US social scientist Kenneth Boulding : ‘If you believe exponential growth can go on in a finite world, you are either a madman or an economist’.

Tuesday, 9 November 2010

9/11/10: Thames Road Wetland report to Bexley Natural Environment Focus Group

Note: Bexley Natural Environment Focus Group is an interface between Bexley London Borough Council and representatives of conservation organisations operating in the Borough. It is attended by various Councillors and Council Officers. The Group has not previously had a report on Thames Road Wetland (TRW) hence the amount of background detail in this particular report, which I am posting here as it may be of interest to a wider audience. In any event the site is in the hands of the Council, so in the interests of public accountability, here we are .....

But first, some 'Then and now' photos that were not part of the original report:

TRW February 2008. Photograph by, and reproduced with kind permission of, Steve Thoroughgood

TRW September 2008. Photograph by, and reproduced with kind permission of, Steve Thoroughgood

TRW October 2010. View closely matching that of September 2008.

to Bexley Natural Environment Focus Group

From: Chris Rose, Site Manager. 9/11/10.


Owned by Bexley Council. Managed under the auspices of (Thames21) Cray Riverkeeper Volunteers led by Ashe Hurst. I accepted the offer of the role of Site Manager in April 2010.

The site is in Crayford on the London/Kent border, by the lower reaches of the River Cray and was created in part mitigation for the Maiden Lane Roneo-Vickers development. It is an old field bounded by the River Cray to the west, Thames Rd to the north, the Dartford to Slade Green railway line to the east and an embankment with the North West Kent Sewerage pipes in it to the south. It was dug out to below the water table, so stays permanently flooded. The eastern end is transected by the canalised River Wansunt.

I have received no prior records from the developer/contractor ecologists as to species already present, water plants introduced, or what may have been trans-located here. Despite official requests, all I have been given is an outline plan showing ground-works and giving a list of the shrub species planted, so I have had to start from scratch. Steve Thoroughgood has kindly agreed to let me use, in presentations and reports, his pictures of the site from February and September 2008, relatively soon after the site was flooded and planted up, that I came across on Google Earth. The most recent GE imagery itself pre-dates the flooding.


The shrub plantings on parts of the Thames Road bank are largely of species not indigenous to the local area such as Guelder Rose and Wayfaring Tree, or are non-native in the case of Sambucus (tentatively) racemosa (which were supposed to be nigra). These have suffered badly from the drought earlier in the year, being on steeply-sloping gravelly ground.

There are a variety of aquatic plants, becoming dominated by Greater Reedmace, with some small patches of Phragmites australis reed bed (Bexley BAP). Ruderal plants of note are Slender Thistle, Annual Nettle and the recent non-native colonist Narrow-leaved Ragwort.

Other species here that are not especially frequent in this part of the Borough are Common Stork’s-bill, Vervain and White Melilot. The very infrequent plant Dittander occurs in large quantity on the Sewer Embankment and is spreading in the ‘bowl’. Star of Bethlehem was found this spring, but I have yet to determine whether it is the native sub-species (probably a garden escape from spoil). Brookweed (Samolus verlerandi) which I discovered in July is an important record as this may now be its only site in London.

Invertebrates will require specialist recording effort. Hairy Dragonfly, Migrant Hawker, large numbers of Blue-tailed and lesser numbers of Azure Blue Damselfly. Recent additions to the list include Roesel’s Bush Cricket, Long-winged Conehead and Wasp Spider.

Common Lizard – UK and London BAP, Grass Snake - UK and London BAP, Marsh Frogs and Common Newts are present.

Breeding birds – Moorhen (probably), Coot, Little Grebe, Reed Warbler (estimated 6-8 pairs)
Visitors – Grey Heron, Little Egret, various ducks including, most recently, a pair of Teal. Used by Black-headed Gulls from the Council Depot site in winter. Good numbers of Goldfinch are conspicuous at this time of year.

Two Water Vole (UK, London and Bexley BAP species) latrines recently found. Some Rabbit activity, but impact on vegetation small.


This spring contractors belatedly installed hibernacula on the Thames Rd bank without prior consultation with myself or Ashe Hurst, using good quality, cleaned, second-hand bricks (rubble from Maiden Lane might have been a ‘greener’ option). Some Star of Bethlehem will have been destroyed as a result, though they were warned it was there. Previous habitat work was disrupted and had to be restored. This south-facing bank has the most extreme temperature variations, so it is questionable whether hibernacula should have been sited here anyway.

Recent work has involved Reedmace-pulling to create and restore open shallow water. The aim is to retain overall vegetation diversity, increase the amount of Common Reed, submergents and non-reedy emergents such as Starwort and Water Mint, and to increase the variety of Odonata.

Careful ‘weeding’ has been done around the Brookweed to remove Teasel seedlings and some Creeping Buttercup. An adjacent area has had the soil level re-profiled, most of the Buttercup removed and bare ground created. Seed has been harvested from existing plants and scattered in this new area, particularly around the clumps of Rush that Brookweed appears to like growing at the foot of, in a bid to increase the number of plants and size of the area colonised. Further such work will be conducted when other operations in this area have been completed.

On the flat, compacted, gravelly north-east corner of the site, sinuous ditches and ‘dunes’ are being created to provide micro-habitat heterogeneityfor thermophilic and burrowing invertebrates.

To increase the Common Lizard population and enable it to colonise more of the site, corridors of appropriate cover will be created where little exists, and some areas of rank vegetation are being opened up. Cut vegetation has been heaped to create Grass Snake egg-laying sites.

Litter is a continuous, but fairly modest problem. There has been some unauthorised horse grazing, but this may actually help diversify the vegetation on some parts of the site. It is not clear if or how this process might be safely and legitimately facilitated and managed in future.

My intention is to involve members of specialist societies in order to properly record more difficult species groups, and to input management advice. They may also be a source of further volunteer labour. T21 has, however, recently handed down a significant increase in Health and Safety paperwork, which could constrain options. A formal site management plan is in preparation.

Any readers of this report who have interesting records from this site, who would like a guided tour or who would like to help with the management work are invited to contact me.

Occasional reports and photographs regarding the TRW site can be found here:

MY DETAILS: Chris Rose ......

Brought up locally. First class honours degree and an MSc in zoological science, Bristol University. Self-taught field botanist. Also have many years of experience of horticulture and cultivated plants. Recommenced recording all kinds of wildlife – particularly in the north and east of the Borough – in 2004, after a twenty year break.

Member of London Natural History Society, the South London Botanical Institute, Kent Botanical Recording Group and the Kent Reptile and Amphibian Group. In October 2010 helped set up a formal London Amphibian and Reptile Group and became both Reptile Officer and South East London Officer (covering the Boroughs of Bexley, Bromley, Croydon, Greenwich, Lambeth, Lewisham and Southwark). Joined the Bexley Natural Environment Focus Group in September 2010.

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