Sustainable drainage systems (SUDS) for business
An overview of sustainable drainage systems and some of the benefits that SUDS can offer to businesses.
Sustainable drainage systems can be used in all types of development to provide a natural approach to managing drainage.
Sustainable drainage systems prevent water pollution and flooding in urban areas. Sustainable drainage systems also create green spaces and habitat for wildlife in towns and cities.
It is good practice to use sustainable drainage systems in all development plans. You may have to include plans for sustainable drainage systems when applying for planning permission.
This guide describes what sustainable drainage systems are, and how and when you should use them on your site.
What are sustainable drainage systems?
The different types of sustainable drainage systems and how SUDS can be used to manage drainage around your business.
Sustainable drainage systems (SUDS) are a natural approach to managing drainage in and around properties and other developments.
SUDS work by slowing and holding back the water that runs off from a site, allowing natural processes to break down pollutants.
Types of sustainable drainage systems
- Source control measures deal with run-off at, or close to, the surface where rainfall lands.
- Site control measures manage the surface water run-off from larger areas, such as part of a housing estate, major roads or business parks. The run-off from larger areas can be channelled to a site control measure using swales (shallow drainage channels) or filter drains.
- Regional control measures downstream of source and site controls deal with the gathered run-off from a large area. These systems use the same principles as smaller scale SUDS, but can cope with larger volumes of water. Rainwater that passes through small SUDS can feed into larger SUDS which deal with the gathered run-off from a wide area. It is best to connect the flows between SUDS components with swales, filter drains or ditches and avoid the use of pipes.
Benefits of sustainable drainage systems
The benefits of SUDS include:
- preventing water pollution
- slowing down surface water run-off and reducing the risk of flooding
- reducing the risk of sewer flooding during heavy rain
- recharging groundwater to help prevent drought
- providing valuable habitats for wildlife in urban areas
- creating green spaces for people in urban areas
Sustainable drainage system techniques
You can use the following SUDS techniques:
Sustainable drainage systems best practice
Legal requirements and good practice relating to planning, design and installation of sustainable drainage systems.
You can use sustainable drainage systems (SUDS) to treat lightly polluted water that runs off from your site, reducing the impact on the environment.
Sustainable drainage systems responsibilities
You must not use SUDS to treat sewage, heavily contaminated run-off or trade effluent. If you cause or allow surface water or groundwater pollution you may be committing an offence and may be prosecuted and fined or imprisoned.
You must consult with the Northern Ireland Environment Agency or Northern Ireland Water before discharging any run-off from your site to public sewers, surface waters or groundwater. If you discharge any run-off without consent or appropriate authorisation you may be prosecuted.
You may have to include plans for SUDS when you apply for planning permission for new developments. It is good practice to include the use of SUDS in all development plans.
If you discharge surface water run-off from a construction site, you must use suitable SUDS techniques.
Sustainable drainage systems good practice
Run-off from hard paving is likely to be contaminated by oil, organic material or toxic metals. Where there is a high risk of contamination by oil, you may need to .
Where possible, you should design SUDS to increase biodiversity and provide habitats for wildlife in the area they drain.
Green roofs in sustainable drainage systems
How you can use a green roof as a sustainable drainage system to prevent pollution and flooding from your business.
Green roofs are an example of source control. Source control measures deal with run-off at, or close to, the surface where rainfall lands. You may need to use additional sustainable drainage system (SUDS) components to control any overflow.
Advantages of green roofs
Green roofs have a layer of vegetation or patches of vegetation as part of the roof cover and can:
- reduce or eliminate run-off from roof areas
- extend the life of your roof
- add insulation to your building during the winter months
- cool your building during the summer by evaporation
- provide sound insulation
- reduce the heat island effect in cities
- provide a habitat for wildlife
You can use a variety of green roofs, including:
- intensive systems - deep soil capable of growing shrubs and even trees
- extensive systems - thin layer of vegetation, such as sedum mats
Disadvantages of green roofs
Green roofs add weight so you should consider them at the construction stage of a new build. For an existing building, an extensive system is recommended as it adds less weight, but you should always consult an engineer to make sure that the structure is safe.
