Eastbury’s Flood Alleviation Scheme (FAS) was designed by the Environment Agency (EA) and opened in June 2015. It was a joint venture between the village of Eastbury, West Berkshire Council and the EA.
The FAS consists of a throttle (in the river course) and a bund across the adjacent fields – think of it as a dam with a big open letter box at river bed level (Fig 1 at the foot of the post). The letter-box opening is designed to allow the river to pass unhindered if it is flowing normally. If the river flow increases above this ‘normal’ level, excess water will be held back as it can’t all get through the gap.
Contrary to popular belief, there is no adjustment available on a day-to-day basis. The scheme is self regulating and can only be adjusted (fine tuned) in the dry season with the agreement of the EA. As river flow returns to normal the levels will equalise on either side of the structure.
The FAS also has a limit on storage capacity and the design took local geography into account. Simply put, the storage area uses the old water meadows, extending upstream from the bund to just short of the Bockhampton Pumping Station and bounded to the North by the main road (the EA, quite rightly, will not allow any flood scheme to adversely affect adjacent communities). If this limit were ever to be reached, the water would simply flow over the top of the bund and Eastbury would lose any further protection (Fig 2). The Eastbury Scheme cannot cause Bockhampton, Lambourn or East Garston to flood.
Environmental enhancements around the scheme include woody structures in the river bed to create a meandering effect for wildlife and embedded rocks in the throttle to act as a fish pass. Rooksnest kindly allowed the scheme to be built on their land near where historic sluice gates once stood but the whole area remains private property and, for this and for reasons of safety, is not open to the public.
This article is based on one written by the Eastbury Village Warden James Potter, who also kindly supplied the photograph of the opening ceremony in June 2015 and the diagrams.