The 2015 river monitoring season gets underway

A guest blog post by Laura


This week marks the start of the ‘spring’ ecology sampling season for my team.  Today I was out collecting invertebrates in Upton, Pershore, Evesham and Broadway, in Worcestershire. I catch the creatures using a method called kick sampling. 

In a nutshell I kick around in the substrate and search under stones to look for invertebrates, they are collected in the net then transferred to a tray.

I pick out all the leaves, sticks and stones, checking none contain invertebrates.  The sample is then tipped back through the net, the water drained off and placed in the container.  

Data is then collected on substrate type, surrounding vegetation, width, depth, plant growth etc.  All this has an impact on the site and can affect the biological water quality and hence the type of creatures present.  Data is automatically uploaded onto a database. 

Once back at the lab the sample is preserved in methylated spirit so the it doesn’t degrade.

Each invertebrate has a score; 1 reflects poor (low) water quality and 10 is excellent (high) water quality.   The photo below shows leeches, molluscs and shrimp (I won’t bore you with the Latin names) from Mere Brook. This initially tells me the water quality is average as these species can tolerate heavy sedimentation and low water quality.  

However, the picture below shows a high scoring cased caddis crawling along the container, its case is made from tiny sand grains.

Cased caddis out of its case

Its’ presence shows the watercourse must be good quality.  Just from poking through the sample in the tray I can see lots of species that indicate good water quality.  Once under the microscope our experts can pick out the smaller species, the scores are added up and this gives the site an overall score for biological quality.


In the photo below can you spot the difference between the 2 inverts and the sticks? That is what samplers are trained to do.  You need attention to detail in this job!

In Piddle Brook at Pinvin and Seaford there were more high scoring inverts present, mostly different types of cased caddis fly larvae.  In photo below you can see the cased caddis fly larvae has crawled out of its case which is made from sand grains.  Some make a case out of tiny sticks and leaves.

The caddis fly larvae places 2 stones on either side of their case when constructing it that create ballast so it can crawl along the riverbed.  It is able to retreat into its case to prevent fish from eating it.  If it didn’t have ballast it would get swept away into the water column. 


I finished the day in Broadway kick sampling the Badsey Brook. Once back at the office, all 3 pairs of waders, trays, nets and gloves were disinfected and hung up to dry.  

This is what we call biosecurity. We take is very seriously as it can prevent the accidental transfer of diseases and invasive species from one waterbody to another.

They’ll be used in the Sud Brook at Gloucester tomorrow when the monitoring programme continues!


Green shoots of recovery on the River Chelt – and lots of them!

It’s just over a year since we finished an ambitious project to realign a section of the River Chelt in Gloucestershire to improve its habitat value and make it more accessible to fish. I’ve been back to have a look how things are working out.

The Project

The River Chelt is a small tributary of the Severn. It rises on the Cotswold escarpment near Dowdeswell, flows through the middle of Cheltenham and joins the Severn at Wainlodes. Over its short length it changes from steep fast-flowing brook to a slowly meandering small river.


The project was carried out about a mile from the Chelt’s confluence with the River Severn, just before it passes under the A38. The river had been significantly modified here to enable the operation of the now redundant Norton mill. It had been straightened to increase the flow velocity and a small weir installed (photo below). The weir presented a significant obstacle to fish trying to swim upstream, while the steep banks offered little opportunity for wetland plants and animals.


During September and October of 2011 we realigned the course of the river to bypass the weir and straightened length. We created a new, meandering river channel, which would have been much closer to its original form, and a range of bank slopes.


In bypassing the weir we opened up a further 6km of the river upstream to fish and a hectare of wetland habitat was created alongside the river.


However, as you know,you can’t make an omelette without breaking eggs, and I have to confess things did look a bit like a building site when we’d finished.


What a difference a year makes

Our new section of river has received a number of good tests over the last year. Repeated bouts of summer and winter flooding through 2012 and 2013 resulted in some very large amounts of water being forced through the new channel and in some cases exceeding its capacity and spilling into its floodplain (as it was designed to do).

The speed of plant establishment and growth has been amazing. Not only have the many small trees we planted with the help of local volunteers settled in well, there is already a good variety of wetland plants along the course of the realigned river.


It’s also very pleasing to see the diversity of habitat developing within the river. Areas of gravel and stones on the river bed should provide good spawning opportunities for fish while fresh silt deposits will be great for feeding birds. Part of the old channel was retained and now provides and excellent refuge for fish and insects.


