Housing developments on functional flood plains

Sally Dray

On Thursday 24 June 2021, Baroness McIntosh of Pickering (Conservative) is due to ask the Government “what assessment have they made of the impact of building major new housing developments on functional flood plains in the context of climate change; and whether they intend to amend planning law accordingly”.

What is a functional flood plain?

The Environment Agency uses flood zones to refer to the probability of river and sea flooding, ignoring the presence of defences. The zones do not take account of the possible impacts of climate change.

Zones 1 and 2 have a low and medium probability of flooding. Zone 3 is divided into 3a, where land has a high probability (1 in 100 or 1 in 200 or greater) of flooding, and 3b, the functional flood plain.

The functional flood plain is land which would naturally flood with an annual probability of 1 in 20 or greater, or land that is designed to flood in an extreme flood. However, the Government says that a flood plain should be identified through local circumstances and not just based on flooding probability. It says that these areas of land are important for making space for flood waters when flooding occurs. An area of land that would naturally flood, but that is prevented from doing so by defences and infrastructure or solid buildings, is not normally identified as a flood plain.

The Environment Agency produces a map every 6 years to show the potential risk and impacts of flooding in the flood risk areas. The latest maps were published in December 2019 and have been used in the preparation of flood risk management plans from 2021 to 2027.

What is the scale of the problem?

The Environment Agency (EA) has said that 5.2 million homes and businesses in England are at risk from flooding. The sources of flooding include rivers, the sea, surface water and groundwater. Some properties are at risk from more than one source of flooding.

The EA stated that, as of 31 March 2019, 121,000 residential properties were in areas at high-risk of flooding from rivers and the sea, and 458,000 were in medium-risk areas. 239,000 residential properties were in areas at risk of flooding from surface water, with a further 395,000 at medium-risk.

In its latest long-term investment scenario publication, the EA said that if current planning outcomes continued for the next 50 years, the number of properties in the flood plain would almost double. This would mainly be because of development in low risk areas. The EA states that effective implementation of planning policy will mitigate flood damages in the long term. However, it stressed that there was a risk that if planning policy was not adequately implemented and enforced, non-compliance with planning conditions could increase. The EA cautioned that this could lead to billions of pounds of extra flood damages in the long-term.

What is the planning strategy for building on functional flood plains?

National Planning Policy Framework

In the National Planning Policy Framework, most recently updated in June 2019, the Government says that “inappropriate development in areas at risk of flooding should be avoided by directing development away from areas at highest risk”. It also says that, where development is necessary, the development “should be made safe for its lifetime without increasing flood risk elsewhere”.

The framework states that “all plans should apply a sequential, risk-based approach to the location of development”. It highlights ways that developers should consider the current and future impacts of climate change, such as:

safeguarding land from development that is required, or likely to be required, for current or future flood management;
using opportunities provided by new development to reduce the causes and impacts of flooding (where appropriate through the use of natural flood management techniques); and
where climate change is expected to increase flood risk so that some existing development may not be sustainable in the long-term, seeking opportunities to relocate development, including housing, to more sustainable locations.

The framework sets out that “major developments should incorporate sustainable drainage systems unless there is clear evidence that this would be inappropriate”.

Planning for the future

In August 2020, the Ministry of Housing, Communities and Local Government (MHCLG) launched a consultation on proposed reforms to the planning system. In the consultation white paper Planning for the Future, MHCLG stated that it was “assessing the extent to which our planning policies and processes for managing flood risk may need to be strengthened along with developing a national framework of green infrastructure standards”.

The consultation closed on 29 October 2020. The Government has said that the consultation received around 44,000 responses, and it will publish its response to the white paper before introducing the Planning Bill to Parliament.

In the Queen’s Speech, on 11 May 2021, the Government set out some further information about the Planning Bill. It said that the bill would provide “more certainty” for communities and developers about what is permitted where. Its aim is to establish “simpler, faster procedures for producing local development plans”, which would include assessing environmental impacts.

Lessons learned review

Following the severe floods in England in 2007, the then-Labour Government asked Sir Michael Pitt to conduct a review of the lessons learned. His review was published in June 2008. It made 92 recommendations over several areas, including reducing the risk of flooding and its impact, and improving advice to those affected by floods.

In its response to the review in December 2008, the Labour Government accepted all recommendations. The Coalition Government published a final progress report in January 2012, which outlined progress made in implementing the recommendations. It said that 43 of the recommendations had been implemented, with a further 40 implemented with ongoing work continuing. Many of these recommendations were met by the Flood and Water Management Act 2010.

What concerns have been raised?

On 8 February 2021, the House of Commons Environment, Food and Rural Affairs (EFRA) Committee published a report on the Government’s policy on flood risk management and its response to increasingly frequent severe flood events. The committee made a number of recommendations to the Government regarding England’s national planning policy, such as:

Explaining how its proposals for planning reform will contribute to better flood resilience outcomes than the current planning system. It should also explain how leadership will be provided within Government so that flood risk and planning policies are integrated within a coherent approach to climate adaptation.
Providing further detail on its proposals for cases in which flood risk advice on planning applications is not followed. The remit of the Environment Agency as a statutory consultee should be expanded to include areas of future risk owing to climate change.
Urgently review whether planning conditions to mitigate flood risk are being fulfilled. It should then bring forward proposals to address any limitations in the powers and resources available to appropriate authorities for the enforcement of planning conditions.

Many parliamentarians have also raised concerns over developer’s automatic right to connect surface water run-off to water and sewerage company sewers. The EFRA committee have said this does not encourage developers to develop sustainable drainage options. In his review, Sir Michael Pitt also recommended that the Government end the automatic right to connect.

Responding to a question on whether the Government would implement Sir Michael Pitt’s recommendation to end the practice, Minister of State for Defra, Lord Goldsmith of Richmond Park, said that:

Planning practice guidance includes a hierarchy for sustainable drainage options that favours non-sewer solutions. Draining to a combined sewer should be the least favoured option in new development, to be considered when sustainable drainage options are not reasonably practicable. Removing the right to connect to an existing sewer therefore would offer no clear benefits over current arrangements and is likely to add costs and delay to the planning process for new housing.

What have other groups said?

In May 2018, the Royal Institute of British Architects (RIBA) published a policy note on the value of flood-resilient architectural design. RIBA stated that the Government would need to work with the construction industry to better manage and respond to flood risks. It suggested a range of proposals to improve decision-making and regulation in this area, including:

Improving decision-making processes to address a broader range of factors and potential solutions to water management issues.
Piloting ‘licences for innovation’ to examine the effectiveness of new approaches to managing flood risk in new developments, and ensuring all new buildings incorporate appropriate measures.
Examining the potential for regulations on flood resilience to be linked to flood zone designations through building regulations and planning policy.