Tag Archives: South East Rivers Trust

Riding for Rivers, London to Brighton Cycle Ride

Last Sunday, Nick and I rode 54 miles in the name of rivers, completing the London to Brighton cycle ride. This blog is our way of saying thank you to all of those who supported and sponsored us along the way.

(If you’re worried you missed the opportunity to sponsor us, you still can, so never fear! The links are below)

http://www.doitforcharity.com/NickHale

http://www.doitforcharity.com/THull

So why on earth did we agree to cycle 54 miles?

Well, to be honest it was a mix of thinking “Ride4Rivers” was a catchy slogan, and being asked to do it when we under the influence in the pub. Before we knew it, our cycling jerseys had arrived in the post and we were beginning a countdown to Sunday 17th September.

What was Ride4Rivers?

The Ride4Rivers team was organised by the Rivers Trust, inviting local trusts and volunteers to raise money and awareness for their local river by joining the London to Brighton cycle ride. In the team were myself and Nick, other rivers trust staff and volunteers, and riders from Five Rivers and the Angling Trust among others. All the money raised by the Ride4Rivers team will go back to the Trusts and help further work to protect and enhance our river ecosystem. So how could we say no really?

The BIG Day

The Ride4Rivers team gathered early in the Sunday morning at Clapham Common with over 4000 other riders.

The team respectfully giving space and attention to the fuel for most to get started, coffee

Within a few miles we came to Hackbridge where the route offered a perfect photo opportunity overlooking the site where we removed four weirs and undertook significant restoration work back in 2014 on the Wandle – with Nick working for us as the contractor at the time!

The river was looking splendid, but there wasn’t time to stop for long, and shortly after we were passing the source of the Wandle at Carshalton Ponds.

A quick pit stop to admire the Hackbridge restoration work

The flat ground of London soon turned to numerous steep climbs as we ascended the North Downs. Fortunately however physics was on our side as what goes up must come down. Soon we had gravity helping us as we descended into the Weald. The atmosphere among all was great as we pushed on mile after mile. Our stomachs began to grumble but the organisers had this covered by laying on an absolute feast at Mile 29, the only thing being they made us work for it by locating the lunch at the top of a steep hill.

Feeling energised if somewhat seized up, progress after lunch began well but then… psssss, Nick got a puncture on his rear tyre. Now I mentioned that neither of us are cyclists, it would appear that since being children our memory of how to replace an inner tube was a little hazy. Sometime later (and with a little help it must be said) we were back on the road.

Sad face

A noise continued to be emitted from my bike that had developed since lunch.  Some 12 miles later as we approached the infamous Ditchling Beacon the noise finally got to me and I figured I should have a little investigate. It appeared that I had been riding with my brake partly on since lunch. Well I didn’t want to make it too easy! Again with our bike maintenance knowledge lacking after a little more unsuccessful fumbling the only thing for it was to disconnect the rear brake.

Ditchling Beacon soon loomed over us and the climb was on, one mile of uphill struggle lay ahead but we were not going to be defeated and soon we summited to spectacular panoramic views with the sun coming out on cue.  More unsuccessful fumbling to reinstate my brake, meant a bit of a hairy descent down to Brighton but who cared, from here it was all downhill to the finish line, the end was near and the prospect of a pint alluring.

Ditchling Beacon summited

We both need to say a massive thank you to all of you who so kindly donated to Ride4Rivers – your backing was so valuable to encourage us along, not to mention the benefit it will bring in helping us to enhance, restore and protect our rivers. Thank you so much! Nick and I also need to thank Steve Wright, Luke and Sam for lending us bikes so that we were able to take part – otherwise it would have been a long walk.

A well earned beer

If you wanted to sponsor, but missed out then our fundraising pages are remaining open for another couple of months so please do give what you can in support of our local rivers.

http://www.doitforcharity.com/NickHale

http://www.doitforcharity.com/THull

 

A new, exciting project to improve water quality on the Beverley Brook

So you know that the roads can be pretty dirty. You see the direct effects of it on your car when you think it’s probably time to give it a clean. The dirt on the roads is also really well illustrated when it snows and soon the pure white snow changes to black slush. But where does all of this dirt come from?

You see trucks and lorries leaking oil and busses belching out thick clouds of exhaust fumes when pulling away from traffic lights. You see gulley pots full of litter, cigarette butts and sand that has run off the nearest building site. Or the paint that is dripped out of vans or has been poured into the curb. You walk along the street dodging ‘dog eggs’ which litter the pavement. Then in winter the roads get spread with grit and salt during cold snaps.

You may consider of all of these things as unsightly or unpleasant when on the roads, but within a short period of time and with a bit of rain, all of these substances are washed away and are out of sight and out of mind. But where does it disappear to?

The answer: often the nearest watercourse.

The initial runoff, known as the ‘first flush’, runs black especially in urban areas. In turn with many other outfalls also discharging the entire river turns black.

First flush on the River Wandle, South East Rivers Trust

So what is in this run-off?

Basically it consists of a nasty cocktail containing pieces of the road surface, tyres, brake pads and other material from engine parts from regular wear. Throw into the mix some fuel, gear oil, grease, brake fluid and antifreeze. Then for good measure add some pesticides, fertilisers, plant detritus, some illicit dumping of substances, inputs from misconnected drains and in winter de-icing grit and salt.

Unsurprisingly road runoff can be detrimental to the receiving watercourse, whose impacts on riverine ecology can be acute or chronic. The sediment smothers gravels vital for invertebrates and fish. The turbid water reduces light penetration so plant communities suffer due to limited photosynthesis. Furthermore, the sediment blocks the feeding mechanisms of filter feeders and gills of other aquatic organisms.

