Rainham Silt Lagoons
Rainham Marshes and Silt Lagoons was owned by the Ministry of Defence and leased to the RSPB. It was then purchased by the RSPB and a section of the land was used to create a nature reserve and education centre in 2000.
The Port of London Authority acquired a long-term licence to dispose of dredged materials into the Lagoons on the remaining area of the site.
The original seven Lagoons were built by the PLA in the 1960’s with a further two being built in 1982.
The filling of these Lagoons with dredged material provided a suitable wetland habitat for over-wintering birds at the time of SSSI designation in 1986. However, dredging ceased in 2009.
Rainham Marshes and Silt Lagoons are designated within the Inner Thames Special Site of Scientific Interest (SSSI), for the populations of breeding and over-wintering birds they support.
The SSSI is adjacent to the River Thames and the RSPB nature reserve lies to the east of the PLA Silt Lagoons.
The SSSI makes up the largest wetland area on the upper Thames and supports a diverse community of bird, plant and insect species. It also contains the most dense population of water voles.
The wider area is part of the Wildspace Initiative, which through its app provides access to the areas surrounding the Lagoons via a guided walk.
The condition of the SSSI began to decline when the disposal of dredged material into the Lagoons ceased. This caused the habitat beginning to dry out and a rough grassland habitat was formed. This habitat was no longer suitable for over-wintering birds but was favoured by raptors and invertebrates.
A restoration plan has been developed in consultation with Natural England and the RSPB to resume disposing of dredged materials into the Lagoons. The aim of the plan is to create a habitat that will fulfil the requirements of the SSSI designation and provide a suitable habitat for a number of bird species. The final plan has been supported by the RSPB, Natural England, the Environment Agency and the London Borough of Havering.
Land and Water Services Ltd have been taken on to carry out operations which will involve initially creating ’pull’ habitats to attract birds away from the site of disposal operations. During this time each Lagoon will be filled independently and the surface will be restored to create a new habitat.
Once the site has been filled to restoration levels the PLA will hand the Lagoons back to the RSPB.
The completed habitat will be a self sustaining mosaic of wetland and higher land with various flora species present. The contours of the completed habitat will be created by building up the silt dredging deposits and a non-permeable clay will then cover the deposits in the wetlands areas and ditches to retain rainwater.
The variation in land elevations and ditch systems, along with the use of permeable and non-permeable material will help to create a wetland habitat suitable for the populations of over-wintering birds in which the site was designated for. The freshwater ditches will also provide an ideal habitat to support the water vole population that is already present at this site.
The success of this project could be largely determined by the return of the over-wintering birds that although have been present in recent years, have been limited in numbers. Although the Lagoons will not be accessible by the public whilst operations are underway, the wildlife can still be seen from the adjacent RSPB site. Subsequently, any bird sightings will be useful in monitoring the recovery of this SSSI.
Page updated Janaury 2022