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Consultation for proposed sustainable drainage regime in Wales

The Welsh Government has begun formal consultations on its proposed mandatory regime for sustainable drainage systems (SuDS) for new developments.

This will involve implementation of schedule three of the Flood and Water Management Act 2010 (pdf).

The prospect is mandatory use of SuDS compliant with national standards on all minor and major development (more than one home or sites larger than 0.5 hectares).

At present, the use of SuDS on new developments is non-mandatory, thus their use is limited and systems are not always compliant with standards. This is due, in large part, to uncertainty around adoption and continuing maintenance, according to the consultation document.

The consultation includes details of a new-look SuDS Approval Body and an approach that ensures that all new developments have a SuDS scheme that meets mandatory standards.

Currently, developers or local authorities must decide to finance the ongoing maintenance of SuDS, where they are built. However, the arrangements for this are highly variable and ad hoc.

SuDS are already used extensively on new developments in Wales. But these are variable in quality and performance, and there is currently a preponderance of ‘hard’ SuDS (largely comprising underground measures and attenuation ponds), with fewer ‘landscaped’ (vegetated) SuDS that can potentially deliver multiple benefits.

Under the new regime unitary authorities in Wales would be the responsible SuDS approving body (the SAB) and would approve new drainage systems before construction can begin. The consultation document suggests that neighbouring councils could share this function.

The government has insisted it wants to integrate SuDS more fully with local development planning at all stages. There will be an opportunity to do this as part of the review of planning guidance for TAN15, which is expected later this year.

In terms of timescales, the administration has proposed that where an environmental impact assessment is required, the SAB must determine an application for approval within 12 weeks and for other applications within seven weeks. Both limits are at least one week less than those under the planning system.

“To ensure flexibility we propose that in all cases the SAB and applicant should be able to agree to extend the timeframe provided the specified timescales have not expired.
“Should the SAB fail to meet these timescales, we propose that the application will be deemed to have been undetermined. We also propose that in these circumstances the applicant should have a right to appeal to an independent tribunal.”

The consultation paper added: “Our policy objective is to deliver effective, multipurpose SuDS in new developments that will be maintained for the lifetime of the developments they serve. To deliver this, it is vital that we enable partnership working between those involved in the design, construction and maintenance of the SuDS.”

Currently about 163,000 properties in Wales are at risk of surface water flooding (120,000 residential and 43,000 non-residential). Flooding from surface water run-off costs Wales an estimated £60 to £130 million a year – 29 per cent of which falls to business.

The risk of flooding is increasing, largely because of climate change and urbanisation. Surface run-off can be a major source of pollution, both directly and from overwhelmed sewers discharging into rivers.

The consultation can be found on the Welsh Government website.


Roger Milne, The Planner