The Poly Aromatic Hydrocarbons (PAHs) (oils) and heavy metals are both known to be toxic to aquatic fauna. High concentrations of heavy metals associated with the ‘first flush’ can ‘shock’ aquatic environments as the water is polluted with levels several times higher the normal concentration. Multiple studies have shown that heavy metals can also cause long term impacts as they bio-accumulate within the food chain.

So what can we do?

It is well known that these contaminants freely bind to sediment. It therefore follows that if the sediment is removed, so too will many of the contaminants. This is the plan to protect the Beverley Brook in Richmond Park.

The Project

The Rivers Trust and WWF are managing three water management projects in the Thames and South East River Basins, for the benefit of both people and wildlife. The wider initiative is funded by the Coca-Cola Foundation and contributes to Coca-Cola’s promise to safely return the full amount of water used in finished beverages and their production to communities and nature by 2020 – an ongoing commitment as they managed to reach this goal five years ahead of target. Globally Coca-Cola works in over 2000 communities and supports more than 248 community water partnership projects in over 71 countries – this being one of them.

A schematic of how a Downstream Defender works

We are delighted to announce that the South East Rivers Trust is delivering one of these three projects which will see a large (and I mean very large) silt trap, known as a Downstream Defender® supplied by Hydro International, installed onto a surface water drain. The drain currently carries run-off from the incredibly urban surrounding catchment directly into the Beverley Brook. The Downstream Defender will trap a large portion of the sediment and associated contaminants, preventing them from reaching the Beverley Brook. Intermittently the trap will be emptied with a gulley sucker and the toxic sludge removed to landfill. Consequently, the health of the river will improve making it a better place for both wildlife and people.

Last Tuesday we launched this collaborative project with the arrival of the Downstream Defender to Richmond Park. We’d like to thank our funders, the Coca-Cola Foundation, as well as all our partners including WWF, The Rivers Trust, the Environment Agency, The Royal Parks, the Friends of Richmond Park and Thames Water. Also a big thank you to Hydro International for supplying the Downstream Defender and for their much appreciated contributions to the launch event. Thank you to all the guys at Kenward Groundworks; Tony, Matt, Dave, Mark and Woody for all your efforts with installing the chamber. And finally thanks to John Sutton from Clearwater Photography for taking photograph of the launch and project.

Partners with the Downstream Defender Silt Trap

 

Celebrating the launch of the project with partners and volunteers

Photos: John Sutton, Clearwater Photography

 

Knowing your rudd from your roach

Our lucky Pollution Patrol volunteers were treated to a FIN-tastic day with our local Environment Agency team, learning all about fish.

It may come as a surprise to some people, but the Hogsmill, Wandle and Beverley Brook all contain a variety of different fish species. Common species across all three rivers include chub, dace, roach, barbel, stickleback and European eels.

But how do you tell the different between these species? For some, it is easier than others. The European eel is quite distinctive compared to the others for example. But as to the rest, it’s a bit more difficult.

Tom Cousins, a local EA Fisheries Officer, started the day for us with a presentation on the different fish species and the key identifying features.

The diagram below shows the external morphology of an average fish, and the features that help us distinguish one species from another.

For example: Roach and Rudd

These two fish are quite similar in appearance, both large-bodied with reddish fins. So how can we tell them apart? The answer is by looking at the mouth.

The roach is a bottom feeder, and its mouth points downwards, with the upper lip over-hanging the bottom lip – whereas a rudd feeds from the surface, and therefore the bottom lip overhangs the top lip.

The presentation from the Environment Agency is available below for you to download, with many more tricks and tips for ID.

Fish ID Presentation

As part of the training day, we also got to witness the Environment Agency’s electrofishing survey at Morden Hall Park on the River Wandle in South London.

It was amazing to learn about the fish in the classroom, and then come outside and see some in the flesh. Each fish caught was measured, and scale samples from some were taken in order to age the fish.

Once they had been recorded and had recovered, they were returned safely back to the Wandle. 

Many thanks to Morden Hall Park for hosting us and to the Environment Agency for running the event!

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

1

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.

2

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!

3

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

4

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.

5

6

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.

7

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

Keep up to date with the Hogsmill

IMG_8518

There is a new newsletter for anyone interested in or involved with the health of the Hogsmill. It summarises the results of River Monitoring Initiative (RMI) sampling together with other pollution monitoring and activities and events along the river.

Hogsmill Newsletter March 2017

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

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!

Untitled

 

 

Hogsmill reconnected to the Thames with new fish pass in Kingston

The Hogsmill gauging station is an Environment Agency flow monitoring structure, essential for water resources planning and regulation.  It is the furthermost downstream weir in the catchment and poses a significant barrier to fish passage, preventing the recolonisation of fish to the river from the Thames below. Addressing passage at this key site has been discussed for several years but due to the sensitivity and importance in the recorded flow-gauging data, in combination with the unconventional structure it has resulted in a complicated and extensive process to identify and develop a suitable solution. JBA have helped inform the positioning of the upper baffle and through a programme of spot gaugings will update the rating of the gauging station.

OLYMPUS DIGITAL CAMERA

The impassable Hogsmill Kingston gauging station

The selected approach is a variation on the Low Cost Baffle (LCB) Solution as we have used elsewhere, whereby rigid baffles are put on the downstream weir face in a specific geometry and spacing to slow the water, deepen the flow and provide a distinct passage route on the weir face. However, due to the significantly steeper gradient at the site in comparison to that the design was developed for, the Trust and EA have modified the arrangement to help promote the correct hydraulics to enable fish to pass.  The maths aside, in essence this meant that each line of baffles is incrementally taller than the last, starting at 120mm and ending at 288mm at the downstream end.

