Project background

The Rye Brook is classed as having ‘Moderate’ ecological status according to the Water Framework Directive and for some time the River Mole Catchment Partnership has been working towards getting the Brook to ‘Good  ecological Potential’, but this is a long and complicated task. You can find out more about the status of the Rye Brook here.

The main categories that the Rye is scoring poorly on are Biological quality elements and some of the Priority hazardous substances. In 2017, the South East Rivers Trust (SERT) completed a survey which identified a series of barriers to fish migration, meaning several species can’t reach valuable habitat upstream. In 2022 the Friends of Ashtead Rye Meadows commissioned a contractor to design a restoration project in Centenary field to improve the habitat for Fish and other species.

Aims of this project

The aim of this project is to produce designs which will:

• make all the barriers in SERT’s 2017 report passable to fish.

• improve the habitat through Centenary Field and Kestrel Fields where the Brook has been made unnaturally straight

• restore the function of the M25 and A243 balancing pond, so that it filters the road runoff before it enters the Rye Brook

If we are able to implement these designs, this will contribute to improving the ecological status of the Rye Brook and reduce the concentration of Priority hazardous substances, getting us a couple of steps closer to reaching good ecological potential according to the Water Framework Directive.

(To read more download the pdf from https://www.surreywildlifetrust.org/sites/default/files/2025-10/Rye%20Brook%20Consultation%20-%20Details%20and%20Designs.pdf)

With regard to Centenary Field the proposed scheme will be to re-establish meanders and remove natural and man-made weirs which impede fish traffic upstream. In addition it will also be to remove the collapsing brick culvert repurposing the bricks in a rock ramp to make barrier 4 passable. (See Diagram below from Consultation)