Tag Archives: Environment Agency

Richmond Park restoration: update two years on

It has now been two years since the river restoration work on the Beverley Brook through Richmond Park was completed. This time has allowed the two restored stretches with a cumulative length of 600 metres to adjust and naturalise in response to the changes which were made. The original blogs describing the works can be read in the links below.

http://www.southeastriverstrust.org/delivery-to-the-beverley-brook-in-richmond-park-phase-1/

http://www.southeastriverstrust.org/tree-planting-in-richmond-park/

http://www.southeastriverstrust.org/planting-on-the-beverley-brook/

A key principle behind the restoration was to reinstate natural processes back to the river by providing energy and diversity which in turn would allow it to ‘self-heal’. The river now has the opportunity to scour and erode the bed which consequently creates in-channel features such as pools, riffles and bars which were almost completely lacking before. The uniform sandy bed has been displaced to expose the rich gravels below, providing much improved conditions for invertebrates and fish spawning.

The bed now undulates ranging from ankle deep riffles to waist deep pools. There is now a huge array of flow types and with it a myriad of habitats. For the first time in decades the Beverley Brook is audible as the flows pass over, under and through the Large Woody Material and as it babbles over the riffles.

Large Woody Material narrowing the channel and kicking the flow around

With all this scour and erosion, sediment is being deposited in areas of slack water, such as on the inside of meanders and among the vast quantities of brash that was installed. This is working to such great effect that the brash in many locations is no longer perceivably brash. So much sediment and seeds have been deposited that these now appear to be natural banks which stabilise and help to narrow the channel to the dimensions that the Brook should naturally have. In turn, the vegetation that is establishing collects more silt, and so the channel continues to evolve and diversify.

A brash- berm on the left naturalising with a diverse mix of marginal plant species

The regraded banks and low lying berms are vegetating now that the erected fence keeps the deer and their intensive grazing habits out. Marginal and terrestrial plants are starting to thrive, providing previously absent habitats. The grass really is greener on the other side of the fence.

Follow up macrophyte, invertebrate and fish surveys will take place next summer. By then these communities will have had time to adjust enabling us to make an informed and scientific assessment of the biological impacts of the work. Until we get the results back, anecdotally we have observed significant changes. As previously described, the plant communities are noticeably diverse and extensive. Fish which were previously almost completely absent from the downstream stretch are now abundant with large shoals of dace, chub and stone loach being very apparent.

A picture describes a thousand words so I will keep the blog to a succinct length (for me anyway) with a selection of before and after shots to demonstrate the points raised above. We will keep you posted when we get the results of the follow up surveys.

Before; over-wide, straight, sandy bed and bland with few marginal plants…

and after two years later!!!

Before

Two years on.

Before

Two years on

Before

Two years on

 

A sandy bottom and over-wide channel

Two years on, gravel with marginal plants

An attractive functioning river returns to Richmond Park

Hogsmill Newsletter: May Edition

The latest edition of the Hogsmill Newsletter is now available to download. It summarises the results of River Monitoring Initiative (RMI) sampling together with other pollution monitoring and activities and events along the river.

Hogsmill Newsletter May 2017

If you have any comments or suggestions about the newsletter please contact:  Peter Short: rpetershort@hotmail.com

River Club Weir Removal

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No 12 on the Hogsmill obstruction hit list was the River Club weir.

With very shallow flows plunging over its crest, and a drop of 0.7 m between the upstream and downstream water levels, this weir on the Hogsmill near Tolworth was a complete barrier to fish passage under the majority of flow conditions. On each flank, the concrete and stone abutment walls were also structurally failing.

After lengthy discussions, in the course of which no justification for keeping or maintaining this weir could be established, we worked with the Environment Agency and Thames Rivers Trust to undertake a full weir removal.

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Once we had accessed and prepared the worksite, we began breaking up the main part of the weir using a long reach excavator with a hydraulic breaker attachment. It’s amazing how solid parts of these structures are, but our operator Roo’s patience eventually prevailed!

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Over 30 tonnes of concrete was removed from the channel and collected by a grab lorry.

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The stone walls were then broken up, and the new bank profiles were installed using a range of sustainable and biodegradable materials.  Native marginal plants and seed were then added to the new banks, which over time will provide erosion control and great habitat.

