Wednesday, 23 November 2016

More urban rivers: The Ravensborne

Deptford creek
Deptford creek
River restoration has been a topic of recent posts, the Ravenborne was amongst the first river in the region undergo this treatment. European LIFE funding as part of a massive urban renewal project has regenerated the centre of Lewisham.

At low tide, it is possible to walk along Deptford Creek, where the Ravensborne ends its journey to the Thames. Here riparian developments have led to some interesting planning gain (on the Lewisham rather than the Greenwich side).
new terraces
terraces topped by sand martin bank
Sheet piling may be the cheapest way of protecting the bank or freeboard but this is useless for wildlife. The  best option is some form of terracing but this is expensive and often tricky to match to the vagaries of tidal water. When properly undertaken and well managed to remove invasive species, the terraces give rise to excellent habitat for plants and fauna of brackish water, where some unusual species have been recorded including a hybrid between Japanese knotweed and Russian vine (pictured). So far only one additional specimen has been identified, at Railway Fields, so it is likely further examples will be recorded.

 Hybrid between Japanese knotweed and Russian vine
Pumping Station
 This 'made' habitat can be managed by groups such as the Creekside Centre, who assist in promoting best pratice and achieving suitable design solutions. It is met with differing levels of enthusiam from developers; the latest pictured above- reaching a great level of sophistication- as architects realise that this is a way of gaining good publicity for their work.

 A view of a Victorian station - pumping sewage up to Bazalgettes southern outfall- a reminder that the Thames Tideway spoil soil is being treated nearby.

Cornmill meadows

Catford SUDs where the Environment Agency have installed a pump that will demonstrate groundwater flow.

Sunday, 13 November 2016

Kingston Cemetery Fungi

Dryads saddle on horse chestnut
Fairy ring
Its rather late in the year to be looking for fungi; the dry autumn and the long grass have meant there has not been much to see. Whilst some species benefit from infrequent mowing - others  do not - wax caps and the corals definitely prefer the shorter, warmer grass. 

Wax cap sp.
Honey fungus
Some birds prefer shorter grass as they find ants on shorter turf, which is exactly where we found the droppings of the green woodpecker, which resembles a burnt out cigarette (see photo).  
Most of the fungi therefore was located on the boles or stumps of old trees such as the honey fungus on the tree outside the Dawson Road gate- no sign of the orange peel fungus that was present last year. The Inonotus hispidus on the ash with the many woodpecker holes (walk in the main gate and turn left).

Green woodpecker dropping
Honey fungus Fishponds
These are all important contributors to the web of life and it was possible to see the fungus gnats flying in the warmer temperatures- as well as spiderlings - that had set up some opportunistic webs around the upturned gills of a late honey fungus found at the Fishponds.

A total of thirteen species was recorded a much reduced number than before (see post 29.10.14 -19.11.14).

Friday, 21 October 2016

Rainscapes in LB Enfield

Following the London Urban Water Management Conference, Thames21 and Enfield Council  organised a tour of the Rainscapes last Tuesday. It was great to see the sites in the raw as well as talk to members of the local Friends groups. 

blocked drain and swale
swale leading to cells

Our first stop was at Lonsdale Road and Aimee Felus from Thames 21 and Ian Russel the borough engineer at Enfield council showed us some of the impressive schemes they had colaborated on, that were custom designed to prevent polluted storm water run-off from entering the streams. This included deculverting part of the hidden Glenbrook river along a woodlot . 
Misconnections from sources of sewage entered the river through various outfalls but are hidden under the road. Here they are seen and can be dealt with and the process starts with a boom to hold back the worst excesses of pollutants, most recently this has been cement washed into drains from building works which has left an amount of white deposit. The water enters a network of cells where the reeds and other water plants strip out 28% of the phosphates and 68% of the nitrates. Road run-off enters the system via swells as the drains have been blocked around the site and the pipes removed, reducing maintenance. The water is pushed around a total of six cleansing cells or basins. Bacteria in the soil break down some of the coliforms present.  Healthy plant growth is essential for this to work successfully and the water to be properly purified. This may mean that tree work must be undertaken which can be unpopular with the local community. However as local residents have been familiarised with the project they now actively join management tasks and are proud of this initiative.

'Fish live here' badges
Most people will never know they are walking over one of London's lost rivers and so the project will install interpretation at some point, over the hidden watercourse. There are badges on some of the drain covers stating that the pipe leads directly to a river. The water in the different cells is continuously surveyed and it can be demonstrated that the water quality that leaves cell 6 to enter the stream is of a higher quality than that entering the system at cell 1. 16 gullies were blocked off and diverted through 'swales'.

Blocked gully
Rushes planted along the swale
Elsewhere swales have been created along grass verges to prevent excessive amounts of untreated run-off entering the stream. Gullies are capped (left) along Howsden Road. Reeds are planted in the excavated meandering swales. All verges could be rain gardens.

The main driver for Firs Farm Wetlands, was to reduce floodrisk. The former culverted Moor stream-a tributary of the Pymmes brook- suffered a number of misconnections, which hid sewage until it entered the Pymmes. By creating extensive wetlands and reed beds these can be cleansed (although tests show that the levels of ammonia and nitrates is still high).

Creating the 'quietway'.
stones prevent erosion where water enters
This is Bury Lodge Park a former council depot and site of the new Enfield 'Mini-Holland' cycle route or quietway. The opportunity has been used to continue the SUDs project diverting the run-off from the main road to a series of wetlands. The lighting here will be infra-red so will only be activated when needed.
Alma rd raingarden

Alma rd mural
This is the Alma road raingarden and interpretive mural to enliven the subway wall. This is an area prone to flooding and chosen as suitable for SUDs. In this example the gullies have been blocked and water is diverted into these newly created flower beds. It can be unpopular where it prevents roadside parking and some community benefit should be derived such as street art, which also serves to inform the public about the benefits of these projects.

