The following general information and history of Weir Wood Reservoir is largely based on “Birds of Weir Wood Reservoir 1954 – 1989” by Barbara M. Mortlock who kindly gave permission for its use.
Weir Wood Reservoir is situated on the northern edge of Ashdown Forest on the East Sussex border. In addition to the reservoir, the area contains scrub and woodland which have grown up since the reservoir was created.
Before human intervention, the reservoir was a valley of the River Medway. By their nature, river valleys are ancient sites, and this valley is no exception. The warmer, wetter climate that followed the last glaciation meant a much greater flow of water in the river. Thus sometime between 6000 and 2300 BC, when people of the Middle Stone Age hunted in the area they might have seen a broad deep river filling the valley, closely surrounded by a thick forest of oak and alder. Two Mesolithic flint implements were found in the exceptionally dry conditions of 1976, showing that people were in the area. One was picked up on the eastern edge of Admirals Wood and the other at a point on the opposite bank. Both were small cutting tools of primitive design.
There is a great gap in the records until the use of the site as an iron works in Roman times. A large slagheap at Walesbeech (beside an inlet on the south bank) marks the precise location. The slag was the residue of an iron smelter or bloomery, which may have been worked for a period sometime between 70 and 210 AD. There was also a late 16th Century iron furnace and forge named “Stone” located by the river at a site now under the west end of the reservoir; furnace slag and forge residue can be found nearby when water levels are low. More information about these sites can be viewed in an illustrated article by clicking the link Iron making Industry.
After this time, when the site lost commercial use, agriculture eventually took over, lasting until the land was purchased for the construction of the reservoir which began in 1951. This was completed in 1952 and the reservoir was filled with water in 1953.
The map above shows Weir Wood as it would have been in about 1860, with the reservoir overlaid in blue.
Weir Wood Reservoir is currently owned by Southern Water who, with various other authorities, have acknowledged its special wildlife value (see below).
Water area – 113 hectares (279 acres)
Maximum depth – 11 metres (36 feet)
Maximum capacity – 1,237,000,000 gallons
Extract capacity – 3,000,000 gallons per day
Nature Reserve area – 152 hectares
Bird Sanctuary (restricted access) – 33 hectares
Water area in the Sanctuary – 19 hectares (when full)
The Nature Reserve
In addition to the reservoir, there are various natural habitats. These include water meadows, marsh, pools, reed and stream beds, hedgerows, mature and coppice woodland. There is also a heronry visible from the hide, usually containing more than 20 nests.
Because of the rich community of breeding, migrating and wintering birds the whole reservoir was declared a Site of Special Scientific Interest (SSSI) in 1966. The western end was classified as a Local Nature Reserve (LNR) in 1988 and in 1994 it was decided to extend the Nature Reserve to cover the whole SSSI. The west end remains a bird sanctuary with restricted access. East Sussex County Council (ESCC) now manages the SSSI in consultation with Natural England and input from the Friends.
Surveys have identified:
- 200 plant species, including some uncommon or rare in Sussex such as Orange Foxtail and Shore-weed
- 257 species of bird
- 28 species of butterfly, including White Admiral and Purple Emperor (both sometimes seen near the hide)
- 17 species of damselfly and dragonfly
- 140 species of moth.
Also seen are three species of deer, mice and voles, snakes and many insect species.
More than 160 nest boxes are maintained in the reserve for species ranging from Blue Tits to Stock Doves, Mandarin Ducks and Barn & Tawny Owls. Two artificial Otter holts were built some years ago and two more in 2010 (no evidence yet of occupation, but still hoping). There are presently three rafts which have been constructed specifically for nesting Terns, and an artificial bank to try and attract nesting Kingfishers.