Guidance for de-silting ponds and streams

What this guidance covers

This guidance is for anyone responsible for de-silting streams and ponds, whether you are a:

land owner undertaking work yourself
contractor working on behalf of someone else

It applies to all types of watercourses, including ponds ranging from small domestic garden ponds to larger ponds used for irrigation purposes.

This guidance:

can help you to minimise the environmental impact of the activity on the water body and downstream ecosystems
provides information about the ecological importance of ponds and streams
shows you how to complete a method statement, this is a document identifying issues and providing appropriate steps to protect the pond and any downstream waters
raises awareness of the legislative requirements that may apply to you

Ecological importance of ponds and streams

A pond is defined in this guidance as a man-made or natural body of water, which holds water for all or part of the year. The sizes of a pond can be as small as 1 m2 and reach in excess of 50,000 m2 in area.

A stream is defined as water that flows naturally along a channel. Under the Water Pollution (Jersey) Law 2000, a stream includes any:

brook
canal
culvert
ditch
lavoir
sluice
spring

Ponds and steams are highly diverse habitats, supporting aquatic and terrestrial life. They provide drinking water, flood protection and a source of food, in the form of insects and plants.

Ponds support two thirds of all freshwater species. Maintaining ponds is one of the most effective ways to protect freshwater wildlife.

Wildlife ponds, introduction and management advice

Preparing a method statement

A method statement is an important written document that you should prepare before de-silting begins in order to plan the work.

Your method statement should:

provide details of the company or individual who will carry out the work and their responsibilities
provide the reasons for de-silting the pond or stream, for example, what you are trying to achieve
include a description of the activity and how it will be undertaken

When creating your method statement you must also:

identify and inform any landowners or users of your planned work, for example, those abstracting water downstream for the purpose of irrigation or drinking
contact Jersey Water directly about the proposed work if de-silting is being carried out in a Jersey Water catchment. For information on Jersey Water catchments visit Prevent water pollution: borehole maps and farm waste management
consider minimising any negative impact on the pond or stream’s ecology by undertaking the work outside the main breeding season for aquatic species. This is ideally late summer or early autumn, between September and November. If you wish to carry out work outside of this time, contact us as there may be additional work needed to protect species. There is a statutory responsibility to do this when the species is protected by the Wildlife (Jersey) Law 2021
be aware of invasive species when de-silting water bodies and consider where the silt is disposed of and the potential risks associated with this. It is recommended that silt is not moved from one wetland site to another, to avoid the spreading of invasive species for example cray fish, or Japanese knotweed
consider leaving a small amount of silt close to the edges of ponds or streams to allow wildlife to return when works are complete
consider undertaking pre and post monitoring of aquatic species and water quality to show the effect of the de-silting process
assess whether the activity has the potential to cause pollution
assess how the waste sediment or vegetation will be disposed of
calculate how much waste sediment will be generated to help estimate the area required for applying to land or the cost of disposal
assess the need to analyse the sediment within the pond. If the sediment is to be spread on agricultural or other land, it's important to determine whether chemical analysis of the sediment is required. The analysis will establish the nutrient value of the sediment and show if it's contaminated
check if any legislative permissions are required

Legal requirements for your method statement

When developing a method statement you'll need to consider the following legal requirements:

Water Pollution (Jersey) Law 2000

The Water Pollution Law provides for the control of pollution in Jersey waters.

Permissions	Silt may appear harmless because it is not directly toxic to aquatic life. It can however cause serious damage if washed down into streams, ponds, reservoirs Deposits of silt can: cause problems with flooding reduce the growth of aquatic plants reduce the oxygen content of the water clog the gills of aquatic animals and fish Ponds which form part of a stream system and those near to a stream, where silt might enter, are considered to be at high risk from silt pollution during pond de-silting. If a stream is being desilted consideration should be given to ponds or reservoirs further downstream which may be impacted during desilting process. Preventing water pollution from occurring should be included within the method statement prior to any work commencing. Silt pollution can be caused by: disturbing pond or stream banks removal of vegetation the movement of machinery within or near a stream or pond To minimise the risk of silt pollution occurring, you should use methods that, where possible, do not contaminate surface water. These include: for more frequent desilting purposes create a silt trap or settlement pond that can be constructed upstream of the main pond. This will reduce the quantity of silt entering into the pond in the first place when preparing to desilt a pond or stream use isolation methods to keep the water away from the areas of work, such as: create a dam to stop water flowing into the pond or area of stream pump the water around the pond or area of stream. This may need to be done in stages for streams due to their length create by-pass channels, before the de-silting process starts only remove necessary vegetation from the bank of the pond or stream, prior to de-silting any water containing silt and other suspended material must undergo a settlement or filtration process before being discharged. The treatment method to dispose of contaminated water will depend on: the amount of water the land available for treatment, discharge or storage the type and quantity of silt the presence of contaminants in the water. This activity may require a discharge permit, contact Pollution Control for advice continually monitor and review the environmental impact of your work and update your management plan as necessary it is important to have a contingency plan in place in the event of pollution occurring. If pollution occurs please contact the pollution hotline on +44 (0) 1534 709535 If heavy plant is being used to excavate the pond, make sure a spill kit is available to use in the event of oil spill in the watercourse. Pollution prevention guidelines on the GOV.UK website
Contacts	If you're unsure whether your proposed action requires permission, contact Pollution Control for advice by emailing  envprotection@gov.je

