What is sustainable drainage?
Sustainable drainage systems, commonly referred to as SuDS, promote an improved approach to the management of surface water runoff that maximizes the additional benefits that can be achieved when compared to traditional drainage systems.
The SuDs approach aims to mimic natural drainage, managing surface runoff at or close to the surface, and close to its source. SuDs aim to control the volume and rate of runoff and provide a range of additional benefits. Well designed and easy to maintain SuDs will deliver a range of important benefits for the local environment, the development and local community.
What is a SuDs Approval Body?
Schedule 3 of the Flood and Water Management Act 2010 (FWMA) established Sustainable Drainage Approval Bodies, or SAB’S, within the Lead Local Flood Authority of County Councils. The Act gives those bodies statutory responsibility for approving and adopting certain approved drainage systems.
The SAB is established to evaluate and approve drainage applications for new developments where construction work has drainage implications, and adopt and maintain surface water drainage systems according to the Act (http://www.legislation.gov.uk/ukpga/2010/29/contents). A drainage application for approval by a SAB must be designed to comply with the current edition of the Ministerial National Standards.
Why are SuDs important?
The requirement to consider SuDS in all new and redeveloped sites in Caerphilly County Borough is being driven by existing and increased local flooding, increased pollution of our rivers, poor natural landscapes, declining biodiversity and uncertainty regarding the impact of climate change.
In particular, traditional piped systems that collect runoff from hard paved surfaces such as roofs, roads and car parks are unsustainable and have contributed to increased flood risk and pollution by:
- Increasing the volume and rate at which surface water is discharged to a receiving watercourse and therefore increasing fluvial flood risk;
- Surcharging during larger rainfall events, with water unable to discharge to the system or emerging through manholes and gullies in areas at lower elevation hence causing localized pluvial flooding;
- Partial or full blockage caused by sediment, debris or pipe collapse which can often go unnoticed until a large rainfall event causes flooding in upstream areas;
- Little to no treatment of surface water runoff, especially from vehicular areas, thereby conveying all pollutants to the natural environment;
- Increased discharge of surface water runoff to combined sewers or wastewater treatment works, resulting in more regular discharge of wastewater to the water environment via combined sewer overflows (CSOs) or insufficient capacity at the wastewater treatment works.
The scale of urbanisation and society’s attitude towards the management of surface water is exacerbating existing issues. It is therefore essential that any new development in Caerphilly County Borough, incorporate sustainable drainage principles. This will help change attitudes towards living with water and mitigate the effects of urbanisation thereby preventing further deterioration.
More information about SAB