Investigating a flood: guidance for lead local flood authorities

Question 1

What your investigation should determine

Accepted Answer

Your investigation must determine:

which risk management authorities (RMAs) have relevant flood risk management functions
if those RMAs have exercised their functions in response to the flood, or if they are proposing to exercise them

You will need to understand:

the source of the flooding
the flood risk management functions of the RMAs
what actions were taken or will be taken by the RMAs

Flood risk management functions are defined in the Flood and Water Management Act 2010. Annex A of the National Flood and Coastal Erosion Risk Management Strategy for England outlines:

the different RMAs
existing roles and responsibilities for flood and coastal risk management activities

RMAs must act in a manner consistent with the Flood and Coastal Erosion Risk Management Strategy for England when carrying out their flood risk management functions.

Question 2

Identifying the need to investigate

Accepted Answer

Becoming aware of a flood

To begin a flood investigation, you must be made aware that there’s been a flood. This is likely to happen:

through reports of flooding from residents or businesses directly to you
through notification from local authority colleagues, emergency services or another RMA
through reports in the media

Flood incident reporting

You should use your external communications to encourage affected people to report flooding directly to the responsible RMA, as they will be best placed to act.

Residents might contact an inappropriate RMA for the source of flooding to ask for help or report the flood, especially where different sources of flooding combine. This can result in each RMA holding different or overlapping property flooding datasets about the same incident. You should gather property flooding data from all relevant RMAs.

You must have a means of gathering information about the flood tailored to your local needs: your approach can be incident specific with information sourced only from those who have been flooded; or less restrictive, by having a standard questionnaire on your public website, to allow the public to alert you to any local incident.

You should use a standard format to gather information, as well as an effective data management system. For example, you can use:

a simple online form on your website
online or paper questionnaires
a bespoke reporting tool, such as the flood online reporting tool (FORT)
other local authority reporting tools

You should provide access to alternative reporting lines for people who do not have access to the internet. For example, you can provide a phone number and give call operators a standard script to use in a flood incident.

You must:

store any data you collect in line with the Data Protection Act 2018
clearly state the intended use of any data at the point of collection
store the data with enough metadata for retrieval and reuse

Initial data collection

Once you’re aware of a flood, you may need to collect some initial data to:

confirm your flood investigation criteria are likely to have been met
try to verify incident reports

This can help you confirm the scale of the flood and decide whether a flood investigation is necessary or appropriate.

If your initial data collection finds that criteria have not been met, you may carry out an informal investigation anyway. You should document your decision not to investigate formally under section 19 of the Flood and Water Management Act 2010.

Read more about choosing criteria and deciding to investigate.

Case study: online form for the public to report flooding

Many LLFAs have a webpage on their local authority website that explains where the public should report flooding from different sources. The webpage may also link to an online survey that collects flooding reports in a standardised way.

One example is Kent County Council’s ‘report flooding’ webpage. This takes the user through to a flood survey. The flood survey asks for confirmation that the user has read the privacy notice. It also explains how the local authority will store and use the data provided.

The form collects data on:

flood location
flood details (date, duration, causes, depths and source)
flood consequences (internal and external flooding, and wider impacts)
authority flood response

This data is available quickly for the LLFA so they can decide whether criteria for a flood investigation are met. The data can also be used and followed up on during the investigation.

Case study: Flood Online Reporting Tool (FORT)

FORT was developed by Dorset Council and has been in operation since 2015.

Users can complete 2 forms. One form is for reporting current flooding. The other form is for reporting recent flooding.

The forms act as a triage and capture details about the:

flood location
flood details
impact of the flood
cause of the flood – this only appears on the form for reporting recent flooding

The tool sends the flood report to the LLFA so they can investigate it. In addition to being a flood reporting tool, the forms allow the LLFA to collate reports and analysis of flood data to inform flood risk planning.

Deciding to carry out a flood investigation

It’s your decision whether to carry out a flood investigation under section 19. Authorities will have their own arrangements for delegating authority to officers to carry out the organisation’s functions, including decisions on flood investigations.

Definition of ‘properties flooded’

For the purposes of the flood investigation data collection, you should use the definition of ‘properties flooded’ and ‘properties affected’ provided in the National Flood Emergency Framework for England. This is a standard non-statutory working definition used by emergency response organisations for the collection of data during a flood. It is not linked directly to qualification for funding or support.

The definition states that ‘properties’ include both homes and businesses.

‘Properties flooded’ are properties that have been flooded internally. That is, where water has entered the property. This includes:

basements and below ground level floors
garages that are in the fabric of the building
occupied caravans and park homes

It does not include:

tents
garages adjacent or separate from the main building

This definition is based on homes. However, it includes businesses and public buildings where water has entered the fabric of the buildings.

‘Properties affected’ are properties which have flooded externally, where either:

water has entered gardens or surrounding areas which restricts access
flooding has disrupted essential services to the property, such as sewerage

For businesses or public buildings, this includes properties where the flood waters are directly preventing them trading or being used as usual.

Defining flood investigation criteria

You should define the criteria to trigger a flood investigation in your local authority area. This will ensure a consistent and transparent approach to decisions about holding flood investigations.

Your flood investigation criteria should reflect local circumstances and flooding characteristics, as every local authority area is different. You should set your criteria to make sure flood investigations are proportionate to the level of risk.

You may prefer to set simple fixed criteria to establish clear expectations with the public, such as the number of properties flooded in a given area. Alternatively, you may prefer to set more complex variable criteria that allow more flexibility.

It may also be helpful to set out circumstances when you will not carry out flood investigation.

You should publish the criteria in a suitable location, such as a:

local authority website
specific policy statement or guidance note
local flood risk management strategy

Criteria may be based on the:

receptors that are affected
scale of the flooding
duration of flooding
frequency or recurrence of flooding

For a ‘typical’ set of criteria, read example flood investigation criteria. These criteria can be adapted for local circumstances using the considerations outlined below.

Receptor criteria

Receptors are people, property, services or infrastructure that are affected by the flooding.

Your flood investigation criteria should consider which receptors are most important and how many receptors are significant. This may vary based on the characteristics and demographics of the local authority area.

Examples of criteria to consider include:

flood depths and velocities causing ‘danger for people’ – read about assessing risks to people
specific number of residential flooded properties – you may decide to exclude non-habitable basements alone from triggering a flood investigation
specific number of commercial flooded properties
flooding of high-risk properties, such as basement flats
flooding of critical infrastructure or disruption to services – for example, hospitals, health centres, clinics, surgeries, colleges, schools, day nurseries, nursing homes, emergency services and utilities sites
flooding or closure of important transport links – for example, highways, railways or transport hubs
area flooded of agricultural land in hectares – you may decide to only include the ‘best and most versatile’ agricultural land, which covers grade 1 to 3a
flooding of sites with heritage or environmental value

Scale criteria

Your criteria should consider what area is covered by the flooding and how close together the receptors are.

For example, if 5 properties that are close to each other are flooded from the same source, this may trigger a flood investigation. However, 5 separate properties flooding from different mechanisms across the local authority area may not warrant an investigation.

Examples of criteria to consider include:

specific number of flooded properties within X km²
specific number of flooded properties in the same settlement, parish or ward
specific number of flooded properties in the same catchment or flood cell
specific length of flooded road or railway

Duration and frequency criteria

Your criteria should consider how long receptors have been flooded, and how many times.

