Sustainable Urban Drainage Systems – New Legislation & What it Means?

Don’t let legislation run-off with you!

Sustainable Urban Drainage (SUDS)

‘SUDS’ or ‘Sustainable Urban Drainage Systems’ are a range of sustainable drainage solutions aimed at reducing flooding and pollution of water courses by controlling runoff of rainwater from front gardens.

Increasingly, home owners and self builders are using impermeable solutions for driveways and front gardens. As water does not soak through impermeable driveways, the water runoff is typically directed to a drain, soakaway area or in some cases onto a public highway.

Permeable?

Modern permeable surfaces work by allowing water to soak through the surface into the ground below reducing the run off into drains. This decreases the opportunities for drains to overflow.

Impermeable?

Means that water runs off the surface and straight into the drains. This also reduces the amount of water that reaches our natural underground aquifers.

Where uncontrolled runoff of rainfall from front gardens goes on to the road the drainage systems can come under strain during heavy, sustained rainfall. This has been contributing considerably to the dramatic floods we have seen of late and it is for this reason as to why new legislation has been introduced.

Since October 2008, homeowners now need to obtain planning permission when using an impermeable material such as concrete, asphalt or non-permeable paving (unless a suitable soakaway, rain garden or drainage system is used) to;

• Pave over front garden areas exceeding 5m² OR
• Replace existing hard standing driveways exceeding 5m²

Planning permission will cost about £150 to obtain and will take around 8 weeks to process. Alternatively, if homeowners want to install a permeable solution such as permeable paving or gravel/green vegetated areas they will NOT need to consider obtaining planning permission.

There are 3 solutions available:

1. Use a new ‘Permeable’ option

Permeable solutions enable water to naturally flow through into the sub soil where it can drain harmlessly away. To help homeowners to comply with legislation, most paving suppliers will now provide a range of permeable paving.

2. Use a traditional ‘Impermeable’ option

Homeowners can still use impermeable solutions BUT must ensure that water runoff is directed to a rain garden or soak away area by using channel drainage. It may be possible to use channels and linear drainage to direct water to the drains which take roof water with agreement of Local authority and water companies in some locations.

3. Use gravel or mainly green, vegetated area

Loose gravel or wheel tracks can create an attractive options on which to park cars. Alternatively, wheel tracks can be surfaced with blocks, asphalt or concrete. Gravel with different shapes and colours are available to make the surface more decorative. Using a grid or a strip of block paving or asphalt at the entrance can limit the loss and spread of gravel from the drive.

Front garden areas can be designed using impermeable OR permeable landscaping, however, good garden design and consideration of environmental issues is essential to meet the requirements of legislation. However, many planning authorities will expect planning applications to demonstrate how a more sustainable approach to drainage is to be incorporated into development proposals and plans, and for detailed design information to be submitted at the appropriate stage.

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