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It’s great to see the channel upstream already returning to a more natural state. Within a few days of removing the weir, a resident koi carp had moved from the upstream pool and was enjoying exploring some new habitat. This bodes well for all our native fish species we know are in other parts of the Hogsmill.

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We had fantastic weather throughout the duration of the project, although we could really do with some rain, as most of the rivers across the South East of the UK are experiencing extreme drought conditions.

A big thanks goes to to our local Environment Agency staff, Thames Rivers Trust, The River Club, two very supportive landowners and Roo Newby for his excavator operating skills.

We’ll now be focusing on the six remaining obstructions to fish passage with our aim of restoring this lovely (previously neglected) river to a more natural and improved ecological state.

Why remove weirs? Some excellent diagrams on how weirs affect river habitat and geomorphology have been produced by the Wild Trout Trust and you can also read our article on how weirs affect fish communities.

Before and After photos

BEFORE AND AFTER 1

The Timelapse Video

Volunteers Join Forces for the Hogsmill

The Hogsmill river doesn’t know how lucky it is!

Last week, 30 volunteers joined SERT and ZSL at London Zoo for the 2017 Hogsmill Forum.

2017_hogsmill_forum_ZSL

The Forum is an opportunity for us and ZSL to say thank you to all the volunteers who help us with our projects on the Hogsmill – Pollution Patrol and the Riverfly Monitoring Initiative.

It is also a chance to share wider plans for the river with the local community,  discussing ideas and actions for the coming year; all of which feed in to the Hogsmill Catchment Partnership which SERT host.

If you are interested in either project, get in touch – volunteering@southeastriverstrust.org

And why not have a read of these presentations which our speakers delivered through the course of the day?

Presentations:

Many thanks to ZSL for hosting us, and for letting us have a look around the zoo after the meeting!

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Three Weirs: Part 3

Author: Nick Hale, Project Officer

Read Part 1 and Part 2 first!

And so 3 weirs fell!

Gatehouse, Weir 1

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New Lodge, Weir 2

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and Dairyhouse, Weir 3

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Watch the video of their removal here:

A total of approximately 250 tonnes of concrete and steel was removed from the river.

Removing the three weirs has unimpounded over 1 km of channel. By reconnecting these previously isolated sections of river, just over 3 km of this part of the Lesser Teise is now fully passable for fish!

Increased flow velocity and diversity has already seen the return of natural processes such as erosion and deposition. The mix of deeper and shallower areas will create a range of habitat niches for invertebrates and fish etc.

Directly upstream of the former weirs, the flows have begun to rework the river bed and gravel berms until its natural gradient is restored (as before the weirs were introduced). A previously drowned-out ‘in channel’ meander sequence has exposed gravel riffles, berms and mid channel bars.

These gravels will be continually reworked in a downstream direction, being replaced by new material from upstream. The well-oxygenated gravel riffles will become ideal spawning habitat for both salmonid and coarse fish like brown trout and chub.

A number fish were identified during the works with species including brown trout, minnow, bullhead, stone loach, gudgeon, dace, roach, perch, pike, brook lamprey and barbel.

This stretch of historically dredged river is typically characterised by steep/vertical banks with little or no marginal habitat. This project has exposed an abundance of berms and marginal features that given time will be transformed into a diverse marginal habitat.

Removing the weirs has eliminated the landowners’ responsibility for the upkeep of the structures and saved costs on the twice a year maintenance visits from the EA to maintain the signage and clear blockages in the channel.

What’s next?

We will be monitoring the river over the next few years to record how the project develops. It will be interesting to see how the higher flows over the winter months rework all the gravels.

In the spring we will sow some native marginal plant seed mix on the lower banks of our structures and take some more photos for the next blog.

A BIG thanks to must go to the landowners, Ian Johnstone and the Kent High Weald Partnership and the Environment Agency for all their help!

The Three Weirs: Part 2

Author: Nick Hale, Project Officer

Read Three Weirs part 1 here.

After many months of planning the project we were finally able to start the fun part and get on the riverbank!

The first job was to take delivery of all the machines and equipment such as the 15m long reach excavator and wheeled dumpers.  Access to the site was quite tricky but having a good delivery driver is always good!

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Mike our excavator driver was raring to go but first we had to install our sediment control features, marker posts to measure changes in water levels/river bed level and also take a few photos for comparison.

It was great to finally get the breaker attached onto the machine and begin breaking out the concrete. The centre of the channel was broken up first, and then the sides.