A longer duration or higher frequency of flooding may mean you would choose to investigate, even if fewer properties were flooded. For example, you may investigate if:

the flooding lasts for a long time, for example weeks or months
properties are flooded more than once in a specific time period
a transport link is closed for a significant period – for example, if a road is closed for a specific number of hours

You can read about significant periods of closure for highways in the Code of Practice for Highway Maintenance.

Repeated flooding from the same source

If a location has flooded several times in the past, you may already understand the causes of flooding and the responsibilities of RMAs. If a flood investigation has been conducted previously, you may decide that another full investigation is not necessary for a new flood event.

If the criteria are met, you should publish a shorter, ‘light touch’ investigation to record basic information. For example, the date and a summary of receptors of flooding in the event.

You could also provide an update on any recommendations or lessons learnt from previous flood investigations. This could be a standalone short report or an addition to a previous flood investigation.

Exceptions to criteria

You may choose to have a protocol for approving a formal investigation even if criteria are not met. For example, because you deem the flooding to be significant for an exceptional or unforeseen reason not covered by the criteria.

Combining investigations

In a large flood event, there may be multiple settlements and catchments where the criteria are met. There may also be a series of flood events close together in time that affect the same settlement or adjacent catchment.

You can decide whether to conduct separate flood investigations or one combined investigation. You should consider the balance of resources when making this decision. You are not expected to conduct separate flood investigations for individual residential properties.

You may decide to produce one combined flood investigation to make the process more efficient. For example, if:

several locations are flooded from the same source in the same event – for example, several settlements along the same watercourse or coast
a series of storms flooded the same locations more than once in a given time period
remedial actions are likely to be similar for several flooded locations

Alternatively, you may decide to produce separate flood investigations to make the process more manageable. For example, if:

different locations are flooded from different sources of flooding in the same event
different incidents have different lead RMAs

Cross-boundary investigations

Where a flood incident affects more than one local authority area, you may consider collaborating with neighbouring LLFAs to conduct a single flood investigation. For example, this could be for flooding in a large rural catchment, along a coastline, or across a combined authority area.

Where organisational structures allow, you could form a partnership with other affected LLFAs and agree a lead partner. This will allow you to pool staff and resources for the investigation to make the process more efficient.

You should consider that each authority may have different approvals or scrutiny processes.

Case study: using existing regional partnerships to conduct a joint flood investigation

On Boxing Day 2015, Storm Eva brought unprecedented rainfall to Greater Manchester. More than 2,250 homes and 500 businesses in the city region were flooded.

The Association of Greater Manchester Authorities has published criteria and protocol for undertaking an investigation.

The 8 affected boroughs of Greater Manchester worked with the Greater Manchester Combined Authority, the Environment Agency and United Utilities to produce a single flood investigation report.

Question 3

Engaging with the community

Accepted Answer

You should engage and collaborate with the community throughout a flood investigation, especially flooded residents and businesses. They’ll be able to share important data and information from their local knowledge of the area, which could have a noticeable impact on the investigation.

The level of engagement you undertake with the community will depend on the scale of the flood event.

You should reassure the community that authorities are aware of the flood event and are actively listening to their concerns.

Flooded residents and businesses may also actively want to participate in the investigation and learn from the outcomes of the investigation once the report is published.

When you engage with the community, it’s important to understand their perspective and recognise that they may be suffering due to the trauma of the flood event.

Your engagement should be:

sensitive
performed at an appropriate time
adapted to the location and demographics of the community
meaningful

Your approach to engagement will evolve through the stages of response and recovery.

You should be open and transparent with the community and clearly explain what can and cannot be achieved from the start of the flood investigation. You should explain how the flood investigation will report on the flood event and make learning points or recommendations. You should be clear on the roles and responsibilities of RMAs for flood risk management.

You should communicate clear objectives and target timescales to the community at the start of a flood investigation. You can provide information during engagement and in your investigation report to increase community understanding.

At this stage, you may need to set out how any future recommendations may depend on:

the statutory duties and powers of RMAs
funding and resources available to RMAs
the role of homeowners and business owners in protecting their property

In some cases, working with an independent organisation that represents the community can support the flood investigation.

Read the Local Government Association’s advice on how to engage with stakeholders.

Ways of engaging

You should adapt your engagement techniques according to the demographics of an area. For example, engagement with a community in a highly tenanted area may need different techniques to areas with a high population of homeowners.

You should aim to provide an equal opportunity for everyone in the community to participate in engagement. You should consider the most effective or appropriate ways of engaging in a community. Every community is different, and you may need to use trial and error to determine the most effective ways of engaging.

You should consider the following factors when deciding how to engage with a flooded community:

home ownership or tenanted properties
residential or business properties
age demographic
social deprivation
previous flood events
nationalities and languages
history of collaborating with the community – this includes your history and other RMAs’ history (where possible)

Methods of engaging can include:

door knocking – this can be more targeted by looking for signs of flooding on the driveways or outside the properties
working with parish councils
working with flood action groups
community engagement events or ‘roadshows’
dissemination of leaflets and questionnaires
social media requests
site visits
councillor ward meetings
holding community ‘drop-ins’

For efficiency, you can first explore existing channels of communications. It may be useful to publish a dedicated email address for residents to report issues to and send evidence.

After building communication channels and establishing a working relationship with the flooded community, you may be able to help them form a flood action group. This can build flood resilience within the community and support local flood risk management beyond the flood investigation.

Engaging during the flood event

The local authority is a category 1 responder under the Civil Contingencies Act 2004 and has a formal role in the immediate response phase of a flood event. As an LLFA, you do not have a statutory role in the response. However, you may provide support to emergency planning teams, depending on your local authority structure. For information about supporting communities during and after a flood event, read the advice for frontline responders.

During and immediately following a flood event, the focus is on supporting the community, rather than investigating the flood. You should communicate in a way that is sensitive to the situation.

Where appropriate, you can ask emergency response colleagues for information that may be useful to a future investigation.

If members of the community offer information during the event, you could ask them to:

report areas that are flooding to the relevant flood RMA
take as many photos and videos as possible to document water levels and flooded properties
collate any other information about where the flooding has come from
keep a diary or notes of the flood event

You must make it clear to members of the public that they should only do these activities where it is safe, and that nobody should enter flood water.

Case study: engagement during a flood event, Buckinghamshire

Over 70 properties were flooded in Buckingham during a flood event in December 2020. During the event, local authority liaison officers were deployed. These were volunteer staff and councillors from Buckinghamshire Council and Buckingham Town Council. Their primary focus was to provide support, help, information and reassurance to the community. As a secondary function, they also gathered anecdotal information and photographs as the event unfolded. These were fed back to the Buckinghamshire Council LLFA and used in the subsequent flood investigation.

Engaging after the flood event

Once the recovery stage has started, members of the community may be more willing to share knowledge of the flood to help the investigation. To understand when a community is ready to engage at each stage, you can work with contacts such as:

parish councils
flood action groups
civil society organisations
community flood wardens
elected members

It’s important to consider your engagement timescale carefully, so you can act quickly but sensitively.

Members of the community may be willing to share information about the flood sources, timings and levels. They may also engage with site surveys or collate records and photographs.

In some circumstances, you may need to collect data more directly from individual members of the community to gather a full understanding of the flood event.

You can also use scheduled events organised by the local authority or voluntary organisations to help collect data from the community.

Residents and businesses may have temporarily relocated if they have been affected by flooding. This means you may need to make additional site visits when they have returned to the area.

