How Fish Passes Work

As we come to the end of Developing the Natural Aire, SImon Watts explains why building fish passes matters.

All fish need to move to feed, breed and shelter. Even fish who spend their whole lives in the river can travel considerable distances looking for the ideal spot. Barbel have home ranges up to fifteen miles. Many freshwater fish migrate much, much further. For migratory species, like Atlantic salmon and the European eel, access to the sea is essential. The Industrial Revolution has left us with a fragmented river. Weirs built to harness the power of water for mills, factories and for navigation, block the way. Fish trapped in their sections are vulnerable to pollution or predation. And species like Atlantic salmon trying to return to our cleaner rivers cannot reach spawning ground in the shallow headwaters.

Why Do We Need Them

Whilst trout and Atlantic salmon can sometimes be seen leaping up waterfalls, weirs present a unique challenge. They are often long and steep. Their surface is smooth with little variation in the flow of water. The deep pools found at the base of waterfalls which fish can leap from are replaced by shallow aprons of concrete and stone. Many coarse fish species cannot jump obstacles.
The Aire Rivers Trust works with partners such as the Environment Agency and landowners to overcome these obstacles. The ideal solution is weir removal which restores natural river habitat (returning the artificial ponded section upstream back to a more natural system). But in some locations this proves impossible. Weirs form part of the urban fabric of our landscape. Some are valued for their heritage or for their amenity value. Buildings are built close to them and complicate their removal.

How Do They Work

Yorkshire Water explains why we need them and how fish passes work

Mid construction footage of the new fish pass at Kirkstall Abbey Weir as part of our Developing the Natural Aire project

An explanation of how an eel pass works from a Canal and Rivers Trust project similar to our Developing the Natural Aire

Where weirs cannot be removed, the solution is engineering. Records show rough fishways built in France during the 1600s. Here bundles of branches were used to create steps in steep channels to bypass obstructions. Engineered fish pass design has come a long way since the first one was patented in 1837 in New Brunswick, Canada. All designs seek to make weirs passable to fish. The majority of modern fish passes on the River Aire are Larinier Passes. Metal baffles in the base of them slow the flow over the weir that fish can swim or leap through.

The reconnection of 60km of habitat in the River Aire by the Developing the Natural Aire project will allow the return of Atlantic salmon, sea trout and other migratory fish. Monitoring conducted alongside the project has recorded a brown trout travelling from Armley Mills to Cross Flatts in Bingley (and most likely beyond) in a huge 80-kilometre journey to search for new areas to feed, breed and shelter in. This journey would have been impossible before Developing the Natural Aire as weirs like Kirkstall Abbey were completely impassible to fish.

The State Of Our River

Reporting Pollution on the River Aire

This blog post was written in mid-October before the government's Environment Bill went before Parliament and the fantastic and widely publicised public debate that has followed it. Unfortunately, we have been delayed in publishing it or updating it due to staff sickness. We are still publishing as it contains (amongst other things) some really interesting maps and data about our catchment.

It's quite a long blog. If you want to find out how to make a difference you can skip to the end to find links to actions to take now.

How healthy is the Aire?

The start of October saw the release of the "State Of Our Rivers" report by the Rivers Trust (a national charity that campaigns on behalf of the Rivers Trust movement). It makes grim reading. England's rivers are failing and looking close to home this story rings true.

Make no mistake, our rivers are improving. We mustn’t let community memories of foam blowing off the river and down streets in Castleford or fish gasping for air below Baildon weir dominate conversations. The passing policeman who told one of the catchment’s river fly monitors “You won’t find anything alive in the River Worth,” was wrong. Our rivers are full of life. Pollution sensitive fish species like Atlantic salmon and grayling can once again be found near Leeds. With them, otters and kingfishers have returned, but our rivers are not good.

Heron on the Aire with Brown Trout

However only five of the 51 water bodies in our catchment have good ecological health.

The State Of Our Rivers" report identifies the key impacts on our rivers as agriculture; the water treatment sector; and the urban and transport sector a quarter. Pollution is not the only problem, though, as abstraction and habitat destruction also play their part in impoverishing our rivers.

Agriculture and the Upper Aire

After finishing tackling large amounts of Himalayan Balsam on Eller Beck, I recently took a walk downstream through Craven looking for other areas it had spread to. Walking downstream for about three kilometres I found almost none. Intriguingly, this isn't the good news story I hoped for. Instead, I found many banks with sparse vegetation, leaving them open to erosion by high flows. Grazing, often at uncontrolled locations where sheep and cattle can actually walk into our rivers, also places significant pressure on our waterways. We know that soil washed into our rivers pollutes our rivers, adding nutrients and smothering the gravels that fish need for spawning.

Within the Aire, much of this comes from livestock rather than arable farming. Work such as that undertaken by the Upper Aire Project is key to excluding livestock from our riverbanks and providing farmers with alternative water sources. For farmers to get on board it is critically important that the government makes it profitable to become involved in environmental schemes. We can only hope that pilot schemes for Defra's Environmental Land Management Schemes start to give the clarity farmers need for long term business planning.

