Management Plan for Chiswick Eyot
Managing Historic Assets and Wildlife Habitat
The following consensus was arrived at between OCPS and Thames 21
in November 2011. It is based on discussion of two documents about the Eyot:
1. OCPS: Significance as a Historic Withy Bed
2. Thames 21: Habitat Management Plan
Objectives and Methodologies
1. Slowing down erosion of the Eyot
This is to be achieved by stabilising the banks of the island.
Methodology:
as per T21 Habitat Management Plan (i) to create and (ii) to maintain soft engineered revetments from natural materials including withies from pollarding the Eyot’s osiers.
Task (i) creation of revetments
Lead body: Thames 21.
As per Habitat Management Plan.
This is preceded by obtaining necessary consents e.g. Flood Drainage Consent and PLA Works Licence. Also by securing funding to obtain and insert posts.
Then using poles and bundles of withies in the green (fascines) produced by the 2012 annual pollarding (see task 2).
Timing: As soon as possible. It will require synchrony with Pollarding (Objective 2). It is a large project and could take several years to complete.
Task (ii) maintenance of revetments.
Lead body: in the first instance T21 but later could devolve to OCPS once instructed.
Timing: As withies decay fairly readily, the fascines will need ‘topping-up’ each year.
2. Retaining historic significance as an historic withy bed
This is to be achieved by maintaining the low level, even appearance of the willows on the main portion of the Eyot.
Methodology:
as per OCPS Significance document by annual pollarding (and replanting osiers where appropriate) of existing pollards. The withies cut will be bundled and stored in the central corral to be used for Tasks 1(i) and 1(ii) above. The poles cut uniquely in Feb 2012 will also be stored to be used in Task 1(i) above.
Lead body:
OCPS but Thames 21 to supply guidance on bundling.
Timing: Annually in February
3. Increasing biodiversity
This is to be achieved by (i) creating conditions for a natural greater diversity of plant growth under the osiers in the historic withy bed. Also by (ii) leading with the goal of increasing biodiversity in the areas of the Eyot not covered by the withy bed.
Lead Body: Thames 21
Methodology:
(i) Litter picking, piling of plant debris, and removing Himalayan balsam as per Thames 21 Habitat Management Plan.
(ii) Methodology for maintaining mature trees/shrubs at either ends of Eyot and existing reed beds to be devised by Thames 21.
Timing: as appropriate in the non-breeding season.
4. Encouraging community involvement whilst safeguarding stability, historic significance and biodiversity
This is to be achieved by (i) improving intellectual access and (ii) encouraging wider but controlled physical access.
Lead Body: Both OCPS and Thames 21
Methodology:
(i) OCPS: to devise intellectual means e.g. by providing interpretation board, talks etc.
(ii) OCPS + T21: to avoid accidents but minimise uncontrolled access, improve physical access in an area not visible from the Draw Dock.
To engage community in unavoidable physical access for pollarding, litter picking, debris removal, bank stabilisation and increasing biodiversity
Management of Chiswick Eyot Update 2012
Managing Historic Assets and Wildlife Habitat
Points from Progress Meeting 14 Dec 2012
OCPS and Thames 21 together with Tony Wileman of LWT (London Wildlife Trust)
1. Slowing down erosion of the Eyot by stabilising the banks of the island.
Two rows of a 25m length of ‘soft engineered’ revetment had been created over the year on the North bank facing the draw dock using bought in (some by T21, some by OCPS) stakes, and then interweaving and backfilling with bundles of withies pollarded from the Eyot. It would appear that this was beginning to trap mud and so was succeeding in its aim. More monitoring was needed. It was reiterated that the revetments once completed would need annual maintenance, particularly topping up with withy bundles.
But it was agreed this rate of completion was too slow to complete the protection of the whole of the North bank and a few areas of the South bank which was needed: erosion and loss of the Eyot without this protection was predicted by TW.
Agreed ethos: To continue to use volunteers as much as possible to consolidate community involvement.
Agreed caveat: Although the corral in which the withy bundles were stored was not a great distance from the entry point of the Eyot, access would be curtailed wherever possible e.g. limited number of persons retrieving bundles in order to minimise erosion and disturbance of wildlife.
Short term plan
The revetment would be continued as far as it was possible to access the bank at low water and as soon as possible. This would be done by T21 organising both Community days in collaboration with OCPS and Corporate days. At present there are sufficient stakes available but there would be insufficient withy bundles pollarded in January for backfilling: more will have to be found. These might be forthcoming from the LWT or LBH. To minimise footfall on the Eyot, could these be dropped off at the draw dock on the day of use?
Long Term Plan
Where it becomes very difficult for volunteers to create the revetment as hard standing is never revealed at low water, it will probably be necessary to get more professional help. Could this be provided by T21 or bought in from a firm such as JR Environmental? Might Section 106 funding from The Fulham Football site development be available? Other possible sources of funding might include SITA, Western Riverside Environmental Fund or even the HLF.
2. Retaining historic significance as an historic withy bed
All concurred with the original decision that the central part of the Eyot should be maintained as a withy bed to retain its historical significance. This would be done by annual pollarding, as in the past, and planting whips (fresh cut stems) in the areas where pollards had disappeared, leaving open ground. The remainder of the withies are to be used as in the past (not abandoned), in this case for the new revetments; the bundles to be stored in the corral. A small number of withies may be retrieved by basket weavers and the charity Roots and Shoots.