Read more about collecting data from the community.

Communities’ role in flood resilience

Communities and individuals also have a role in improving their own resilience to flooding. As the LLFA, you can use the process of a flood investigation to raise community awareness and further increase resilience.

You can support them to take actions such as:

Case study: communities working with RMAs to respond to flooding, Nottinghamshire

The Community Flood Signage Scheme in Nottinghamshire allows trained members of the community to close roads during times of flooding. The scheme promotes road safety, but also aims to stop vehicles creating bow waves through flood water. Bow waves can cause further damage to property and distress to residents. The scheme is led by Nottinghamshire County Council LLFA and currently has over 180 active Flood Signage Wardens in 15 areas across Nottinghamshire. This scheme builds partnership with communities and aids communication during flood events and subsequent flood investigations.

Frequently flooded communities

You may wish to proactively build relationships through working with an at-risk or frequently flooded community outside of a flood event. This can improve collaboration, the community’s ability to respond, and information sharing during a flood event.

You can do this by:

sharing information on preparedness for flood events
working with flood action groups and flood wardens
working with parish councils and community leaders
supporting the development of local flood plans

You can get support for these activities through civil society organisations such as the National Flood Forum and Communities Prepared.

Question 4

Working with partners

Accepted Answer

You may need to work with partners to investigate a flood event, especially when it has more than one source of flooding. You must notify any relevant RMAs when you undertake an investigation.

Duty to co-operate

Flood and coastal erosion RMAs have a legal duty to co-operate. You and other RMAs should follow this duty for flood investigations. Read guidance on how to carry out the duty to co-operate.

You and other RMAs must work together within your roles and responsibilities.

At the beginning of an investigation, you should:

engage with other RMAs with a role in the flood event
agree responsibilities with these RMAs

Your engagement may include individual communications or discussions within established working groups, depending on the scale of the flood event.

You should collaborate with partners throughout the investigation to make sure information is accurate and to develop lessons learnt and effective recommendations.

Read the Local Government Association’s advice on how to engage with partners.

Partnership and working groups

Local partnership and working groups may already be set up between RMAs. Arrangements will vary depending on different factors, such as:

governance within a two tier or unitary authority
geographical area
local demographics
resources of RMAs

You can use existing networks and working partnerships to communicate and collaborate with other RMAs to support a flood investigation report through:

effective data sharing
progressing investigations
decision making
endorsement from all RMAs

For larger, more widespread flood events, you may need to establish a specific multi-agency task group to support the flood investigation. This should include all relevant RMAs and partners. The task group could also include representation from the community through a spokesperson or third party.

You should also consider establishing a multi-agency task group when working with neighbouring authorities to investigate a flood.

Role of partners in investigating a flood

Although it’s your duty as an LLFA to investigate a flood event, the investigation will need the support of other RMAs and partners.

The following sections explain how each partner may provide this support. This is not an exhaustive list.

RMAs and partners may also provide data to support an investigation.

Environment Agency

Following a significant flood event where the source is a main river or the sea, the Environment Agency may undertake their own review. This could include detailed analysis, which you may use to support your flood investigation.

For smaller scale flood events, the Environment Agency may be able to help you to:

collect data
investigate the flood event
develop learning points or recommendations

Highways authorities

Highways authorities may respond to a flood event. They may be able to provide information about:

highway flooding
how the highways drainage infrastructure responded to flooding
their response to flooding

Highways authorities can also help to develop learning points and recommendations.

Water and sewerage companies

The local water and sewerage company may receive reports of flooding. They may be able to provide information about:

flooded properties or infrastructure
how their infrastructure responded to flooding
their response to flooding
sources of flooding

They may also offer information to support your investigation and the development of learning points or recommendations.

Internal drainage boards

Internal drainage boards (IDBs) exist in areas where there is a special need for drainage.

You should consult IDBs when a flood event either:

is within the boundary of the IDB
intersects with watercourses under the IDB’s jurisdiction

The IDB may be able to share:

data from the flood event
how their infrastructure responded to flooding
their response to flooding

They may also be able to help develop learning points or recommendations.

Response roles

Other authorities may be involved in responding to a flood event, such as:

the emergency services
local district or borough councils

You can compile the information they collected during the response to capture a timeline of the flood response and information about the event.

Response roles may work with you to develop recommendations to improve response to flood events.

Community groups

Communities will have local knowledge of the area that’s helpful to your flood investigation. Groups of flooded residents or organisations supporting communities may have information and ideas to manage the local flood risk.

You could engage with community groups such as:

faith groups
sport groups
charities
businesses

Other organisations

You may work with other organisations to gather information, such as the Canal and River Trust and Network Rail.

These organisations do not have a formal responsibility to manage flood risk under the Flood and Water Management Act 2010.

However, the organisations may have information about how their assets have been affected during a flood event. In these cases, they may work with you to develop learning points and recommendations.

Ways of working

During the response phase, category 1 responders will follow the guidance in Data protection and sharing guidance for emergency planners and responders.

After the event, you can request information from other RMAs in connection with their flood and coastal erosion risk management functions. This comes under section 14 of the Flood and Water Management Act 2010.

To make the data sharing process more efficient, you can work with RMAs to:

find out the most appropriate contact in each RMA for data sharing
create agreements for proactive data sharing – for example, RMAs may agree to share data with you monthly
use standard formats for information requests

You should consult each RMA to establish the most effective way of requesting information. You can consult them outside of a flood event to agree an approach to use during a flood response.

Where a widespread flood event occurs across multiple authority areas, RMAs may need to provide data or information across these authority areas. You can co-ordinate data requests with RMAs on a regional level for consistency and efficiency across authority areas.

You could enter into data sharing agreements with other organisations, such as other RMAs, public bodies or private companies that hold relevant data for the investigation. This means they can share the data with you more quickly and efficiently following a flood event.

For example, there may be an agreement between a water and sewerage company and an LLFA. This agreement would allow the water and sewerage company to share records of flooding, flood risk management work undertaken in the area and asset data.

It’s more efficient and effective to establish data sharing agreements in advance, rather than setting up a one-off agreement for a single flood investigation.

Data sharing agreements enable the provision of a level of information compliant with the Data Protection Act 2018. They also protect and manage use of the data.

The duty for RMAs to co-operate can support and promote data sharing related to flood risk management.

Anglian Water has a standard data sharing agreement they enter into with all LLFA partners in their area. The agreement covers:

requirements under the Data Protection Act 2018
limits on sharing data
how licensees can use the data

Anglian Water always makes the agreement with a public body licensee, but they allow for sharing with contractors working on their behalf. Once the agreement is in place, Anglian Water can share a range of data, including callout logs, flooded property data and asset information.

Anglian Water shares a package of information with all licensees on a proactive basis every 2 months. There is also an online form that LLFAs can use to request up to date information following a flood incident. Anglian Water usually responds to requests within one month.

Question 5

Collecting data

Accepted Answer

Planning and protocols

For efficiency, you can plan data collection protocols in preparation for a flood event. Protocols can be locally specific and can include:

arrangements for staff allocation
prioritisation of data collection
timescales for collection
health and safety and methodology

Using protocols can make your data collection more consistent across flood events.

