SUDS
Sustainable Urban Drainage System

Here at UK Resin, our resin bound gravel driveways are Sustainable Urban Drainage System compliant - 100% permeable, allowing water through into the ground and preventing surface puddles.

SUDS is Sustainable Urban Drainage Systems, but then some say it is Sustainable Drainage Schemes, or Sustainable Drainage Systems. Whatever: the key point is that it is sustainable drainage - a series of methods for dealing with drainage in a sustainable manner, using technologies that minimise the environmental impact of our lifestyles, buildings, structures and surfaces. In simple terms, it's a re-think of what we, as a society, do with all the surface run-off, grey water, effluent and sewage we produce.

water-permeability-of-resin-bound-driveway-gravel

Background

Over recent years in Britain, there has been a subtle change in the rules and regulations that cover the general principles behind surface water drainage.

The two most directly relevant publications are...

Building Regulations Part H3
Updated to emphasise the requirement to deal with surface water at source (source control) rather than dumping it into existing sewer systems.

Planning Policy Guidance Note 25 (PPG25)
Government requirement that "all new developments should collect, treat and ideally re-use storm water where it falls"

There's been a gradual realisation that we can't keep sending everything we're not sure about to expensive Effluent Treatment Works (ETWs) and dumping all the collected rainwater directly into our streams and rivers. ETWs represent massive long-term investment with significant lead times and can be difficult to site, especially in smaller communities. The ones we have are struggling to cope with all the shi... stuff we dump on them, to coin a phrase, and a significant proportion of the effluent treated doesn't actually need all that expensive flocculation, sedimentation and filtering.

When it comes to surface water, the run-off from roofs and pavements, this is reasonably clean and really doesn't need cleaning-up before being returned to the environment. There'll be some sediment picked up from the roof or the paving, and there could well be some contaminants, such as oils from leaky engines, but by and large, it's not that bad. Obviously, the roofs and pavements being drained will have a direct effect on the 'quality' of the surface water: gritty or sandy surfaces may have an elevated sediment content, and run-off from a busy highway is likely to contain more contaminants than run-off from a patio or driveway, but relatively simple techniques can be used to 'trap' sediment and contaminants before the water is released.

Benefits of SUDS

The benefits of SUDS are numerous, but key pluses are:

  • Flood control and better management of storm water at source (source control)
  • Pollution control
  • Recharging of groundwater regimes and aquifers
  • Reduced construction and maintenance costs
  • Improved environment

Technologies

There are dozens, if not hundreds of different SUDS applications, ranging from reed-bed treatment systems for polluted water, to settlement ponds for sediment, to simple swales and filter drains. Schemes are usually site-specific, taking a range of core technologies and using them either singly or in combination to create and application that deals with the surface water drainage for a particular site.

The core technologies involved include:

  • Permeable Paving
  • Infiltration and attenuation systems (Including soakaways)
  • Filter drains
  • Swales
  • Rain Gardens
  • Ponds and Wetlands

Reasoning

Recent experiences with winter flooding, summer droughts worsened by over-abstraction from aquifers for potable water to supply our communities, and increased levels of building on natural flood plains, have brought us to the realisation that by collecting water from hardscapes (roofs and pavements) and then channelling it via underground pipes to a suitable stream, lake or river, we're actually exacerbating the problem. This 'traditional' system accelerates the hydrological cycle; dramatically reducing the time between a raindrop hitting the ground (or roof) and it entering a watercourse that will eventually lead back to the sea, and reducing the storage capacity of the system by artificially diverting water and by-passing the partially-emptied aquifers.

In an undeveloped environment, the raindrop soaks into the ground where it lands, and travels through the underlying strata, being naturally filtered during its passage, and eventually joining the body of "groundwater" at the water table. There's a natural flow regime within the groundwater that results in the aquifers, the water-bearing rock layers, being recharged (topped-up). The cycle is slowed down or "attenuated" and the storage capacity of the system as a whole is massively increased.

In essence, SUDS applications seek to use the natural environment as a conduit for collected water, mimicking what would happen if us pesky humans hadn't messed up everything with our buildings and pavements.

Permeable pavements and driveways

Permeable or porous paving systems defy conventional construction thinking which, for more than 2,000 years, has focused on getting surface water off and away from the pavement structure as rapidly as possible. The surface water is actually directed into the pavement and then stored or released into the environment in a controlled manner.

A porous resin surface, like those laid by UK Resin, are an excellent and incredibly popular example. For more information, speak to our expert team today and we'll be happy to help.