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breaking-out-concrete

The weirs were certainly well built! Sheet piling had been installed at the up/downstream ends of each weir to key it into the riverbed and act as the formwork when casting the concrete. Lots of 6mm steel rebar had been used to provide extra strength, and in some places the concrete was almost 1m thick.

Removal of the sheet pilling was quite a challenge at the first weir, with the downstream section being 1.8m in length.

Mike gradually broke up the weirs into manageable pieces, which were loaded into the wheeled dumpers and transported to the collection site. A local company was contracted to collect the waste material using grab lorries. Each weir was made up of about 80 tonnes of concrete which was about 5 grab lorry loads per weir.

concrete

Chestnut faggots were secured with chestnut posts (both locally sourced) to form the line of the new bank.

A marginal shelf of site-won soil was then encased in coir matting behind the faggots and secured to the banks with oak pegs. We will come back to plant these up in the spring.

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With high spirits and with the weather thankfully on our side, we tracked up the bank to do battle with the next two weirs. Although the construction of each was similar, each site posed its own challenges. However one by one they fell, with all three weirs being removed and banks reinstated in a three week period, reinstating flows and passage for the first time in over half a century.

The benefits of the work were made clear before we had even pulled out of the site. We saw numerous fish passing the previous barrier to explore the stretch upstream.

Look out for our third and final blog on the Three Weirs Project to see some before and after photos and the timelapse video!

The Three Weirs: Part 1

Author: Nick Hale, Project Officer

An Environment Agency assessment of the Teise and Lesser Teise, two tributaries of the Medway in Kent, indicated there is a problem with wild fish stocks in the river.  Generally there is an absence and/or low abundance of key expected species such as brown trout, chub, predatory perch and pike, roach and stone loach.

In fact, the situation is probably even worse than this assessment indicates as a large proportion of the fish caught here are derived from artificial stocking, masking the figures of the wild population.

So what can be done about it?

One major contributing factor to these poor wild fish populations is the presence of barriers to fish migration: weirs. Weirs fragment the available habitat, prevent fish from reaching spawning grounds and change the geomorphology of the river channel as well. (For a reminder about the pros and cons of weirs, our very own Dr Chris Gardner wrote an excellent article recently on how weirs affect fish communities).

The Medway Catchment Partnership have been looking at barriers to fish migration in a bid to address this on a catchment scale. As a start, last year we successfully removed Harper’s Weir, restoring fish passage to a 3.5 km stretch of the River Teise. However, if you travel downstream, you are confronted by more and more weirs.

The Three Weirs Project looked to tackle a set of three weirs on the Lesser Teise, continuing this great work.

Where are the Three Weirs?

The Three Weirs, named Gatehouse (1), New Lodge (2) and Dairyhouse (3) are located on a 1.2 km stretch of the Lesser Teise near Chainhurst, Kent. All three are concrete weirs, likely originally installed in the mid-20th century for the purposes of agricultural land management.

weirs

What ecological benefits will result from removing the weirs?

The presence of a weir creates an impounding effect whereby the upstream water levels are much higher than normal.  This drowns out any natural features within the channel making it more like a canal than a river.

Impounded channel upstream of Dairyhouse Weir.

Impounded channel upstream of Dairyhouse Weir.

Removing the 3 weirs will increase the hydromorphological diversity (flow and river bed structure) of this stretch of river. Natural processes such as sediment transport and gravel mobilisation will return, exposing a range of original channel features like gravel berms and meanders. For example, the removal of Harpers Weir revealed 16 new riffles.

Ecological benefits will be seen both upstream and downstream of the existing weirs with salmonid and coarse fish being able to migrate through this previously unpassable stretch, improving their ability to carry out their full life cycle and ultimately increasing their chances of survival.

Localised improvements in water quality through faster, low flow conditions will reduce the build-up of ammonia and phosphates and increase dissolved oxygen to support a wider range of invertebrates. To capture these changes, an invertebrate survey has been undertaken by Robert Aquilina at specific locations along the proposed works area.  This process will be repeated in September 2017 to record any changes in diversity and abundance of the invertebrate community living within the channel.

In preparation for full removal, the wooden boards that were fixed to the crest of all 3 weirs were removed in 2015 with help of the Environment Agency. This reduced some of the impounding effect and allowed the channel upstream to adjust and stabilise prior to a complete removal of the structures in the future.

The next step now is to remove the weirs, but you’ll have to wait for part 2 to find out all about that!