We’ll monitor the progress of the site over the coming years to see what species of plants, fish and birds move in, but the initial signs are very promising. Indeed, as if to prove the point, as we arrived a large egret which had been feeding along the river, flapped lazily away!


Part of a much bigger plan

Our work on the Chelt is just one of hundreds of projects across the country aimed at improving our rivers. It’s all part of the plans to deliver the objectives of the Water Framework Directive which requires us to improve the health of rivers.

We’ve identified where the condition of rivers isn’t as good as it should be and the causes of the problems. There is a variety of issues affecting our rivers: man-made alterations to their shape and form (like here on the Chelt), obstructions like weirs, pollution from single point sources, pollution from run-off of chemicals, soils and nutrients, low flows and the presence of alien species. We’re working with partners to develop long-term plans to tackle them all.

Discover more in our interactive presentation:

Gardening skills to help fish

On Tuesday 25th March representatives from eight angling clubs, from the Shrewsbury area and further afield, met on the River Roden north of Shrewsbury for a demonstration day of river habitat restoration techniques using large woody debris. The day was organised by Environment Agency Fisheries staff in conjunction with the Wild Trout Trust, with the aim of providing representatives from local angling clubs (and partners such as the Severn Rivers Trust) the opportunity to witness and take part in practical demonstrations of techniques, which they could then put to use in future back on their own stretches of river.


Despite the weather the day was a great success, with 19 attendees treated to demonstrations of various techniques such as pleaching (hinging) of hazel / alder / willow / hawthorn trees alongside the riverbank and also the introduction of brushwood structures to margins of river.

All techniques have the aim of creating dense cover for juvenile fish species. However, they also have the benefit of improving river bank protection by making it more resilient to erosion. Brushwood gathered from nearby coppicing work and recent storm damage was also utilised, whilst fixing methods included stakes and wire for bundles and also pinning trees with metal bars so they don’t dislodge form the riverbed.

The work will help to trap silt and clean the gravel on the river bed to provide improved trout spawning habitat.

More habitat days are planned on the River Frome in Gloucestershire and River Leadon in April, again organised by our Fisheries staff and led by the Wild Trout Trust.

Events like these are made possible by the money we receive from fishing licence sales, buy yours here.


Fishy health checks in Shropshire

Our fish monitoring programme is now in full swing and our people have been undertaking lots of electric fishing surveys. On Wednesday 18th June we surveyed the River Onny near Onibury in Shropshire.

Using electric current we surveyed 100m of the River Onny and caught:

127 juvenile Salmon

18 Brown Trout

3 Grayling

2 large eels

We measured all the fish and removed 3 scales from each salmon and trout in order for them to aged by our Brampton Laboratory.

This is a fantastic result! We counted salmon redds (nests) on this same stretch in October and November last year and saw salmon spawning, redds and dead kelts (fish that have died from exhaustion after spawning).

The large numbers we caught shows the river in a great health and that not all the redds got washed away by the winter floods.

Staff from the Centre for Environment, Fisheries and Aquaculture Science (CEFAS) joined us and took 30 salmon parr away to check if they have a parasite, Gyrodactylus salaris.

It is a category one notifiable disease. The parasite has decimated rivers in Norway and CEFAS check each catchment in the UK every 5 years. Luckily no parasites have been found in our rivers to date.

Trout and chips (of the micro variety)

We have lots of weirs in rivers which are used to provide us with flow information which we use to issue flood warnings and control abstractions in times of dry weather. However, these structures can prove difficult obstacles for fish to get over, reducing the lengths of river available to them. We assist fish passage wherever we can and on many structures have built fish passes.

This week we have been carrying out some research into how easy it is for fish to use one type of fish pass. The location was a gauging weir at Bishop’s Frome on the River Frome in Herefordshire.


The weir has a Hurn baffle fish pass installed. This has slots which are placed in a row straight up the weir face to encourage fish to jump straight up and over the weir. This is a common installation on our gauging weirs as they are gently sloping.
On longer, steeper slopes, the baffle slots go diagonally up the slope so the fish can expend energy, then pause, before going again, all the way to the top.

We commissioned our consultants, APEM, to investigate whether such a design is suitable as an ‘all species’ (chub, dace, roach, trout) fish pass or whether it is trout specific. We have started the investigation by looking at how easily trout can negotiate the pass.

