Why delivering sustainable drainage is more important than ever

With population growth and further urbanisation putting pressure on our water resources, as well as the climate emergency becoming of ever-increasing importance to everyone, it’s time to view our drainage strategies as more than just a way of ensuring we always have water where we need it and never have water where we don’t want it.

Instead, it’s time to recognise the true value of sustainable drainage systems (SuDS) and deliver these in a way that meets the needs of our future.

What are SuDS?

SuDS, as defined in The SuDS Manual, is drainage designed to mimic natural systems in delivering effective surface water management together with key environmental and social benefits.

Typically, we refer to “the four pillars” of SuDS to reference water quality, water quantity, amenity and biodiversity. SuDS components can take many forms but they are all designed with these four pillars in mind, whether that’s by managing local flood risk, protecting water quality by reducing pollution, or making use of rainwater close to where it falls. 

Different SuDS components are used to infiltrate, absorb, harvest, convey, treat, store, and control runoff – integrating these processes through the development and its landscape.

These components can be at the surface or underground, but they should be integrated through the development and local landscape. However, it’s the ones at the surface (which are designed to be multi-functional) which provide the most opportunities for benefits.

Suds drainage

Image: Institution of Civil Engineers

Why is sustainable drainage important?

The environment is climbing the ranks in terms of people’s priorities and so it’s becoming increasingly obvious that we must recognise the value of existing resources.

One of these valuable resources is water. The average person in the UK uses 150 litres of water every day and with plenty of energy and CO2 required to run it, heat it and pump it, we need to find as many ways as we can to make this aspect of our lives more sustainable.

Sustainable drainage systems that manage and re-use surface water, rather than simply control runoff, offer a lot more environmental benefits. The components can also incorporate vegetation for further advantages to the local landscape. But research suggests that the current English Non-Statutory Technical Standards (NSTS) has a very limited scope (by focusing solely on delivering the hydraulic control of surface water runoff from new developments) and is constraining possible progress within the industry.


Looking beyond sustainability

As important as it is to consider the impact on our environment when planning a drainage strategy, the possible benefits don’t begin and end there. A number of initiatives have highlighted the value that SuDS and blue-green infrastructure can offer to society and businesses on a much wider scale.

By providing better quality spaces, reducing flood risk, improving climate resilience and enhancing habitats and biodiversity, there can be a huge boost in physical health, mental health and overall wellbeing.

A key challenge that the industry is facing though is that the current NSTS aren’t consistent with actual SuDS delivery. It’s becoming increasingly clear that these should be updated to include multiple benefits to ensure that the ambition to deliver high quality SuDS can be realised.