Seething Wells: Drainage of the Filter Beds, 2011

During 2011, the Filter Beds were drained for the purpose of 'inspecting the structure of the basins'. Whilst destroying  the breeding  habitat of 5% of the County little grebe population as well as Nationally Rare and County Notable invertebrates, it  allowed an interesting mosaic of habitats to be created. These included wet grassland, wet mud and reedbed. Reedbed is a national priority habitat.It is important for a host of rare species and it is very scarce in our borough. The reeds were a mixture of phragmites and lesser typha Typha angustifolia, the latter being less well known in the London Region. For example, we have reedbed in Chessington, which was found to be a roost site of c50 reed the time the largest known County roost site. At the time of writing the reedbed has been destroyed, cut reeds have been piled up in the platforms between the beds and dead reeds are floating in the water.

Of the  mosaic of habitats apparent during August wet grassland areas incorporated 3 persicaria species including pale persicaria Persicaria lapathifolia, previously recorded at only 6 sites across the borough.These plants can be important for seed eating birds especially post-breeding autumn flocks including sparrows, finches and linnets. The latter are a bird once regularly recorded in many areas of the borough, including the cemetery but are now confined to the green belt farmland. This habitat would have been ideal for them had it not bee removed by heavy machinery during October, 2011.

Watch out for lapwings, either foraging in the newly created wet mud, especially around the margins of the vegetation or roosting in large numbers as weather gets colder. We have recorded flocks of up to 200 birds during the winter months and they often swoop and cry over the Portsmouth Road when disturbed. If you cannot see them on a cold night when walking along the Portsmouth road, listen for their pee...wit....

Please let me know if you see any vegetation works on the filter beds. Some of the habitat changes could damage the site forever. Removal of some vegetation could be contrary to the Habitats Regulations (see emerging entries on the bat interest). Allowing vegetation to develop in the vertical brickwork of the sloping sides of the basins, is an obvious way of destroying the future viability of this location as a heritage site.


  1. You should be aware that these filter beds have been drained again (Jan 2018)

  2. Thanks we know about the draining - look out for the lapwings and little egret that are enjoying the muddy pools


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