The UK is notorious for its mild and damp weather, with almost 1150mm of rainfall last year, its safe to say the United Kingdom is always at that slight risk of flooding, and this is even more prominent in urban areas, due to the lack of sufficient drainage.
Everyone is familiar with the disruption floods can cause, not just for property owners, but traffic and many business owners. An old yet infamous example is the ‘Beau Trap‘; a 19th-century word for loose paving slabs before or during a rain/shower. It’s an unfortunate occurrence that many have experienced – stepping on the edge of a paving slab that has a build up of water underneath, causing their foot to become soaked! This is just one (slightly insignificant, yet irritating) example of surface water flooding.
Past generations completed a great job in producing a big network of drainage, sewer pipes, and water systems, however as the urban growth speed has increased exponentially, the below-ground drainage systems have not caught up (although recent works on the Thames Tideway tunnel is expected to help greatly).
The faster urban areas are built, the faster ‘surface water drain off’ is increased, which is water that would, in natural circumstances, permeate into the ground. Long periods and short bursts of rain are currently just running off the surfaces and not permeating, which in turn backs up at inadequate drainage systems/sewers then eventually contaminates local waterways. This results in huge insurance claims.
However, this threat can be seriously reduced through the implementation of Sustainable Urban Drainage Systems, or in short, SuDS.
There are a lot of ways to do this, with so many systems in the market to assist in mimicking the natural process of rainfall as it lands.
Sud systems can be above or below ground, hard engineered or as green as desired. There is no need to leave this concept to new development – most systems have a retrofit ability.
There are many examples mentioned in the ‘London Sustainable Drainage Action Plan‘. The main focus of this plan is on the retrofitting of sustainable drainage to existing buildings, land and infrastructure within London.
“By 2040, London will manage its rainwater more sustainably to reduce flood risk and improve water quality and security. This will maximise the benefits for people, the environment and the economy.”
One of the most effective and simple ways to help achieve this vision is to use porous surface systems, there are many options on type and blends, with added ability to be creative and keep at the forefront of project design and end user UX (user experience).
Retrofit SuDS surface systems:
|Resin Bound Systems||Paths, Pavements, Drives, Parks|
|Hybrid Rubber Aggregate/ Resin Bound System||Paths, Pavements where high flexibility is required|
|Tree Pit Systems||Tree surrounds of areas of fast drainage requirement|
|Resin Mulch Systems||Low maintenance areas needing weed control/tree surrounds|
These systems have generous porosity to avoid surface water drain off and remaining maintenance free and durable for foot and light traffic.
Typical water flow rates: