In Wales, the law of flood management is entirely statutory, being regulated primarily by domestic legislation; there is also relevant European Union legislation, including in relation to the control of waste waters and the water industry (including sewerage and drainage).
1. The Flood and Water Management Act 2010 makes provision for an extensive regime of flood management, concentrating on prevention and preparation rather than on reaction once a flood occurs. The 2010 Act requires local authorities and certain other public bodies with local environmental responsibilities to prepare strategies for the management of flood risk. Lead responsibilities under the 2010 Act are divided between: local flood authorities; the Environment Agency; Ministers; and Regional Flood and Coastal Committees, established under the Act. Where a flood occurs, general powers and duties of local authorities and the emergency services will be engaged. In extreme cases, powers under emergency regulations may also become available (see: Emergency regulations). Directive 2007/60 on the assessment and management of flood risks creates a parallel set of duties arising out of European Union law, which are transposed by the Flood Risk Regulations 2009/3042.
Meaning of "Flood"
2. The concept of "flood" is defined for the purposes of the law of flood management by s.1 of the Flood and Water Management Act 2010. The principal aim of the definition is to include anything that might naturally be described as a flood, irrespective of whether it is caused by excessive rainfall, the breach of a dam or any other kind of natural or structural incident - s.1(2). The definition also serves to exclude from questions of flood management two specific issues which are left to be addressed by other legislation: (a) sewerage overflows, and (b) burst water mains, each of which is addressed by the law relating to the water and sewerage industries (see: Water industry, Sewerage industry).
Meaning of "Risk"
3. The 2010 Act centres around the concept of managing "risk" of flooding (and coastal erosion - see: Coastal erosion). Section 2(1) of the Act defines "risk" as: " a risk in respect of an occurrence assessed and expressed (as for insurance and scientific purposes) as a combination of the probability of the occurrence with its potential consequences. " Although at first sight this simply over-complicates what is a simple English word with a plain meaning, the purpose of the statutory definition is to qualify the simple meaning of risk in relation to the statutory duties imposed by the Act so that, in particular, when devising strategies for management of potential floods public authorities are both permitted and required to factor in the consequences of floods. So, for example, it is this that justifies local authorities as assessing an area as being an area of low risk even if floods are more or less inevitable at certain times of the year, if the consequences of the naturally-occurring floods for people's private or business lives are negligible. This in turn facilitates the targeting of resources - as directed by the strategies and plans required by the Act - on those flood-risks that pose the greatest threat to normal life.
"Flood Risk Management Function"
4. The 2010 Act operates in large part by reference to flood risk management functions. That term is defined in s.4. It includes functions under the 2010 Act itself, but also other functions under Acts relating to water or drainage; it is also capable of being extended by Order - s.4(2)(f) - see the Flood Risk Management Functions Order 2010/2232.
National flood and coastal erosion risk management strategy
5. The Welsh Ministers have a duty to maintain a strategy for flood risk management in England - 2010 Act s.8. A key part of the strategy is designed to identify administrative issues such as which other authorities have actual or potential responsibility for flood management; but it also considers broader environmental issues such as the likely impact of climate change. There are broad consultation requirements in the preparation of the strategy, including a requirement to consult the Secretary of State. Public authorities with responsibility for flood risk management are obliged to have regard to the strategy when exercising their functions - s.12. See the Welsh Government's National Strategy for Flood and Coastal Erosion Risk Management.
Local flood authority strategy
6. Section 10 of the 2010 Act requires each lead local flood authority in Wales to maintain a strategy for local flood risk management. The lead local flood authority for an area in Wales is the county council or county borough council for the area - s.6. Public authorities with responsibility for flood risk management are obliged to have regard to the strategy when exercising their functions - s.12.
