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Flood and Water Management Act, 2010


This document aims to give an overview of the Flood and Water Management Act, 2010 from the point of view of the drainage engineer involved in the design process. The Department of the Environment, Food and Rural Affairs (DEFRA) web site has several fact-sheets looking at different aspects of the Act including from the point of view of the developer, the local authority and also gives details of the funding for local authorities.

Following the extensive flooding during the summer of 2007, the government commissioned Sir Michael Pitt to investigate the causes of the flooding, the lessons to be learnt and to propose a way forwards. The Pitt Report was completed in June 2008 and the Flood and Water Management Act was the government's response although the Act is largely only applicable in England and Wales. The Act covers a number of areas in addition to those directly involving drainage matters, including administrative matters regarding water resources, water company billing matters and special administration for failing water companies. The measures directly involving drainage include matters regarding reservoir safety, giving the Environment Agency (EA) an overview of all flood and coastal erosion matters, unitary and county councils managing local flood risk and encourage the use of sustainable drainage systems (SUDS) for new developments. These measures with the exception of those involving reservoirs will be examined in more depth below.

The Flood Risk Regulations, 2009 were made to address the requirements of an EU directive and set in train many of the requirements of the Flood and Water Management Act with respect to flood risk management.

History of SUDS

The run-off from a natural catchment depends on a number of factors such as topography, soil type, the existing moisture content of the soil and so on. A natural catchment, however, tends to act like a sponge, rainfall falls on the ground and vegetation and the majority is soaked up, some to be gradually released over a period of time. In contrast an urban area with a 'traditional' drainage system significantly reduces the water entering the ground and greatly increases the peak flow entering the local watercourse. To counter this, for many years attenuation facilities have frequently been incorporated into new development to reduce the peak flow so as not to cause overloading to, and flooding from, the local watercourse. Unfortunately the design of a typical 'balancing pond' means that relatively low intensity rainfall passes through the pond with little attenuation and of course the problem of a reduced amount of water entering the ground remains. This means that for a large catchment, the river still suffers from increased peak flows during long, relatively low intensity storms which are the types of rainfall likely to result in flooding in this type of catchment. There is also likely to be reduced flows during dry weather. It is to try to combat these problems that the overall SUDS concept has been introduced. SUDS aims to mimic the natural drainage of a catchment by reducing and slowing down the run-off from a site. The SUDS techniques available include green roofs, soakaways, rainwater harvesting, permeable pavements, infiltration trenches, filter strips, rain gardens, filter drains, swales, detention basins, wetlands and retention ponds.

The SUDS approach was originally developed during the 1990's, drawing on many ideas emanating from the United States and Sweden, although many of the individual techniques had been in use for some time before that. From the engineers point of view, guidance was made available by the CIRIA publications covering design, in 2000 and best practice in 2001. These were consolidated and updated with the publication by CIRIA of the 'SUDS Manual' in 2007. Although at the time that the Flood and Water Management Act reached the statute book some progress towards the wider use of SUDS had been made, progress was slow. It was generally believed that the concept was held back by the absence of a suitable body to adopt and maintain the SUDS infrastructure.

Provisions of the Act

As mentioned above, the EA is to have an overview of all coastal and flood risk management and “must develop, maintain, apply and monitor” a strategy for flood and coastal erosion risk management in England. In Wales, Welsh Ministers will carry out this function. The EA must also establish Regional Flood and Coastal Committees (RFCCs) who will take over the role of the existing Regional Flood Defence Committees but with the additional remit of coastal erosion. A lead local flood authority (the unitary or county council for an area) must develop, maintain, apply and monitor a strategy for local flood risk management in its area which will cover surface runoff, groundwater and ordinary watercourses. The RFCCs will guide the EA flood and coastal risk management activities and will also assist in scrutinising local authority's risk assessments, maps and plans. The lead local flood authority will investigate incidents in its area to identify the relevant flood risk management body. They will then inform the responsible body of the results of their deliberations. They will also maintain a register of structures or features which are important regarding flood risk. The Act also gives the EA power to raise a levy for a lead local flood authority regarding flood and coastal erosion management.

Drainage approving bodies will also be established and these are to be the unitary or county council for the area. The minister, however, has the power to appoint a body to all areas or one area in preference to the unitary or county councils. The drainage arrangements for projects of national importance will be approved by the Infrastructure Planning Commission. It should be noted that county councils in particular do not have a great depth of knowledge of drainage matters and this lack of experience will be difficult to address in the short term.

National Standards for SUDS, covering design, construction and maintenance is to be introduced and this is currently in preparation and will be published by the minister for consultation in due course. The National Standards are said by DEFRA to “allow for local conditions to be taken into account” which presumably includes such things as ground conditions. In could be imagined that the National Standards will rely heavily on existing guidance such as the 'SUDS Manual'.