With this novel approach the Trust and the Environment Agency are keen to establish how efficiently the pass/easement operates, as the principle could be adopted at other similar challenging sites. In order to get a comprehensive assessment, an exciting opportunity arose to work with Durham University who will use the project as part of a wider study looking at fish passage past human made barriers. That’s the good news. The bad news being that in order to be ready for the dace spawning season I was committed to delivering for three weeks through the bleak days of January and February. The summer would have been far too pleasant.

Due to the non-standard design the baffles were manufactured as a bespoke commission carried out by Northwood Forestry & Sawmills, made of oak as opposed to the standard recycled plastic. Once complete, myself and Norm spent the first week of the year huddled in his workshop drilling and bolting the stainless steel angle to each baffle which would enable them to be securely fixed to the concrete weir. All 36 pieces of the jigsaw were complete, coded and stacked in the lockup ready for installation.

049

In the workshop with Norm fixing the stainless steel angle to the baffles

050

Half of the baffles with angle attached and coded ready to go

The baffles would have to wait, as first we needed to help fish of the anguilliform variety, eels, to also be able to successfully navigate past the weir. With the eels having already made the 6000+km epic journey from the Sargasso Sea we were keen to ensure this weir would not be an abrupt dead-end. Although there was an eel pass on the weir, it has been largely ineffective for some time. A new and improved pass was called for, so out with the old and in with the new.

053

Out with the old…

062

and in with the new

With the eel pass installed, preparation to fix the baffles was underway. This primarily revolved around creating a dry working area, not necessarily an easy task when working in a river but with the temporary coffer dam supplied from RN Inspection Services this was achieved with unbelievable effectiveness.

073

The coffer dam installed providing a manageable working area behind

For the next two weeks, Roo and I lugged baffles, drilled holes, spaced, chocked, clamped, injected resin, removed then re-erected the dam and battled the elements. As the jigsaw slotted together the theoretical schematic drawing I was now well familiar with became a reality.

087

The baffles being clamped into position before the stud secured to the concrete with resin

090

Getting into the flow of things

133

Half way!

153

Time to move the dam and install the second half of the baffles

191

Finished! The notch bisecting the baffles to allow a deeper channel for fish to pass

Once complete, the time came to remove the dam and allow the water to flow over and through the baffles. With this action the Hogsmill became re-connected to the Thames once again.

The time lapse of the build conveniently summarises the full 3 weeks into 1 minute video can be seen here:

199

About to ‘pull’ the dam

211

Flow and fish passage returned to the channel

Over the coming year JBA (hydrology experts) will undertake a spot flow-gauging program, to ensure that the weir continues to gauge accurately with the modifications. Meanwhile Angus at Durham University and ourselves will monitor the LCB fish pass/easement aiming to understand its performance for coarse fishes such as chub, dace and roach.

184

One aspect of the monitoring is a camera looking across the upper notch

A BIG thanks to: All those involved in the various teams at the Environment Agency, partners in the project especially those in Hydrometry and Telemetry and Fisheries.  Angus, Martyn and Jeroen at Durham University for bringing their wealth of monitoring experience and expertise to the project. JBA for carrying out the hydraulic assessments associated with the project. Bedelsford School who kindly agreed to us hooking up to their electricity supply to power the monitoring equipment. Rob Waite at the Royal Borough of Kingston for helping us to secure access and parking at the site. The Thames Anglers Conservancy, especially Will, for getting involved and helping to install the eel pass. Norm Fairey for your continued help with all things fishy and manufacturing. And my good mate Roo for the long hours, hard graft, permanently cold hands and near permanent good humour.

 

Get ready for London Rivers Week 2017

Get your diaries out and calendars open, the dates for London Rivers Week 2017 have been confirmed!

LRW logo finalLondon Rivers Week 2016 brought together many partners across London, delivering a total of 35 public events to get everyone involved with their local river. This year, we want to make it even bigger and better.

London Rivers Week 2017 will start on Monday 26th June and run through to Sunday 2nd July. During this week, organisations across London will put on a variety of river themed events including cleanups, guided walks, information talks, citizen science taster sessions and more.

To find out more about London River Week, check out the Thames 21 website page where all the events will be listed: http://www.thames21.org.uk/londonriversweek/

Until then, keep your eyes peeled for more details on what is to come!

20161935823_00d2bef0b3_o

Three Weirs: Part 3

Author: Nick Hale, Project Officer

Read Part 1 and Part 2 first!

And so 3 weirs fell!

Gatehouse, Weir 1

gatehouse-1

New Lodge, Weir 2

new-lodge-2

and Dairyhouse, Weir 3

dairyhouse-3

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!

1

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.

2

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.

10 14

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!

Eel Passage on the Hogsmill

During the summer a collaborative project between Zoological Society of London (ZSL), Surrey Wildlife Trust Kingston Group and the South East Rivers Trust (SERT) was undertaken to improve elver and eel passage on one of the lower weirs of the Hogsmill, the Clattern Bridge weir.

The European eel is a critically endangered species and needs all the help we can give it.  Pollution, overfishing, global warming, disease and habitat loss have all contributed to the demise of this charismatic species. The eel has a fascinating and mysterious life cycle in which it starts life in the Sargasso sea as a larvae, migrates across the oceans via currents to European rivers, metamorphosing a couple of times on the way to become glass eels and then elvers.

