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 smaller restoration project is now in the planning stages for
2006, to take place 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 2004, there is a picture storyboard available for download
below.