In the news: MPs demand overhaul of Environment Agency to protect communities from rising flood risk

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Source: www.getreading.co.uk

Winter is on the way – and makes this report on future flood prevention from the Environment, Food and Rural Affairs Committee (released today) very timely.  Today’s report, ‘Future flood prevention’, http://www.publications.parliament.uk/pa/cm201617/cmselect/cmenvfru/115/115.pdf  builds on previous works such as ‘Floods and Dredging – a reality check’  from CIWEM
http://ciwem.org/wp-content/uploads/2016/02/Floods-and-Dredging-a-reality-check.pdf   and others, recognising that in many cases, traditional approaches to managing flood risk are not only unaffordable and unsustainable – they don’t always work and are neither, the only – nor, sometimes, the best solution.

The report highlights how a catchment wide approach is central to achieving an affordable and sustainable response to flooding in a more populated future, facing the consequences of climate change.

The Catchment based approach (CaBA) https://www.catchmentbasedapproach.org/   and Catchment Partnerships are well placed to drive this forward and deliver real solutions to communities not able to benefit from more traditional ‘hard engineered’ and expensive schemes. Existing Catchment Partnerships have developed strong links between local communities, local authorities, the Environment Agency, wildlife trusts and large institutions such as water companies and local industries, and are already delivering projects that enhance and protect our precious water resources and habitats; using a holistic approach to achieve multi-benefit solutions.

At the South East Rivers Trust, we are proud to host and co-host river catchments across the South East, and are increasingly involved in projects addressing local flood issues. In September, the Loddon Catchment Partnership  http://www.loddoncatchment.org.uk  supported a resident-led workshop, hosted by the Loddon Basin Flood Action Group and the University of Reading, on the potential for natural flood management projects to help residents who are at risk of flooding in Berkshire.

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Although there is a need for more evidence to inform best practice (but see Wilkinson ME, Quinn PF, Welton P. (2010) Runoff management during the September 2008 floods in the Belford catchment, Northumberland. Journal of Flood Risk Management, 3(4)), schemes such as those described in the report have shown the potential to achieve cumulative benefits from linked, practical projects that use techniques as diverse as increasing the area of land that can absorb water by planting woodland, to creating extra water storage areas by installing ‘leaky dams’ of natural materials that slow and divert water during high flow events.

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Reproduced from Future Flood Prevention (EFRA Committee report)

http://www.publications.parliament.uk/pa/cm201617/cmselect/cmenvfru/115/115.pdf

It all makes so much sense! – BUT there are challenges. The report highlights that the key to the success – or even existence of these projects lies in taking the whole community along, and providing realistic payments to landowners whose livelihoods are affected by these schemes. In discussions at our Cuckmere and Pevensey Catchment Partnership meeting http://www.cplcp.org.uk  farmers stressed the need for these payments to be an ongoing income stream, rather than one-off payments that do not reflect changes to their business model. This necessity is also highlighted in the report along with the criticism that government response to flooding has been reactive rather than pro-active, resulting from too short time scales for meaningful, strategic planning.

Improving communications across all areas of local planning is also essential. Highlighting the potential for new developments to embrace these methods can only help mitigate against the effects of yet more impermeable roofs, roads and pavements contributing to localised surface flooding.

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Source: BBC Berkshire.

Water quality improvements are on par at Richmond Park

Shortly I will post another blog updating you on how the river improvement works in Richmond Park are settling in one year after they were completed. Although the river habitat works have been completed (for now!) work has by no means ended. In addition to improving the habitat, our attention is also focused on addressing the poor water quality entering into the Brook.

Upstream of the Richmond Park golf course, rain water pours off the surrounding urban catchment and notably down the incredibly busy and often choked A3 at Roehampton Hill. It then flows down the gulley pots, into a surface water drain before this opens out into a ditch which flows across Richmond Park Golf Course before discharging into the Beverley Brook. Such road runoff is known to cause detrimental effects to the aquatic environment, not only from the significant quantities of sediment carried in it, but additionally from the contaminants bound to it. These include Poly Aromatic Hydrocarbons (PAHs), hydrocarbons and heavy metals. Our aim was to therefore capture the sediment and the contaminants before they reach the Brook. This was achieved with a two pronged attack.

