uDS deliver much-needed flood protection and prevent surface water run-off from overloading the UK’s already strained drainage and sewer networks. They protect environmental water quality and add value to urban spaces through public amenity and green infrastructure.

So why has widespread implementation of SuDS been so elusive? It’s now nearly 10 years since the devastating 2007 floods which prompted the seminal Pitt Review to make a raft of recommendations, including tackling surface water flooding through more robust policy and regulation. Yet since then we have been on a policy merry-go-round.

In the meantime, we have continued to suffer severe flooding events. The hard facts about climate change and the likelihood of more intense rainfall in future are impossible to deny. The pressure on our surface water drainage infrastructure to provide resilient protection for water quality and quantity is reaching breaking point for some communities.

Seeking professional views

What is holding back progress? Hydro International, through the Engineering Nature’s Way initiative, conducted the ‘SuDS: The State of the Nation 2016’ survey to get the views of professionals working ‘at the coalface’.

We were left in no doubt that those who design and seek approval for SuDS developments, as well as those who review and approve them, all feel passionately about getting to the bottom of the SuDS conundrum. Conducted between March and May 2016, our survey generated more than 360 detailed responses with personal insights from professionals resulting in over 1000 additional comments.

We published a summary and analysis of the results at the end of 2016. This was timely, as the Government has promised to review the effectiveness of delivering SuDS through the planning system in England in 2017. Our findings also chimed closely with ‘A Place for SuDS’, a report published in February by the Chartered Institution of Water and Environment Management (CIWEM) and the Wildfowl and Wetlands Trust (WWT) supported by a number of other national environmental and professional architecture groups.

Housing hold-ups?

Hard on the heels of the CIWEM report came the Government’s Housing White Paper, stating in no uncertain terms that fixing Britain’s ‘broken’ housing market is an overriding priority. The White Paper was by no means a response to the SuDS lobby, yet its timing felt significant. Developers are under pressure to accelerate building of much-needed homes in the UK. There’s no doubt they have to make hard commercial decisions about land-take and construction costs that can be perceived to conflict with ambitions for more ‘natural’ management approaches to surface water drainage.

Maintenance and adoption

Designers, specifiers and developers all need to be confident their SuDS schemes can be handed over smoothly to a new owner or adopting authority once the project is complete, otherwise they may be reluctant to include them.

Both the results of our survey and the CIWEM report suggest that current regulation is not sufficient to ensure that any new SuDS scheme will continue to perform as designed and to be maintained properly.

As a result, there is inertia amongst those expected to adopt them, and a lack of agreement about who should own them.

In particular, the majority of respondents to our survey (69%) believed that uncertainty around the maintenance and through-life performance of SuDS components is presenting barriers to adoption. Most (73%) also believed that more standard technical guidance is needed on the long-term maintenance of SuDS components.

The detailed comments suggested a lack of confidence amongst some authorities about taking over ownership of SuDS from developers. Some respondents felt that clearer policy is needed to ensure the appropriate public authorities, including water companies adopt SuDS.

Proprietary SuDS

Through our survey we were also keen to explore with professionals the opportunities for proprietary systems to facilitate more widespread adoption. It’s clear that most of our respondents saw the value of proprietary systems. Manufactured systems, for example, Hydro-Brake Flow Controls, underground modular storage and infiltration, or hydrodynamic vortex separators, all present opportunities as enablers and facilitators of SuDS that can also help to ensure developments are built cost-effectively.

The vast majority of survey respondents (73%) agreed that designing from a full SuDS toolbox facilitates a sustainable approach. Most also agreed that proprietary SuDS components are essential to the SuDS toolbox (77%), and can facilitate Green Infrastructure (70%) as well as help to ensure the long-term maintenance of SuDS features (63%).

However, CIWEM’s Big SuDS Survey results indicate that proprietary systems are only being implemented in just over 7% of SuDS projects. This suggests that many professionals may be frustrated in being able to use proprietary systems to deliver workable and practical SuDS solutions.

Engineering Nature’s Way

While above-ground, ‘natural’ systems are the romantic ideal, every design for SuDS must be founded on precision-controlled, pragmatic engineering. Only then will they deliver sustainable outcomes against measurable performance targets.

To make progress in policy and practice, we must adhere to principles that ensure repeatable and predictable performance for every SuDS scheme. We also need to take steps to measure and record their performance wherever possible. Only then can we be confident that robust flood protection will be achieved, along with wider multiple sustainable benefits.

For a copy of the SuDS: The State of the Nation report and further background on SuDS policy and best practice, visit Hydro International’s knowledge-sharing hub.