Open Aireways

Ellie's Weir...ed Blog

In this post our GIS whizz Ellie Spilsbury outlines some of the work we have been doing to identify ways to improve the sustainability of the fisheries in our rivers and hopefully aid the return of salmon for the first time since the Industrial Revolution.

Look closely and you will see hundreds of Minnows collecting at the bottom of this weir, unable to ascend. See the area in the water that looks dark brown; they are Minnows.



Visit each of the three sections for more detail:

A familiar Story

Data analysis with a Salmon Splash of professional opinion

(Tr)outcomes expected










A familar story

Once upon a time, our River Aire had the highest Salmon population of any Yorkshire river. Then came the Industrial Revolution, which saw the wool and fabric industry boom throughout Yorkshire. Mills were constructed accompanied by weirs to harness our river's energy. Although the mills are now closed and are becoming swanky new flats, the weirs often remain, isolating ecosystems that lie between them. Weirs disrupt the natural transport of sediment downstream, causing a build-up of silt and gravel behind the weir, which is detrimental to the habitat of spawning fish. Since 2011, one of the Aire River Trust’s goals has been to increase the connectivity of our river and its tributaries by removing or re-configuring weirs to allow fish passage. Following earlier work to install fish passes through and downstream of Leeds, significant steps towards this goal were made in 2022 with the successful construction of four fish passes as part of the DNAire project.

When we see water flowing over weirs, creating the sounds of waterfalls and visually pleasing white waters, it is easy to forget their man-made heritage and artificiality. It is hard to imagine seeing through the eyes of a migrating trout or salmon; every cell in its body instinctively directing it upstream to spawn, using both the stars and the earth's magnetic field for navigation and then facing an unpassable wall of Yorkshire-dressed stone. It is often not just the height of the weir that presents the issue but the combination of weir height and the shallow depth of the concrete sill below the weir. The height at which salmon and trout jump is directly affected by the relative depth of the water at the foot of the barrier and the “hydraulic jump,” which boosts their leap.

The Environment Agency (EA) has identified around four hundred river obstacles within the Aire Catchment. However, we believe there to be many more. For example, the EA recorded two barriers to fish passage on Pitty Beck, yet on our Bradford Becks Walkovers, we found 11. This pattern is most likely repeated on each beck.  Currently, tackling the removal of every weir in the catchment is unattainable. So, how did we prioritise them into a workable top twenty?

Data analysis with a Salmon splash of professional opinion

With help from The Rivers Trust, we are the first regional rivers trust to code an ArcGIS tool to accurately calculate the length of a river (including tributaries and forks) that would be opened and re-connected by the removal of every mapped weir in the Aire Catchment. Alongside this, we analysed ecological assessment data, invertebrate biodiversity, local community data (including deprivation), and weir visibility to the public. We assigned a score to each outcome and designed a weighted decision-making matrix that identified the weirs that scored the most highly. The data only tells us half the story, so we took our results to our expert team and discussed those weirs for which a solution in the short(ish) term might be feasible.

Once we had twenty feasible weirs, it was time to ground truth our ideas. The purpose of site visits is to add or, more often, diminish our confidence in the feasibility of the weir so that we only carry the most achievable sites to the next stage. We evaluated the weirs’ condition, site access, utility services or abstraction points, and landowner engagement by photographing and recording the area, our thoughts, and encounters.

The most surprising discovery for me was the actual size of a weir. After months of viewing photographs without visual perspective, weirs can appear to be half the scale of the real-life structure. Take a moment to analyse this photo: how tall do you believe it to be? See the very bottom of the blog for the upside-down answer.






(Tr)outcomes

We are fast approaching the end of the site visits and write-up stage. It is time to narrow our shortlist of twenty weirs down to four. So, it will be back around the table for our professionals to decide on the four “leak” proof projects to invest in. These four weirs will be subject to a comprehensive feasibility study and design process. I hope my next blog post will include more designs, machinery, hard hats and re-naturalised rivers.