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Oil from the A3 covering the surface of the pond in the golf course. Thick black sediment covers the bed

First of all, mid-fairway at the upstream end of the golf course we opened the ditch out to create an on-line pond, known to us as a silt trap but to golfers as a feature water hazard. With help from Rob McInnes, the pond’s size was calculated so that all coarse sediment down to 0.1mm would drop out as a consequence of lowering the velocity of the flow. A shallow marginal ledge was incorporated along the length of the pond, which has been planted with a mix of wetland plant species to promote deposition, whilst providing species and habitat diversity. By emptying the pond regularly, the silt is removed from the system and the effectiveness of the trap is maintained.

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Starting to open the ditch out

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A few months after completion, the pond is trapping plenty of silt (and plenty of golf balls)

The second measure took place a few hundred metres further down the ditch where an existing online pond, in the shape of a ring doughnut, provided an excellent opportunity to be modified to create a wetland. The plan was to re-jig it so that the doughnut became a U-shape. This prevents short-circuiting, therefore increasing retention times, reducing velocities and again promoting a depositional environment.

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The pond before works start

The pond was too deep to plant straight into, so we needed to find spoil to fill it in. What better way to produce the spoil than dig a second wetland immediately upstream of the first, which will increase the treatment capacity further.

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Re configuring and filling in of the pond

Six thousand plants consisting of over 20 species were planted in the wetlands. The dense structure created by the plants results in even finer sediments being captured than in the silt trap upstream.

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The wetlands newly planted with 6000 plugs and fenced off

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August and the plants have established

Furthermore, this has now created a fantastic wetland habitat full of dragonflies, damselflies and frogs to name a few. Both the silt trap and wetlands have been fenced off and have bird twine strung over them to prevent the large population of geese from nobbling the plants before they had the chance to establish. The total area of both is approximately 800 metres square.

A simple water level control structure was created at the outlet of each wetland. As sediment accumulates and reduces the depth of water over time, another drop board can be put in, allowing the water depth to be increased, therefore reducing maintenance requirements and prolonging the life of the wetland.

The effectiveness of the installed measures is currently being monitored, however a coincidental site visit during a pollution event helped to anecdotally demonstrate the effectiveness. Run-off from a presumed building site was bringing significant quantities of sand rich water into the ditch. After the silt trap, the turbidity of water flowing out was visually improved. Walking further down the ditch network, after flowing through both wetlands, we were incredibly impressed to see that the water flowing out and into the river was clear to the eye. Although this was always the theory behind why we created these features, to see it work first hand to such a great effect was brilliant and hugely satisfying. With contaminants generally being bound to sediment, this clearly demonstrates not only a reduction of sediment input to the river but indirectly of contaminants too.

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Thick sandy water flowing into the sediment trap

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Water in the ditch downstream of the sediment trap and both wetlands

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Significantly improved water clarity entering into the Beverley Brook

Job done!! (for now anyway). I am now working up the next phase of water quality improvements. Updates will follow shortly.

As always, the success of this project is down to the valuable contribution of many people and organisations.

Big thanks to the ongoing project partners; the Environment Agency, Defra, The Royal Parks and Friends of Richmond Park. Thanks to Jon Dummett and Gary Stewart at Glendale Golf Course for surprisingly being so willing in allowing us to dig up their course and for their continued support since. Thanks to Rob McInnes at RM Wetlands & Environment Ltd for guiding the designs, Ben and the guys at Aquamaintain for braving the cold February days delivering the work and again for planting it up. Thanks to Thames Water for providing the flow meter which was installed in the ditch network to inform the design and finally, to Layla at Queen Mary University for monitoring the work.

The 2016 Hogsmill Forum

The Hogsmill River may have its problems, but it is one of the lucky urban rivers to have huge community support and many enthusiastic volunteers.

We run our Pollution Patrol on the Hogsmill, tracking down polluted outfalls and misconnections. While ZSL run the Riverfly Monitoring Initiative which uses the kick sampling of invertebrates to check for organic pollution.

So to thank everyone for their hard work, both projects combined for a joint Hogsmill Forum – kindly hosted by ZSL at London Zoo.

Hogs Forum

The event was a huge success with some really interesting discussions on the priorities for the Hogsmill going forward. Below you can download PDFs of the presentations.

Presentations:

 

Delivery on the Dour

Last month, we ventured all the way to Dover to start delivery of our River Dour Restoration Project.

The Dour is a short river, roughly 4 km in length, which runs into the sea at Dover Harbour.