Cows grazing beside the River Aire
Photo © Bill Harrison (cc-by-sa/2.0)

The Leeds Flood Alleviation Scheme Phase 2 is a unique opportunity for the Aire catchment. It echos a key theme of the State Of Our Rivers report that nature holds the key to us becoming climate-resilient. Renaturalising and remeandering channels; reconnecting floodplains; together with the creation of natural flood management features like tree planting, leaky dams and soil aeration hold the key to reducing the flood risk to our homes and communities. We are currently involved in a pilot project working with landowners to identify natural flood management potential. If you would like to know more please get in touch.

In the meantime, we will once again be planting trees this winter. Even with the disruptions of Covid, our staff and volunteers have planted over 5,500 in the past two years. There will be many more needed.

Planted trees

Get involved

You can help improve our local rivers by volunteering at one of our weekly volunteer sessions. the work we do ranges from planting trees to cleaning up the riverbank to laying hedges. Through this we hope to will introduce you to our fantastic river, others who care about it and offer you an enjoyable and rewarding experience.

We're particularly keen to recruit volunteers for our new citizen science project. The work they will do will help us understand our catchment, its health and the opportunities for improvement in it. You can find out more on our volunteering page.

If you spot pollution happening you can report it to the Environment Agency on 0800 807060.

Two leaves sit in a graphic that divides text

The impact of cities like Bradford and Leeds

The sewerage infrastructure that runs our streets was first put there by the Victorians and fundamentally, whilst populations have grown and the way we live has changed, those sewers are no longer up to the job. House building puts increasing strain on the sewerage network. To prevent sewage backing up into our homes, water companies are permitted to overspill untreated sewage into rivers during extreme rainfall events. However, these discharges happen with alarming regularity. The worst combined sewer overflow in our catchment is at Ingrow Lane in Keighley and discharged for a total of 2092 hours in 2020 (139 events of over 12 hours). You can explore your local area on the Rivers Trust's interactive sewerage map here. The blame for this doesn't rest solely with water companies and housebuilders. We buy new stuff and flush disposal cleaning products downpipes that were never built for them. Wet wipes form a depressing feature of every river clean up we do. We need the government to bring legislation that not only impacts water companies but manufacturers too. If you use wet wipes, please put them in the bin and NOT down the toilet.

At the launch of the State of Our Rivers report the Minister for the Environment Rebecca Pow boasted that, over the hill in Ilkley, her government has taken the step of designating the first river with the first inland bathing water status. This is a river I swim in regularly with my kids but she omitted to mention it is completely failing to meet the standards for this. (She also incorrectly named the swimming spot Otley which would no doubt horrify a few locals!) We all deserve rivers that are fit to play in whether it be fishing, swimming or canoeing.

Yorkshire Water has made some significant improvements over the past couple of years but our water bodies are still heavily impacted by both partially treated and untreated sewage discharges. Industry has played a huge role in the history of Airedale and we find a great deal of it remains along the banks of the Rivers Aire and Wharfe. We need to work with these industries to help them understand the risks they pose to the environment. Both Bradford and Leeds made the top five areas with serious water pollution incidents.

To tackle pollution in our rivers we need major investment in our sewage infrastructure. This is something that we not only need the government to demand but also to be willing as water consumers to pay for it.

Two leaves sit in a graphic that divides text

The change we need

All these problems need urgent action. Our rivers cannot wait for politicians and corporations to improve our environment little step by little step. They need bold leaps into action.

We need robust legislation to protect our waterways and an Environment Agency that is funded well enough to enforce them.

We need the funding in place that enables charitable partners, farmers, landowners and water companies to make the investments that create sustainable change. Some of this will come from the government but some must come from us recognising the value of our environment and accepting that we must fund it, for example through the prices we pay for food.

We also need to take local action - wet wipes and fat in the bin not down the drain, take your litter home with you (you might leave it on the land, which is bad enough, but much of it then gets blown or washed into our rivers, get a qualified plumber to put in your washing machine or dishwasher and make sure they connect to the sewer and not the surface water drains and come to volunteer your little bit "every little helps" (to steal ASDA's tag line!)

Two leaves sit in a graphic that divides text

Exploring our catchment

Only when people realise there is a problem are they likely to act. So we believe the best way to create this change is to share information. We need to connect communities to their river and each other to demand and bring about change. By making this data public we can hold regulators and polluters accountable.

As an example of the sort of information we hold and make freely available, the following map was created as part of a workshop to look for opportunities for improvement within Bradford Council's area. We want to use data to drive our decision making allowing us to make the most impact with our work.

This might seem a bit 'techy' but bear with us, it is simpler than it looks.

You will need to press the ">>" button in the top left hand corner to reveal the legend. Then click the tick boxes to add or remove layers of information from the map. Clicking the ">" button by each layer will reveal the full key.

An explanation of what each layer means can be found below.