There are existing good practice guides that give detailed advice on collecting data successfully after a flood. These include:

British Standards Publication ‘BS 85600:2017 Post-event flood assessments – Guidance on investigating flooding incidents’
guidance on post event appraisal – a best practice guide on monitoring, recording and analysing events

Where possible, you should also record metadata when collecting data. This includes the:

data source – for example, aerial photography, visual, memory or survey
data provider – for example, public, the Environment Agency, emergency services or water company
data quality – specific information on the quality of data, if appropriate

Survey and observed information

You should collect evidence, information and data as soon as it’s practically possible and safe to do so. This helps to avoid inaccurate reporting or misinformation.

Data might be collected by:

LLFA officers
other local authority staff who are on site
the Environment Agency and other RMAs
contractors
community groups
individual members of the community

It may be possible for responders to collect data and evidence during the response stage, particularly if a pre-agreed protocol is in place. For example, they may be able to collect photographs.

Where one or more local authority teams plan to visit a flooded location, collaboration between council departments such as the Highways Authority can make the collecting flood data more efficient.

You or your partners may also be collecting data about properties eligible for grants under the flood recovery framework. When this is the case, you can combine these 2 purposes so that the data is only collected once.

Community

You should engage with the community sensitively, considering their stage of recovery. Read more about engaging with the community.

Members of the community and community groups (such as flood action groups) will be the primary source of information, data and narrative. For example, they can provide:

eyewitness descriptions
impact statements
videos and photos
CCTV and doorbell footage

They can provide information about:

which properties flooded
duration of flooding, including periods of service disruption
previous flood events
efficacy of flood warnings and flood response plans, including the type of media used to receive warnings
recovery efforts, including insurance claims and remedial works to private property

You can use online tools to collect data from communities. For example, you can:

provide a link to online cloud storage where people can upload photographs and videos
distribute online questionnaires through community noticeboards, parish councils, community groups and social media groups

Case study: collecting data from communities, Suffolk and Oxfordshire

Suffolk County Council created a standard community evidence collection document. This acts as a single repository for data and information from the community. The LLFA works with the parish councils and residents to collate the information. This is then included in the flood investigation. The LLFA also uses the data to tailor site visits and community workshops.

Oxfordshire County Council supports the formation of community flood recovery groups. These groups collate and share information, data and learning about flood events using Google Maps.

Site investigation

Most flood investigations will include one or more site visits. These help you to understand what happened during a flood event, and to meet and listen to affected members of the community.

The time you spend on site investigation should be proportionate to the scale of the flood event and resources available.

The data you collect on site will depend on the type and severity of the flooding. However, it could include:

properties flooded – for example, the number, locations, property type and routes of water ingress
estimates of flood depths inside and outside properties
details of individual property flood resilience measures or temporary defences, including the dates of installation and maintenance if known
critical services, infrastructure and other receptors flooded
flood defence or drainage asset condition – for example, visual assessment of asset or defence type, any damage or structural failure and the presence of blockage
indicators of maximum flood extents, such as locations of debris deposited at the edge of the flood extent (known as ‘wrack marks’)
observed flood mechanisms and pathways
evidence of pollution or sediment deposition
photographs

When taking photographs, you should make sure the digital camera you’re using has location data enabled so it stores the GPS coordinates of the photo as metadata.

You can collect data more efficiently by using technology. For example, you could use:

apps for mobile devices that can automatically locate data points and photographs
laser measurement tools
a drone survey – make sure the drone is operated by an appropriately trained person with the correct licences

You should work with internal teams in the local authority when gathering data. Collaborating on site visits and data collection will be more efficient and lead to more consistency in the information.

Where the flooding is primarily from a source that another RMA manages, it may be helpful to meet its representatives on site to review the evidence together. Read more about working with partners.

Surveys

You or other RMAs may undertake or commission additional surveys, if it would help you to understand the causes of the flooding. For example:

topographical surveys
surveys of flood extents or property thresholds
jetting and dye tracing of drainage assets
CCTV survey of drainage assets
asset condition inspections of flood defences or other assets

To avoid delaying the flood investigation, you may make a recommendation for specific surveys to be undertaken by the relevant RMA.

Open data sources

Open data sources can provide helpful background information your flood investigation.

Flood and coastal erosion risk mapping

Data sources include:

Check the long term flood risk for an area in England – online map of modelled risk from rivers and the sea, surface water, reservoirs and groundwater (where data is available)
Check coastal erosion risk for an area in England – online map of national coastal erosion risk mapping
Get flood risk information for planning in England – online map of flood risk information for planning

Flood warnings

Data sources include:

Flood alerts and warnings – online map of live flood alerts and warnings currently in force
Environment Agency real time flood monitoring Application Programming Interfaces (API) provide access to near real time data on flood warnings and alerts, measurements of water levels and flows, and information monitoring stations
Historic flood warnings – spreadsheet listing severe flood warnings, flood warnings and flood alerts issued since the flood warning system went live in 2006

Hydrology, hydrometry and flood history

Data sources include:

Asset mapping

Data sources include:

Geology and environmental designations

Data sources include:

MAGIC map – online map of Defra data on land-based and marine environmental designations, which also includes soils and aquifer data
British Geological Society Geology Viewer –showing bedrock and superficial geology maps
British Geological Society GeoIndex – online map with access to a wider range of data aimed at professionals, including geology maps, borehole scans and interactive 3D models

Flood vulnerability

Data sources include:

Climate Just map tool – online map showing neighbourhood flood vulnerability index, based on demographic data that indicates susceptibility and ability to prepare, respond and recover

Historic mapping

Data sources include:

Ordnance Survey map viewer from the National Library of Scotland – map viewer of old Ordnance Survey maps of the UK

Geographical information systems data

You can download geographical data in different formats to use in investigations and display in maps in the flood investigation report. You should display the correct licence statements on all maps.

Environmental data is available on the Defra data services platform, under open government licence. You can register to access certain partner datasets that are not available to the public. Examples of useful data include:

Ordnance Survey MasterMap water network
Ordnance Survey background mapping at various scales
aerial photography
flood map for planning (rivers and sea) and associated datasets
risk of flooding from surface water and associated datasets
statutory main river map
spatial flood defences
recorded flood outlines
national receptor database
river obstacles
flood warning and alert areas
historic flood warnings
reservoir flood extents
internal drainage board administrative boundaries

Defra survey data is an online map-based portal where you can download survey data under open government licence. It includes:

Light detection and ranging (LiDAR) digital terrain models
bathymetry
SurfZone digital elevation model (combines LiDAR and near shore multi beam sonar bathymetry elevation data for intertidal zone)
vertical and oblique aerial photography

Satellite data

You can access viewers for satellite and earth observation data online:

Copernicus browser from the European Space Agency – combines publicly available Earth data, including Sentinal-2 Normalised Difference Water Index (NWDI), which highlights water bodies and could be used to determine flood extent
Global Flood Awareness System (GloFAS) from the European Commission – operational system of the European Commission’s Copernicus Emergency Management Service (you can access this for free, but you will need to register)

Local authority data

You may have access to council-owned or licensed third party data. This will vary depending on whether your area has a unitary or two tier system.

Local authorities may hold data such as:

local flood incident databases
observations and witness statements – these could be from local authority liaison officers, or from the local authority emergency planning resilience team or civil contingencies team
highway authority drainage asset locations
coastal protection authority data
highway duty logs and road closures
flood risk asset register – this may be available through the local authority website
local flood modelling outputs
water company assets
hydraulic models for surface water and ordinary watercourses

Risk management authority and third party data

Other RMAs and organisations also collect data relevant to flood investigations. These may not be publicly available.

