The government has consulted on new proposals for implementing sustainable drainage systems (SuDS). Under this initiative, the government is proposing to deliver SuDS through the planning system rather than through SuDS approval bodies (SABs).
SuDS were promoted by the Pitt review in 2007 as a means to reduce flooding. Proposals to increase its uptake were included in Schedule 3 of the Flood and Water Management Act (FWMA) 2010. The principle behind SuDS is that a scheme is designed to mimic the natural drainage of the land by dealing with rain where it falls, as far as is practicable.
Previous SuDS proposals involved the establishment of SABs in unitary or county councils. The SAB’s would approve a scheme’s design and ensure that construction, operation and maintenance of the system is compliant with a National SuDS Standard. Under this system developments would have needed approval from both planners and SABs before a project can go ahead.
This approach, however, was not popular with developers faced with the challenge of coordinating approvals from the separate bodies. Under the latest proposal SABs will no longer be required.
The withdrawal of Schedule 3 of the FWMA and the proposed changes will mean that SuDS will no longer be a legal requirement but will be an additional planning consideration. The consultation proposes strengthening the existing planning system to incorporate an ‘expectation’ for SuDS on new developments. Drainage designs will then be approved using the tried and tested planning system.
However, since it will be down to each individual planning body to decide on their SuDS requirements, this piecemeal approach to drainage could lead to inconsistencies nationally and may result to disputes between developers and local authorities.
That said, having to deal with a single body will simplify the process for developers and may help avoid delaying a development, which is a good thing.
An effective SuDS design, however, requires a holistic rather than local focus. The absence of SABs will mean that local authorities will need a depth of drainage knowledge not generally found in town or district planning bodies - as is evidenced by the number of homes built on flood plains. A lack of knowledge of wider surface water run-off and retention issues may force councils to subcontract out this work, which will need funding - but where does the money come from?
Planning authorities can also chose not to insist on the implementation of SuDS where their costs affect the viability of a development, which could mean a SuDs solution can be ignored if a local authority is set on developing an area.
In addition, with SABs scrapped no single body will now be responsible for the adoption and maintenance of SuDS. Instead, it will be up to developers to propose a suitable mechanism for the lifetime of the scheme, the cost of which should not be passed on to the homeowner, which means that there will be less certainty in terms of responsibility and liability for maintenance.
Of some concern is that the proposal only covers developments of ten houses or more. This could see developers building large plots in phases of up to nine homes so as not to breach the SuDS threshold. And, in its current format, the proposal will not address the cumulative effect on run-off of large numbers of small developments in an area.
Nevertheless, the 10-home threshold is a good starting point, providing measures are put in place to enable resources and expertise to be scaled up over time.
It is also of concern that the consultation document refers to SuDS almost exclusively in terms of water quantity and flood mitigation. This is a far narrower definition of SuDS than that generally accepted as best practice, which, in addition to water quantity also promotes water quality, amenity and biodiversity.
Whatever the outcome of the consultation, CPSA’s members are well positioned to provide SuDS solutions. The proposed changes may result in more drainage systems connected to sewers via flow control, attenuation and storage systems, than under the original Schedule 3 proposal. In this event, CPSA members’ reputation for producing reliable products will continue to provide whole-life value.
However, should the outcome for SuDS remain more closely aligned with the original plan under Schedule 3 using SABs, new proprietary precast concrete SuDS components continue to be introduced that can effectively sit alongside vegetated SuDS and traditional gravity sewer systems.
We await the government’s decision.
Stuart Crisp is business development director at CPSA.