Once in rivers, such as the Thames and the Hogsmill, they migrate upstream to find habitat in which to grow and develop into yellow eels. After 5-20 years of life in rivers like as the Hogsmill they metamorphose again into silver eels and travel back to the Sargasso Sea to complete their life cycle.  Weirs and habitat loss in our rivers are factors that cause issues for eels and stop their upstream migration to suitable habitat.

This project involved installing plastic tiles covered in regularly spaced plastic protrusions onto the weir face.  The weir at Clattern Bridge is smooth and has shallow fast water flowing over it.  The tiles allow eels to wriggle up the weir and into the river upstream enabling them to carry on their migration. Eels are not very good swimmers compared to other fish and prefer to ‘wriggle’ so increasing friction in this way is ideal for them!

Below is a great video of eels using a similar design on the Wandle:

Armed with a couple of battery drills, some long drill bits and various stainless steel fixings we attached a continuous line of tiles to the weir surface.

eels1

It was a lovely sunny day and perfect for a day in the river!

eel2

A big thanks to the Kingston local branch of SWT who provided funding for materials, drill bits and fixings and to ZSL for supplying manpower and eel tiles.

Elvers migrate upstream between April-September and so we are hoping they will appreciate our efforts when they arrive in 2017!

Author: Tim Longstaff

clattern-bridge-23-september-2016-3

How Weirs Affect Fish Communities     

By Dr Chris Gardner

River restoration describes a set of activities that help improve the environmental health of a river or stream. These activities aim to restore the natural state and functionality of the river system to promote improved fish populations, biodiversity, recreation, flood management and development. Restoration to improve fisheries tends to focus on increasing habitat quality and diversity, and a popular method of achieving this is by addressing barriers such as weirs.

Humans have adapted rivers for our own use, modifying them to facilitate land use for agriculture and development, navigation, water supply, power generation and other priorities. Fish evolved in rivers before humans had this influence and are therefore not adapted to the modifications we have made, such as dredged sections, straight uniform channels and weirs.

However, weirs and their associated downstream pools and upstream slow deep reaches are valuable and popular fishing spots as they provide habitats and daytime refuge areas for large adult fishes. So a balance needs to be struck between improving the river ecologically (more fish!) and providing areas where fish are likely to congregate in the daytime when anglers are on the banks (hot pegs!)

Weirs impact rivers in three main ways;

  1. Habitat fragmentation is frequently caused by human activities which disrupt the continuity of habitats used by wildlife and is a terrestrial conservation issue as well as an aquatic one. Habitats which were once continuous become divided into separate fragments, restricting the movements of organisms (g. fish) and separating them from habitats / resources / other fish required for their survival / the completion of their life-cycle. Fragmented habitats are also less resilient, preventing re-colonisation after pollution incidents and lowering genetic variability, due to the restricted effective population size, potentially placing populations at an evolutionary disadvantage.
  2. River habitat is degraded by the creation of an impounded reach upstream (river-like habitats become lake-like) drowning out natural features like riffles, causing important spawning and nursery habitats for river fishes to be lost, thus lowering recruitment and breeding success. Also, natural processes such as sediment transport are prevented. Rivers are naturally dynamic with erosion and deposition occurring in balance, creating a highly varied mosaic of micro-habitats for all life-stages of fishes. Weirs arrest this natural tendency for change, creating a uniform static environment. Upstream an over deep river channel akin to a lowland river is formed in the impounded reach which may be inappropriate for the fish community (for instance, barbel habitat may become bream habitat). Impoundments also alter the temperature regime, oxygen content and cause siltation in the upstream reach.
  3. Sediment transport is halted by weirs, reducing the supply of gravel to the downstream reach, leading to incised channels and reduced spawning and nursery habitats. River channels are natural systems with erosion and deposition occurring in balance. Sediment (e.g. gravel) is shaped and sorted by water flow patterns creating a large diversity of habitat types that support a high diversity of wildlife. Weirs stop natural processes and impact river channels in two main ways; Upstream – Sediment transport is interrupted by the weir, sediment (e.g. gravel) accumulates upstream. Due to the lack of energy in the impounded reach, sediment (e.g. gravel) is not shaped and sorted by the water flow and therefore creates a uniform habitat that supports a lower diversity of wildlife. Downstream – Sediment transport is interrupted by the weir, reducing the supply of sediment (e.g. gravel) to the downstream reach, which is vital for creating habitat features for wildlife. This lack of sediment from upstream leads to increased erosion of river banks and bed leading to channel incision (when a river has cut downward through its riverbed. The river begins at one elevation and incises downward through its bed while leaving its floodplain behind [higher]) throughout its course). Incised channels have knock-on impacts for;

Ecology: The incised channel only connects to its floodplain in extreme flood events, thus higher than normal water velocity is maintained in-channel during small to medium flood events. Aquatic wildlife (e.g. juvenile fishes) may become swept downstream during high flow events. Due to the steep banks there is also a lack of marginal transitional habitats, which is an important habitat in its own right, but also provide a refuge for wildlife in flood conditions.

Flooding downstream: Flood risk may have been increased downstream. Again, the incised channel only connects to its floodplain during extreme flood events, therefore the floodplain cannot store water in this location during small to medium flood events. This water that cannot be stored in the floodplain is quickly transported downstream, where it may contribute to flooding.

Addressing the impacts

Removal of the weir should always be the considered as the preferred option, which solves all the main issues described above. However, total removal is often not possible due to the way the landscape has developed since the weir was built, and there is also a need to take account of the wishes of the land owners and river users, like anglers, who may value the weir and its effect on the river channel. Dependant on this, the next best option may be a partial removal (lowering of the weir) and/or the implementation of a fish passage solution, which solves part of one problem (reducing the impounded reach) and all of the other (connecting the upstream and downstream habitats). Fish passage solutions include natural bypass channels (preferred as these create additional habitat), rock ramps and technical fish passes e.g. Larinier.