River Worth Improvement Plan

Current projects

Footpath works pave the way for better becks in Bradford

Sometimes the path to healthier streams and rivers lies alongside and not in the water. Local environmental charity, the Aire Rivers Trust has been hard at work improving a Bradford footpath to reduce soil running into the stream - boosting water quality and encouraging wildlife to flourish.

The work is the first ecological improvements brought about by “Better Becks,” an exciting partnership between the Environment Agency, Yorkshire Wildlife Trust, the Wild Trout Trust and the Aire Rivers Trust. Through the project experts from the trusts walked over 60 kilometres of streams looking for ways landowners could make changes to the way streamside land in Bradford is managed to produce improvements to water quality.

“We’re delighted another important part of the Better Becks partnership project is underway, boosting water quality and enhancing habitats so that wildlife can thrive. We’re looking forward to working further with our partners in the coming months to turn opportunities identified during this project into ecological improvements in watercourses in and around Bradford.”

Ineke Jackson, Environment Agency Project Manager

Locating water quality issues

The streamside path is Shipley Glen. A popular area with local dog walkers. Loadpit Beck flows down a narrow valley in Shipley Glen through the village of Eldwick and into the River Aire near Saltaire. It is named after the nearby small Late Bronze Age iron ore (or lode) workings which once forged the axes used to clear the land for agriculture. The project noted with concern that the increasing number of visitors since 2020 had caused a footpath that crossed the stream to widen and erode. Soil from the footpath was washed into the stream by rain and the many dogs enjoyed its cool water.

Creating volunteer-led solutions

Volunteers from the Aire Rivers Trust have built new walls to reinforce the footpath and drains to keep water from running over it. Over the past weeks, they have moved almost 70 tonnes of gravel and cobbles to resurface the footpath and create a mud-free area for dogs to wade to avoid the mud being disturbed. The work aims to reduce the amount of soil washed into the stream as it brings nutrients that reduce water quality and smothers the gravel where fish will lay their eggs. They have been helped in their work by members of Bradford Metropolitan Council’s Countryside and Rights of Way Team.

With the support of our volunteers were improving water quality in Shipley Glen and footpaths for walkers.

“Our volunteers have greatly enjoyed the challenge the work provides. It's good fun but also makes a real difference to the health of our rivers. This project is a great example of organisations coming together to achieve the shared aim of having a healthy river system full of life. We hope walkers will enjoy the new path and maybe catch a glimpse of wildlife, like kingfishers, we expect to thrive with cleaner water.”

Simon Watts, Operations Manager with the Aire Rivers Trust
Changes to our riverbank that benefit people and wildlife.

You can read a little more about Better Becks here

TROUT

The Wild Trout Trust contributes to several Aire Rivers Trust projects and initiatives, such as the Better Becks programme. It helps that Prof Jonny Grey, the WTT Research & Conservation Officer, is an Airedale resident and has a good working knowledge of his local system. One of his projects (TROUT), independent from ART but with similar aspirations and goals as the Better Becks project, is producing some very encouraging data.

TROUT – or Tackling Resilience on Underperforming Tributaries – is a 5-year project funded under the Yorkshire Water Biodiversity Enhancement programme. It aims to do what it says on the tin by improving habitat both instream and within the riparian zone and boosting trout fry numbers as a result. The WTT use brown trout as a sentinel species – if there is a healthy, wild, sustainable population of trout in a stream or river, it suggests that there is sufficient water of sufficient quality flowing through a mosaic of sufficient quality habitat to fulfil the various requirements of the trout life-cycle. And being in the middle of the food chain, lots of trout suggests plenty of food (mostly riverine and land-based invertebrates such as mayflies, shrimp & worms) and also plenty of food for predators of trout (otter & heron etc).

Young of year trout fry ~70mm in length

What form might habitat improvement take? Because I have been focussing mostly on headwater tributaries to boost spawning, it generally involves methods to sort and keep gravel free from silt so the trout can lay eggs and they’ll incubate safely. Adding wood, wiggling channels, providing cover and shade, and preventing fine sediment from washing in are all important, as is ensuring adult fish have free access in and out!