Permissions

Silt may appear harmless because it is not directly toxic to aquatic life. It can however cause serious damage if washed down into streams, ponds, reservoirs

Deposits of silt can:

cause problems with flooding
reduce the growth of aquatic plants
reduce the oxygen content of the water
clog the gills of aquatic animals and fish

Ponds which form part of a stream system and those near to a stream, where silt might enter, are considered to be at high risk from silt pollution during pond de-silting.

If a stream is being desilted consideration should be given to ponds or reservoirs further downstream which may be impacted during desilting process.

Preventing water pollution from occurring should be included within the method statement prior to any work commencing.

Silt pollution can be caused by:

disturbing pond or stream banks
removal of vegetation
the movement of machinery within or near a stream or pond

To minimise the risk of silt pollution occurring, you should use methods that, where possible, do not contaminate surface water.

These include:

for more frequent desilting purposes create a silt trap or settlement pond that can be constructed upstream of the main pond. This will reduce the quantity of silt entering into the pond in the first place
when preparing to desilt a pond or stream use isolation methods to keep the water away from the areas of work, such as:

create a dam to stop water flowing into the pond or area of stream
pump the water around the pond or area of stream. This may need to be done in stages for streams due to their length
create by-pass channels, before the de-silting process starts

only remove necessary vegetation from the bank of the pond or stream, prior to de-silting
any water containing silt and other suspended material must undergo a settlement or filtration process before being discharged. The treatment method to dispose of contaminated water will depend on:

the amount of water
the land available for treatment, discharge or storage
the type and quantity of silt
the presence of contaminants in the water. This activity may require a discharge permit, contact Pollution Control for advice
continually monitor and review the environmental impact of your work and update your management plan as necessary
it is important to have a contingency plan in place in the event of pollution occurring. If pollution occurs please contact the pollution hotline on +44 (0) 1534 709535

If heavy plant is being used to excavate the pond, make sure a spill kit is available to use in the event of oil spill in the watercourse.

Pollution prevention guidelines on the GOV.UK website

Contacts

If you're unsure whether your proposed action requires permission, contact Pollution Control for advice by emailing  envprotection@gov.je

Wildlife (Jersey) Law 2021

The Wildlife (Jersey) Law 2021 provides for the conservation of wild animals, wild birds and wild plants in Jersey.

Permissions	Certain species listed in the Schedules to the Law are legally protected. These include: toads eels frogs other pond-dwelling fauna aquatic plants The Law safeguards these species and, in some cases, their breeding or resting habitats from potentially harmful activities, such as pond or stream de-silting. Any activity that may pose a risk to these protected species and habitats could require a licence. Before any work starts, an Ecological Method Statement should be prepared to outline measures to avoid harm. In some instances, an ecological survey may also be needed to assess potential impacts and inform appropriate mitigation.
Contact	Protected species and wildlife licensing Wildlife ponds, introduction and management advice If you're unsure whether your proposed action is against the Law, contact Natural Environment for advice by: calling  +44 (0) 1534 441600 emailing  environment@gov.je or wildlifelicensing@gov.je

Permissions

Certain species listed in the Schedules to the Law are legally protected. These include:

toads
eels
frogs
other pond-dwelling fauna
aquatic plants

The Law safeguards these species and, in some cases, their breeding or resting habitats from potentially harmful activities, such as pond or stream de-silting.

Any activity that may pose a risk to these protected species and habitats could require a licence.

Before any work starts, an Ecological Method Statement should be prepared to outline measures to avoid harm. In some instances, an ecological survey may also be needed to assess potential impacts and inform appropriate mitigation.

Contact

Protected species and wildlife licensing

Wildlife ponds, introduction and management advice

If you're unsure whether your proposed action is against the Law, contact Natural Environment for advice by:

calling  +44 (0) 1534 441600
emailing  environment@gov.je or wildlifelicensing@gov.je

Waste Management (Jersey) Law 2005

The Waste Management (Jersey) Law provides for the control and management of waste operations within Jersey.

