Are ‘good intentions’ leading us to SuDS heaven or SuDS hell?

Written By: Market Development Director, Hydro International.

Pond with Deep Water Sign

DEFRA ‘s good intentions are to make Sustainable Drainage Systems (SuDS) compulsory in England and Wales from April 1 2014 for developments of more than one property.  However, their assurance of providing 6-months notice ahead of ‘D-Day’ has now been withdrawn.

Nobody knows, but we could be given as little as three months ‘official warning’ of commencement of the Flood and Water Management Act’s ‘Schedule 3’, mostly due to the strictures of the parliamentary and Whitehall processes.

So, the question is – if the road is paved with Defra’s good intentions, are we approaching SuDS hell or SuDS heaven?

There’s no doubting the commitment, tenacity and hard work that the DEFRA team has put into delivering a set of National Standards and associated guidance that everyone in the industry can sign up to (even if we may disagree on some of the detail).  As a member of the ‘Task and Finish’ working groups set up to review the draft standards and guidance, I attended the latest workshops at the end of September, and I believe there was a very positive mood amongst the delegates there.

There’s still some details to be finessed, but SuDS standards seem to be in good shape overall and, in the main, entirely positive.  Yes, it could be difficult for Local Authorities to prepare to set up SuDS Approving Bodies in a short notice period, but some have made great strides already and are practising the principles of SuDS without the letter of law.  At the other end of the spectrum there are authorities that have adopted a more ‘wait and see’ attitude.  But all Lead Local Flood Authorities have received significant funding towards capacity building so have the opportunity to prepare on the basis of an April 2014 start date.

Representations, particularly from housebuilders’ lobby and the input of the Task and Finish groups themselves, have contributed to refining the wording and ensure the standards are workable alongside other pertinent legislation.

The positive principles that SuDS are expected both to control flood risk and to improve the quality of surface water are now well-defined.  This will provide a robust regulatory framework in England and Wales for surface water treatment for the first time, which is very encouraging.

Inevitably, most energy has been focused on developing the standards and guidance that underpin good SuDS design.  The ongoing performance and maintenance of SuDS features still needs further definition.  Indeed, it’s highly likely that adopting authorities will take a few years to truly get to grips with the full operational, maintenance and costs implications of SuDS under their jurisdiction.

It’s important to define the maintenance requirements for vegetated features such as ponds or wetlands alongside manufactured elements of a drainage scheme such as a vortex separator.   For manufactured devices, providing a proven, predictable maintenance schedule and costs is straightforward.  But how will the full costs and maintenance schedule of a pond be accurately defined?

Unfortunately, I know of even so-called ‘exemplar’ natural SuDS designs where subsequent poor maintenance has compromised the original design performance of the scheme.  So, it’s important to develop ways of predicting maintenance and demonstrating repeatable performance.

At Hydro we have developed an online Selection Tool which is available for anyone to explore the choices for surface water treatment features according to catchment area and receptor.  The tool suggests an example treatment train, the resulting pollutant removal and indicative construction and maintenance costs.  You can then change / modify the components in the treatment train and see the resulting changes in pollutant removal as well as comparing capital and whole-life costs.

So, to answer my own question, I believe we’ll be on the road towards ‘SuDS heaven’ by April 2014, but we’ll be a long way from achieving perfection.  The industry will continue to learn and refine its practice on the basis of experience.  Knowledge-sharing initiatives such as Engineering Nature’s Way and Susdrain will provide a vital resource for all stakeholders as the body of exemplar schemes continues to grow.

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Alan West says:

A well written article & I concur with the sentiments. Here in Melbourne, Australia we’ve had 6 years experience with compulsory pollutant reduction targets for developers & I’ve had 15 years experience as a senior local government engineering manager in fine tuning maintenance cost for vegetated bio-filtration systems such as rain gardens. It would seem that local authorities could do worse than learn from our experience implementing systems in large cities. I’d be happy to share my conference papers.

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