The design of a fish passage solution (e.g. a natural bypass channel) needs to take into account the wishes of other river users (e.g. anglers), provide free passage and attraction flow for a range of sizes of the species of fish present through a wide range of flow conditions, and be deliverable for the usually tight budgets available for such works. Modelling, using an existing locally specific Environment Agency flood model (a computer simulation of the rivers flow at a specific location), can be used to satisfy these needs and to ensure no increase in flood risk for any nearby residential properties. This approach is best practice and gives all concerned (residents, deliverer and the regulator) the confidence to implement schemes with the simplest, most cost effective design.

4

Photo 1 – Harpers Weir on the River Teise (Medway catchment, Kent), which was recently removed revealing thirteen new gravel riffles, additional spawning habitat for the native brown trout.

3

Photo 2 – A newly constructed nature like bypass channel around an impassable weir (visible to the left) on the River Darent, Kent.

Migratory fish? All fish!

So, just to reiterate, weirs affect fish communities by causing three main impacts. The first is habitat fragmentation, which prevents fish migration and separates fish from habitats and resources that they need to survive and reproduce. If fish do not have access to appropriate spawning habitat, successful recruitment will be reduced. The second is habitat degradation, as a barrier impounds or backs up a river, producing a lake-like habitat in the upstream section instead of a free flowing river; drowning out natural features like gravel riffles, that are important spawning and nursery areas. And the third is interrupting sediment transport that builds the habitats used by wildlife and fishes.

It is often thought that restricting the movement of fishes only affects ‘migratory’ species such as salmon, sea / brown trout and eels, as their migrations are relatively easy to observe and for many centuries man has been exploiting these behaviours to harvest these fishes from our rivers with fixed traps like eel racks and fishing weirs. However, all fish migrate to some extent, and all fish have life stage specific habitat requirements affected by habitat degradation. Salmonid species are not the only fish that spawn on gravel riffles: coarse species such as barbel, chub and dace are also affected by fragmentation and habitat degradation caused by impoundments. As with all fish species, recruitment success is dependent on the most limiting habitat requirement, potentially causing a population bottleneck. If a section of river can only support 100 juveniles of one year class as a result of the poor quantity or quality of juvenile habitat, this will limit the adult population size, as the adult population cannot be more than 100 of each year class.

Riffles provide cover in the form of weed growth, and are difficult places for predatory fish to hunt due to the fast current. They provide an abundant food supply of invertebrates, and overhead cover from a heavily rippled surface that hides them from predatory birds and other animals. Riffles are a good place to live if you are a baby trout or young salmon. They are also the preferred habitat for juvenile barbel. Riffles hidden under lake-like habitat upstream of a weir, lack the characteristics that make them great juvenile barbel habitats. If there are low numbers of small barbel, then there will be small numbers of big barbel and eventually no barbel at all.

Here, the trout and salmon fraternity are ahead of the game. The economic value of salmon (commercial and recreational) and the large declines in salmon populations since the 1980s have caused scientists and anglers alike to research and understand what the habitat requirements are for all life stages of these fishes. They have used this information to minimise potential population bottlenecks or limiting factors, due to available habitat. There are many things impacting our fish populations, but in-river habitat is the one thing that is relatively easy to address and benefits all wildlife. Organisations like the Wild Trout Trust have been encouraging progressive thinking and educating game anglers in fisheries management and river restoration. Lots of great work is going on out there, which is having a real positive effect on stocks. Coarse anglers need to take heed and follow this successful model, if we are to continue to enjoy high quality river fishing.

Coarse fish migrate and need to move around a river system to locate specialised habitats required at certain times and during certain conditions. Adult coarse fish such as chub, barbel, bream and roach migrate to spawn, often upstream, but also searching out the highest quality spawning habitat available to increase the survival of their eggs. Coarse fish lay their eggs on gravel (chub and barbel) and weed (bream and roach). The eggs take a few days to hatch into larvae and these larvae are then free-drifting with the flow of the river, until they find a suitable slack.

The movement of fishes

Modern telemetry tracking studies using implanted radio or acoustic tags have revealed these migrations. For example, in 2010 Dr Karen Twine, of the Environment Agency, radio tracked 20 adult barbel (6-15lb) in an 8.2 km reach (between two impassable weirs) of the Great Ouse for a year and a half. She demonstrated that the barbel utilised most of the river length available to them and made seasonal movements to spawning and over wintering habitats. Similarly, in 1993 Dr Martyn Lucas, of Durham University, radio tracked 31 adult barbel (2-6lb) over 15 months in a 7.2 km reach of the River Nidd, a tributary of the Yorkshire Ouse, with open access to the Ouse. Again these fish were highly mobile, ranging over sections of river from 2-20 km in length, and their movements were associated with seasonal shifts in habitat, upstream spawning migrations and downstream migrations to over wintering habitats in the lower reaches and main River Ouse. Fish will basically move as far as they are able, to fully exploit the best available habitat / resources: the more limited those resources, the further they will go.