Filter strips and filter drains in sustainable drainage systems
How you can use filter strips and filter drains as a drainage system to prevent pollution and flooding in your business.
Filter strips are strips of ground where water running off a site can pass, allowing some or all of it to soak away. The rest often enters a swale - shallow drainage channel - or another sustainable drainage system (SUDS) component. This strip of ground can also be used to filter grit and other particles from the run-off.
Filter drains or filter trenches can be used beside roads and other impermeable surfaces, but should be avoided at busy road junctions or where rainwater can become heavily contaminated. Filter drains allow the run-off to soak away into the surrounding soil. Filter drains are filled with stones or gravel. This stone fill collects particles and helps to prevent pollutants from entering groundwater. You can use a filter strip or swale to reduce the level of pollutants entering the filter drain.
You can use filter drains for source control and to convey run-off between SUDS measures.
Permeable paving in sustainable drainage systems
How you can use permeable paving as a sustainable drainable system to prevent pollution and flooding from your business.
You can use permeable or porous paving as a source control measure for small roads, pavements, car parks and yards. Source control measures are sustainable drainage systems (SUDS) that deal with run-off at, or close to, the surface where rainfall lands.
Rain passes through the surface, either through gaps between individual blocks or permeable material such as gravel or porous asphalt, trapping pollutants below. Once there, many pollutants are broken down by natural processes.
By using permeable paving you can also prevent water pooling on impermeable surfaces, avoiding puddles and ice on car parks.
Download a diagram of how permeable paving works (PDF, 58K).
Large amounts of water can be stored temporarily under the surface. This reduces the chances of flooding.
Swales in sustainable drainage systems
How you can use shallow drainage channels on your business premises to prevent pollution and flooding.
A swale is a shallow drainage channel with gentle side slopes in the ground where water running off a site can collect and soak away.
Swales can be used to channel run-off from roads, yards and car parks where it collects into pools before soaking away. You can also use swales to carry water through a site.
Swales can run alongside roads so that run-off from the road surface can drain directly to the swale. You can also use them in the treatment of lightly contaminated run-off from hard standing around farmyards and farm roads.
When building a swale, you can include check dams to slow the flow of water. This allows the sediment to settle out. You can also use swales to carry water between sustainable drainage system (SUDS) features instead of using pipes. This can reduce the cost of construction and maintenance.
Swales can be used for linking SUDS dealing with run-off from individual sites and SUDS that manage the run-off from large areas.
Detention basins, ponds and wetlands in sustainable drainage systems
How you can use detention basins, ponds and wetlands as sustainable drainage systems to prevent pollution and flooding.
Where rainfall lands on a surface, you can use source control sustainable drainage system (SUDS) techniques to control run-off at, or close to, the source. This includes permeable or porous surfaces such as permeable paving, swales and filter strips.
To deal with heavy or persistent rain which produces more run-off, you can use site control SUDS, which are downstream of source controls, to manage the surface water run-off from larger areas, such as:
- parts of housing estates
- major roads
- business parks
Detention basins
You can use detention basins to store run-off from large areas. Water usually runs into these from conventional drainage systems or from upstream SUDS.
Detention basins let run-off spread across a wide floor area and only fill after heavy rainfall, when they will hold large volumes of water. This lets pollutants settle out before the water soaks away or discharges slowly downstream.
Ponds and wetlands
If you want to store water for longer, you can use ponds instead of detention basins. This allows natural processes, using bacteria and sunlight, to break down pollutants before the water eventually flows into downstream watercourses. Ponds can also be a welcome addition to urban areas, encouraging plants and wildlife.
You should never use existing ponds or wetlands to treat run-off. Always create new ponds to avoid damaging or disturbing the wildlife that is already in the area.
You can also connect a number of ponds, or include wetland areas in tackling run-off from large areas. Wetlands contain a larger amount of vegetation and are more suitable for treating contaminated run-off. Newly created ponds and wetland areas are ideal for treating lightly contaminated water from farmyards and farm roads.