Thames Young Mariners, Riverside Drive, TW10 7RX Planning application 22/3139/FUL


Application 22/3139/FUL

During April this year, we visited the expo at the Thames Young Mariners who were expounding their vision for expansion..... We fed back our views and now we are trying to match this to a planning application that has just been submitted.

Demolition of existing buildings and construction of replacement buildings with associated residential accommodation, changing block, replacement staff accommodation and outdoor activity equipment including high ropes, climbing wall, coasteering course, supporting pontoons with associated hard and soft landscaping and parking.


For eighteen years, I was the volunteer wildlife ranger on Ham Lands, which crossed over into the Mariners site. Back in the day, it was considered a 'reservoir' for wildlife, especially for slow worms & badgers as well as a nesting site for kingfishers and a large stand of bee orchids. I used to monitor - amongst other things - the birds and butterflies - and a file was kept in the office to enter sitings.

Gradually, this special site become fenced and it has been difficult  to monitor, but it is apparent that many trees have been felled, the orchid colony area is now used as a forest school, and an intensification of use has degraded the habitat. 

So, the planning application provides an opportunity to address the six large stands of non-native invasive species such as Japanese knotweed, Norway maple, goat's rue and snowberry. Dead wood is burnt in fire pits, the under storey is poor due to  the ground being very compacted, where grow chiefly hybrid bluebells and cow parsley.

During the April expo, we were told that the buildings are not fit for purpose and that the new build will be 500 sq.m. bigger than present, with the enlarged area coming from existing hard standing. That sounds fairly benign doesn't it?  Until reading the planning application. 

According to the DAS  (Design and Access Statement) the existing gross internal area is 1795.95 and the proposes total gross area appears to be very much a movable feast.Whatever their configuration, the buildings will be two storey and will have a considerable impact on the immediate landscape, especially from the light pollution from windows.

Bat surveys

Whilst the existing buildings, have low potential for bat ingress, with roofs covered with bitumen felt (see above) and the UVPC fittings offer little by way of encouraging  bat ingress, a one night post - breeding bat survey is hardly sufficient.

There are many tree holes on the site - if not already removed by tree works that have been extending the fishing swims - and I note bat boxes on some of the trees. If any of the newly installed activities, remove vegetation, fragment tree lines, impact on foraging areas, or cast light on these areas then a wider landscape scale bat survey should have been implemented, given the large water body, broad-leaved woodland  and good connections to other designated sites. 

But the  surveys should have considered that the ecology of the site not just the minimalist question of whether bats were using the buildings. Most importantly, it should have considered the impact on the surrounding nature reserve, Ham Lands.

The Preliminary Ecological Assessment (Surrey Wildlife Trust November 2020) has not been submitted with the documents according to the list on the planning file. I would like to see their recommendations. This might lead us to wonder if the Middlemarch winter survey had been carried out during the growing season might we see more Biodiversity Net Gain.

Interesting that this development has been planned for some time yet the bat survey was post - breeding, the PEA November and the walkover February. It did not place static bat detection equipment within the lake area to see whether Myotis bats visited the site.

Evidence base

I can see no discussion on the impact of this scheme on protected species or the invertebrates that will be affected by the intensification of use at this site. As the built environment increases both in height and footprint so does the urban gradient. The taller buildings will increase the light pollution at the site. This increase is widely known to haemorrhage species. There is a vast body of work on the effect of this increase on all wildlife receptors but especially on bats, as it is said that even an increase to 60% urban gradient will lead to a decrease in pipistrelle bat activity (when considering the urban gradient or the built environment, lighting always plays a part).

Birds and bats are often  reduced in their activity due to a reduction of insect species. Artificial light at night (ALAN) is changing in quality due to the installation of white LED street lighting. The disturbance of aquatic habitats by ALAN is of particular concern as human settlements and activities are often located near water bodies, and many aquatic species
are sensitive to ALAN.

Focusing on adult aquatic insects, an experimental approach was employed in the riparian zone of a structurally simplified river within a dark rural landscape. Two studies were used to (a) estimate the magnitude of the capture effect of white LED lamps and (b) to explore how captures at lamps vary with their distance from the river. Both studies sampled mayflies, caddis flies  and true flies repeatedly during mid-to-late summer using modified flight intercept traps positioned adjacent to portable LED lamps. In Study A, lit traps were paired with unlit controls. In Study B,lit traps were positioned at six distances up to a maximum of 80 m from the stream edge. For each of the three study orders, captures were significantly higher in the lit treatment compared to the dark control, with medium to large effect sizes.

For all study orders, captures at lamps significantly reduced with increasing distance from the river edge. Rapid declines in captures were recorded for mayflies (from 10 m) and Ecaddis flies (40 m), with a more gradual decline in true flies from 60 m that continued up to the maximum sample distance. Previous research indicates that LED lighting can be less attractive to flying insects than broader spectrum alternatives. However, this study demonstrates that the effects of white LED lamps on flying adult aquatic insects should not be dismissed. The study concludes that as a precautionary approach, and until finer recommendations are available, we recommend that LED lamps should be excluded from a buffer zone of ca. 40–60 m around rivers*. That is a lot and is already enshrined within Richmonds Biodiversity Action Plan.

LED lighting threatens adult aquatic insects: Impact magnitude and distance thresholds D. Carannante et al.

It is difficult to find any information regarding the lighting that will be used in the scheme, the final pages of the Sustainability Statement Atkins attest: -
'5.9.3. Light Pollution'
High efficiency internal and external lighting will be used throughout the development in conjunction with alighting control system incorporating daylight and presence detection as appropriate. This will ensure that lights are switched off when not required to minimise light pollution.
So where is the lighting statement pertaining to bat conservation along these lines?
Features used by bats must not be subjected to light spillage or they may refrain from using corridors.
All bat species are adversely affected by the lighting of roost access;
Most bat species are adversely affected by the lighting of foraging areas;

Bats do not ‘go to sleep’ for the whole period of the winter. They emerge for the purpose of drinking every ten days on average. This means that they often hibernate near water and may use riparian trees for this purpose.
They will also emerge to feed during mild spells and will head for water where insect food is guaranteed. The Habitats Regulations (2009) states that it is an offence to ‘impair the ability of bats to hibernate’, which should include their known natural tendency to gravitate towards humid areas.

Additional material species

The staff themselves attest to three month visitations of grey Atlantic and harbour seals that haul out onto the pontoons. The latter is on S41 of the NERC Act and therefore material within the planning process.

and what of the slow worms.......... This application reads as a history of what we cannot do on the site which rather obfuscates the details of what is actually planned. There is no detail on the light fixtures and the impact of light pollution. It fails to discuss the impact on the sites receptors because the work was undertaken at the wrong time of year. It has been poorly presented and the impacts particularly on Ham Lands Nature Reserve have not been evaluated.


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