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Part of: Flooding

Related to: Risk of Flooding Vulnerability to Flooding , Flooding Incidents , Climate Change Mitigation and Adaptation, Heat Waves, Rural Areas, Built Environment, Natural Environment, Travellers and Gypsy Travellers, Biodiversity, Ecosystem Services,Green Infrastructure and Spaces, Transport InfrastructureHouse Prices and Tenure, House Conditions, Children and Young People, Older People, Ill Health and Disability

Key Facts

  • Large watercourses, known as “main rivers” are within the regulatory control of the Environment Agency.
  • The Environment Agency has duties and powers with regards to flood warnings, flood risk mapping, the construction of flood defences and the consenting and enforcement of works near to or within main rivers.
  • Bath and North East Somerset Council is a Lead Local Flood Authority. 
  • The duties assigned to the LLFA are: to develop, maintain, apply and monitor a strategy for local flood risk management in its area, and to establish and maintain a register and record of structures or features which are likely to have a significant effect on flood risk in its area.
  • Both Chew Stoke and Chew Magna fall within, and benefit from, the EA's flood warning service.
  • In 2015 B&NES Council developed the Local Flood Risk Management Strategy 2015-2025. This is a ten year plan for the management of flooding from local sources.

Are we meeting the needs?

Flood management

Flood and Water Management Act 2010 1 - The Flood and Water Management Act 2010 was developed with the aim of addressing issues raised by devastating floods such as those of summer 2007 which caused enormous physical and economic damage. It included measures to ensure that risk from all sources of flooding, not just rivers and seas, are managed more effectively

In accordance with this Act there are a number of different bodies and authorities with duties and powers relating to flood risk management.

The Environment Agency (EA) 2 – was established in 1996 to protect and improve the environment. One of its key areas of responsibility is flood and coastal risk management.  Large watercourses, known as “main rivers” are within the regulatory control of the Environment Agency. The Environment Agency has duties and powers with regards to flood warnings, flood risk mapping, the construction of flood defences and the consenting and enforcement of works near to or within main rivers.

Lead Local Flood Authorities (LLFAs) 3  4 – All Unitary Authorities and two tier County Councils are Lead Local Flood Authorities (LLFAs). Therefore, Bath and North East Somerset Council is an LLFA. The purpose of LLFAs are to lead on the management of local flood risk.This involves working closely with partners involved in flood and water management, known as Risk Management Authorities. In the Bath and North East Somerset area these include:

  • The Environment Agency
  • Wessex Water
  • The Emergency Services
  • Highways Authority

Under the Flood and Water Management Act 2010, LLFAs have been assigned a number of duties and powers relating to the management of local flood risk from ordinary watercourses, ground water, and surface water.

The duties assigned to the LLFA are:

  • To develop, maintain, apply and monitor a strategy for local flood risk management in its area.
  • To establish and maintain a register and record of structures or features which are likely to have a significant effect on flood risk in its area.

LLFAs have the powers to:

  • Do works to manage flood risk 
  • Investigate flooding incidents
  • Designate structures/features which affect flood risk
  • Request information from a person in connection with our flood risk management functions

Local maintenance regimes to reduce the risk of flooding and its impacts 5

Bath and North East Somerset Council

B&NES Council Highways department are responsible for routine maintenance of the highway drainage system. Gullies and their immediate pipe connection are emptied and cleansed as part of an annual proactive maintenance programme. Highway drainage with persistent problems are programmed for a greater cleansing frequency.

B&NES Council Drainage and Flooding team carry out a programme of annual watercourse maintenance on Ordinary Watercourses that are deemed to be critical in terms of flood risk (normally due to their proximity to property or infrastructure). This involves the removal of debris or vegetation that may have an impact on flow capacity and flood risk. Trash screens on these watercourses are also cleared and any build-up of trash is removed reactively.

Environment Agency

The Environment Agency carries out maintenance on rivers and streams designated as Main Rivers. Their annual maintenance programme can be found on the Environment Agency’s website.

Wessex Water (sewers)

Wessex Water carries out maintenance on public sewers. More details on sewer maintenance can be sourced through the Wessex Water website www.wessexwater.co.uk

Riparian Owners

If a property is adjacent to or backs onto a river, stream or other watercourse, then it is likely that the land owner will be the riparian owner and as such own the land up to the centre of the watercourse.

Riparian owners have a right to protect their property from flooding and erosion, but will need to discuss the method of doing this with the Lead Local Flood Authority within B&NES or the Environment Agency depending on the classification of the watercourse. Riparian Owners also have responsibility for maintaining the bed and banks of the watercourse and ensuring there is no obstruction, diversion or pollution to the flow of the watercourse.

Flood Warnings 6 - Areas in the UK deemed at risk of flooding fall within the EA's flood warning service. This service generally aims to issue flood warnings with a two hour lead time (time between warning and expected flooding event), unless the catchment falls under a rapid response catchment. In this case, half an hour is the target time. The aim of course is to give people the earliest possible advance notice of the chance of flooding, recognising this involves probabilities rather than certainties.

