Policy paper

Yate and Chipping Sodbury: reducing the risk of flooding

Updated 10 October 2017

Introduction

The Environment Agency wants to reduce flood risk to homes and properties in Yate and Chipping Sodbury. About 100 homes and 40 businesses are at risk of flooding from the River Frome and its tributaries. There is a 1 per cent chance of serious flooding each year. The risk is expected to increase with climate change causing higher river flows.

Areas identified

Flooding occurs because the River Frome has insufficient capacity. Improvements have been made over the years alongside new developments in the river corridor, but these haven’t kept pace with the growing flood risk. Surface water run-off from heavy rain has added to the flooding problem.

Flood warnings are issued to low-lying properties in both communities. In Yate these include:

• Bennetts Court
• Station Road
• Swan Field
• Treeleaze
• Orchard Close
• Milton Road
• Tyndale Avenue
• Celestine Road
• Blenheim Drive
• Whitley Close

In Chipping Sodbury these include the properties off St John’s Way and the Blanchards Farm area.

Flood alleviation options

The Environment Agency has carried out a preliminary study that identifies 3 options:

• flood storage
• river channel widening
• property level flood-resilience

The indicative costs of the individual options are £3.7 million, £300,000 and £100,000, respectively.

As well as exploring each option separately, a combination of all 3 options is also under consideration. The combined option would provide the highest standard of protection but would increase the cost of the scheme to approximately £4 million. If this full option is pursued, it could provide environmental benefits such as habitat creation. Weir modification to improve fish passage was also considered. However, this work is now starting on Environment Agency-owned weirs in Yate and due for completion early 2022.

If affordability prevents this combined option, a scheme offering a lower standard of protection - including channel widening and flood-resilience measures for properties most at risk - could be taken forward. The flood storage area could be developed at a later date, if funding becomes available.

An earlier option that involved the construction of 1.8km of flood walls was rejected on the grounds of being too expensive (£10 million). It also raised sustainability concerns.

For a successful scheme to go ahead, any benefits must outweigh the costs. In addition to reducing flood risk to a significant number of homes and businesses, the final scheme should reduce flooding on 3 local roads (A432, B4569 and B4060) and prevent flood damages estimated at £10 million.

Flood storage schemes are an effective way of providing flood alleviation. The Environment Agency has built several in recent years. Examples include Tubbs Bottom, that reduces flood risk downstream of Yate. Schemes are also being considered for Taunton in Somerset and Wrington to the south of Bristol.

Consultation held to date

More than 100 people came to a consultation event at Chipping Sodbury Town Hall on 1 March 2017. Download the consultation materials here.

At the public exhibition the Environment Agency presented the following options:

• Flood storage area: build an embankment dam to hold flood water in storage upstream to the East of Chipping Sodbury in an existing rural flood plain of 2 tributaries to the River Frome.
• Channel widening: widen the existing river along St. Johns Way to create a 2-stage channel and increase flood flow capacity.
• Property level measures: make the most vulnerable properties more resilient with very localised defences or property level measures, specifically for isolated properties in Nibley, downstream of Yate.
• Environmental improvements: being considered alongside the flood risk management solutions, including modifications to the existing weirs to improve fish passage.

The Environment Agency received over 40 responses from paper questionnaires. This helped it to better understand the river flooding problems in the area and local issues that may affect the options under consideration. There is general support to reduce flood risk, and all options proposed are more or less equally supported, with a small preference for a flood storage area.

A concern expressed by many residents related to plans for housing development to the east of Chipping Sodbury and how this might conflict with the location identified for the flood storage option. From initial investigations, the Environment Agency thinks the project would be compatible with the proposed development and might go some way towards funding the flood storage scheme. However, the Environment Agency is aware of the various planning reasons why the proposed development at this location may not go ahead, so the project is being progressed independently at the current time.

Another concern advised by some stakeholders is that the channel widening option could increase flooding downstream. The Environment Agency considers that the option may be feasible in combination with the flood storage option to avoid such adverse effects.

Other issues connected with the channel widening option include the need to protect and enhance the Frome Valley Walkway (a very popular route) and the potential loss of habitat along the river corridor and future maintenance of the river channel. These are all very valid points the Environment Agency is considering. You reported past river flooding problems, including:

• river flooding affecting St Johns Way, Manor Way, Vayre Close, Grace Close, Wickham Close, Bennetts Court, Hatters Lane, Ross Close and Brook Street.
• flooding in the St Johns Way area on 5 occasions over 10 years (1995 to 2005)
• flooding over the railway line on one occasion

You said that:

• high river levels can cause drains to back-up leading to problems, eg at St Johns Way
• bridge constrictions on the River Frome can cause localised flooding (Yate, Chipping Sodbury)
• surface water and sewer flooding also cause problems, eg at Badminton Road (Old Sodbury)

Many of you expressed concern about the high cost of home insurance attributed to flood risk. More information is available online.

Current preferred option

Following a detailed inspection of the river, discussions with residents and appraisal of options, the Environment Agency arrived at a preferred option. This is a combination of a flood storage area and property level measures.

This combination of options provides the highest standard of protection, at a total cost of around £4 million.

Next steps

The Yate and Chipping Sodbury scheme is still in its early stages. The Environment Agency’s main challenge is securing other sources of funding before selecting a preferred option. It can apply for Defra Flood Defence Grant in Aid and Local Levy funding but, due to the funding criteria, currently there would still be a considerable funding shortfall before it could deliver the preferred option.

In view of the shortfall the Environment Agency cannot say when a scheme could be implemented. This will depend on being able to secure the necessary funding from government and other sources. The Environment Agency welcomes any further feedback from the community and local stakeholders on how the funding gap can be found.

Due to the funding challenges for the preferred flood scheme the Environment Agency is considering carrying out modifications to the existing weirs to improve fish passage in advance, as sufficient funding may be available for this.

Contact

For further information email colin.taylor@environment-agency.gov.uk or ring 02030 250148.