You should request this data as quickly as possible. This is because it may take time for the organisations to collate and provide it. Your request should clearly explain:

the purpose of the request
how the data will be used
the duty of the RMA to co-operate

You may also need to create a data sharing agreement. You should consider this when thinking about timescales for the investigation.

Read more about risk management authorities’ duty to co-operate and data sharing agreements.

Environment Agency

Environment Agency gauge data and geographical data is available as open data online. Read more about Environment Agency open data.

The Environment Agency may also hold data on:

properties flooded
asset operations
response actions
duty logs
hydrological summary reports
hydraulic models for rivers

You can request data by emailing the Environment Agency at enquiries@environment-agency.gov.uk.

You can also discuss the availability of local data with your local partnership and strategic overview (PSO) contact.

The Environment Agency is required to respond to data requests under the Freedom of Information Act and the Environmental Information Regulations.

Water and sewerage companies

Water and sewerage companies may hold data such as:

properties flooded
asset operations – for example, pump start and stop times
response actions
duty logs
flow level trends (recent and historical)
spill data
maintenance records
hydraulic models

You can request data through your local water and sewerage company liaison or flood risk management officer. Water and sewerage companies are required to respond to data requests within 20 working days.

Internal drainage boards

Internal drainage boards may hold records of:

asset operations
river telemetry
duty logs

You can request data through your contact for the local internal drainage board.

Canal and River Trust

The Canal and River Trust may hold records of:

duty logs
telemetry data on canal pound levels
asset controls
damage incurred to Canal and River Trust assets

You can request data by emailing water.information@canalrivertrust.org.uk.

Fire and rescue services

Fire and rescue services may hold records of:

flood incident call logs
duty logs

You can request data directly from your local fire and rescue service.

As a Category 1 responder, they will follow the guidance set out in Data protection and sharing guidance for emergency planners and responders.

Local resilience forums

Local resilience forums may carry out an event debrief and review of multi-agency response following a flood event. You can request this information through the local contact for your local resilience forum.

You may find useful information in social media posts, including photographs, videos, descriptions and locations of flooding.

You should verify any information you find on social media. The time you spend on online investigation should be proportionate to the scale of the flood event and resources available.

Many parish councils, flood groups, and village communities have their own social media accounts. For areas where regular flooding occurs, you could follow these accounts to increase awareness of new floods.

You can search social media for hashtags related to flooding. You should also use your communications to encourage people to use a specific hashtag with location tagging. Using social media in this way will help to make you aware of the locations that have been affected. There are also software products available which can monitor media for mentions of flooding.

Other online sources can provide useful information, for example local and national news websites.

You should consider copyright when using online information. You should not publish information or photos belonging to others without permission.

Data storage

You should:

keep all data and information collected for each flood investigation in one place
save any metadata and licences for third party data alongside the data you collect
clearly name files and folders to a locally agreed standard
store files in a clear and organised way so it’s easy to find information in the future – for example, if you need it for a freedom of information request

You must store personal data securely in accordance with the Data Protection Act 2018. Find out more about data protection.

Question 6

Understanding the event

Accepted Answer

Your analysis of the available data to understand the flood event should be proportionate to local factors, such as the scale and consequences of the flooding.

You can use the ‘source, pathway, receptor’ concept to describe and understand the flooding:

source – identify where the water that affected the receptors came from
pathways and causes – identify how the water travelled towards the receptors
receptor – identify what was affected

Getting an initial understanding

Desk based review

You can get an initial understanding of the catchment or coast affected by the flood event through conducting a short, desk based review of available data and mapping. For example, you can review:

long term flood risk mapping
topography and catchment areas
soils and geology
watercourse mapping
drainage assets
flood defence locations and existing flood management activities
historic flood records
historic ordnance survey mapping

This information can provide an important foundation for your flood investigation. It’s especially helpful when you’re investigating a location where you do not already have a good understanding of flood sources and mechanisms.

Historic flooding

To improve your initial understanding of the flood event, you should find out about the location’s history of flooding.

Your investigation should document the history of flooding to a proportionate level of detail, using information from your desk review and engagement. For each previous event, it should include:

the date
the scale or extent of flooding
a summary of receptors affected

This information will give you helpful context for the investigation. It can help you understand the awareness and preparedness of the community, existing flood risk management activities and the potential for future funding.

Sources of flooding

You should determine the sources of flooding to understand which RMAs may have responsibilities under the Flood and Water Management Act 2010.

You can get information to determine the flood sources from:

site visits, including any observations and data collected
residents’ photos and anecdotal evidence
discussions with RMAs
a desk-based review

The main sources of flooding in England are:

rainfall or surface water – water from rainfall falling directly onto the ground
main river – water from a main river
ordinary watercourse – water from an ordinary watercourse
groundwater – water coming up from underground aquifers
sea – water from the sea, estuaries, or coastal lakes because of any one or any combination of tidal levels, storm surges, wave action and tsunamis
sewer – water from surface water sewers, foul sewers or combined sewers

Flooding is often caused by 2 or more sources of flooding in combination. You should consider complex interactions between sources. It may be difficult to determine which flood source is responsible for flooding particular receptors.

Event analysis

As a minimum, you should review the available data to understand the scale and duration of the flood event.

Where appropriate, you should capture the following information:

rainfall profile – including the depth and duration of rain for the event, or for the winter season in the case of groundwater flooding
river levels or flow – including peak level or flow, and a hydrograph of the event for gauged main rivers
groundwater levels – levels over the winter season at nearest borehole
tide levels – peak and duration the critical tide level was exceeded
summary of meteorological conditions leading up to the event

You may decide to analyse the data further to understand what the annual probability was of the flood happening. Estimating probability is a technical exercise and you may not be able to do for every investigation. If your organisation does not have staff trained to estimate probability, you may be able to get support from consultants or other RMAs. You can also read about estimating probability in the flood estimation guidelines.

You should state probability as the ‘annual chance of occurrence’ of a flood. This is the probability of a flood of this magnitude or greater occurring in any one year as a percentage.

The level of technical detail in your analysis should be appropriate for the scale and consequences of the event. You are not expected to undertake detailed hydrological studies or hydraulic modelling as part of the flood investigation, as this will delay the outputs. You can make recommendations for further technical studies.

For major events such as named storms that cause flooding from main rivers and the sea, the Environment Agency usually compiles a hydrological summary report. This may be sufficient or be a helpful starting point for your event analysis.

Rainfall event analysis

Rainfall probability is the most direct measure of the flood probability if the flood source is:

surface water
sewer
ordinary watercourses with small catchments

You can get estimates of rainfall depth from rain gauge data and from rainfall radar data. Rain gauge data is usually more accurate, but the location of the rain gauge may not be close to the location of flooding. Rainfall radar has continuous coverage. If both types of data are available, you should compare them and your investigation should acknowledge uncertainty in the data.

You can download recorded rainfall data from the Hydrology Data Explorer.

You may have access to software that allows you to quickly estimate the annual chance of occurrence of the storm from rainfall radar data. You can also use the Flood Estimation Handbook web service from the UK Centre for Ecology and Hydrology. If you use the service, you’ll need to pay for access.

Your analysis should describe other factors which increase runoff, such as the antecedent conditions and how saturated the ground is. These will influence how severe the consequences are for a particular rainfall event.

Fluvial event analysis

If the flood source is a main river or ordinary watercourse with a larger catchment area, you can estimate the annual chance of occurrence of the fluvial flood. This will be influenced by the catchment characteristics, antecedent conditions and the spatial distribution of the rainfall across the catchment.

