Sustainable Urban Drainage Systems (SUDS)
What are SUDS?
SUDS, or Sustainable Urban* Drainage Systems are a sequence of
water management practices(1) and facilities(2) designed to drain
surface water in a manner that will provide a more sustainable
approach than what has been the conventional practice of routing
run-off through a pipe to a watercourse.
*The use of the word 'urban' is frequently omitted, but the
meaning is still the same.
1. Practices involved are what is termed 'good housekeeping' or
'best management practices'. Such practices include:
- Mitigation of accidents that may result in pollution
- Reduction of polluting activities;
- Reduction of polluting materials;
- Bunding of oil tanks;
- Water harvesting.
2. Facilities are generally constructed arrangements. Such
- Permeable surfaces;
- Filter strips;
- Filter and infiltration trenches;
- Detention basins;
- Underground storage;
Other facilities exist that often come as proprietary products
offering hydraulic controls or silt trap arrangements. These may
also incorporate materials with properties able to encourage
adsorption of certain polluting substances such as oils and toxic
SEPA is the statutory agency responsible for protecting the
water environment in Scotland, under the Water Environment Water
Services (WEWS) Act. On that basis SEPA requires the use of
effective, appropriate Sustainable Urban Drainage Systems (SUDS)
features in new developments.
Developers, SEPA and Scottish Water are encouraged to discuss
proposed developments at an early stage, even before approaching
the planning authority. Government planning advice is available in
Planning Advice Notes (PANs) and Scottish Planning Policy (SPP)
releases from the Scottish
A national stakeholder group was established in 1997
- the Sustainable Urban Drainage Scottish Working Party
(SUDSWP). The SUDSWP website provides
more information on SUDS.
How are SUDS regulated?
Under the Water Environment (Controlled Activities) (Scotland)
Regulations 2011 it is a general* requirement for new developments
with surface water drainage systems discharging to the water
environment that such discharges will pass through SUDS. All
reasonable steps must be taken to ensure protection of the water
* Two exceptions exist to this
1. Where the development is only a single
2. Where the discharge is directly to coastal
waters (this does not including transitional waters).
The Controlled Activities Reguations (CAR) provide regulation
under General Binding Rules (GBRs) 10 and 11 for SUDS. Please refer
to the Related Items box for more information.
SUDS in Scotland - the Scottish SUDS
The findings of a major survey into the use of sustainable urban
drainage are summarised in the SNIFFER report (SR (02) 09), 'SUDS in
Scotland - the Scottish SUDS database'. The survey highlighted that
the use of SUDS has become standard practice in Scotland, with over
700 sites being listed and nearly 4000 systems having been