Sustainable Urban Drainage Systems – better known as SUDS – are designed to lower the risks of flooding in any particular area by creating more efficient means of draining water from areas prone to flooding without over-filling our existing drainage system.
A significant contributor to the issue of flooding is the continual expansion and densification of urban areas. These town and city areas tend to be built up using great expanses of impermeable materials which prevent rainwater from draining away as it falls, and this has become a major factor in the floods which have befallen the UK in recent years. Our old Victorian drainage systems simply can’t cope with the amount of rain they’re expected to handle.
Thankfully, since the 2010 Water and Flood Management Act, SUDS have been mandatory in new developments in the UK. It is also hoped that SUDS will be introduced during the renovation of older properties in order to further reduce the future risk of flooding across the country.
What does a Sustainable Urban Drainage System do?
- Slow down the rate at which rainwater flows into our older drainage systems
- Improve the quality of rainwater flowing into the drains
- Reduce the damage caused to the environment & wildlife habitats by heavy rainfall
To achieve these three main aims, SUDS implement a number of different measures:
Creation of more permeable surfaces. The improvement of drainage and the reduction of the risk of flooding are dependent upon the introduction of permeable outdoor surfaces. More permeable surfaces include gravel, blocks, or tiles with spaces left between them to allow for drainage through to a layer of soil. This SUDS method has many applications and is popular with many kinds of property. For this to work, the underlying soil must also be permeable so a heavily clay-based soil is no good. The soil also needs to be clean and contaminant-free to avoid any harmful substances being washed into another body of water where it could cause environmental damage.
Rainwater harvesting. There are several good reasons to harvest rainwater rather than allowing it to wash away. Preventing rainwater from getting to the drains both reduces the risk of flooding and saves that water for practical uses around the home. Rainwater is great for use in washing, cleaning, gardening, and toilet flushing. Whether using a simple water butt in the garden or a more complex underground rainwater harvesting system, there is plenty that can be done with water saved from running off the roof and into the drains.
Formation of ditches, ponds, and wetlands. Sometimes, a more obvious landscape feature can be used to prevent flooding. Manmade ponds, ditches, and wetlands can effectively control the rate at which water drains away from a densely built-up area. Water is collected and then gradually released by a process known as attenuation. When completely drained, these spaces blend into the wider landscape and are usually covered with grass or other vegetation.
Green Roofing. A relative newcomer to the building site, green roofs are sprouting all over the place. Although they have actually been used throughout history, they have recently enjoyed something of a renaissance as designers strive to become more environmentally responsible in their practices. Whilst green roofs slow down the rate at which water reaches the ground and drainage systems, they also provide other advantages such as air purification, wildlife habitats, and home insulation.
Why do we need SUDS?
Sustainable Urban Drainage Systems are not only good for preventing flooding. Better drainage systems are useful for filtering rainwater and preventing the spread of contaminants including salt, oil, and sediment, and keeping them out of the water systems where they can cause harm to wildlife and habitats.
Rainwater management is very important in maintaining a safe and manageable balance when particularly bad weather afflicts the country. SUDS are well designed to ensure that our outdated drainage systems continue to cope and to prevent further flooding catastrophes.
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