Upstream art  Is an educational program utilising art to communicate the function and importance of storm drains. UpStream Art gives artists the opportunity to express themselves with semi-permanent public art in the form of a small-scale outdoor storm drain mural. The purpose of UpStream Art is to 'draw attention to the usually discreet concrete and iron infrastructure with the hope that observers stop and think about where the water flows after it enters a storm drain. If residents understand that stormwater flows untreated to creeks, streams, rivers and lakes, then they will be more conscious of potential pollutants that can enter those waterways. This project, along with the involvement of a vibrant art community, is unique and has a positive impact on water quality protection'.

Sunday, 16 October 2016

DEFRA and Natural England come to Tolworth Court Farm Moated Manor

 Elliot gives a team talk
On Friday team members from Natural England and DEFRA,  from  the south-east and London regions, descended on Tolworth Court Farm Moated Manor on an awayday; to assist us with the ongoing management of the site. Elliot gave a tool talk, prior to participants extending the dead hedge along the boundary with the Hogsmill footpath. Materials were procured from a local woodsman who delivered to us before the day began.


Hazel faggots  and stakes were unloaded and taken to an area under where the previous group - a Duke of Edingburgh award scheme- had finished. By the end of the day our compost toilet had a coat of protective paint and the hedge had increased substantially in length.

dead headge
Panisha and Robbie painting the compost loo
Participants were surprised at the amount of bird life present as we watched jays,  woodpeckers and kestrels; as well as a number of small birds such as goldfinches.
Many thanks to participants Panisha, Piotr, Andrew, Claire, Chloe, Corallie, Anna and the two Robbies!

Wednesday, 12 October 2016

Habitat Creation at Hampton Court Park

Members of the Richmond Biodiversity Partnership enjoyed a walkover of the paddocks at Hampton Court Park (aka Home Park) to see the newly created wetland habitats- including  sluices to aid control of the Longford River-  installed over the last two years.

Part of good stewardship of the wildlife in this  oasis- is the control of mink -which are prevalent in this catchment, particularly from the river Mole and our stretch of  the Thames. They have caused havoc with local water vole populations.
male and female mink skins
Male mink

The  skins emphasised the size difference between  the male and female, with the latter able to gain access to a water vole burrow.The wildlife officer demonstrated the use of the mink rafts, which are in use at many wetland sites in  south-west London.

mink raft with the lid off
Eel trap had one elver
This one is missing the roof to demonstrate the wet clay, which serves to reveal footprints of the visiting animals, to warn of the possible presence of mink.

We were told that the rafts are no longer baited with food as they became a magnet for rats, but instead a gland is obtained from America, which once attracted a mink within 20 minutes of being employed.

We were shown the sand martin bank-these are also successfully attracting this declining migrant across south-west London at the London Wetlands Centre and Eel Pie Island.
sand martin bank

Hogsmill Electrofishing

Hogsmill Lane
Over the last two days members of the Environment Agency have been undertaking fish surveys at four locations along the Hogsmill. This is from Hogsmill Lane (just off Villiers Road) to Oakland Way-Chamber Mead KT19 upstream, just  across the borough boundary.

This type of survey is  usually undertaken by boat - although backpacks were used in the shallows upstream at Ewell. Circular electrofishing 'anodes' attract the fish, which swim towards the the charged equipment, where they are stunned but not harmed. They are then decanted to large buckets for further examination or 'processing'.

During the initial survey  at Elmbridge Meadows, a surprising catch of ~100 fish was made in the first of three runs. This is virtually one fish every metre of the ~90m netted area and included: chub, dace, roach, stone loach, gudgeon, stickleback, minnow, bullhead and an eel.

At  Worcester Park Road-Tolworth  A240  a similar number of fish were caught. By far the majority of the minor species were minnows, which were not located in the Ewell site. A rudd caught at this location was a surprise, as it would be more at home in still water, so had probably been introduced or had somehow introduced itself.
Measuring a rudd

The coarse fish are measured and in some cases a scale sample is taken - presumably for DNA analysis. The minor species are not  measured, although it can  be difficult for an untrained eye to tell them from the many young chub - which are measured - and  demonstrate natural recruitment. No perch were located, although there is a shoal below the gauging station at Watersplash Close in Kingston, so maybe they cannot negotiate the weir.

Silver eel about to return to spawn
eel on eel board Hogsmill lane
Fun and games are averted, as the eels are measured by using a special 'eel board'. This prevents some of the larger animals from thrashing around and aids examination of the condition of the animal. Some were transforming into silver eels; laying down fat for the journey to the Sargasso in the Caribbean where they breed. The eel board facilitates gentle return to the water of the animal without too much handling.

Friday, 30 September 2016

Local Rivers Day

Local Rivers Day was held at KEC on Saturday 24th September. Amongst the displays were The Environment Agency on local flood alleviation plans, the Hogmsill Community Garden, the Hogsmill river project, and the London Waterkeeper-Theo Thomas- who campaigns for clean and thriving rivers in parks, including swimming zones created along the our non-tidal stretch section of the Thames, as well as helping to monitor the Hogsmill. 

There was also a magnetic fishing pond complete with mini supermarket trolley created by Danielle O'Shaughnessy for the children.