It has been a planning aim for some time of Croydon Council to open up the stretch of Norbury Brook that runs through Norbury Park. This has also been wish expressed in various consultations in recent years.
The Environment Agency is currently preparing proposals to open up (deculvert) the stretch of Norbury Brook that goes through Norbury Park as wide of a wider exercise to reduce flooding from the Brook as it flows through Thornton Heath and Norbury on its way to become the River Graveney. It is one of many projects around the country looking at deculverting rivers and streams. It decided to hold a meeting on 6 July with representatives of local groups because of the master planning exercise for Norbury Park that the Council has commissioned, and which the 19 August event is part of.
Environment Agency Meeting 6 July
The meeting was attended by Norbury Brook Alliance, Norbury Allotments Society, Friends of Norbury Park, Manor Farm group, Friends of Thornton Heath Recreation, Thornton Heath Community Action Team, and Love Norbury. As Norbury Brook lies within the Wandle Valley Regional Park area, representatives of the Wildlife and Wandle Trusts were also present.
The Environment Agency spoke about its work and why deculverting could help reduce flooding and showed examples of schemes elsewhere. There were floods on the River Graveney and the Brook in 1928, 1937, 1968 and 1981. The area is therefore regarded as a flood risk one suitable for investigation as to preventative action. The Wandle Trust spoke about the work that opened up the Wandle through Wandle Park. Different stretches of the Brook pose different problems, which will affect potential solutions. Ideas were discussed as to what could happen.
The Agency is now working up options for consultation and then will cost potential solutions and try and line them up with the Park master plan. One possibility for the Park is to include a water storage area underground. The cosmetic side (tree and other planting, etc) are not funded from Government grant to the Agency and would require other sources of funding, which the Council and local groups could help with. The timetable is that if a scheme is viable and fundable the Agency envisages submitting a planning application in September 2018, with implementation if approved in autumn 2019 or early 2020.
One issue was left as a quandry, the fact that sections of Thames Water’s drainage system go into the Brook, and that excess surface water is becoming a problem especially with the Council unable to prevent non-permeable front garden driveways. A storm drain flows into to allotments section of the Brook.
2008 Pre-feasibility Study
Towards the end of the discussion it was mentioned that in 2008 the Environment Agency published the Norbury Park River Restoration Pre-feasibility Study produced by a team of consultants. The Agency has now made that report available. The rest of this blog posting and the ones that follow provide a summary and extracts from it. The full report, which includes detailed maps showing the different ways in which the Brook could flow can be seen here:
Assessment of Outline Options
The Study assessed outline options for restoring or re-naturalising the Brook which flows through in a culvert and concrete channel. This was done assessed according to their ability:
- to improve the morphological and habitat quality of the Brook
- to increase the biodiversity and amenity value of the Park
- to enhance opportunities for flood storage within the Park
- to contribute towards the delivery of London river restoration policies and key objectives from the Thames Catchment Flood Management Plan
- to contribute towards the delivery of key Water Framework Directive (WFD) objectives
The consultants recommended that the existing culvert and concrete channel should be replaced with a new meandering channel which crosses the Park.
‘This channel should have a natural platform and bank profile and accommodate a diverse range of conditions capable of supporting a range of in-channel and riparian habitats. This will provide the opportunity for BAP habitats such as reed beds and standing water to be established. The channel will provide a reduced level of flood risk within the catchment through an increase in capacity together with the benefit of a flood bund located’ within and around the edge of the park … and that enhancement works are undertaken within the channel immediately upstream of the park.’
The way it flows through the Park within two concrete-lined channels, a culvert, and a short open reach high, steep sides fenced off to prevent public access to the watercourse, means that the Brook is ‘disconnected from both the wider environment and the local community and is currently of low habitat value.’
The consultants pointed out that ‘In addition to achieving biodiversity gains, previous studies have demonstrated that river restoration schemes undertaken in public parks have also resulted in considerable increases in visitor numbers and public participation in those areas.’ They evidenced the 78% increase the visits to Sutcliffe Park in Eltham increased by 78% following restoration works on the River Quaggy.
They anticipated that the works they proposed would enhance the Park for the benefit of the wider environment and the local community.
To be continued