Co-operation between authorities
7. Section 13 of the Act requires specified authorities to co-operate in the exercise of flood risk management functions. The Natural Resources Body for Wales and lead local flood authorities have information-gathering powers for the purposes of flood risk management - s.14. Local flood authorities have a specific duty, in effect, to co-ordinate flood response by local agencies once a flood incident occurs (one of the respects in which the 2010 Act is not confined to advance planning) - s.19. The Welsh Ministers have power to make grants in respect of expenditure incurred or expected to be incurred in connection with flood or coastal erosion risk management in Wales - s.16. The National Resources Body for Wales "may issue levies to the lead local flood authority for an area in Wales in respect of the Natural Resources Body for Wales' flood and coastal erosion risk management functions in that area" - s.17. The Flood and Coastal Erosion Risk Management (Levies) (England and Wales) Regulations 2011/696 provide for the issue of levies. The Natural Resources Body for Wales has to report to the Welsh Ministers about its flood risk management functions - s.18. The Welsh Ministers can issue directions about co-operation and transfer of functions - s.20, and about restructuring of bodies in respect of flood risk - s.29.
Register of flood-critical structures and features
8. Lead local flood authorities are required to keep a register of structures and features which can have a significant effect on local flood risk - s.21. The register is open to public inspection.
Designation of features
9. In addition to the lead local flood authorities' register, Sch.1 to the 2010 Act allows certain authorities to designate a structure or feature as being something that "affects a flood risk". The designating authorities are: the Natural Resources Body for Wales; a lead local flood authority; a district council (whether or not it is a lead local flood authority); and an internal drainage board. The principal effect of designation is that "a person may not alter, remove or replace a designated structure or feature without the consent of the responsible authority" - para.5. The restriction is enforced in part by designation being a local land charge - para.5(2); there are also connected offences - see para.11. The procedure for designation is set out in Sch.1. For non-statutory guidance about the designation system see: Designation of structures and features for flood and coastal erosion risk management purposes: Information note.
10. The Board has power to categorise particular items as flood defences, but not everything can be so categorised - for discussion of the proper application of the England-equivalent policies for categorisation see R. (on the application of Manchester Ship Canal Co Ltd) v Environment Agency  EWCA Civ 542;  J.P.L. 1406. For discussion of compensation issues relating to construction of new flood defence schemes see Parkhill v Environment Agency  UKUT 23 (LC).
Regional flood and coastal committees
11. The Natural Resources Body for Wales is required to divide Wales into regions and to maintain a Regional Flood and Coastal Committee for each region. The functions of the Committees are primarily consultative - s.23. Constitution and procedure of the Committees are determined by subordinate legislation under the 2010 Act. See the Regional Flood and Coastal Committees (England and Wales) Regulations 2011/695.
12. There is an over-arching duty to aim to contribute towards sustainable development in exercising flood-risk related functions - s.27. The Act does not, however, define sustainable development; but it does give the Welsh Ministers power to issue guidance about what it means and how people are to take account of it - s.27(2).
13. Flood management obviously inter-links with the law on the water industry and on drainage: (see: Water industry, Sustainable drainage).
14. European Union Law on management of flood risk: Directive 2007/60 creates a parallel set of duties arising out of European Union law, which are transposed by the Flood Risk Regulations 2009/3042. The terminology of the 2009 Regulations closely maps that of the 2010 Act, and the two were prepared in parallel for precisely that purposes. Similarly, the duties imposed by the Regulations are of a similar nature and are couched in similar terms, but varied so that they also reflect the terminology and requirements of the Directive. In particular, the Natural Resources Body for Wales is required to prepare assessment maps and reports - regs 9-12; and to identify areas of flood risk - reg.13; and to prepare risk management plans - reg.25. Lead local flood authorities also have duties under the Regulations.
15. There is potential for uncertainty about the extent to which the two sets of duties, under the 2010 Act and the 2009 Regulations, are complementary; if, however, they were inconsistent in any respect, then of course the 2009 Regulations (which are made under s.2(2) of the European Communities Act 1972) would take precedence, in accordance with the provisions of the 1972 Act.
16. It is possible that designation of a structure or feature as flood-risk critical under Sch.1 to the 2010 Act could engage the Convention rights relating to the enjoyment of property.
17. Commencement: For commencement of the 2010 Act in relation to Wales see Flood and Water Management Act 2010 (Commencement No. 1 and Transitional Provisions) (Wales) Order 2016/79. Article 2 specifies 1 April 2016 for commencement of amendments of the Reservoirs Act 1975 introducing a new legal framework relating to the safety of large raised reservoirs.