F1: Disruption or unwanted impacts from flooding or coastal erosion
Short Description
This indicator will track changes in the impacts of flooding and coastal erosion on people’s lives. The approach to the finalisation of this indicator will continue to be refined to ensure it aligns with the government’s policy statement on Flood and Coastal Erosion Risk Management. Currently the indicator tracks changes in the number of residential and non-residential properties at risk from various sources of flooding by level of flood risk. The government works through Risk Management Authorities (RMAs) and Regional Flood and Coastal Committees (RFCCs) to reduce the risk of flooding and erosion. The policy statement sets out a commitment to develop a national set of indicators that will enable us to track progress towards our aim of increasing resilience in flood and coastal erosion risk management.
Readiness and links to data
This indicator is not available for reporting in 2024 in a finalised form. An interim indicator is presented here covering a) the number of residential and non-residential properties at risk of flooding from rivers, seas and surface waters and b) the number of properties in areas at risk of flooding by source each year, allowing both a more detailed breakdown of the number of properties at risk from flooding (a) and the observed trends over time (b).
The Environment Agency modelling and mapping of the flood risk around a property is grouped into 4 categories of flood likelihood from high (a greater than 1 in 30 chance in any given year) to very low (a less than 1 in 1,000 chance of flooding in any given year). The modelling approach has gone through a significant update over the past few years, and a new national assessment of risk will be available from late 2024 using this approach. This new approach will combine national and local modelling into a single source of information on the likelihood of flooding to areas around a property. This approach takes into account river, sea and rainfall information, the topography, as well as flood assets, such as flood defences and their condition. Alongside this, the Environment Agency is also developing richer information about flood risk, including the possible impacts of climate change for specific climate change scenarios.
The government set out its policies to tackle flood and coastal erosion risk in the long-term in the Flood and Coastal Erosion Risk Management Policy Statement. The Environment Agency's National Flood and Coastal Erosion Risk Management Stategy for England sets out measures and actions to achieve a nation resilient to climate change. Delivery is led by the Environment Agency and other risk management authorities as set out in the Flood and Water Management Act 2010.
The Environment Agency's annual Flood and coastal erosion risk management report expands upon this indicator with additional datasets and case studies as well as highlighting details of government investment into tackling flooding and coastal erosion.
Although the Environment Agency does not routinely carry out economic cost analysis of all floods, it has published cost of flooding reports following the winter 2013 to 2014 and winter 2015 to 2016 floods. The flood and coastal erosion risk management annual reports (from 1 April 2011) provide further context and statistics about the impacts of recent major flood events.
Development of the indicator will be informed by the Environment Agency led research project into the development of long-term indicators, which was published in November 2022. Building on the research project, work is now underway to explore the further development and where possible, data collection, for a prioritised set of these indicators. This includes real world testing of some of the indicators at the local level through the £200 million flood and coastal resilience innovation programme.
Notes on indicator
The level of risk of flooding is defined upon the likelihood of areas around a property flooding each year, broken down into 4 categories:
• High: each year there is a greater than 3.3% chance of flooding
• Medium: each year there is a chance of flooding between 1% and 3.3%
• Low: each year there is a chance of flooding between 0.1% and 1%
• Very Low: each year there is a less than 0.1% chance of flooding
Between the 2021/2022 and 2022/2023 datapoints the information surrounding the underlying property information has been improved, including individual properties in shared buildings, such as residential flats. This has increased the number of properties identified to be at risk since the previous datapoint. This does not reflect an increase in risk, but rather a better understanding of the level of risk.
Some properties are at risk from flooding from multiple sources. For example, it is estimated that 660,000 properties are at risk from flooding from rivers, the sea, and surface water. Due to the complexity and nature of groundwater flooding, it is not possible to assign a likelihood to it, however it is another source of flooding and poses a risk to properties.
Indicator components
Figure F1a: Number of properties in areas at different levels of risk of flooding from rivers and the sea, and from surface water, 2022/2023
Table F1a: Number of properties in areas at different levels of risk of flooding from rivers and the sea, and from surface water, 2022/2023
| Level of risk | Rivers and the sea: Non-residential properties | Rivers and the sea: Residential properties | Surface waters: Non-residential properties | Surface waters: Residential properties |
|---|---|---|---|---|
| High | 91,500.00 | 123,500.00 | 95,800.00 | 273,000.00 |
| Low | 293,900.00 | 859,200.00 | 531,300.00 | 1,983,700.00 |
| Medium | 228,500.00 | 456,500.00 | 119,700.00 | 419,900.00 |
| Very low | 126,000.00 | 601,200.00 | - | - |
Trend description for F1a
In total, across the 2022/2023 financial year 2,780,400 properties were at risk of flooding from rivers and the sea, of which 2,040,400 were residential properties. This includes 215,000 properties at a high risk of flooding (greater than 3.3% annual likelihood) and 685,000 properties at a medium risk of flooding (between 1% and 3.3% annual likelihood).
Properties at risk of flooding from surface waters were 3,423,400 over the 2022/2023 financial year, of which 2,676,600 were residential properties. This includes 368,800 properties at a high risk of flooding (greater than 3.3% annual likelihood) and 539,600 properties at a medium risk of flooding (between 1% and 3.3% annual likelihood).
Assessment of change
No assessment of change was undertaken for this indicator as it represents a snapshot in time across the 2022/2023 financial year and no trend is available for assessment.
Figure F1b: Number of properties in areas at risk of flooding by source each year in England, 2018/2019 to 2022/2023
Table F1b: Number of properties in areas at risk of flooding by source each year in England, 2018/2019 to 2022/2023
| Source of flooding and risk | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 |
|---|---|---|---|---|---|
| Rivers and the sea at high or medium risk | 872,000.00 | 852,000.00 | 846,000.00 | 822,000.00 | 900,000.00 |
| Rivers and the sea at low or very low risk | 1,677,000.00 | 1,638,000.00 | 1,652,000.00 | 1,661,000.00 | 1,880,400.00 |
| Surface water | 3,181,000.00 | 3,173,000.00 | 3,173,000.00 | 3,173,000.00 | 3,423,400.00 |
Trend description for F1b
The final year of data, 2022/2023, has the highest number of properties at risk from all sources of flooding with 900,000 at a medium or high risk, and 1,880,400 at a low or very low risk from rivers and the sea, with 3,420,000 properties at risk from surface waters across all levels of risk. This peak, as outlined in the notes section, is a result of methodological improvement and does not reflect an increase in risk.
Excluding the final datapoint, since the time series began in 2018/2019, until the 2021/2022 financial year, the number of properties at risk from rivers, the sea and surface waters has remained fairly stable, with a gradual decrease observed. Overall the number of properties at a high or medium level of risk has fallen by 50,000 properties from 872,000 in 2018/2019 to 822,000 in 2021/2022, equating to a 5% reduction. The number of properties at a low or very low risk from rivers and the sea, as well as those at risk from surface water flooding have reduced by 0.2% and 1% respectively across the same timeframe.
Assessment of change
No assessment of change was undertaken for this indicator as there are insufficient datapoints since the methodological improvement in 2022/2023.