The Act introduces a requirement for the approval of the surface water drainage systems for most types of construction work including patios. Approval is required before commencement of construction work. Obviously the act will need some interpretation, particularly regarding patios and the minister has power to vary the definition. The Town and Country Planning (General Permitted Development) (Amendment) (No 2) England Order 2008 has already placed restrictions on the paving of front gardens which can in some circumstances significantly increase the paved area connected to the drainage system built to serve the road. Growth in this paved area would increase the flows in the highway drain or public sewer so contributing to local flooding and probably ultimately to the flooding of watercourses. It is interesting to note that section 163 of the Highways Act, 1980 also contains powers for the highway authority to stop water being discharged onto the footway of the highway. Applications for drainage approval under the Flood and Water Management Act, will if appropriate, be combined with the application for planning permission or if planning permission is not required can be applied for independently.

Paragraph 16 of schedule 3 of the Act amends the Water Industry Act 1991 by adding section 106A which changes the right to discharge surface water to sewers. Section 106 of the 1991 Act originally gave adjacent property owners the right to drain foul and surface water to a sewer. This was subsequently amended by the Water Act, 2003 to allow the water company to refuse this if it was felt to be “prejudicial” to the sewerage system. This power has been applied with varying degrees of enthusiasm, in some cases to the extent that it was blamed by developers for stopping all development (including redevelopment) over wide areas. The new section 106A says that new developments may now only discharge surface water to the sewer if the site's drainage system has been approved under the Flood and Water Management Act. The power to refuse connection if the surface water flows were deemed to be prejudicial to the sewerage system is now also removed. This represents a slight improvement, as far as developers are concerned, over the previous situation.

The approving body may approve or reject an application or approve with conditions. The Approving body will have a duty to adopt any new drainage system which meets certain criteria including, that it was constructed in accordance with national standards, that it has been constructed in accordance with the approved plans and that it is a sustainable drainage system as defined by the minister. A non-performance bond will be a requirement for an agreement to adopt to ensure that local residents or the adopting authority are not left with an unsatisfactory system. Sustainable drainage systems can include permeable roads although if these are to be adopted by the highway authority, that part would not be adopted by the Approving Body. The Approving Body is not under an obligation to adopt a drainage system which serves only a single property but may adopt a SUDS system that it does not have a duty to. Presumably, in this case, an appropriate commuted sum to cover future maintenance costs would be appropriate. Once adopted, the approving authority is under a duty to maintain the drainage system in accordance with the national guidelines.

Part of the Act relating to the EA and the local flood authorities developing strategies for risk management was implemented from 1 October 2010. It is expected that the remainder of the Act will be implemented in April 2011 but that the SUDS provisions will be delayed until late 2011 or in 2012.


A large part of the country is covered with impermeable soils meaning that some SUDS techniques involving infiltrating the rainfall into the ground are not practicable and this significantly reduces the options available. It should also be borne in mind that inappropriate SUDS techniques used with impermeable soils in the wetter parts of the county such as Wales are only creating the flooding problems of the future.


The provisions of the Act are being introduced as the government announces that local government and DEFRA are facing cuts of 28% and 29% respectively over four years so it seems very likely that the measures will be under funded. These cuts mean a reduction of £110m in planned capital expenditure on new flood defence over the four years. DEFRA say, however, that the Act will be funded and that they will raise the local levy to bridge the funding gap. In addition the government feels that there will be savings from the transfer of private sewers to the water companies since local authorities will no longer be involved in resolving problems in that area.

Presumably government envisages that the approval and supervision of the construction work on site will be self financing, being paid for by the fees paid by developers. The minister is to make regulations on the level of fees for this.

In the first few years the adopted infrastructure will be new and should be in good condition and so will not require large amounts of capital spending. There will however be a requirement for ongoing maintenance. It is presumed that a maintenance period will be a condition of the adoption agreements although we will have to wait until the national standard for SUDS is published to confirm this. Maintenance periods are usual for the adoptions of sewers under section 104 agreements and for new highway under section 38 agreements. A maintenance period will, again, further delay the need for spending on maintenance by the local flood authority.


Many people feel that the unitary and county councils lack experience in SUDS and drainage matters in general and although training can be given, it will be difficult to make up the deficit in experience.

The mandatory use of SUDS techniques in the surface water management of new sites together with the adoption and maintenance of these features is a very worthwhile exercise in terms of the reduction of flooding. It will however take many years to have an appreciable effect on flood risk.

As outlined above, the Act gives the EA and the lead local authorities the duty to make and apply flood risk strategies but without proper funding to investigate flooding and carry out works, this is largely meaningless.

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Last Modified 17 January 2011.