There was some concern about how the pollards which were now beyond the pale i.e. outside the recently constructed ‘hedge’ (see 3.below) could be reached for pollarding.
OCPS were liaising with LBH to include the Eyot in the Old Chiswick Conservation Area.
3. Increasing biodiversity
Plant diversity:
In the withy bed: A great deal had been done to this end over the year.
Removing Himalayan Balsam: It had been calculated that 188 person hours had been devoted to this and vast swathes of 7’ high plants had been destroyed. TW depressingly said that in his view this task would have to go on annually indefinitely as there was so much stock of it up river. But CC said he had seen good improvement elsewhere. Apparently there was research afoot to find a biological control.
Removing rubbish: This had been done on a number of days, with the PLA supplying cages to collect it. This system of collection had a number of problems and LBH would probably be asked to help in the coming year instead. Rubbish removal has included removing a layer of broken down polystyrene and old balsam stems. TW said that the depositing of polystyrene on the island showed the flow rate of water over it at the moment was not particularly fast. This meant that the soil exposed by its removal together with the mat of old balsam stems would not lead to greater erosion of the ‘topsoil’ at the present time, and would allow seeds to germinate.
Removing nettles: Nettles were now much more common than they once were on the island. This year only a little removal had been done with the aim of allowing plants which were more abundant in the past to flourish. But TW said the problem was that nettles are one of the few native plants to flourish in these conditions of soils over-enriched with nitrates (ragwort was another). They also attracted insects and their perennial roots (unlike the annual balsam) were helpful in binding the soil. It was decided at present that, where they were preventing essential access, to keep their growth in check, they would be cut back but their roots left in place.
Tree-covered areas at ends of the island: At present it was felt that action was not needed in these areas. TW reported that the types of tree that would flourish best in these areas would be alder, grey willow and goat willow.
Diversity of fauna
TW reported that by far the most important fauna on the Eyot was the colony of snails. It was agreed that he should approach a conchologist from the Conchology Society who had shown great interest in undertaking a survey.
TW reported that the reed beds were at present too small to support nesting reed warblers even though these birds could be observed as visitors. He suggested ways of enlarging the beds, perhaps even by floating islands of reeds. These might present a problem for navigation but could help with silting/anti-erosion.
T21 had recently created ‘dead hedges’ along the North bank of the Eyot for a number of reasons: to act as a safety barrier as there was a steep drop into the mud as some points, to deter footfall in these eroding areas, to clear heavy plant debris from the rest of the withy bed, and most importantly to create hedges for small nesting birds such as robins and wrens which were denied such a habitat by the annual pollarding of the willows. These ‘hedges’ would not be increased in height (so as not to obliterate the view of the withy bed) and would gradually ‘settle down’.
4. Encouraging community involvement whilst safeguarding stability, historic significance and biodiversity
The agreed understanding of the Meeting was that Chiswick Eyot was a ‘unique but fragile space’ and special care is needed to maintain it. This ‘message’ would underlie all communications with the public.
Physical access:
* should always be supervised and restricted to the planned work days of T21 and OCPS.
* numbers at any one time should not be excessive
* in the nesting season (March/April/May), access should be restricted to the outer bank of the North side of the island.
Intellectual access
* OCPS website is to be up and running in 2013 and will be vital in getting the message of ‘unique but fragile’ across. Links with T21’s and the LWT’s websites (and v.v.) are to be included and something about the agreements between OCPS/T21.
* Information Board: A board about the Causeway had been in place for a while with no unfortunate side effects. All agreed that one with the message ‘unique but fragile’ about the Eyot would be helpful in deterring unwonted physical access. Isleworth Ait had one with lots of images; and Hammersmith had two along the riverside, one halfway to and one just after Hammersmith Bridge. Its ongoing upkeep must be factored in. There was a suggestion that Fuller’s might be involved and information about the brewery and Eyot combined on one board. Great thought must be given to its positioning.
Appendix: Useful information which emerged during the Meeting
Oliver’s Ait: TW reported that this was owned and managed by the PLA. It did not flood at high tide (and so destructive Canada geese were able to nest there) and was covered in tall trees, mainly sycamores whose roots were rotting. The ground was polluted with lead and mercury from Victorian industry (particularly a smithy) that had been there. Now the high revetments are being eroded from below and research being undertaken on what next steps could be taken to prevent this.
Isleworth Ait: TW reported that this was owned and managed by Thames Water. It does still have a small withy bed but is mainly tall trees.
Numbers of withy bundles produced p.a.: Pollarding produced about 120 bundles in Feb 2012 when 2 years of growth were cut.
Rate of use of bundles: about 10 bundles per metre needed for backfilling revetment.
Natural regeneration of willows: TW stated that the seeds of the willows probably do not germinate as the ground was too rich in nitrates from pollution.
Reeds: These were ‘common reeds’.
Rodents: Only brown rats likely.
Mitten crabs: T21 reported from a recent seminar that these were now in competition with crayfish so it is to be hoped their numbers might diminish. They were ubiquitous in fresh, brackish and salt water. It was the female gonads which were the delicacy.
LBH: All matters concerning the environment had been outsourced and those concerning the natural environment were with Chris Slack at Continental Landscapes Ltd. T21 reported they had liaised with him and he had approved of the T21 2013 work plan for the Eyot.