We were addressing fish passage at a weir near Kearsney Abbey at Minnis Lane. Here the Dour runs through a ruined building, causing blockages to fish passage with the presence of several small weirs. The river itself has started to create its own bypass channel and our aim was to enhance this channel to allow fish passage upstream of the site.

Minnis Lane Site

Installing Brash BundlesTo do this, we installed brash deflectors to concentrate the flow of water to a narrower section, ensuring there was enough flow for fish to swim up without becoming stranded.

We were joined by 6 local volunteers on the day to help us install 12 brash deflectors in the stream.

Each deflector was secured in place with hazel posts and wire to ensure they stayed in place in higher flows.

By placing the deflectors so that they’re pointing upstream, we directed the flow of water into the middle of the channel, creating a deeper section for fish and eels to swim up.

We will be back to finish the site off soon and see how our deflectors are working.

Many thanks to our volunteers who helped on the day: Bethany, Katharine, Lilian, Ray, Simon and Tom. And a big thank you to the local Scout Club for letting us park our van in their carpark.

So before….

Before 1Before..

Before 2

After!

After 1

After..

After 2

Happy Anniversary to the Hogsmill Pollution Patrol

Pollution on the HogsmillWith the start of 2016 comes the One Year Anniversary of our Hogsmill Pollution Patrol scheme – and what an amazing job it has done so far!

Throughout 2015, our trained volunteers have been monitoring 15 outfalls on the Hogsmill for signs of pollution such as misconnected appliances and sewage discharge.

Together they have submitted 470 reports of pollution to us. Working with the Environment Agency and Thames Water, we have been able to start investigating these issues and begin work towards rectifying them to improve water quality on the Hogsmill River.

To read the latest update of our work, please download our Newsletter below.

Pollution Newsletter December 2015

If you see pollution on your river, call the Environment Agency hotline on:

0800 80 70 60

Pollution

River Restoration in Richmond Park

Richmond ParkWe’ve started our latest restoration project in Richmond Park, working to enhance the Beverley Brook in partnership with The Royal Parks, The Environment Agency, the Friends of Richmond Park and the Beverley Brook Catchment Partnership.

Richmond Park is well known for its deer and its nationally important terrestrial habitats, e.g. acid grassland. Given this high status you would be forgiven for thinking that the river was also in good shape.  However, it’s actually not and its wildlife is relatively impoverished.

About 14% of the length of the Beverley Brook runs through the Richmond Park and so restoring the river through the park, presents an excellent opportunity to make a real difference to the whole river ecosystem.

Why is restoration needed?

The Beverley Brook, like many of London’s rivers, has been heavily modified in the past leaving a highly uniform river channel lacking in habitat diversity. The river channel has been over-widened and in places deepened along most of its length with all natural woody material and instream features being routinely removed from the channel for decades. Due to these reasons there is little variation in flow and depth and subsequently there is little habitat diversity for fish and aquatic invertebrates.

RP Before 2In addition to this the banks are very steep and the river is incised (if you stand on the top of the bank the river is quite a long way down!) and the banks have been subject to increased erosion due to the intense grazing of deer. The deer enjoy eating the succulent river bank plants. This means there is little vegetation left and there are no root structures to hold the soil on the river bank in place and so it washes into the river.  You may have seen a sandy bottom on the river bed: this isn’t actually what it’s meant to look like and is a result of the soil washing in and smothering the natural gravels on the river bed. This is a problem for the river ecosystem as many of the plants and animals that would naturally live in the Beverley Brook need the gravelly river bed habitats to survive.

SiltyBed           SteepBank

A natural river system has the ability to self-regulate but when it becomes modified, the processes can get out of kilter and we may need to intervene to kick start them again.  All of the modifications to the Beverley Brook have left the river with little power, taking away the opportunity for the channel to naturally fix itself with geomorphological processes.

RP Before 1What we are doing

A large river restoration project in the Park has been developed and funded in partnership with the South East Rivers Trust, the Royal Parks, the Friends of Richmond Park, the Environment Agency and the Beverley Brook Catchment Partnership. The aim of this project is to naturalise 600 m of the Beverley Brook through the park using a number of simple restoration techniques. These include:

  • Adding Large Woody Material to increase flow variation and provide a greater complexity of habitats for aquatic wildlife.
  • Re-profiling the incised and steep banks to enhance marginal habitats.
  • Narrowing and remeandering the channel to create a diversity of different flow patterns and produce marginal wetland berms.
  • Erecting fencing and river gates to temporarily exclude the deer to allow the banks to stabilise and for vegetation to recover.
  • Creating slower flowing areas as refuge for animals during the high flows which are typical of urban rivers such as the Beverley Brook. This is particularly important to help fish establish and not be washed downstream (and possibly right out of the river) in heavy rains.
  • Address the contaminated road run-off input into the river from the A3 by creating a siltation pond and wetland to trap and clean the silt from the road.