APEM staff electro-fished the River Frome and caught 14 brown trout (all over 150mm). The fish were anaesthetised, and a PIT tag (micro chip) was inserted into the fish. The fish were measured, the PIT Tag serial number recorded against the length and they were released downstream of the weir.


When a fish passes through antenna loops placed at the top and bottom of the weir, a camera and sensors record the bar code and capture an image of the fish which is recorded on a hard drive.


Five days after the fish were released 5 have gone over the weir (they were detected by the upper antenna). Strangely those 5 fish include the smallest (188mm) and the largest fish (338mm) that we tagged. The other 9 fish appear to still be nearby as they have been picked up by the lower antenna loop but have yet to make it to the top.


The antenna loops will remain in place for at least another week to help monitor the movements and behaviours of the fish when confronted with this type of baffle configuration.

Measuring progress on the Horsbere Brook

Our fishery folk have been out on the Horsebere Brook in Gloucester undertaking an electro-fishing survey as part of our Fisheries and Biodiversity investigation programme. This was following work at Brockworth, between Mill Lane and the A46, to help address some of the issues that affect habitat quality and wildlife in the brook.


The project manager, Cathy Beeching also invited members of the community and three Brook Wardens were able to attend.


The brook is classified as poor overall for fish, under the Water Framework Directive, due to a lack of some fish species you’d expect to find such as bullhead and brown trout. This is partly because the shape of the river, and its banks, has been changed from their natural state over the years. Channel straightening, man-made banks, tipped rubbish and rubble have all reduced space for water and wildlife. Although the Horsebere Brook is a naturally active and changing watercourse, erosion and siltation has been exacerbated by water running quickly off neighbouring hard urban areas.

At the three survey locations, some eels, perch and roach fry were caught.


Even two brown trout were found upstream of the habitat restoration site, showing a welcome improvement in fish species.

What were the Improvement Works?

As part of the Environment Agency led improvement works last summer we restored two cut off meanders. This lengthened the brook and created more habitat. One meander bypassed a section of concrete channel, which had scoured out a deep drop in the river bed and blocked fish movement.


We also worked with Severn Trent Water to replace two failed and unsightly Storm Water Outfalls. The headwalls, which form the pipe outlet, were set a little further back from the bank, and constructed with more natural materials, to help them blend into the environment and reduce the speed of water entering the brook. At the same time the opportunity was taken to scoop out the river bank to restore a natural profile and wetland edge, and improve views and access to the brook, including more space for water in high flows.


These interventions complemented an ongoing programme of improvements by the local community, with the Parish Council and Severn Vale Housing and Tewkesbury Borough Council, to stop fly tipping, and enhance the brook.


We hope that all the volunteers who have planted trees, picked litter, maintained paths and made brushwood bundles for the restoration works will welcome the improving diversity of wildlife in this important urban brook.


Lem Brook Himalayan Balsam carnage!

We’ve just finished a pilot project with the Worcestershire Wildlife Trust in the Wyre Forest which seeks to completely wipe out Himalayan Balsam (HB) along the length of an entire stream.

Why – it’s pretty!

There’s loads of HB growing along streams and rivers right across the UK and it does indeed look very impressive. It was introduced to the UK in 1839 as a garden plant. Problem is, it’s too successful at spreading and out- competes native plants resulting in large areas where nothing else grows. It also spreads very quickly, particularly along watercourses. HB produces 5-6000 viable seeds per square metre!

In the winter the HB all dies back leaving large areas of bank free of vegetation. When there is a flood or high water a lot of soil gets washed into the stream or river clogging the gravels on the bed. Fish and insects then find it difficult to breed and survive in these conditions.

Problems in the Wyre

The Dowles Brook is the largest stream running through the Wyre. We know that sediment is a problem and one of the reasons it fails its Water Framework Directive status.

By carrying out extensive surveys of the area (on foot!), we found the worst HB problems were on the Lem which is a small tributary of the Dowles Brook.

So our plan is to blitz the Lem Brook and see if HB can be completely eradicated.

What we’ve done

The challenge is big. We’ve contacted 28 landowners and carried out a detailed survey of 6km of brook.

Out of them 16 landowners are directly involved and 3km of bankside have been completely cleared by hand.

We know that HB seeds stay viable for up to 2 years so we will be returning next year and beyond. We will also continue to survey any re- growth and monitor any improvements in water quality.

Some folk think hand pulling can’t achieve full eradication. We’re carrying this project out on a single small catchment to see if it can!