TROUT involves 3 sites in each of the Aire, Nidd & Wharfe catchments and I measure success against a number of control becks. I will focus on the Aire outcomes here, but it’s useful to place these in the wider context of other Dales rivers – see my summary of the overall project on the WTT pages, here.

One site is the goit in Hirst Woods at Seven-Arches and it is slightly atypical to the other sites in the project in that the focus is for ‘coarse’ species rather than trout per se. I posted a blog about early developments last year, here. In a nutshell, the work resulted in a doubling in the species count and increased the abundance of fish from 10s to 1000s! Build it and they will come…..

Haw Beck flows between Embsay and Skipton behind the Skipton Quarry and from there into Eller Beck. Tarmac Ltd and another local landowner have allowed us to exclude livestock, plant trees, introduce wood and generally diversify the habitat, as well as remove a redundant low-head weir. Indeed, ART volunteers helped me with the trees. In 2 years, we have boosted the trout fry numbers by 10x.

Pinning woody deflectors into the upper reaches of Haw Beck

The third site, Flasby Beck, flows into Eshton Beck and ultimately into the Aire below Gargrave. It just needed a good dose of wood, big wood, to kick the channel about a bit and provide refugia. So it wasn’t terrible, to begin with, but it was underperforming! There are now 6x the number of trout fry able to reside at the site.

Volunteers measuring trout fry next to a deposition bar created by introduced wood still visible in the bankside herbage

Relatively simple interventions give rise to big wins over a relatively short time frame. TROUT runs for 2 more years and I will be monitoring until the end to see if those population boosts are sustainable. More information is available, here.

Aire Catchment Network Conference 2021

Aire Catchment Network logo

On 13th April 2021, we held our first virtual conference. We are all used to Zoom by now, but it was still a little odd to see and hear our colleagues across the catchment in tiny rectangles on our screen. We look forward to being able to meet in person, on the riverbank, across the catchment, even in a meeting room! Hopefully soon...

A varied agenda held people's interest all morning and is leading to action to further improve our River Aire and its catchment. We recorded the event and this can be found with the chat that followed below.

List of speakers

1.Billy Coburn, Catchment Officer, Aire Rivers Trust: Catchment Mapping as a Project Advocacy Tool.

2.Fiona Sugden, Project Manager, Environment Agency and Ian Coldwell, Project Manager, White Rose Forest: Leeds Flood Alleviation Scheme Natural Flood Management.

3. Phil Lyth, Yorkshire Farming and Wildlife Partnership and Suzie Knight, Yorkshire Wildlife Trust: Upper Aire Project and 10 years of Landowner Engagement.

4. John Cave, INNS Team Leader, Yorkshire Wildlife Trust: Translating National INNS strategy to the Aire Catchment.

5. Ben Aston, Technical Specialist, Yorkshire Water: Yorkshire Water Investment into the Catchment including Biodiversity Fund.

Followed by a discussion on topics of interest.

Find out more

If you would like to be kept up to date on what we are all doing to improve the catchment, please fill in this form to sign up to our monthly update. You can also explore our work in the Aire Catchment Network section of our webpage.

Visit the Aire Catchment Network

Please get in touch with Billy Coburn, Catchment Officer, if you want to offer, or need, help with any project in the catchment.

How clean is our river?

How clean is the River Aire?

Overall WQ classification - 2016 below and 2019 above

Every six years, the Environment Agency publish data showing the state of our rivers relative to the standards required by the Water Framework Directive (which has been transcribed into UK law post-Brexit). This blog explores behind the headlines that caused outrage when the results were first published and led to a stinging blog by myself and reveals a very different picture to that which might be imagined if you only read headlines. In fact, the River Aire is improving - not a lot, but significantly.

Does it pass or does it fail - both!

My headline is not that all rivers fail, but that the Aire has improved in many ways. Whether it passes or fails depends upon what data you use and how you look at that data. It's not a simple story, so settle back and read on...