So it is going to be a busy couple of months on site and we are all excited about the results this project will bring!

You can read more about the project and how Richmond Park access will be affected during works on the Royal Parks website here.

RichmondGrid

Wombles of Wimbledon: Beverley Brook

Last week, Luke and I were lucky enough to spend three days on the Beverley Brook in Wimbledon Common.

Like many rivers, the Beverley Brook has been modified over time to fit into our more developed urban landscape. Within Wimbledon Common, the river has been over straightened and reinforced with wooden toe boarding. As a result the flow of the river has become very uniform and lack the diversity needed for water biodiversity.

To address this we started a project to install Large Woody Material (LWM) into the river channel. LWM replicates a natural occurrence of trees and branches falling into rivers which then provides habitat for fish and invertebrates. The use of LWM in the right places can transform a still, slow-moving river into a highly diverse river channel with a variety of habitats for all life stages of fish and invertebrates.

Part of the Womble Team

Over the three days we had a number of volunteer helpers to help us move the timber logs, position them within the channel and fix them in place with hazel stakes and wire.

Luke and Lawrence led the event, explaining how the positioning of the logs effected the flow of the river and could influence bank erosion. For example, if we placed a log facing downstream, this forced the flow of water into the bank creating a natural meander bend. Natural gravel deposits held in the bank will scour out and become available in-stream for fish and invertebrates.

The timber logs were heavy!

So working as a team, over three days we worked out where the logs would be of most benefit and got to work securing them in place.

It was hard work. Moving the large logs took four people and was still a struggle. However once they were in the river, they became a lot lighter. Once positioned, each log had to be secured with four hazel posts which were forced into the ground using a post knocker – another exhausting piece of equipment.

Securing

Once surrounded by hazel stakes, the logs were secured further with wire to be sure they were going nowhere in a flood.

In total we installed 17 LWM structures along a stretch of 200 m, approximately. Here are some photos to show you how the still slow-moving channel has now been transformed!

One finished deflector

Many thanks to all the volunteers for coming: Charles, Dave, Denisa, John, Keith, Kristina, Lawrence, Mark, Mike, Paul, Phil, Rob, Sue and Wally.

More deflectors

More!

What have we been up to?

We have had a busy start to 2015 – maybe it is time for you to catch up with what we have been up to?

River Restoration ~ Luke has been busy transforming the Ravensbury Park Back Channel on the River Wandle for both the local community and wildlife. Read all about his progress here.

Pollution Control ~ Olly has been working hard trialling new methods to mitigate against urban diffuse pollution. We have trialled Siltex in Carshalton Ponds and installed Mycofilters at problematic outfalls.

Looking Forward ~ We’ve got restoration projects this year on the Hogsmill and Beverley Brook so keep your eyes peeled for more updates!

What do your local rivers mean to you?

You have the chance to have your say in how your local river is managed in the future. 

The Environment Agency has published draft River Basin Management Plans for every river in the UK and they want to hear your opinion!

To help you get involved and add your voice, WWF have created an easy way to make your opinions heard.

Got a couple of minutes? Answers these quick 5 questions. 

Got a bit longer? Give us more detail on what you value to be important to your local river here. 

Share this with your friends and family – #SAVEOURWATERS

SaveOurWaters-infographic

The Problem with Urban Duck Ponds

Carshalton PondsIn a highly developed landscape such as Greater London, urban ponds can provide an important haven for wildlife and therefore it is important to keep the waters happy and healthy.

Unfortunately over time urban ponds tend to fill up with sediment washed from the surrounding area such as leaf litter and bird droppings. Have you ever been for a walk along the Wandle to Carshalton? If you have, you will have undoubtedly seen a mass gathering of wildfowl at the ponds. These high densities of geese and ducks can be a particular problem with their droppings increasing the organic content of the ponds, resulting in algae blooms and a deterioration in the water quality.