Other studies on less fragmented rivers with more limited essential habitats have shown that fish have the potential to move over very long distances, where they are able to, due to absence of weirs that would otherwise restrict their movements. During my PhD in 2006, I tracked the movements of 80+ adult common bream (4-7lb) over four years in a long 40 km reach of the Lower River Witham, a very uniform fenland river in Lincolnshire. My bream were tightly shoaled and relatively immobile in a deep tributary off the main river at the upstream extent of the reach during the winter, moving short distances of, on average, about <5 km a month, up and downstream. In the spring, they became highly mobile moving on average 30 km a month utilising the entire length of the river available to them, with one individual moving over 120 km in a single month! At this time they were visiting shallow tributaries off the main river, before using these for spawning in late May / early June. Once they had spawned, they spread out and spent the rest of the summer in the main river foraging, again moving on average 20-30 km a month up and downstream. In the autumn they moved back upstream to the deep tributary for the winter. This same yearly pattern was observed throughout the study.

These studies demonstrate that adult fishes use different habitats at different times of the year and require free passage between them. Habitat requirements are different for adult and juvenile fishes, so during its life a fish will have many different habitat requirements. These requirements will be more crucial for juvenile fishes, due to their vulnerability to predators and therefore their need to find safe cover. If any one habitat type is lacking, limiting or inaccessible, there will be consequences for individual survival and therefore the population as a whole. Weirs often restrict populations to those reaches that have sufficient connectivity to enable life-cycle completion, with the availability of the most limiting habitat type being the controlling factor or bottleneck for the population.

Flood resilience

During my PhD I re-captured three of my bream that I’d been tracking for over a year and moved them 35 km downstream. They returned to their original point of capture within, on average, two weeks. Other fish species have also been shown to have this homing instinct and are therefore very aware of their surroundings. Floods often displace fish downstream, where there are no barriers to their movements, fish will follow their homing instinct to return to their previous area of residence once the flood has subsided. However, if the flood pushes them over an impassable weir they cannot return and as such fish can work their way further and further downstream.

One concern anglers and fishing clubs may sometimes have about weir removal is that club waters often only stretch for a few hundred yards, and anglers will want to keep ‘their’ fish in ‘their’ water. Weir removal presents a risk that fish may move to another section of river, free range fish! However, addressing degraded and fragmented habitats will improve the environment and lead to a healthier ecosystem with more fish in the longer term for all.

Drought resilience

A common misconception raised by anglers and members of the public, is that weirs delay river discharge and therefore make the river more resilient to drought. Weirs do hold back a quantity of water in the upstream impoundment, however on the river catchment scale this is generally a very insignificant amount, unless the weir is tens of metres high (i.e. a dam to create a reservoir). This impounded water does not slow the rate the river discharges at the catchment scale, they just store water in the upstream impoundment at the local scale and once the impoundment is full, the river flows over the weir at the same rate it enters the impoundment. If we use filling the kitchen kettle as an analogy, the kitchen tap runs and the kettle fills up. The tap is the river and the kettle the impoundment, once full the kettle overflows at exactly the same rate as the tap runs and the water bill ticks up exactly the same.

In the event of drought, rivers tend to dry from their upstream end first, impoundments upstream of weirs can and do provide refuge areas for fish in such an event, however these areas are likely to be heavily silted (as impoundments accumulate silt due to the lack of flow) and will quickly deoxygenate due to biological processes in the accumulated silt, given no freshening flow from upstream, leading to fish deaths. Fish will move downstream naturally in response to a drying river, using the rivers flow as a means of navigation (this is known as rheotaxis; negative rheotaxis for moving downstream with the flow and positive rheotaxis moving upstream against the flow). However if the fish encounter an impoundment upstream of a weir on this journey (a refuge migration), and there is no flow going over the weir, due to the drought, there will be no flow cues to navigate by. In this situation the fish will be unable to move any further as they simply will not be able to locate the exit. If no weirs exist, in the same drought situation, fish will move downstream just the same, seeking out deeper fresher water for refuge in the lower reaches of the river and once the drought has broken, be able to move back upstream to their previous haunts. When I worked in Dorset, there was a winterbourne stream (a stream that only flows when the aquifer is full, usually in the winter months), a tributary of the Dorset Stour, which had a number of weirs along its length. Every winter the stream would flow well and fish (usually trout and grayling) would enter to spawn. However, once summer arrived the springs that fed the river would stop and the river would dry. However, the weirs created impoundments that would trap fish and they would require rescue by the authorities and local residents to move them back to the main river and unfortunately mortalities would usually occur, even with such interventions. So in fact, perhaps counterintuitively, weirs actually reduce a rivers resilience to drought and can cause fish kills if fish become trapped in upstream impoundments instead of being able to move naturally in response to their environment.

Conclusion

The impacts caused by weirs are problems for coarse fish as well as salmon and trout: the principles may not be as well understood or as popular, but they are real. We need to address this and other factors that are limiting fish populations if our rivers are to fulfil their ecological potential.

2

Photo 3. Juvenile barbel have similar habitat requirements to salmon and trout parr: riffles provide cover from weed growth, an abundant food supply of nymphs dislodged by the fast current and overhead cover, due to the heavily rippled surface, that hides them from predators.

1

Photo 4. Male bream guarding marginal spawning sites in a shallow tributary off the main River Witham, Lincolnshire, in late May. Bream utilise oxbow lakes as spawning sites in natural ‘unmodified’ rivers: these shallow fen drain tributaries provide a surrogate habitat that allows them to reproduce. If these were unavailable or inaccessible due to impassable weirs, the bream population would suffer.

Working on the Eden

In August 2016 we were contracted by Kent Wildlife Trust to install a backwater on the River Eden near Penshurst in Kent.

The river Eden is in the upper reaches of the Medway catchment and joins with the Upper Medway approximately 1 km downstream from Penshurst.

What is a backwater and why is it needed?

A backwater is an aquatic habitat connected to the main channel, sometimes only during higher water levels. Backwaters can be formed naturally as a river migrates across its floodplain, cutting off meanders.