Permissions	You may require a waste management licence to deposit silt on land. Waste means any substance, including sediment and vegetation removed from a pond, which is discarded. Waste sediment should either be: disposed of at a site licenced under the Law silt containing protected species such as eels, should not be removed and disposed on another site. A licence is required for the removal of protected species from the silt. Local ecologists who hold a licence can be contracted to carry out this work spread on land if the use of the waste is beneficial to the environment or to agriculture, for example, on farmland by recycling nutrients to the soil in accordance with a nutrient management plan. Such spreading is exempt from waste management licensing as it is the recovery of waste. It can only take place where it can be shown to: be beneficial present no risk of harm does not amount to waste disposal Analysis of the silt may be required where there is a risk of contamination of the agricultural or other land where silt is spread. Ponds and streams can accumulate sediments that can be hazardous where runoff is from agricultural land or roads and urban land. The scale of the de-silting operation and is a key factor in determining controls under the law. For example, small quantities of silt which can be deposited on the adjacent banks of a pond or watercourse will be exempt as long as the activity does not significantly endanger human health, the environment or flora or fauna. It is advisable to leave small amounts of silt close to the pond pr stream edge to allow wildlife to return. If you're treating silts and vegetation, by mixing or screening, or dewatering silts, for example by storing in lagoons, before moving to other sites you should contact us for further advice about compliance.
Contact	If you're unsure whether your proposed action requires permission, contact Pollution Control for advice by emailing envprotection@gov.je

Permissions

You may require a waste management licence to deposit silt on land.
Waste means any substance, including sediment and vegetation removed from a pond, which is discarded. Waste sediment should either be:

disposed of at a site licenced under the Law
silt containing protected species such as eels, should not be removed and disposed on another site. A licence is required for the removal of protected species from the silt. Local ecologists who hold a licence can be contracted to carry out this work
spread on land if the use of the waste is beneficial to the environment or to agriculture, for example, on farmland by recycling nutrients to the soil in accordance with a nutrient management plan. Such spreading is exempt from waste management licensing as it is the recovery of waste. It can only take place where it can be shown to:

be beneficial
present no risk of harm
does not amount to waste disposal

Analysis of the silt may be required where there is a risk of contamination of the agricultural or other land where silt is spread. Ponds and streams can accumulate sediments that can be hazardous where runoff is from agricultural land or roads and urban land.

The scale of the de-silting operation and is a key factor in determining controls under the law. For example, small quantities of silt which can be deposited on the adjacent banks of a pond or watercourse will be exempt as long as the activity does not significantly endanger human health, the environment or flora or fauna. It is advisable to leave small amounts of silt close to the pond pr stream edge to allow wildlife to return.
If you're treating silts and vegetation, by mixing or screening, or dewatering silts, for example by storing in lagoons, before moving to other sites you should contact us for further advice about compliance.

Contact

If you're unsure whether your proposed action requires permission, contact Pollution Control for advice by emailing envprotection@gov.je

Water Resources (Jersey) Law 2007

The Water Resources (Jersey) Law provides for the protection, management and regulation of water resources in Jersey.

Permissions	You may require a water resources licence to impound water if you propose to create a new impoundment or alter an existing impoundment in such a way that will alter the level, flow or character of water in a source of supply or affect wildlife or plants dependent on the source of water. Examples include a dam on a stream, diverting a stream course or creating an irrigation reservoir. Planning permission may also be required.
Contact	If you're unsure whether your proposed action requires permission, contact Pollution Control for advice by emailing envprotection@gov.je

Permissions

You may require a water resources licence to impound water if you propose to create a new impoundment or alter an existing impoundment in such a way that will alter the level, flow or character of water in a source of supply or affect wildlife or plants dependent on the source of water. Examples include a dam on a stream, diverting a stream course or creating an irrigation reservoir. Planning permission may also be required.

Contact

If you're unsure whether your proposed action requires permission, contact Pollution Control for advice by emailing envprotection@gov.je

Planning and Building (Jersey) Law 2002

The Planning and Building (Jersey) Law provides the means for the control and sustainable development of land. To provide the means to protect, enhance and conserve and to use wisely the natural beauties, natural resources and biodiversity of Jersey.

Permissions	Planning permission may be required to: dispose of materials removed from a pond to surrounding land store materials, however temporary any subsequent re-use of the materials within the land
Contact	If you're unsure whether or not your proposed activity requires planning permission contact us for advice, prior to any work starting. Tel: +44 (0) 1534 445508 Email planning@gov.je