Cliffe Pools are located on the southern shore of the Thames Estuary, 6 km east of Gravesend and 8 km north of Rochester. The area is designated a Site of Special Scientific Interest (SSSI), Special Protection Area (SPA), Ramsar site and Environmentally Sensitive Area (ESA) and forms part of the wider North Kent Marshes SPA. The site was acquired as a reserve by the RSPB in October 2001.

Case study date







Westminster Dredging Ltd

Mineral Planning Authority

Medway Council

Mineral Type

Clay & Shale

Habitat(s) Created

Saline lagoons

Restoration / Priority Habitats

Saline Lagoon
Islands and Shallow Margins

Partnership Working

Blue Circle Industries
Natural England (formerly English Nature)
Westminster Dredging Ltd
Medway Council

Key Issues

Un-authorised Access
Copper Contamination
In-filling with Marine Dredgings

Public Benefits

Public access
Education programme


Cliffe Pools are located on the southern shore of the Thames Estuary, 6 km east of Gravesend and 8 km north of Rochester. The area is designated a Site of Special Scientific Interest (SSSI), Special Protection Area (SPA), Ramsar site and Environmentally Sensitive Area (ESA) and forms part of the wider North Kent Marshes SPA. The site was acquired as a reserve by the RSPB in October 2001.

The 237 ha support a range of habitats including saline lagoons, brackish pools, grasslands, salt marsh, mud flat and scrub. The 111 ha of saline lagoons and 27 ha of brackish shallow pools were created through clay extraction for the cement industry.

The site is renowned for wading birds, with large flocks moving from the Thames Estuary onto the pools on winter high tides, a wide range of passage birds in autumn and spring and breeding avocets, redshanks, lapwings and ringed plovers.

Planning history

Clay for the cement industry was extracted at the site until 1972, leaving a series of pits that flooded to form pools. From the 1960s onwards the site was used by Westminster Dredging Ltd for the licensed disposal of river dredging deposits by infilling of the pools.

In the 1980s, discussions commenced between English Nature, RSPB, Blue Circle Industries Plc (the former owners of the site) and Westminster Dredging Ltd (the dredging disposal operators). This culminated in an agreement to alter the original plans for infilling the remaining pools for the benefit of nature conservation.

Early dredging activity filled in 60 ha of the site’s north-western clay pits with a mixture of sand, gravel and silt dredgings, upon which developed a rich mosaic of upper salt-marsh, grassland and hawthorn/bramble scrub. The pits adjacent to the north-east also received dredgings but were not entirely filled, resulting in the creation of a suite of 27 ha of rain-fed brackish pools.

To the south, ongoing dredging disposal into the saline lagoons is part of the 40 year agreed restoration plan between RSPB and Westminster Dredging Plc. The silt is piped in directly from the Thames estuary, from where it is removed in order to maintain navigable shipping lanes.

Habitat creation details

The site had a long history of un-authorised access, fly-tipping and anti-social behaviour. Therefore, before restoration work could commence, considerable effort had to be put into site safety and removal of contaminants. With help from Medway Council, a grant was secured from the Office of the Deputy Prime Minister (now Department of Communities and Local Government) to clear up an area of substantial copper contamination.

The saline lagoon habitat originally developed as a by-product of the dredging activity, whereby the old clay pits had marine or estuary dredgings pumped into them in a solution of estuary water. This led to the formation of large, deep and often featureless saline lagoons. Because of the high conservation status of the habitat, specialist saline lagoon ecologists were consulted to improve these as part of the restoration planning process.

The restoration aims to create a complex of mixed depth saline lagoons and brackish pools where birds can feed. Within this, islands and shallow margins will be formed for nesting and roosting birds. This work will increase the value of the site for wintering, passage, and in particular breeding water birds, while maintaining and improving its value for the specialist saline lagoon invertebrate species. Installing mechanisms to control and manage water levels within the brackish pools and lagoons will enhance them further.

Restoration will be achieved primarily through:

  • Targeted disposal of dredgings to infill existing saline lagoons; to reduce their depth to increase feeding habitat for waterfowl; and to create nesting islands.
  • Creation of shallow margins through re-profiling of the edges of currently deep lagoons to provide open and vegetated margins.
  • Creation of additional islands through isolation and re-profiling of existing causeways and, if practicable, excavation of areas in the northernmost brackish pools.

Deeper areas will be retained to help maintain more stable salinities within the shallower areas of these water bodies.

The rate of restoration largely depends on the quantity and type of dredging being deposited at the site and this will determine priority for the order of work. When only small to medium quantities of dredgings are available, priority will be to deposit them in areas with a lower capacity to create islands and shallows. Larger quantities will be deposited in the larger lagoons. In order to protect the lagoon invertebrates, an area has been set aside as a refuge for them.

This approach to the site’s restoration is a good example of a partnership between a conservation charity and a commercial dredging partner that will provide a sustainable use for dredging material.

Public benefits

The restored reserve will form the centrepiece of a flagship environmental project for North Kent and the Thames Gateway that will attract 40,000+ visitors per annum.

The RSPB is taking a phased approach to the delivery of this major project. Initial phases have included habitat enhancement work and the development of visitor facilities. New paths were created and existing ones upgraded, along with several new viewing mounds and watch points. This is one of a number of projects that Waste Recycling Environmental Ltd (WREN) helped fund.

WREN has supported various elements of work at Cliffe Pools Nature Reserve, using Landfill Tax Credits of Waste Recycling Group Ltd (WRG) under the Landfill Communities Fund (formerly the Landfill Tax Credit Scheme). All of the projects funded by WREN have improved visitor access to the reserve and the important heritage it supports. An RSPB Project Officer was employed to work with the local community, helping enhance the environment and green tourism in the local communities around the reserve. Medway Council and The Medway and Swale Estuary Partnership supported this post financially.

With the support of SEEDA (South East England Development Agency), the RSPB have opened a new car park and entrance which has provided safe parking for the first time. In the same year the Douglas Glanfield Memorial Trust and Bernard Sunley Charitable Foundation provided the funding for interpretation and signage. SEEDA also funded a three year project management post to deliver these improvements and develop detailed plans for the site.  These include new hides and a reception area along with facilities to enable the delivery of an outdoor education programme and to encourage lifelong learning, leading to greater involvement among local people and promoting long-term sustainable use of the area.