You can estimate fluvial flood probability using UK industry standard practice for estimating flood flows as outlined in the flood estimation guidelines. If a hydraulic model is available, the flood can be compared with modelled flood events of different probabilities.

You can download recorded flow and river level data from the Hydrology Data Explorer.

The Environment Agency may conduct analysis of river flow gauge data on main rivers as part of their hydrological summary report following any significant event. They should share this directly with you for the purposes of the flood investigation.

Tidal event analysis

If the flood source is the sea or an estuary, you should estimate the annual chance of occurrence of the nearest observed tide level for the date of the flood. You can find out observed tide levels on the Environment Agency’s tide gauge readings website.

To estimate the annual chance of occurrence of the observed tide level at your location, you can compare it with estimated coastal flood levels. You can find estimated coastal flood levels in the Coastal Flood Boundary Conditions for the UK Technical report. This gives coast flood levels at specific locations around the UK coast, for a range of annual chances of occurrence.

You can find more information about coastal flood levels on a 12km grid on the UK Climate Projections (UKCP) website. You can access this for free, but you will need to register.

You should add an allowance for climate change to estimated coastal flood levels from the base year of 2017 using UKCP18 data for climate change. You should use the regional sea level climate change allowances.

Groundwater event analysis

There is no accepted industry standard method for determining the annual chance of a certain groundwater level occurring.

You can compare the level of the groundwater in the nearest available monitored borehole with groundwater levels from previous years. By doing this, you can determine if similar levels have been observed frequently in the past, or if they are a rare occurrence.

Pathways and causes

Flooding is a natural occurrence. To understand the causes of flooding, you should examine the pathways the water took to reach the receptors. You should also examine any mechanisms that may have affected that pathway or made the consequences of flooding worse.

Pathways include:

overland flow – for example, over fields or along a road
exceeded channel capacity by overtopping banks
exceeded capacity of highway or local drainage systems
exceeded capacity of sewer – for example, through a manhole
overtopped a flood defence

Factors that may affect the pathway include:

breach or failure of defences or impoundments – for example, embankments, walls, dams or reservoirs
mechanical failure of infrastructure – for example, mechanical flood defences, pumps or gates
poor condition or lack of maintenance – for example, of bridges, channels, culverts, trash screens or sewers
obstruction or blockage – for example, of bridges, channels, culverts, trash screens or sewers
tide and or river locking

If you identify factors which have affected the pathway, you should try to record evidence of them during the investigation. You should work with RMA partners as needed. For example, you could conduct a joint site visit to lift manholes to identify a blockage in a sewer.

Flooding may be a result of a combination of causes and pathways. It may not always be possible to determine the exact cause of flooding for particular receptors. You should acknowledge this uncertainty in the flood investigation, but it should not stop you from presenting findings.

You do not need to carry out hydraulic modelling as part of a flood investigation, but it can help to:

understand pathways and causes of flooding
show flooding on a map when engaging with the community

You can read more in the technical standards on hydraulic modelling.

Receptors

You should record as much information as possible about the:

receptors of flooding – who and what was affected by flooding
severity of the flood consequences

People

You can assess the ‘danger to people’ caused by a flood (for example through loss of life and injury). Defra’s flood risk to people guidance advises how to estimate flood hazard and categorise it in terms of danger. The danger categories are subdivided into ‘danger for some’, ‘for most’ and ‘for all’.

You can document the consequences of flooding on people and the community using information received during your engagement with the community. This is an opportunity to summarise people’s experiences and the qualitative, less tangible effects of flooding, these may include:

effects on mental health – for example, anxiety, stress or trauma
effects on physical health – for example, illness from contact with sewage or living in damp conditions
loss of personal possessions
time spent out of residences and in temporary accommodation
disruption to normal life – for example getting to work, local shops or social activities
financial strain

The Climate Just Map Tool includes a neighbourhood flood vulnerability index that can help you to understand the susceptibility and ability to prepare, respond and recover, based on demographic data.

Case study: Impacts on people, Royal Borough of Kensington and Chelsea

The Royal Borough of Kensington and Chelsea conducted a flood investigation into flooding in July 2021. The flooding caused internal flooding to more than 550 properties in the borough.

An online questionnaire was shared with the community. The questionnaire asked about the:

effects of flooding on property
sources of flooding
history of flooding

The questionnaire also included the open question “How has the flooding affected you? Please provide any further information on how the flooding has affected you or your business. This could include flood damage to your property, loss of revenue, effects on mental health.”

Anonymised quotes from the responses to this question were included in the receptors section of the flood investigation as a series of ‘witness statements’. These helped convey a sense of the mental trauma and intangible cost of the flood on the affected residents and businesses.

The Royal Borough of Kensington and Chelsea has now made a flood reporting form available at all times on their website. The format closely follows the questionnaire sent out during the flood investigation. This allows for the continuous collection of data, which could be used in future flood investigations.

Property

You should confirm the effects of flooding on properties by using data collected from RMAs and residents. As a minimum, you should record the:

number of residential properties flooded (internal flooding)
number of commercial properties flooded (internal flooding)

Read the definition of ‘flooded properties’.

Where available or appropriate, you can record the:

number of residential properties affected (external flooding)
number of commercial properties affected (external flooding)
number of properties with vulnerable residents – for example, properties with elderly or disabled residents
number of residential properties built after 1 January 2009 – this relates to Flood Re eligibility criteria
number of new properties (residential or non-residential) or existing buildings converted into housing before 1 January 2012 – this relates to flood and coastal erosion risk management grant-in-aid eligibility criteria

Where available, you can document additional detail on the effects of flooding on properties. For example:

depths of flooding inside properties
how long properties were flooded for
points of entry of flood water into properties
existing property flood resilience resistance and recoverability measures fitted, and their effectiveness

Infrastructure, agriculture and environment

You should confirm the effects and duration of flooding on infrastructure and the environment by using information from RMAs and the community.

As a minimum, you should record:

flooding of critical infrastructure – for example, hospitals or schools
disruption to services – for example, utilities or water treatment
flooding or closure of main transport links – for example, primary roads and single entry points or railways

Where available or appropriate, you can record:

local road disruption
area of agricultural land flooded
flooding of environmentally designated sites

Actions taken

You can understand and document the actions taken by RMAs during and immediately following the event by working with partners. You should focus on if they have exercised their flood risk management functions. For example, you could consider remedial actions taken such as unblocking gullies, or operation of flood defences.

To help you to understand the effects of the flood on people and other receptors, you could look at the timings of:

communications
flood warnings
responders attending flooded locations or evacuating people

You can consider using a factual account such as an event timeline to document the response to the incident by RMAs, first responders, the community and other relevant organisations.

Case study: analysing RMAs’ actions, London Borough of Sutton

The London Borough of Sutton conducted a flood investigation into significant flooding in the Worcester Park area on 4 different occasions in 2021. Around 40 properties were flooded internally. The investigation included a record of each RMAs’ actions before, during and after each event. The LLFA found this useful when asked to respond to freedom of information requests relating to the response after some time had passed.

Mapping

You can use a map to present the results of the investigation visually. For example, a map can show sources, pathways and receptors. You can use Open GIS layers or Ordnance Survey MasterMap to identify and locate important services and transport infrastructure.

