Dartford and Erith Policy Unit: Thames Estuary 2100
What needs to be done to manage flood risk and adapt to rising sea levels in Dartford and Erith, one of 23 policy units in Thames Estuary 2100 (TE2100).
Applies to England
Map centred on the Dartford and Erith policy unit boundary. This policy unit extends from Erith Pier to Greenhithe, to the south of the River Thames, and includes parts of Dartford and Crayford. The map extends around 1 kilometre (km) in all directions to show the surrounding areas. The flood risk layer shows that in most of this policy unit there is a 0.1% or higher chance of flooding each year without the existing flood defences. In some areas the risk is reduced by defences.
Description
The Dartford and Erith Policy Unit includes areas of undeveloped and developed marshes and parts of Dartford and Crayford. It extends from Erith Pier to the riverfront town of Greenhithe on the south bank of the River Thames.
The councils responsible for this area are:
- London Borough of Bexley
- Dartford Borough Council
The River Darent and a tributary, the River Cray, pass through the policy unit. The lower reaches of these rivers pass through the largely undeveloped Dartford and Crayford Marshes.
Use the Thames Estuary 2100 (TE2100) map to view all the policy units.
Local areas at risk and types of flooding
Many of the new developments in this area are in the flood zone, including:
- the Dartford Northern Gateway
- riverside areas with housing and improved connections to the river
The areas at risk of tidal flooding include the marshes and some residential and commercial areas.
Further inland, there is a risk of fluvial flooding from the River Ebbsfleet.
The types of flooding that could affect this policy unit include:
- tidal flooding from the Thames downriver (east) of the Thames Barrier or from the Darent and Cray rivers – when the tide overtops or breaches flood defences
- fluvial flooding from the Darent and Cray rivers or marsh drainage systems on Crayford, Dartford and Stone Marshes – when heavy rainfall causes rivers to overflow their banks or defences
- Surface water flooding – when heavy rainfall is unable to drain away
- groundwater flooding – when underground water stores (aquifers) overflow
- a combination of the above
Managing flood risk in this area
To manage these risks, there are tidal flood defences downriver (east) of the Thames Barrier:
- the Dartford Creek Barrier prevents flooding from tidal water levels on the Rivers Darent and Cray
- secondary tidal and fluvial flood defences on the Darent and Cray rivers
- local fluvial flood defences
- drainage system outfalls in Crayford, Dartford and Stone Marshes
The use of the entire marsh area for flood storage is currently restricted by the presence of the Darent Industrial Estate.
We use flood alerts and flood warnings to inform people about potential flooding so they can take appropriate action.
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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
Tidal 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. Dartford Borough Council is developing a riverside strategy for the fluvial and tidal reaches of the River Darent.
By 2030, councils should work with communities in the other parts of this policy unit to plan how their riverside will look in future.
Find out more about the riverside strategy approach.
Thames Estuary Partnership
The Thames Estuary Partnership will work with communities, councils, the Environment Agency and other partners to update the Thames Strategy East.
This landscape vision for the river corridor will include a riverside strategy approach to tidal flood defence upgrades.