The Principle of SUDS
SUDS or Sustainable Urban Drainage Systems are a sequence of water management practices and/or facilities designed to drain surface water in a manner that will duplicate the natural water cycle and can be physical structures built to receive surface water runoff. They are located as close as possible to where the rainwater falls and provide the options of infiltration and attenuation. Additionally, they treat surface water using the natural processes of sedimentation, filtration, absorption and biological degradation.
Recent research shows that typically up to 80% of sediment, 60% of phosphorous and 80% of nitrogen can be removed from stormwater through infiltration, together with substantial levels of heavy metals and hydrocarbons. This natural treatment provides the ideal opportunity for rainwater conservation and re-use (harvesting) for a variety of non-potable applications e.g. toilet/urinal flushing, irrigation, laundry, process water, vehicle washing, refrigeration, coolant use, etc. It also creates a cleaner output to the sewer or recharging of the groundwater where rainwater harvesting isn’t used.
Such source control principles and techniques, also called Best Management Practices (BMPs) are part of planning controls in most areas and are becoming increasingly incorporated within new development projects.
Current Guidance / Legislation on SUDs
The four basic principles of SUDs
Don’t hard pave surfaces unnecessarily – Porous Paving
Soakaway where possible or attenuate if necessary – Stormwater Management
Re- use if possible – Rainwater Harvesting
Improve Water Quality