Twickenham Riverside Terrace Group

A riverside in trust for the community

Press Release: Biodiversity Study of Twickenham Poolsite

Press Release: Biodiversity study of Twickenham Poolsite

While the site has lain undisturbed, it has become home to a variety of endemic and exotic plant species. Further research and modelling is required, and these findings underscore the need for an Environmental Impact Assessment of the site (which the previous Council refused to carry out).

Twickenham Riverside Environmental Audit Meeting

The Terrace Garden Group, in conjunction with the Riverside Coordination Group, recently had the opportunity to gain an insight into to the potential biodiversity along the Twickenham riverside when the initial results of investigations were presented to an Environmental subgroup.

The Twickenham Pool site has apparently been under the watchful eye of ecological researchers for some time, with interesting results, not least of which is that their findings add more weight to the argument that an Environmental Impact Assessment (EIA) should have been prepared as part of the Dawnay Day Planning application.

Biodiversity Survey: summary of findings
The abandoned Baths site is, after 22 years, a refuge for urban wildlife – having been colonised by endemic and exotic plant species alongside the original planted varieties. Unusual, less competitive species are able to gain a foothold by the prevention of ‘crowding out’ by fast growing ruderal or weedy species.

A survey conducted on the site over some fifteen years has shown the regeneration of a significant, biodiverse river foreshore and riverbank site. Some 85 species of plants have been recorded. The biodiverse environment provides feeding grounds and habitats for traditional riverside wildlife, including bats, that exist in notably heavier concentrations that elsewhere along the riverbank.

Importantly, exotics that have invaded other river-side sites have not flourished on this site, leaving the native, local Thames-side species to regenerate. The site has remained relatively uncontaminated by fertilisers and other water-bourn materials carried from upstream.

All species on the site are essential for the regeneration of locally adapted flora along the local river banks and hence, eventually, will lead to more sustainable populations of local flora, fowl and fauna. The range and locally adapted characteristics of the species are crucial for the future well-being of Richmond’s river-foreshores.

Impact of redevelopment on the Twickenham Baths Site
The Dawnay Day scheme (now subject to a forthcoming Public Inquiry) proposes a large development that rises up to 15 metres (roughly equivalent to 5 storeys) above Embankment level, and would go down to a depth of more than 7 meters (roughly equivalent to two storeys) below the Embankment level.

As no Environmental Impact Assessment was prepared, no assessment was done as to the physical impact of such a construction project. No calculations were provided to show the likely displacement of the river bed adjacent to the building. The weight of water in the tidal Thames immediately in front of the proposed building varies with the tide.

Without a consistent weight of water, it can be argued that a building of the size proposed, that will be built into the river foreshore, river bank and flood plain, is likely to cause heave in the river bed. In the particular circumstances of the site, where the main navigation channel passes on the other side of Eel Pie Island, the consequence of even a few millimetres of heave will be, briefly:

  • the diversion of more water around the far side of the Island
  • the slowing of the water current on the Twickenham side
  • the deposition of silt with a slower current
  • the silting up of the Twickenham channel
  • the decreasing of Richmond’s overall flood capacity.

Without extensive research, including an hydraulic model, this effect can neither be accurately predicted nor calculated.

Wind tunnels
The construction of a large buildings right up to the boundaries of the site will channel wind down Wharf and Water Lanes. The effect on the river and Eel Pie island has not been calculated. There may be safety implications for rowers, especially those who are learning.

Noise levels
Trees disperse sound. The removal of trees from within the site could lead to increased noise levels for Eel Pie Island residents and others in Water and Wharf Lanes, and the flats in King Street. The effects have not been assessed.

Opportunities
The Terrace Garden Group believes that the new information on the range of species of plant and wild life to be found on the site reinforces their idea of undertaking only the minimum of works to open up the site for public access, as represented by the existing Planning Permission held by the group and as currently being updated.

These ideas include:-

  1. Biodiversity in the urban context
    Some of the scientific experts who carried out the survey would like to see the Baths site become an example of the regeneration of biodiversity in the urban environment, having an important educational function in bring school children and others back in touch with nature.
  2. Riparian Plants: regeneration programme
    The site could perhaps, with a little work, become the source of riparian plants made available to the public. An important initiative could be commenced by the Group almost immediately, perhaps in partnership with Kew Gardens, for a regeneration programme of a wide range of local riverside species and, in time, the controlled regeneration of the river banks. The site could become a show site, providing an example to other riparian boroughs.
  3. An Educational Landscape, Plant and Wildlife Management Regime
    The Terrace Garden Group’s proposals can and will be adapted to incorporate the findings from the Biological Diversity Survey
Illustration by Martin Stearman of how a green approach to the pool could look.

A green approach

This illustration shows how the differing requirements for retention of buildings, plants and wild life, and public access could be integrated.

Next Steps
When the scientific information is properly collated and formatted the Terrace Garden Group will make it available to the Council for inclusion in their considerations as to the future of the Riverside Baths site, together with the offer to the Council by the Twickenham Riverside Terrace Garden Trust to implement, with the new Council’s assistance, our proposals to ensure early and continued public access to this important riverside site.

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