You should consider the presentation of the mapping in your investigation. You should get advice on the scale and detail of the mapping from data protection officers in your local authority. You could:

indicate flooded areas using whole streets or indicative polygons
represent how many properties are flooded by aggregating them at a grid square, street, or postcode level
use ‘hot spots’ or ‘heat maps’ based on the number of properties flooded

You must archive the licences for any data and display the relevant copyright statements on any published maps.

You should consider your organisation’s accessibility requirements when designing maps. You should also provide alternative text (alt text).

Case study: mapping flood impacts, Greater Manchester

The joint Greater Manchester Combined Authority conducted a flood investigation into flooding on Boxing Day 2015. Over 2,200 properties suffered internal flooding.

The Greater Manchester Storm Eva flood investigation mapped the distribution of properties flooded from all sources across the whole area. The mapping showed the number of properties flooded in each 1km² grid square. This produced a ‘heat map’ showing the worst affected areas.

Case study: mapping flood impacts, Royal Borough of Kensington, and Chelsea

The Royal Borough of Kensington and Chelsea conducted a flood investigation into flooding in July 2021. 550 properties suffered internal flooding.

The investigation produced a map showing flooded streets. This showed the worst hit locations, and was accompanied in the report by a street-by-street description of the flooding’s source, pathway and receptors. The report also included a map showing the number of flooded properties in each 100m² area.

Question 7

Learning lessons

Accepted Answer

You should use flood investigations to review and identify learning points and successes following a flood event. This will also help you to understand whether each relevant RMA has exercised, or is proposing to exercise, its functions in response to the flood.

You should not place blame on any RMA for the flooding. However, flood investigations allow you to make the case for partnership working to reduce the risk of future flooding.

Where you have identified learning points, you can include recommendations in the report. You do not have to provide fully formed solutions to flooding issues. This would take time and risk delaying the publication of the investigation.

You should develop recommendations in collaboration with relevant RMAs, other organisations and the community as appropriate.

Some remedial actions may have already been completed during the investigation period. You should capture and document these actions in the report.

Collaborating to develop recommendations

You should develop recommendations collaboratively with other RMAs. This can ensure the recommendations:

are effective, realistic and aligned with each organisation’s role
reflect the regulatory environment relating to individual RMAs
give consistent messages to communities

Other RMAs have a duty to co-operate with the flood investigation.

If you have identified that more than one RMA has flood risk management functions for this flood event, you may choose to use a partnership group. You can form a new flood investigation partnership group or use an existing partnership group. The group can review learning points and discuss joint investigative actions, quick solutions and longer term recommendations.

If the recommendations include community involvement, you may consider developing them with the community. For example, this could apply to recommendations to improve community resilience.

If the responsibility for a recommendation sits clearly with another RMA, you can invite them to help to word it.

Organisations may complete their own internal review of the flood event and have expertise on the potential solutions. You should request they share outcomes with you for use in the flood investigation.

Read more about working with partners and engaging with the community.

Types of recommendations

Common recommendations in flood investigations may relate to:

maintenance and repairs
review of operational protocols
performance and inspection of flood defence or drainage assets
review of flood warning thresholds
further technical studies – for example, hydraulic modelling
feasibility, options development or business cases for proposed flood risk management schemes
community preparedness and resilience
providing information to property owners – for example, on property flood resilience, Flood Re and Build Back Better

Your recommendations should concentrate on flood risk management responsibilities. Emergency response or civil contingencies recommendations would usually be made by local resilience forums. However, you may be able to use their recommendations to support your own recommendations.

Making recommendations achievable

You should present recommendations as clear and measurable actions with an assigned lead organisation.

Recommendations should be realistic, especially where funding to implement recommendations is not guaranteed. For example, if there is a potential capital scheme, you might recommend the relevant RMA to seek funding for a feasibility study or business case.

Where possible, you should link the recommendation to a duty, power or role. Annex A of the National Flood and Coastal Erosion Risk Management Strategy for England outlines existing roles and responsibilities for flood and coastal risk management activities.

The lead organisation for the recommendation will usually be the RMA with the relevant duty, power or role. You should highlight where other organisations may also need to support the action.

If the action is for the community, you should assign it to a suitable community organisation, such as a flood action group or parish council. If there is no suitable organisation, you should supply advice and information to support the community to set up a flood action group.

RMAs and other organisations have different objectives, structures and funding mechanisms. You should provide reasons and supporting evidence for recommendations so that RMAs and other organisations can justify funding to address them.

If a recommendation relies on getting funding or has other constraints, you should make clear the risks to completing the recommendation.

You may need to get support from senior representatives of the local authority or other RMAs to make progress on long term or complicated recommendations.

You may wish to summarise recommendations in the public flood investigation report but also keep a more detailed action plan that you’ve agreed with partners.

Timescales for recommendations

When setting timescales for implementing recommendations, you should consider that:

some recommendations will be quick to implement, while others may take several years
some actions will be aligned with other schemes and programmes of work
local resources and the availability of funding will affect timescales
you, as the LLFA, have no power to enforce recommendations

Timescales may be relatively simple. For example, ‘short term’, ‘medium term’ or ‘long term’.

Where possible, you should collaborate with the lead organisation for the recommendation to agree realistic and achievable timescales. This will help to manage public expectations.

Read more about how to track and follow up recommendations.

Question 8

Publishing and sharing

Accepted Answer

You must publish your flood investigation and notify RMAs when you have done this. This will increase flood risk understanding and help to align RMAs’ strategic flood risk management activities.

Structure

To help you structure your report, it’s recommended that you use the example flood investigation report structure.

The detail of your flood investigation report will depend on the scale of the flood event and the resources available. In addition, each flood event will be different, and the stages of investigation may vary accordingly.

Data protection

You should seek advice from your data protection officers on use of data that has been collected, and the content of your report. Different local authorities may have different guidelines on what can be published.

When collecting data, you must clearly state how the data will be:

shared
used
retained

Data may need to be shared with other RMAs for the investigation, or it may be subject to Freedom of Information requests.

You should make your flood investigation report factual and descriptive. You must protect people’s data and avoid presenting any personal information, such as residents’ names or contact details.

You and other RMAs will have collected addresses of flooded properties as part of the investigation. You must avoid listing property addresses in the published report. You can present information about the number of properties flooded by street name or neighbourhood. You can seek advice from data protection officers within your local authority, if needed.

Find out how to present maps.

Accessibility

You must write the flood investigation report in plain English. It should be comprehensible to members of the community, so you should use concise, non-technical language. If technical terms are necessary, you should clearly define them.

You should publish flood investigation reports in either HTML format or as accessible PDFs. You may have communications officers within your local authority to advise on this.

You must support as many users as possible to access your online report. Many local authorities have their own internal guidance on creating an accessible document.

There is guidance on understanding accessibility requirements for public sector bodies.

Review of your report

Once you have prepared a draft flood investigation report, you should invite feedback from RMAs, the community and other partners. This will help you to fact check the information presented in the report and get endorsement for the recommendations before it’s published.

The review process will vary between local authorities, due to the differences between unitary, two tier and coastal authorities. You may also consider asking for ‘peer reviews’ from neighbouring authorities, or those in the same Regional Flood and Coastal Committee area.

Where relevant, you should check with the community that information in the report is factually correct. You can do this by sharing appropriate sections of the report through pre-established communications. You can ask the community to nominate a contact to share the document and collate feedback, such as the parish council or flood action group.

To avoid delays to publishing the flood investigation report, you should agree a clear deadline for feedback with partners and the community.

