Sustainable Drainage Systems (SuDS) are used to manage surface water run-off, primarily to prevent flooding and pollution. This is achieved through the implementation of one or more specially built structures designed to control and treat surface water.
Understanding SuDS and Their Application
At their core, SuDS are systems comprising various structures specifically engineered to handle water run-off from surfaces like roads, roofs, and paved areas. Their application is intrinsically linked to the goal of mitigating the negative impacts of development on the natural water cycle.
As referenced, SuDS are employed in conjunction with good management of the site. This combined approach ensures that surface water is managed effectively from where it lands to where it eventually flows or infiltrates, focusing on the critical outcomes of preventing flooding and reducing pollution.
The Core Purpose: Preventing Flooding and Pollution
The primary context or "where" SuDS are used relates directly to their function:
- Preventing Flooding: By managing the volume and flow rate of surface water run-off, SuDS help to reduce the risk of flooding in developed areas and downstream.
- Preventing Pollution: SuDS components are designed to capture, filter, or treat pollutants carried by run-off, such as sediment, oils, and nutrients, thereby protecting the quality of receiving waters.
Therefore, SuDS are used wherever effective surface water management is needed to achieve these environmental protection goals.
How SuDS Achieve Their Purpose: Control Methods
The practical implementation of SuDS involves a range of control methods and structures. These methods work together in a treatment train approach, handling water at different stages. According to the reference, common control methods include:
- Prevention: Techniques that reduce run-off at the source (e.g., good housekeeping, reducing impermeable areas).
- Filter Strips/Swales: Vegetated areas or channels designed to slow down run-off, filter pollutants, and encourage infiltration.
- Permeable Surfaces/Filter Drains: Paving or linear structures that allow water to soak through, reducing surface flow.
- Infiltration Devices: Structures like soakaways or infiltration basins that allow water to soak into the ground.
- Basins/Ponds: Areas designed to store surface water temporarily or permanently, allowing for settlement of solids and biological treatment.
| SuDS Control Method | Description | Primary Function(s) |
|---|---|---|
| Prevention | Reducing run-off volume and pollution at source. | Minimize Need |
| Filter Strips/Swales | Vegetated areas for slowing, filtering, and infiltration. | Flow Control, Filtration, Infiltration |
| Permeable Surfaces | Paving that allows water percolation. | Infiltration, Flow Control |
| Filter Drains | Underground gravel drains allowing water to enter and infiltrate. | Conveyance, Infiltration, Filtration |
| Infiltration Devices | Structures promoting ground absorption (e.g., soakaways). | Infiltration, Flow Control |
| Basins/Ponds | Storage areas for water (temporary or permanent). | Storage, Flow Control, Settlement, Biological Treatment |
These diverse components allow SuDS to be tailored to specific site conditions and requirements, ensuring effective surface water management aimed at preventing flooding and pollution.