I started work as a Pollution Prevention Officer on 1st July 1974 and have been involved, one way or another, with our river ever since and you might think, from the headlines, that all of the money, time and thought that has been put into improving the River Aire over the 45 years in which I have been involved has been wasted. That's not true - so here is my interpretation of way over 250,000 individual 'analyses' done by the EA on the River Aire in the last three years. In order to do that, and to make what is happening understandable, I need to look at three key issues:
1) The 'one out, all out' rule
2) Ecological data
3) Chemical data

One out, all out

According to the ‘one out all out’ principle of the Water Framework Directive (WFD) good status of a water body is reached if all parameters (aka analyses) are classed as good. Missing one single parameter is sufficient to downgrade all of them. Essentially, if they analyse for 50 different chemicals and one fails then the whole river fails regardless of how good the other aspects of river chemistry are. Think about this. The more chemicals you analyse for, the more chance of the river failing regardless of whether there has actually been a deterioration and if you suddenly decide to analyse for a 51st chemical then the risk of failure increases even though the quality might not actually have changed. Well, this is what happened.
Whilst this might be considered as an application of the precautionary principle, the approach has several disadvantages. With such a principle, the classification obtained does not reflect any partial progress made, especially on the reduction of significant pressures. In some cases, parameters such as hydromorphological and physicochemical elements may better reflect changes in the water status while biological parameters are used to reflect the status of the whole ecosystem.
Moreover, it is subject to quirks such as introducing new parameters into the mix (such as Polybrominated Diphenyl Ethers - PBDEs, mentioned below) and thus increasing the chances of failure regardless of whether there has actually been any change. This is what happened to cause all waterbodies to fail for chemical status. See below for more detail.

Ecological Quality

Let's look at the ecological data first - after all this is the good news relating to data about the fish, invertebrates, plants etc in the river. They just 'sense' the state of the river without bothering about pesky EU Directives - remember that we have salmon below Leeds waiting to find their way upstream to spawn and the middle/upper Aire is a strong trout and grayling fishery. They don't do very well in failing rivers!

There is still some way to go, but steady progress is being made and many (most?) of the 'Moderate' classifications would be better were it not for the actions of our predecessor generations who thought they were doing right but weren't. Many are Moderate because they have been designated as 'Heavily Modified' because they were canalised, culverted, had weirs installed, straightened, had stone or concrete walls put in place and so on, so they are no longer natural in appearance or function. Much of this damage to the natural state of our rivers will take generations to resolve and may never be done - how, for example, do you de-culvert Bradford Beck when it runs underneath some of the most iconic buildings in the centre of Bradford or the River Aire running beneath Leeds City railway station?

Chemical Quality

Now let's look at the chemistry. The EA analyse for a very wide range of substances, from Dissolved Oxygen through Biochemical Oxygen Demand (the amount of degradable material in the water - often from sewage) to some real 'exotics' such as Polybrominated Diphenyl Ethers PBDEs - we will come back to these shortly. According to this data not one single waterbody passes! This is the data that caused all the fuss and it needs to be taken in context and the reasons for the mass failure understood.

Looking wider, the picture is actually improving, and faster than for the ecology. This chart shows the percentage of all the individual tests that passed the relevant limits for each of three years.

Chart showing % of individual chemical analyses passing WTD water quality standards
% of individual chemical analyses passing WTD water quality standards

Again, there is still some way to go, but progress is being made.
Planned (and financed!) improvements to Phosphate and Ammonia discharges by Yorkshire Water will help substantially and we expect this to be significantly better in 5 years' time.

What's causing the failures?

So what happened to the chemistry of our rivers? Simple really - the EA started to analyse for a couple of exotic, yet ubiquitous, organic chemicals and found them everywhere (after all, they are ubiquitous!). PBDEs and something called Perfluorooctane Sulfonate (PFOS for short). They also changed their method for looking for Mercury and found it to be more widespread than first imagined.
Horror, you might think! Well, maybe not. These chemicals have been in our environment for decades,

PBDEs for instance have been used as flame retardants in a wide range of products including electrical and electronic equipment, textiles and foams. Releases occur during use and disposal of these products and they continue to enter waste water treatment works. They may be present in soil as a result of the spreading of sludge to land. PBDEs may also be released into the water column by the re-suspension of contaminated sediment or the transformation of decaBDE, which is still in use in industrial products. They may also volatilize and be deposited aerially.

