Sustainable Drainage Systems (SUDS)
Earlier in this report, the author outlined the importance of the SUDS initiative and its benefits for drainage systems. One of the biggest problems of SUDS is the question of who is responsible for maintenance after a scheme has been installed? Scotland has the benefit of a framework agreement between Scottish Water and local authorities as to the division of maintenance responsibilities for SUDS. There is no similar agreement in England and Wales , although CIRIA has been attempting to produce one.

In Scotland there is specific provision under the Water Environment and Water Services Act 2003 for Scottish Water to take over the maintenance of SUDS schemes at a future date, when they have finished producing a technical specification for SUDS which can be agreed by all stakeholders. This maintenance work will be funded by the Scottish Executive.

Even though SUDS was not part of the original remit of flood appraisal group meetings, in practice, the subject has been discussed in great depth at many of the regular flood appraisal group meetings in Scotland over the last two years. This has had great value in encouraging and helping local authorities introduce SUDS correctly. Scottish Water and SEPA have been able to address the problems and queries raised by local authority staff, and the author has been able to influence the way in which SUDS have been adopted to protect the interests of insurers. The author is, however concerned that the many questions and misconceptions which have been resolved in Scotland through flood appraisal group discussions may still exist in England and Wales, where planners do not have the benefit of regular meetings with experts who can give advice and spread best practice. (It is interesting that while SEPA seem to be mainly concerned about water quality issues, the Environment Agency is equally concerned about using SUDS in the context of flood alleviation. It is certainly an important factor in any consideration of flood issues, and it seems to the author perfectly appropriate as a topic for flood appraisal group meetings.)

The author is a member of the North East Scotland Flood Appraisal Group (NESFLAG) which has produced a guidance note booklet for developers and regulators which contains helpful advice on Drainage Impact Assessments (DIA). This booklet has been very successful in helping many local authorities in Scotland. The author would strongly endorse the guidance given in this booklet, which would be of value not just in Scotland but for local authorities throughout the UK . It recommends that the DIA includes sensitivity testing for new drainage schemes to assess the flood risk, including "consideration of the flow route for 50 and 200 year return period rainfall events showing no detriment to land or property as a result of overland flow."

In other words, the drainage system should be able to cope with a 200-year flood without causing damage to property or gardens.

The author has also prepared a set of frequently asked questions based on questions raised at numerous flood appraisal group meetings, and this is available in electronic format from the author on request ( david@crichton.sol.co.uk )

«back to top«