Tagged: Hogsmill River

Hogsmill River Biodiversity Update

London Zoo hosted the annual Hogsmill Forum, where professionals and volunteers including members of the Kingston University Biodiversity Action Group discussed issues faced by the Hogsmill River – a tributary of the Thames River which flows along the boundary of the Kingston School of Art. Discussions focused on how to implement solutions to improve the river. The South East Rivers Trust updated on issues relating to important catchment plans for the Hogsmill. The aim of the meeting was to improve communications between volunteers and the main agencies and groups working on the river and to support development of volunteer work in the river catchment.


A monthly Hogsmill Newsletter summarises the results of River Monitoring Initiative (RMI) sampling on the Hogsmill in February, together with other pollution monitoring and other river-related activities and events – click through to this link to access the PDF newsletter to find out more.

River Monitoring Initiative (RMI) is a national scheme for monitoring the health of rivers. Volunteers undertake regular surveys using a standard net sampling technique to count the number of certain “water quality sensitive” invertebrates. An overall “score” is then calculated. A sharp fall or a drop below a “trigger” level could indicate pollution. This can then be reported to the Environment Agency (EA) to enable further investigation. Misconnected wastewater pipes and cross-connected sewers are a major source of pollution in the Hogsmill. Under a Pollution Patrol scheme organised by the South East Rivers Trust (SERT), volunteers undertake regular assessments of the outfalls thought most susceptible to pollution, the results being reported to EA and Thames Water (TW) to help steer remedial work.


Image: Thames21

Thames 21’s “lab boat” – “HMS Kingfisher” – is being tested on the Hogsmill. This remote controlled boat has sensors that measure several indicators of water quality, such as dissolved oxygen, conductivity and temperature. Hopefully it will soon be able to measure nitrogen, phosphates and more. It also has software enabling the data to be geo-referenced and viewed in real time. The plan is to survey as much of the Hogsmill as possible over the next few months to create a map of water quality on the river and then to repeat this as often as possible over the rest of the year. The boat will also be available to measure water quality soon after any new pollution incidents or a sharp change in RMI score. Thames21 are looking for local volunteers to assist in surveys – contact  caitlin.curry@thames21.org.uk

Transforming the Hogsmill – Volunteers joined the Malden Manor Community Group for a clear-up by the Hogsmill in Old Malden. With support from SUSTRANS, the Kingston Environment Trust and the Ahmadiyya Association “large rubbish” was removed from the river bed; a riverside path was restored; and bulbs were planted. Scrub clearance beside the Tolworth Brook completed preparations for the “capital works” stage of the project to revitalise the Raeburn Open Space in Berrylands. Contractors are scheduled to start work soon taking out concrete banks, removing a weir and installing a new bridge.


Images: Peter Short

With Environment Agency funding and support from the local council, South East Rivers Trust is undertaking a feasibility study of ways to mitigate the impact on the upper Hogsmill chalk stream of the poor water quality in the Green Lanes Stream. It is currently investigating an option that would divert the Stream through a meandering channel across Chambermead meadow re-joining the main river about 200 metres downstream of the current confluence. Wetlands and ponds and scrapes would be constructed in the meadow that would reduce the impact of pollution and sediment and also lower flood risk by attenuating peak flows down the Stream. If you’d like to know more about the project contact: toby@southeastriverstrust.org


London Rivers Week: Hogsmill River restoration

Building on the success of last year, London Rivers Week, 26th June to 2nd July, 2017 aimed to encourage Londoners to take pride in the city’s waterways, understand the challenges they face and come together to create a healthy future for our rivers.

During the week City Hall held a conference entitled “Why Restore Rivers?” where developers had the opportunity to listen to the benefits of including river restorations. A brief document called How River Restorations Enhance Developments in London, outlining some of the benefits of such work, is now available.

London Rivers Week showcases some of these newly restored natural spaces and raises awareness about how they are vital for Londoners’ wellbeing. Environmental organisations including the Zoological Society of London, London Wildlife Trust, the Environment Agency, Thames Estuary Partnership and the South East Rivers Trust have all joined forces with Thames21 and are putting on free events during the week.


Click on the map to read about 23 projects where you can visit to escape the city and get beside rewilded rivers, including 2 projects close to Kingston University. The Hogsmill River runs directly past the Kingston School of Art Faculty and the university’s Sustainability Hub the Biodiversity Action Group has worked with The South East Rivers Trust, constructing a natural riverbank to increase habitat provision and improve its appearance. Over three phases, timber deflectors were introduced, brash and gravel added to the river and then planted. Read more here: Hogsmill River transformed into wetland and Hogsmill River transformed into wetland – revisited

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Hogsmill River transformed into wetland – revisited

The previous post ‘Hogsmill River transformed into wetland’ described the steps taken earlier this year to improve green spaces on the Knights Park campus at Kingston University for both wildlife and people.  The project is a collaboration between Kingston University and South East Rivers Trust.  Now 3 months later the culmination of the Hogsmill habitat improvement project can be seen to have been hugely successful with increased biodiversity and an improved aesthetic for the Thames tributary as it passes through the campus grounds.

