The Rye Brook is a tributary of the River Mole in Surrey
and flows through Ashtead Common. Over the years, urban and
agricultural development has had a detrimental effect on the Rye
Brook, with the result that it supported little wildlife
and periodically flooded local houses. During Summer 2005, a
major River Restoration Project was undertaken along part of the
Rye Brook on the Common, with support from a number of different
organisations. The aim of our project was to restore natural
processes to the river corridor of the Rye Brook on Ashtead
Common.
River restoration encourages natural processes such as erosion,
the depositing of minerals and occasional flooding. The City of
London employed a river engineer to design a scheme that would
reintroduce meanders to a 390-metre stretch of the river channel
lengthening it to 450 metres and creating the profile found in a
natural watercourse. In 2004 contractors excavated a mosaic of
ponds and scrapes (shallow pools) alongside the new
channel which will fill with water when the Rye
floods over its banks.
The restored Rye Brook provides a variety of freshwater and
wetland habitats, improving the quality of the entire river system
and supporting a diversity of wildlife. The new meanders and
network of ponds and scrapes can hold 2,500m3 of water
and would potentially allow about 1.5 hectares of the Common to
flood. A 250 metre low embankment across the
valley, constructed with material excavated from the
ponds and scrapes (together with the flow control structure -
built by volunteers) now limits water flowing downstream reducing
the 1 in 100 year flood peak flow.
A second smaller restoration project took place 2006, on a
section of the Rye Brook adjacent to the area restored in
2004.
To find out more about the Ashtead Common River Restoration
Project, there is a picture storyboard available for download
below.
Download the Sustainable River Restauration case
study (168kb)
River restoration project photohistory
(1mb)
River restoration
explained (612kb)
River restoration
leaflet (441kb)