Preventing water pollution when working close to water

If you pollute the water environment, you are probably committing an offence.

In Northern Ireland you must have consent from the Rivers Agency before you place structures in any waterway that are likely to affect its drainage. Contact your local Rivers Agency office for further information.

Northern Ireland: Rivers Agency Area Offices

DAERA has produced a handbook is for landowners and people and organisations involved in carrying out activities that may alter the physical characteristics or flows of rivers and other waterbodies. The activities covered include dredging and substrate addition, removal of bankside vegetation, bed and bank reinforcements, flow manipulation and culverting.

DAERA: Surface Waters Alterations Handbook

In Scotland, if you carry out building and engineering works in inland waters or carry out activities close to waters that could significantly affect the water environment, you must either:

  • comply with certain general binding rules (GBRs) which apply to low-risk activities
  • register your activity with SEPA
  • obtain a licence from SEPA.

Any static plant or machinery used within 10m of any:

  • river
  • burn
  • canal
  • ditch
  • loch
  • wetland
  • coastal waters

must be placed on a suitable drip tray with a capacity equal to 110% of the capacity of the fuel tank that supplies the equipment. You must make sure that the equipment you use does not leak oil.

Empty drip trays regularly to make sure that they can contain any spills.

CAR Practical guide

SEPA: Silt control while dredging 2015

SEPA: Removal of sand, silt or clay from the bed of previously straightened rivers and burns which are ≥1m and <5m wide

Guidance for Pollution Prevention (GPP) 5 contains guidance on measures you can take to avoid causing pollution during building and engineering work.

GPP5 Works and maintenance in or near water (Adobe PDF – 782KB)

Good practice

You may be committing an offence if you allow a watercourse to become blocked or polluted. The following good practice guidance will help you avoid this.

Ground preparation

Consult your environmental regulator and your water company or water authority at the planning stage to check if there are any water protection measures for your site that you must comply with.

Contact your environmental regulator

Water UK: Contact your water company

Scotland on Tap: Water and sewerage providers in Scotland

Construct silt traps or other forms of sediment control in areas where there is a high risk of erosion. Fine sediments such as clay, silt and fine sand can have an adverse effect on flora and fauna, such as blocking the gills of fish and preventing light from reaching the leaves of plants. Coarse sediment can have a serious impact on fish spawning grounds and can block channels in rivers and streams.

Install collector drains immediately after cultivation especially where large volumes of run-off could reach a forest road.

Collector drains should not end close to a watercourse. Ideally they should end on flat ground to allow sediment-laden water to fan out and soak away. You should protect watercourses and the surrounding vegetation by establishing a buffer area, a zone of undisturbed vegetation between the cultivation area and the watercourse.

When deciding the width of the buffer area around a stream you should consider:

  • if the stream is up to 1m wide, you should establish a buffer of at least 5m on each side
  • if the stream is important for fish spawning and is less than 1m wide, you should have a buffer area of at least 10m on each side
  • if the stream channel is 1 to 2m wide, you should use a buffer of about 10m on each side
  • if the stream channel is over 2m wide, you should create a buffer of about 20m on each side.


If your supplier has treated your planting stock with insecticide, you must not store or soak it in a watercourse before you plant it.

Trees, especially conifers, can capture and transfer atmospheric pollutants to surrounding ground. This can cause the acidification of surface waters, especially in upland forests. This can prevent successful fish spawning and can cause damage to a number of plants, including sphagnum mosses in upland bogs.

Speak to the Forestry Commission or Forest Service Northern Ireland when planning your planting operation. They will be able to help you identify which areas are most at risk.

Scottish Forestry

Forest Service Northern Ireland

Tree maintenance and lifting

If you produce Christmas trees you will need to shape trees by pruning and shearing to maximise their selling potential. Keep streams free from cut branches as far as possible.

Lifting is the term used to cover all methods of removing (felling or digging) young trees from the ground either by hand or by machine.

When you remove or lift young trees from the ground, you are likely to cause silty water run-off. This could pollute nearby rivers or streams.

If your site is prone to erosion, only work during spells of dry weather to reduce run-off.

Inspect local watercourses regularly for evidence of discoloration or sediment build-up, particularly at the drainage outlets in plantation sites. Install sediment traps if you find signs of pollution.


If you are harvesting in a water supply catchment area you should contact your water company or water authority. They will want to make sure that your work is not affecting the water supply.

After harvesting, make sure that you clear drains and natural watercourses of any blockages that have occurred.

Before you begin work, you must check to see if there are any protected species such as otter and water vole in any streams or watercourses close to the site where you intend to harvest.

If you find or suspect that protected species are there, you must change your felling plans to protect their habitat and limit any disturbance.

Nature conservation and forestry

Keep streams and buffer areas free from harvested branches and tops.

Consider cableway extraction for sensitive sites and catchment areas.

If you plan extraction routes on steep slopes, dig shallow cross ditches to reduce water movement and erosion.

Create adequate brash mats and maintain their structure.

Fell trees away from watercourses to reduce the risk of brash and logs causing blockages and disturbing freshwater habitats.

Forest Research: Forests and water

SEE ALSO: Forestry sector guidance

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