PFOS has been used in a range of domestic consumer products, as well as in industrial processes and in aqueous film forming foams used in fire-fighting. Older consumer products such as carpets, textiles and upholstery that have been treated with PFOS or related substances will continue to act as a source of PFOS. Emissions can occur during the use, washing and disposal of such items, entering the environment via waste water treatment works, urban runoff or waste management facilities. PFOS can be present in soil from historical sources or from the spreading of sewage sludge to land.

And finally Mercury, which has been used in electrical equipment such as thermostats and batteries, cosmetics, wood preservatives, textile treatment agents, dental fillings, measurement devices and as an antifouling agent on boat hulls. A major use of mercury has been in mercury amalgam dental fillings, although this is now declining. Atmospheric releases of mercury are significantly greater than direct emissions to water, with thermal power plants and combustion installations being the largest industrial source emitters. Aerial deposition originating from outside the UK is now a significant source of mercury.

All three of these substances are now controlled (and substantially banned) internationally and are so ubiquitous and persistent that it is expected that they could be around for at least another decade. Realistically, there is little that a Rivers Trust or indeed the EA can do to further reduce these chemicals unless we find a point source discharge (we are checking, just in case).

Want the raw data?

If you want to look at the raw data yourself, you need to be looking here for chemical data and here for ecological data. Be warned - it's a very clunky process and you will end up with huge quantitites of data in spreadsheet format. But if you persevere and are handy with Excel then it's intriguing stuff.
This blog has opened the curtains and seen that things are better than might have been imagined. If you want to go a layer deeper in understanding the data and/or how the classification system works then do contact us.

Conclusion

Contrary to what the headlines might have suggested, the River Aire is actually improving for both chemical and ecological standards.
There is some way to go yet, but we have to be heartened by the fact that we have such a good existing fish population and by the plans of Yorkshire Water to spend large sums to further improve the situation.
Not that we will rest on any laurels - there is work to do and The Aire Rivers Trust plans to be at the forefront of pushing for and delivering the necessary improvements.

Glossary

Hydromorphological?

Hydromorphology is a term used in river basin management to describe the hydrological (water flow, energy etc) and geomorphological (surface features) processes and attributes of rivers, lakes, estuaries and coastal waters. The Water Framework Directive (WFD) dictates that the ecology of surface waters is protected by correctly managing their hydrology and geomorphology.

Hydromorphology assessment and prediction requires an evaluation of aquatic habitat composition and the dynamic nature of water bodies and facilitates sustainable restoration.

Physicochemical?

The physicochemical status of a waterbody is linked to a series of measurments of the physical condition - Temperature for instance - and the basic chemistry - Ammonia, Phosphate, pH, BOD etc...

Dissolved Oxygen

This is the amount of oxygen dissolved in the water. All life needs oxygen, so this is an indicator of the ability to support life.
It is typically about 10 milligrams per litre, but the maiximum depends on the temperature of the water (the hotter it gets, the less oxygen the water can carry and so the more stressed the biota become).

Biochemical Oxygen Demand

Biochemical oxygen demand (BOD) represents the amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic (oxygen is present) conditions at a specified temperature. The lower the better as high levels (above 5?) suggest pollution.

A new era in catchment management

Integrated catchment management on the Aire is about to take a new leap forward.

Just a year after the creation of The Aire Catchment Network, we are delighted to announce the appointment of Billy Coburn our new, full time, Catchment Officer for the River Aire. Billy comes to us from Thames21 with valuable expertise across the range of catchment host activities and will lead all of our catchment hosting activity.
Starting on 1st September, he will be working with an ever-increasing range of stakeholders in the Aire to help deliver our vision of:

"A gold standard example of the recovery of a post-industrial river"

They key roles of the post and the areas where we plan to make a difference, are:

You can contact Billy on billy.coburn@aireriverstrust.org.uk

This appointment comes courtesy of funding from Yorkshire Water and The Environment Agency

Top