Timescales for publishing

The time needed to publish a flood investigation report will depend on different factors. These include the:

severity of a flood event
resources available to investigate and report on the flood event
number of ongoing investigations following a series of flood events
scrutiny and approval process for publishing the report

An ideal timescale to prepare the draft flood investigation report is within 6 months of a flood event. Approvals and publication may take longer. If this is not possible, you should aim to complete the evidence gathering within this 6 month period.

You should capture the flood event and learning points in a succinct way. You should not delay publication by waiting a long time for surveys or developing fully formed solutions. Read more about making recommendations.

In all cases, you should keep the community and stakeholders informed of the expected timescales for publishing. You should give frequent progress updates using appropriate channels of communication. For example, you could use websites, social media or direct emails to stakeholders.

Publishing approval

You will usually need to go through an internal approval process before publishing a report. Approval processes vary between local authorities.

You should understand the approval route at an early stage so that you can allow sufficient time, particularly if a scrutiny committee meeting is needed.

The findings of a flood investigation can sometimes be sensitive for partners or the local authority. In these situations, you may need to seek legal advice internally within your local authority.

Where to publish

You must publish the report online in an open, free and easy to access location.

Local authorities will usually have a section of their website containing other information on flood risk management where you can suitably host the report.

You may also wish to provide a way for people to contact you with any responses or queries. For example, an email address or a website submission form.

Pro forma

There is a pro forma to capture important information about flood investigations. This allows the Environment Agency to collect information in a consistent way, and to understand national and regional trends.

You should use the pro forma to capture a minimum of important information. You also have the option to add more detailed information.

You should send the completed pro forma to your local Environment Agency area flood and coastal risk manager.

Download the pro forma from the Environment Agency’s site supporting local authority flood and coast projects. You need to register to access this site.

You must notify relevant RMAs of your investigation. Once you publish the flood investigation report, you should share the online publication link directly with all contributing partners and stakeholders. You should share the report with:

RMA partners
flooded residents
your local Environment Agency area flood and coastal risk manager

Within the local authority, you should consider sharing the report with the:

corporate and divisional directors
service manager
ward councillors and portfolio holders
local highways authority
emergency planning, resilience or civil contingency colleagues

Outside of the local authority, you should consider sharing the report with:

your local Regional Flood and Coastal Committee
other partners – for example, the Canal and River Trust
community group and parish council representatives
emergency services
individual residents who have been engaged in the process or affected by the event

You should announce publication of the flood investigation in line with your local authority’s communications policy. This could include announcements through the press and social media.

Question 9

After publishing

Accepted Answer

Informing future work

You and other RMAs should use flood investigations to inform future flood risk strategies and investment.

Flood investigation reports can support flood risk management activities by:

informing flood risk assessment for future development sites
identifying opportunities for partnership working to support collaborative flood risk management and explore funding opportunities
raising awareness of riparian ownership
shaping local strategies and plans by highlighting priority areas
supporting investment in new technical studies
supporting decision making such as land drainage consenting
supporting the strategic case in business case development for flood alleviation schemes where appropriate
contributing to shaping planning and priorities for other RMAs
contributing to a national overview of flood events making it easier to understand and analyse

Case study: Informing future work, Pix Brook catchment, Central Bedfordshire

Central Bedfordshire Council published flood investigation reports following flooding in Stotfold in July 2015 and June 2016. Blockage of a bridge made flooding worse in the 2015 event, but not in the 2016 event.

The LLFA realised RMAs would need to do more work to understand the causes of the flooding. They formed an effective RMA partnership to complete the flood investigations. Recommendations in the 2016 investigation focussed on working with these partners to improve catchment scale understanding of the watercourse and identify solutions to flood risk issues.

The flood investigations provided the evidence that enabled the LLFA to apply for several funding streams. Local levy and partnership funding were used to carry out modelling. This has been used to understand the role of assets in local flood risk management and develop a long and shortlist of options to improve resilience.

The LLFA developed a fully costed flood scheme and secured grant-in-aid funding. Several developer contributions have been secured through section 106 agreements under the Town and Country Planning Act 1990. Part of the scheme has been delivered on one site, meaning the development is more beneficial for the community. The LLFA has unlocked further funding through the Flood And Coastal Resilience Innovation Programme fund for the ResilienTogether project in the catchment.

Case study: Pednormead End flood resilience project, Buckinghamshire

The Pednormead End flood resilience project is a £3.3 million capital scheme. It is funded through flood and coastal erosion risk management grant-in-aid partnership funding and local levy to protect more than 100 homes.

There is a long history of flooding in the area, with the most recent flood events in 2001, 2006 and 2014. The council’s business case for the grand-in aid cited a flood investigation in 2014 as part of its evidence

The scheme provided funding that will enlarge a culvert and has offered property flood resilience measures to homes at risk.

Tracking progress

You should periodically review the progress of any recommendations set out in a flood investigation. However, the responsibility for implementing a recommendation remains with the lead RMA.

For example, you could review progress every 6 months, along with other RMAs. You can conduct the review during routine partnership group meetings or conversations with RMAs that cover the flood investigation area. You can also review recommendations alongside strategy updates or flood risk planning activities. Your review will demonstrate the influence and positive interventions that result from a flood investigation.

Sharing the report with the local authority scrutiny committee or your regional flood and coastal committee (RFCC) can help you track the progress of recommendations. It will also help the committee understand trends in regional flood risk management

You may wish to publish the progress of recommendations. You can create a ‘live document’ as an appendix to the flood investigation report and periodically update it.

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What your investigation should determine

Identifying the need to investigate

Becoming aware of a flood

Flood incident reporting

Initial data collection

Case study: online form for the public to report flooding

Case study: Flood Online Reporting Tool (FORT)

Deciding to carry out a flood investigation

Definition of ‘properties flooded’

Defining flood investigation criteria

Receptor criteria

Scale criteria

Duration and frequency criteria

Repeated flooding from the same source

Exceptions to criteria

Combining investigations

Cross-boundary investigations

Case study: using existing regional partnerships to conduct a joint flood investigation

Engaging with the community

Ways of engaging

Engaging during the flood event

Case study: engagement during a flood event, Buckinghamshire

Engaging after the flood event

Communities’ role in flood resilience

Case study: communities working with RMAs to respond to flooding, Nottinghamshire

Frequently flooded communities

Working with partners

Duty to co-operate

Partnership and working groups

Role of partners in investigating a flood

Environment Agency

Highways authorities

Water and sewerage companies

Internal drainage boards

Response roles

Community groups

Other organisations

Data sharing

Ways of working

Data sharing agreements

Case study: proactive data-sharing, Anglian Water

Collecting data

Planning and protocols

Survey and observed information

Community

Case study: collecting data from communities, Suffolk and Oxfordshire

Site investigation

Surveys

Open data sources

Flood and coastal erosion risk mapping

Flood warnings

Hydrology, hydrometry and flood history

Asset mapping

Geology and environmental designations

Flood vulnerability

Historic mapping

Geographical information systems data

Satellite data

Local authority data

Risk management authority and third party data

Environment Agency

Water and sewerage companies

Internal drainage boards

Canal and River Trust

Fire and rescue services

Local resilience forums

Social media and online news

Data storage

Understanding the event

Getting an initial understanding

Desk based review

Historic flooding

Sources of flooding

Event analysis

Rainfall event analysis

Fluvial event analysis

Tidal event analysis

Groundwater event analysis