Chew Magna and Chew Stoke 7 8

Following the 2012 flooding in Chew Magna and Chew Stoke, the risk management authorities have been working together on a number of actions to help the recovery process and to investigate possible measures to help reduce future flood risk and impact.

Warning signs and flood depth markers have been installed at the Pilgrim’s Way ford

Flood warnings – Both Chew Stoke and Chew Magna fall within, and benefit from, the EA's flood warning service, generally for Chew Stoke this service aims to issue flood warnings with a two hour lead time.  However, because Chew Magna is a rapid response catchment, the target lead time (time between warning and expected flooding event) is half an hour.

New warning procedures went live in June 2013 and make use of the Chew Stoke Stream level gauge. Warning from a gauge more local to the risk area should help to improve the quality of the warnings issued and provide more lead time.

Flood forecasting models - The EA’s flood forecasting team is currently developing flood forecasting models for Chew Stoke and Chew Magna. Once developed and implemented these models will provide duty staff with predicted river level information for both sites and thus an earlier indication of enhanced river levels that could result in flooding. In turn, this will also allow duty staff to issue warnings earlier.

Flooding emergency plan - The emergency plan for Chew Magna was developed by the Parish Council following flooding that occurred in the village on 11th January 2008 and contains separate flood warnings to cater for the Winford Brook and the River Chew as they react independently during periods of heavy or prolonged rainfall.

Property Level Protection- At the time of the 2012 floods, 69 properties in Chew Magna had formal flood protection in place as part of the Property Level Protection (PLP). Properties in Chew Stoke on the other hand had no formal flood protection in place, but those affected in the 2012 floods have since been included in a PLP scheme.

What can we realistically change?

Bath & North East Somerset’s Local Flood Risk Management Strategy 2015 – 20259

In 2015 B&NES Council developed the Local Flood Risk Management Strategy 2015-2025. This is a ten year plan for the management of flooding from local sources. The purpose of this strategy is to help inform the Council, partners and communities about local flood risk, where it is most significant, how it can be managed, and who is responsible for doing so. The overall goal of the strategy is to help reduce risk to homes and businesses, which will include buildings and areas with significant heritage value.

In line with the Councils statutory responsibilities as a Lead Local Flood Authority, the focus of the Local Flood Risk Management Strategy is on flood risk from surface water, groundwater or Ordinary Watercourses, which we are now directly responsible for managing, and termed ‘local’ sources under the legislation.

The Local Flood Risk Management Strategy does however also consider flood risk in line with the Council’s coordinating responsibility. As part of this, it outlines the roles and responsibilities of other Risk Management Authorities (Environment Agency, Highways England, Bristol Water; and Wessex Water) who manage other types of flooding within B&NES, and how the Lead Local Flood Authority is working in partnership with these organisations.

A series of objectives have been defined to help structure and govern the implementation of the Local Flood Risk Management Strategy. These objectives are to:

  • Objective 1- improve understanding of local flood risk;
  • Objective 2 - promote community awareness and build capability for appropriate action;
  • Objective 3 - manage local flood risk through capital and maintenance investment;
  • Objective 4 - prevent inappropriate development that creates or increases flood risk;
  • Objective 5 - improve flood preparedness, warning and ability to recover.

Types of flood risk management measures discussed in the strategy:

  • Source control measures aim to control flood water at their source by increasing storage, reducing the rate of runoff or increasing the volume of water which soaks into the ground.
  • Pathway measures aim to effectively manage the movement of flood water through both natural and manmade drainage systems.
  • Receptor measures aim to reduce the likelihood and/ or impact of flooding on people, property and environment.

The diagram below outlines some forms of these flood risk management measures.

Figure1: Flood risk management measures outlined in Bath & North East Somerset’s Local Flood Risk Management Strategy 2015 – 202510

Maximising the wider benefits of flood risk management11

Flood risk management intervention can offer a significant range of wider benefits beyond reducing flood risk. For example, it can:

  • protect or enhance the environment by improving water quality, physical characteristics of the shape, boundaries and content of watercourses, creating habitat or new biodiversity;
  • provide amenity for local communities;
  • ensure areas with historical importance and value can be better protected;
  • improve mental and physical health through reduction of stress associated with flood risk, and creation of new amenity features integrated into the design of a scheme;
  • support economic regeneration, and;
  • unlock additional land for future development. 

For more information please see Bath & North East Somerset’s Local Flood Risk Management Strategy 2015 – 2025.

Chew Magna and Chew Stoke Investigation Reports 2011-12 12

Some of the improvements suggested by the Chew Magna and Chew Stoke Investigation Reports 2011-12:

  • Better recording of evidence of property flooding – e.g. use of apps and social media to improve the ease and level of public reporting of flooding incidents, to ensure complete record of the impacts is obtained
  • Improvement to the flood warning system, such as to base flood warnings on rain gauges and rainfall forecasts rather than river levels.
  • Chew Valley model development to explore operational and flood management options
  • Holding of flood surgeries and events to raise flood awareness and understanding of options to reduce risk.
  • Updating of community emergency action plans
  • Improvement of land and road drainage
  • Assessment of the potential and funding for an enhanced package of PLP measures for those included in the previous scheme