This stretch of the Hogsmill River has been heavily engineered in the past to allow for development along the banks.  The resulting straight channel and concrete walls offer little for wildlife.  This is a collaborative project between Kingston University, The Environment Agency and Royal Borough of Kingston-upon-Thames.

Volunteers have introduced timber, woody debris, gravels and native marginal planting to create a new naturalistic river.  This will encourage a natural river processes which creates a greater diversity of habitats needed for wildlife.  Much of the timber felled has been coppiced (a traditional woodland management technique) so will regrow in time.

If you would like to get involved please email biodiversity@kingston.ac.uk

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The task was to plant up the new riverbank areas with marginal plants ready to take advantage of the spring warmth. Following earlier preparatory work, 1000 plants were planted amongst the brash and gravel, all typical marginal species native to Britain: marsh marigold, fool’s watercress, water mint, watercress, greater and lesser sedge, flag iris and bur reed.  Since then the plants have flourished and now further planting has taken place to increase the biodiversity of planting and water animal count.


 Bank building and timber staking – March/April ’14

30 June5Second round of planting July ’14

The 2 images above show how the banks of the Hogsmill have been transformed over a period of less than 4 months. The first images shows the timber staking and bank building that took place prior to planting and the second image shows additional plants ready for planting to add to the earlier planting which is now established.  We will not know how successful the planting has been until higher levels of water and faster flowing water returns in the autumn and winter.



Views up and down stream showing thick vegetation as the planting becomes more established.  A chicken wire fence erected to protect the young plants from waterfowl and an orange mesh fence along the bottom of the wall to catch windblown litter.  It is hoped both of these can be successfully removed at a later stage once the plants are fully rooted into the river bed. Gravel has been added to the bank floor to encourage fish to spawn and ramps have been added so that river fowl such as moorhens and ducks can access the planted areas for shelter.

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Hogsmill River transformed into wetland

Volunteers turned out in force to see the culmination of the Hogsmill habitat improvement project at the Knights Park campus, Kingston University.  The project is a collaboration between Kingston University and South East Rivers Trust.  The Kingston University Biodiversity Action Group works within the University campuses and local area with the aims of improving green spaces for both wildlife and people.  


The task was to plant up the new riverbank areas with marginal plants ready to take advantage of the spring warmth. Following earlier preparatory work, signs of silting up and diatom growth in the brash and gravels were appearing – a sign there are plenty of nutrients in the water. 1000 plants were planted amongst the brash and gravel, all typical marginal species native to Britain: marsh marigold, fool’s watercress, water mint, watercress, greater and lesser sedge, flag iris and bur reed.

  • Marsh Marigold (Caltha palustris) is a member of the buttercup family which flowers between March and June. We even had one or two flowers on the ones we put in which gave a very welcome injection of colour.
  • Water mint (Mentha aquatica) grows with creeping runners which is good news for colonising our new riverbank. A plant of multiple benefits as the leaves can be used similarly to other mints and the flowers are attractive to bees too.
  • Branched Bur Reed (Sparganium Erectum) will provide an important habitat for wildfowl nesting, roosting and feeding once established. To help it on its way we ensured it was planted in the slower flowing, shallower to avoid submergence and dislodging.


But planting these in flowing water, albeit slowed by the brash and gravels, was a test of skill to get them the right height to avoid those sensitive plants being submerged and others floating away altogether! Gauging the correct depth was an unenviable task, as the river levels here at the Hogsmill vary quickly and frequently. By the time the full project is finished, many plants may need to be repositioned as the water levels will change over time.


To give the plants the best start possible, rootballs were wrapped in hessian tied with twine then given an additional scoop or two of clay soil to supplement the soil they came with.  A chicken wire fence erected to protect the young plants from waterfowl and an orange mesh fence along the bottom of the wall to catch windblown litter. As the riverbank planting establishes the need for these will lessen and they will be removed to let nature take its course.

Interpretation signs were introduced to explain what has been done so campus users can understand the improvements and to highlight the benefits for wildlife. Hopefully in months and years to come, we will see a wide age-range of fish making use of the new conditions, more birds and bats taking advantage of the wealth of invertebrates it should support, and a visual feast of pretty flowers and grasses on the riverside.