Backwater habitats can be used on rivers that have been straightened or resectioned to increase the diversity of flow, habitat and ecology.

In this case we were asked to install a backwater that would provide two important functions for the river depending on the flow. In high flows, the backwater would become a refuge of slack water for adult fish to rest in until the normal flows return. In normal flows, the shallower water left in the backwater will warm up quicker than the main channel and act as a nursery area promoting the growth of young fish fry.

willows

Photo provided by Kent Wildlife Trust of project area last Winter 2015

What we did

The project got off to a quick start with local tree surgeon Ivan Carson, from Penshurst Tree Surgery, making short work of the 3 cricket bat willows.

These willows were coppiced to near ground level to allow more sunlight to reach the backwater – helping to raise water temperature during normal flows. A bonus benefit of this tree removal is a reduction in the amount of leaf litter entering the backwater, reducing future maintenance.

With a tight schedule, work on the backwater commenced. First the old fence was removed and the topsoil was stripped back.

Our expert excavator, Jimmy, started shaping the backwater entrance. All the spoil we removed was tracked to the far end of the landowner’s orchard to improve their existing track.

Everything seemed to be going smoothly until Jimmy’s bucket hit something solid! This turned out to be a huge tree trunk of approx 1 m diameter running parallel to the river, across the backwater entrance.

digger-and-trunk

trunk

With no idea how long the trunk might be, we decided to remove the central section. Most of it was actually below water level, which meant our saw wasn’t quite up to the job. Fortunately, Ivan kindly lent us one of his and the obstacle was overcome by our very own Toby.

The silver lining of this small delay was that we didn’t need to install any large woody as cover for fish.  We even spotted a Perch of approx. 1.5 lbs sunning itself in the shallows until it was spooked, and darted underneath one of the remaining stumps – woody cover in action!

Whilst Jimmy was finishing off the backwater, Toby and Alex started to install the new fencing around the backwater. This fencing will exclude cattle from the backwater, preventing over-grazing and reducing bank erosion.

fencing

With the backwater construction complete, it was time to add the plants. Marginal plant plugs were added around the backwater, and wild flower seed was scattered on the ground to provide some ground cover before winter.

clearing-up

The landowner seemed really happy with the final result – especially once he saw all the marginal plants.

The project took 6 days to complete and we look forward to seeing how the backwater matures overtime.  Lots of fish fry were spotted on our most recent site visit which suggests we did a good job!

dsc_0011

The Hogsmill: A Work of Art

You may remember that earlier this year we were lucky enough to spend a week in the Hogsmill with the Lower Mole Partnership. It was a chilly week in March but all our volunteers were enthusiastic and we managed to restore 500m of river through the Hogsmill Local Nature Reserve. With wood from the local area we created 9 brash berms, narrowing the river to increase local flow diversity. We pulled out 48 railway sleepers to reconnect the river to a natural bank, and in more difficult places we naturalised the bank with pre-planted coir rolls. A busy week to say the least.

hogsmill-merge

What we weren’t aware of was that Peter, from the Lower Mole Partnership, turned our week in the river into a work of art. Check it out…

imgp3013

It was such a great week and we hope to be back again – with another painting!

Outfall Safari on the Hogsmill

ZSL and the Hogsmill Partnership are looking for volunteers to help us map polluted outfalls on the Hogsmill this October.

While walking the Hogsmill you may have noticed all the different pipes that can be found along the river bank. These pipes are usually part of our surface water infrastructure, transporting clean water from our roads and roofs into the river. However in some cases, these pipes or outfalls can be polluting the Hogsmill as they have been misconnected.

Polluted Outfall

Misconnections are a BIG issue for urban rivers and the Hogsmill Catchment Partnership have been working hard to start addressing this on the Hogsmill River.

A misconnection is when a toilet or washing machine has been connected to the surface water drain heading straight to the river, instead of the sewer system. You can read more about misconnections at on the Connect Right website.

Connect Right

This October, ZSL are running an Outfall Safari to map all these pipes heading into the Hogsmill, and assessing their condition to check for misconnections.

Volunteers will receive training on how to recognise signs of pollution at these outfalls and record the pipes on a new smartphone app. This survey data will greatly improve our understanding of the river system and help to target sources of pollution.

Interested?

If you would like to join the team, you can sign up on EventBrite to register your interest. Once you’ve registered, more information will be sent to you about where and when the training sessions will take place.

Sign Me Up!

For more information contact by email: Joe.Pecorelli@ZSL.org, or phone: 07974 725 557
Outfall BannerPlease register your interest to help at: hogsmilloutfalls.eventbrite.co.uk

You’ll need to read this before your training session: 2016-Pre-training-information-for-Hogsmill-Outfall-Safari-Volunteers..pdf

Planting on the Beverley Brook

The Beverley Brook in Richmond Park has had a serious makeover recently. Through the Park, the river was severely overwide and slow moving, leaving a silty channel bed with little habitat variation for invertebrates and fish. Earlier this year, we undertook a large scale restoration project on a 600m stretch of the Brook – you can read all about what we did and why in Toby’s blog here.

Before and After Beverley Brook

Following this, we teamed up with the Friends of Richmond Park to plant trees along the banks of the Beverley Brook – providing shelter and shade in just the right amounts.

GetImage2The next step was marginal planting – so we called in some reinforcements…

Thanks to our successful bid to Tesco’s Bags of Help fund, we have been able to organise two planting days on the Beverley Brook – adding 6000 plants to the restored stretches of river. These will grow up to create great marginal habitats as well as replenish the seed bank of the river downstream.

