting that monitoring data is limited on the effect of measures at the catchment scale.

A sound evidence base is required to support the mitigation of rural diffuse pollution, both in terms of stakeholder buy-in and accurately targeting measures to achieve the most cost-effective improvements. SEPA holds good information on sources of pollutants, their transport pathways and processes as well as their impact. This information will be made available in a user-friendly format to land managers and their advisors regarding their local area.