Guidance

Isle of Grain Policy Unit: Thames Estuary 2100

What needs to be done to manage flood risk and adapt to rising sea levels in Isle of Grain, one of 23 policy units in Thames Estuary 2100 (TE2100).

Applies to England

Map centred on the Isle of Grain policy unit boundary. This includes the village of Allhallows, freshwater marshes and industrial infrastructure but does not include the village of Grain. The map extends 1.5 kilometres (km) north, 2km south, 2.5km west and 3km east of the policy unit boundary to show surrounding areas. The flood risk layer shows that, in much of the policy unit, there is a 0.1% or higher chance of flooding each year without the existing flood defences. The risk is reduced by defences.

Description

The Isle of Grain policy unit includes the village of Allhallows, freshwater marshes and industrial infrastructure.

A large part of the policy unit is a designated Special Protection Area (SPA). The freshwater grazing marshes are designated, so no new development should be permitted in these areas.

The council responsible for this area is Medway Council.

Use the Thames Estuary 2100 (TE2100) map to view all the policy units.

Local areas at risk and types of flooding

The areas at risk of flooding are mostly road and rail infrastructure and residential properties.

There are some very large facilities in the industrial area, including:

  • London Thamesport
  • Grain LNG (liquified natural gas) Import Terminal
  • NeuConnect electricity interconnector

It is of strategic and economic importance that these sites and any future developments are protected.

The NeuConnect electricity interconnector development might need its own defences due to the flood risk in the area.

The types of flooding that could affect this policy unit include:

  • tidal flooding from the Thames and Medway, including Yantlet Creek – when the tide overtops flood defences
  • fluvial flooding from local watercourses including the drainage systems on the Allhallows and Grain Marshes – when heavy rainfall causes rivers to overflow their banks or defences
  • a combination of these

Managing flood risk in this area

To manage these risks there are:

  • tidal defences on the Thames and Medway, including Yantlet Creek
  • drainage systems outfalls for Allhallows and Grain Marshes

This policy unit overlaps with the Isle of Grain to South Foreland Shoreline Management Plan (SMP). It is essential that there is good communication between Thames Estuary 2100 and the Isle of Grain to South Foreland SMP to ensure that there is no conflict between the flood and coastal management policies and action plans developed by these 2 strategies.

The Environment Agency also uses flood alerts and flood warnings to inform people about potential flooding so they can take appropriate action.

Sign up to receive flood warnings in your area.

Flood risk management policies for this area

Thames Estuary 2100 sets flood risk management policies for each area of the estuary. The policies range from P3 to P5 and outline how we should manage that area’s tidal defences.

In this area, a P4 policy applies.

This means we will take further action to keep up with climate and land use change so that flood risk does not increase. We will need to work with other risk management authorities to do more to manage flood risk.

Find out more about flood risk management policies.

Local requirements: who needs to do what

Flood defence owners

By 2040, tidal flood defence owners in this policy unit should:

  • work with the council, developers and local infrastructure providers to adapt defences and achieve multiple benefits through proposed development
  • work with the Environment Agency to raise defences where required

For further information read outcome 2: improving fixed flood defences.

Local councils

There is currently no riverside strategy for this area. By 2030, councils should work with communities to plan how their riverside will look in future.

Find out more about the riverside strategy approach.

Environment Agency

The Environment Agency will work with Medway Council and Uniper (the relevant energy supplier) to review how the Isle of Grain should adapt to rising sea levels. This will include an assessment of how standards of protection for critical infrastructure are maintained and integrated with the P3 flood risk policy. They will also clarify roles and responsibilities for delivering sustainable flood risk management.

Network Rail

Network Rail will work with councils and the Environment Agency to ensure transport infrastructure in Kent is resilient to increasing flood risk. This will support growth in the outer estuary.

Thames Estuary Partnership

The Thames Estuary Partnership will work with communities, councils, the Environment Agency and other partners to scope the need and potential extension of the Thames Strategy East or creation of an alternative Joint Thames Strategy to cover this policy unit.

Any agreed landscape vision for the river corridor will include a riverside strategy approach to tidal flood defence upgrades.

Updates to this page

Published 19 April 2023

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