What does the future hold for Sustainable Drainage Systems?
The ability to mimic natural drainage and ground water processes, and deal with storm water at its source, allows Sustainable Drainage Systems (SuDS) to be more efficient and sustainable. So what is holding them back?
Sustainable drainage systems currently exist in construction guidance rather than policy, and does not reduce the costs associated with building properties, so it is not always considered by housebuilders. However, as flooding risk rises globally due to climate change, and systems such as the ECO-90™ even claim to be carbon negative, SuDS have the potential to help form a more sustainable construction repertoire.
Launched in the UK in 2012, the Groundwater Dynamics ECO-90™ SuDS device sits 30cm underground and draws in surface water, utilising its movement underground to draw more water into the top of the device. This technology helps drain flood waters effectively by essentially encouraging water to move into less saturated soil.
As more sustainable technology emerges, it may not be long before we see more large-scale projects implement these innovations in complex schemes. A future with an Aquobex-Groundwater Dynamics partnership could bring innovative SuDS solutions integrated with community-wide flood mitigation and property-level flood protection.
The Local Government Association, whose members after all control planning, describe SuDS thus:
Sustainable Drainage Systems (SuDS) are designed to manage surface water as close to its source as possible, to mimic natural drainage and encourage its infiltration, attenuation and passive treatment.
SuDS even has a Tier System that says storm water discharge should be:
- Tier 1 – Into the ground
- Tier 2 – To a surface water body
- Tier 3 – To a surface water sewer, highway drain or another drainage system
- Tier 4 – To a combined sewer
However, the Tier system is contained in a document called ‘Non-Statutory Technical Standards for Sustainable Drainage: Practice Guidance’. This hardly implies any need for compliance and despite planning guidance advising developers to prove why they ended up applying for a non-Tier 1 system, it only needs a developer to say that no Tier 1 solution was available and the planning moves to lower Tiers.
From drought and flood resilience, to recharging aquifers and water courses, to protecting micro eco-systems, SuDS aims are laudable. With climate change impacts you could even upgrade this to ‘imperative’.
SuDS reality is the real money doesn’t care
“Why should we try any of this sustainable housebuilding stuff? No one is asking us to do it. The Government just wants us to build lots of houses, our shareholders just want us to make a profit, and house buyers just want an affordable house.” That was the input of a major housebuilder to the Bricks & Water 2018 Policy Connect report. Speak to a Consulting Engineer about drainage and they will say that cost is the imperative in drainage design.
The cheapest drainage system is one that can collect storm water and chuck it into a sewer. This is a result for the developer because once the water is in the sewer it is no longer their problem as to what happens next. And as long as the planning system lets them get away with it, they will keep doing it.
SuDS has to go legal
Apologies for using the Covid word but it has achieved some unexpected side-shows. SuDS is one such. We all now pretty much understand that ‘guidance’ is not the same as ‘legal’. Whilst SuDS flip-flops around in a flood of countless, seemingly never-ending planning decisions that favour concrete, pipes and sewers for storm water drainage, the SuDS ‘guidance’ remains toothless and largely irrelevant to the construction sector. That’s a shame and an admission of policy failure.
Maybe a piece of Matt ‘Hancockesque’ diplomacy is needed. He soon realised there’s no bite in his belief in ‘civil duty’, whereas legal obligation and fines worked wonders.
SuDS needs to reinvent itself
Its aims are fine. It’s relevance to the construction industry is missing. It can only have a future when it addresses below the ground drainage at source. Pretty above ground landscaping does not drain a built construction site. Rain water was made for below the ground soils – that’s how nature works. By focusing on below the ground and gaining traction with Local Authority planning, the construction sector will have to relearn SuDS, allowing new solutions to emerge. We can even show how our Tier 1 drainage system can actually make more money for developers, putting the economic argument against SuDS to the sword.