Birds Birds Birds

So what can we do?

The Wandle Trust are trialling Siltex in Carshalton Ponds as a potential solution to the surplus of silt.

Siltex

Siltex is a natural chalk-like substance which helps to increase the speed of silt breakdown by stimulating natural processes. It is environmentally friendly and is harmless to plants and animals.

In the next week, we will be applying the Siltex powder to the mud in Carshalton Ponds. The effects of Siltex will then be monitored closely over the next few months by our staff to determine the effectiveness of the measure and its effects on water quality.

We will of course keep you updated with our news – so keep your eyes out for more Siltex blogs.

Pollution-Busting on the Wandle

Over the last 2 years, the Wandle Trust has been intensifying efforts to tackle the considerable problem of pollution in the river. Often contamination can be tackled by our partners in the Environment Agency, tracking down pollution to the source. However, this does not work for all sources of contamination.

For example, contaminants such as particles from car exhaust, the loss of engine oil and other contaminants from the roads can all be washed into the river from no one “point” source. This is known as diffuse pollution.

DiffusePollutionTo illustrate this, there are about 2.5 million cars in London, and 16% of them leak oil. It has been calculated that this would equate to 261,635 gallons of oils dripping onto roads every year! Much of this oil will work its way into London’s surface water drains and then the rivers.

Although changes to the law and car technology may help one day in the future, we need to start acting now. It has been the Wandle Trust’s mission to find out how the contaminated waters from the surface water drains can be cleaned up before entering our river. This is vitally important because water quality is a major determinant of what wildlife can live in the rivers, how beautiful the rivers are, and how much the community value their local water landscapes.

In the current phase of our Pollution Busting Project, four measures are being installed and trialled to determine their effectiveness in reducing the contamination coming into the River Wandle. These measures are the most promising selected from several which were investigated by the Trust and they are called:

  • Downstream Defenders
  • Mycofilters
  • Siltex
  • Smart Sponges

There will be more information about these appearing on our websites in the coming months. We look forward to telling you more about this exciting new phase of our work!

Of rock-ramps and fish

And the fish easement work on the Hogsmill continues. This time our work is focused on the river around the Thames Water Sewage Treatment works situated in Berrylands, Surbiton, specifically the stretch from the railway bridge down towards Kingston Cemetery.

The over-widened channel here reduces water depth which, along with three small weirs and a lot of concrete-lined channel in between, effectively prevents fish from moving upstream.

So these weirs will have to go. Or will they? Toby’s work connecting reaches of the Hogsmill to free fish movement has shown an alternative – slow the flow and over they go! Building rock ramps and pool passes drown out these structures enabling fish to navigate their way over them.

Illustration of a typical rock-ramp (Source: Thorncraft and Harris, 2000)

Illustration of a typical rock-ramp (Source: Thorncraft and Harris, 2000)

After a few essentials from the Environment Agency, Thames Water and Network Rail we ought to have this project going in the next couple of months. More to follow shortly…

Reference

Thorncraft G. and Harris, J.H. 2000. Fish passage and fishways in New South Wales: A status report, Technical Report 1/2000 prepared by NSW fisheries for Cooperative Research Centre for Freshwater Ecology.

A selfish shellfish!

The invasive quagga mussel (Dreissena bugensis) has been found in the Thames Catchment on the River Colne!

What is the quagga mussel?Quagga Mussel

The quagga mussel is an invasive freshwater filter-feeder with an extremely large capacity to filter water and the ability to grow large dense populations. When established, these combined traits can result in a reduction in the availability of nutrients and oxygen to our native aquatic wildlife, damaging a freshwater ecosystem.

Economically, the quagga mussel is a big problem as well. With its prolific breeding, this invasive mussel can clog water pipes, filters and turbines damaging our infrastructure. Furthermore it disrupts recreation, fishing and aquaculture industries by growing on equipment and boats.

All in all, it is not a welcome sight!

What can be done about it?

Currently there are no recommended methods for controlling populations of this mussel. Therefore our only option is prevention.

Biosecurity needs to be increased in the Thames Catchment to ensure the mussel isn’t accidentally transferred to our other river systems. For more details on how to step up your biosecurity – visit Check Clean Dry.

To find out more about the quagga mussel’s impact outside its native range, take a look at this video from North America where this mussel, and its relative the zebra mussel, have already had a devastating impact.

Image credit: Quagga mussel – GBNNSS