The River Ravensbourne and Glassmill Pond

The River Ravensbourne is a tributary of the River Thames, flowing for 17km from its spring in Keston, London Borough of Bromley, to its confluence with the Thames at Deptford. The area around the Ravensbourne is mainly urban and residential. However, it does flow through some greenspaces, including Church House Gardens in Bromley where Glassmill Pond is located. This historic millpond is one of the oldest features in Bromley, associated with one of 11 mills on the Ravensbourne mentioned in the Doomsday Book. Therefore, it holds great heritage value within the area. Originally, Glassmill Pond and the River Ravensbourne were separate waterbodies. However, in 1955 the river was diverted to flow through Glassmill Pond with the aid of two weirs at the inflow and outflow points. While this offered good news at the time, the connection initiative between Glassmill Pond and the River Ravensbourne has also brought some challenges such as flood risk and barriers for wildlife to thrive.

Flood risk and fish barriers

If left without intervention, the pond would eventually silt up completely, significantly reducing water transport through the area and increasing flood risks both locally and upstream. The impoundment weirs at Glassmill Pond also present significant barriers to fish movement through the area, as well as altering the natural flow of the river and reducing the presence of natural river habitats.

Glassmill Pond project details and design

In June 2014, during a public consultation presentation,  we worked with the community and stakeholders to develop a restoration proposal that included an independent river channel separated from the Glassmill Pond, flowing adjacent to the left bank. By separating the River Ravensbourne and Glassmill Pond, the sediment coming down the river should, for the most part, carry on downstream and not deposit in the pond. This should slow down the rate of siltation of the pond and maintain its depth for some longer periods of time.

The river system with new pools and riffles will aim to offer a unique ecosystem that has been missing in this area – one that lives in the memory of some of the local people. The restored pond will add to the public amenity of the area. Furthermore, with the enhanced riparian zones and islands, there will be plenty on offer to support diverse wildlife.

Elsewhere, the removal and modification of the impoundment weirs will restore fish passages through this area of the Ravensbourne, contributing further to the restoration of aquatic biodiversity. Local volunteers will also have the opportunity to contribute to restoration activities through the planting of vegetation around the pond and on the newly created bund (containment system), as well as through the implementation of long-term site management.

Upcoming activities

Tree works and vegetation management activities will take place this winter (2022/23) to prepare the site for the upcoming restoration works. This will allow more sunlight into the new channel and thus the establishment of bankside and in-channel vegetation that will support a wider diversity of species. In addition, the obtained material will be utilized in the construction works and in creating structures in the new river  to increase habitat diversity for aquatic species.

For more information please contact:

River Restoration Officer Miguel Sanabria – miguel.sanabria@thames21.org.uk

or

River Restoration Manager Carolina Pinto- carolina.pinto@thames21.org.uk

We would like to thank all of our partners for all their support.