Across the two days (Saturday 9th & 23rd April), we were joined by a total of 65 volunteers.  To start each day off, Toby gave a quick tour of the works so far while I colour coded the plants on where they should be planted. Blue plants were to be added on the water line, red and yellow to be in the marginal zone and green to be higher up the bank.

IMG-20160420-WA0011

We had ordered a variety of species, some of which are currently absent from the Brook due to the last couple of centuries of mans’ influences. We used similar and nearby rivers such as the Hogsmill and Wandle as a guide for what should be there and used historic evidence, such as Milais’s Ophelia, which was painted on the Hogsmill, to direct these choices. By planting in our fenced sections, we give the flora a chance to establish a seed bank ensuring they continue to flourish on the river for many years to come.

Ophelia 1851-2 Sir John Everett Millais, Bt 1829-1896 Presented by Sir Henry Tate 1894 http://www.tate.org.uk/art/work/N01506

Ophelia 1851-2 Sir John Everett Millais, Bt 1829-1896 Presented by Sir Henry Tate 1894 http://www.tate.org.uk/art/work/N01506)

With 65 volunteers and 6000 plants, everyone had a target of 92!

IMG-20160420-WA0012

Most of our planting was focused on the new berms created when Toby narrowed the river.

We also installed two kingfisher nest boxes along the banks of the brook. These boxes are specially designed for Kingfisher nesting. They are buried into the bank and lined with mud to allow the birds to create their nest more naturally.

Kingfisher Nest

IMG-20160420-WA0015 (1)

Big thank you to our volunteers: Abane, Ajith, Alana, Amanda, Anishka, Barbara, Bella, Bindu, Brandon C, Brandon O, Brian, Carolyn, Charles W, Charles C, Chris, Dave J, Dave W, David H, Ed, Edward, Eric, Gearoid, Graham, Guy, Harriet, Heather, Ian, Jane E, Jane P, Janet, Jill, John, Jon, Kish, Loredana, Lucy, Mariam, Mark, Matthew, Mike, Nicola, Path, Phil, Rhianna, Roger, Rosie, Sharika, Shivani, Steve, Vela, Victoria and Wally

IMG-20160420-WA0016

Planting

About Tesco Bags of Help

Tesco teamed up with Groundwork to launch its Bags of Help initiative across Scotland, England and Wales. The scheme has seen three community groups and projects in each region awarded grants of £12,000, £10,000 and £8,000 – all raised from the 5p bag charge. Bags of Help offers community groups and projects in each of Tesco’s 390 regions across the UK a share of revenue generated from the five pence charge levied on single-use carrier bags. The public voted in store to decide which local groups should receive the £12,000, £10,000 and £8,000 awards.

Award Winning Restoration on the Wandle

Our rehabilitation work on the River Wandle’s Carshalton Arm has won the Urban Category of the 2016 UK River Prize.

By opening up fish passage, enhancing river habitat, addressing urban diffuse pollution and reintroducing brown trout, we have attained ‘Good Ecological Potential’ for the Carshalton Arm and re-established trout for the first time in over 80 years!

We attended the Awards Ceremony in Blackpool this week at the River Restoration Centre‘s Annual Conference to collect our award and showcase our project to the wider river community.

We wouldn’t have been able to achieve this without all the people and organisations who helped us along way. To express our gratitude, we created this short film about the journey this project has taken us on.

Restoring the Hogsmill with Volunteers

A lot of our projects recently have been large scale – removing weirs, installing fish easement solutions and reprofiling large sections of river. But now it was time for the real professionals to step in…

Volunteers

For one week in March, Toby and I were in chest waders in the Hogsmill in Ewell. Over 5 days, we were joined by volunteers from the Lower Mole Project and other local volunteers from the Hogsmill Pollution Patrol and the Wandle – all trying river restoration first hand.

The River Hogsmill is a chalk stream in south London where we’ve been working to increase habitat connectivity over the last few years. Toby has been busy removing weirs where possible, or installing rock ramps to make them passable to fish.

In Ewell, Toby removed 3 small weirs to open up fish passage throughout this 1.6 km stretch. What was missing was fish habitat.

So what did we do?

The Hogsmill through the Open Space is artificially straightened and canalised with wooden toeboarding. There is little habitat variation in channel with slow moving water and a silty bed.

Straight Channel

On the first day, a team of volunteers got stuck in pulling out the large railway sleepers serving as toe boarding. Over the next four days, a total of 48 sleepers were removed – the first step in naturalising the bank for 1km through the park.

Sleepers

Meanwhile, carefully-selected trees were felled to increase light reaching the river. With this material, we started to create brash berms to narrow the channel and increase flow.

A holding log was placed at the downstream end of the berm and secured in place with posts and wires. Then brash from the surrounding areas was added to build up a berm.

Holding Log

This was all secured in place with chestnut posts and wire across the brash after some technical “squishing”…

Squishing

Over the next four days, the volunteers created a further 8 berms. You can see from the photos that the river began to respond instantly. Flows were increased where the channel was narrowed and scoured pools started to form.

On the last day we moved our attention further downstream to the site of a weir removal in 2014. Here a small weir and concrete abutment walls were reduced, but due to the close proximity of the path had to leave a semi-engineered bank.

To enhance this, pre-planted coir rolls were fixed along the bank to soften this edge and create a more natural marginal habitat.

Coir Rolls

To install these though was no simple task. They were secured in place with chestnut stakes and wire thread round the posts and through the mesh of the bank line. Believe me, that was a skill in itself…

Wiring Coir Rolls

Here are some photos of what we all achieved..

Finished!

Big thanks to everyone who came along!! We’d also like to thank Epsom & Ewell Borough Council and the Lower Mole Project.