Public Paths Outer / Bradford Public Paths / Other Paths Outer - Public footpaths in the Bradford area. Supplied by the Council as three layers but can be considered one dataset. This map was produced for a Bradford event so data has not been added for Craven or Leeds.

EA Risk of flood rivers Aire Clip - An Environment Agency assessment of flood risk/

Bradford Council Land - Land owned by Bradford Council

Cat1 2 Env Pollution Incident Aire Catch / Cat 3 Pollution Incident Waterbody heatmap - Water pollution incidents categorised from Category 1 (most serious) to Category 4 (least serious and not included in this map). Category 3 incidents are mapped as a heat map rather than individual incidents (as Category 1 and 2 are). You can read more on page 36 of this document here.

RiverObstaclesLayer Aire Catchment - Obstacles blocking fish passage in the river.

YorkshireWaterEDM2020 Clip - Yorkshire Water "Event Duration Monitoring" recording how long and how frequently combined sewer overflows released diluted sewage into water courses. You can read more here.

WB Aire Catchment WFD 2019 Fish 08OCT / WB Aire Catchment WFD 2019 Invertebrates 08OCT / WB Aire Catchment WFD 2019 Phosphate 08OCT / WB Aire Catchment WFD 2019 Ammonia 08OCT / WFD River Surface Water Aire Catchment only 2019 - The EU’s Water Framework Directive (WFD) which was adopted by the UK in 2000, imposes standards for the improvement of all aspects of water environments, including rivers, lakes, estuaries, coastal waters and groundwater. It requires surface water or ‘blue space’  to be of good quality by 2027. It assesses a number of chemicals and ecological components and rates them from High to Bad.

WB Aire Catchment WFD 2019 - Individual catchments are given assessments based on the lowest scoring component.

Aire Catchment River outlines - Our major watercourses.

OSMapWaterCourses Aire Clip - And minor ones.

Aire Catchment - The area covered by our catchment.

Two leaves sit in a graphic that divides text

A call to action

There are lots that you can do to make a difference. Why not join us as a volunteer on the riverbank or make small changes in your home, like installing a water butt? The Aire Rivers Trust doesn't work alone. Nearly every river has Rivers Trust and we have an umbrella organisation called "The Rivers Trust" that campaigns on our behalf. Head to their website to learn more about the issues facing our rivers and to help them by writing to your MP.

If, after looking at the map above, you have suggestions of projects for us to develop to improve the Aire catchment please get in touch with our Catchment Officer, Billy Coburn, by emailing him at billy.coburn@aireriverstrust.org.uk .

Two leaves sit in a graphic that divides text

Electrofishing in Hirst Woods

A guest blog by Prof Jon Grey from the Wild Trout Trust.

Back in May, the new footbridges constructed by Aire Rivers Trust in Hirst Woods over the old mill goit made an immediate and obvious impact on the walkers, both two and four-footed. But they were also built to reduce the human impact in the goit itself. Over the past months and with input from the Wild Trout Trust, members of Saltaire AC have been working steadily towards reinstating the flow and reintroducing some habitat features to benefit the flora and fauna of the goit.

This has involved the removal and relocation of accumulated boulders and freeing up the compacted sediments in between to allow fresh water to flow through the goit even under summer conditions. The water bubbling over the riffles (shallow gravelly stretches) provides a very different habitat to the slower deeper stretches which remain quite silty on the bed.

Volunteers from Saltaire Angling Club installing brush mattresses

It is hoped that with some higher flows over winter, much of the silt that accumulated when the goit was blocked up will be flushed out or relocated to the sides where we have installed some ‘brash mattresses’. These are densely packed branches and twigs tucked behind chestnut posts on the inside of bends to accentuate the sinuosity of the channel (make it more wiggly) and create dead zones into which the silt will percolate and eventually stabilise the material. As the woody material breaks down over time, marginal plants should colonise and further stabilise the structure.

Brash mattresses also provide excellent nursery habitat for young fish with plenty of protection from both flood flow and predators. More physical diversity in the channel allows for more biological diversity too.

Brash mattresses in the old mill goit

The impacts on fish are much harder to ‘see’. However, part of the funding for the habitat-focussed project from the Yorkshire Water Biodiversity Enhancement Fund was ring-fenced for monitoring pre and post works. On Friday 19th Sept, we electric-fished the full goit in exactly the same manner as we did last year prior to any improvements.

Last year from the relatively stagnant water of the blocked goit, we caught very few fish (~60) from only three species: three-spined stickleback, stone loach, and minnow. The stickleback is characteristic of slow or stagnant waters and the stone loach favours a more silty bed. Hence, the impoverished fish community reflected the sorry state of the goit then.

This year, we caught six species, adding chub, bullhead, and gudgeon to the list. All of these ‘new’ species favour more flow, especially the bullhead that was typically found around the new riffles on the cleaner gravel and cobble. Furthermore, the goit was teeming with fish this year. We did not bother to net minnow after the first 10m and I would estimate we would have had several thousand if we had continued. The small chub (~100mm) and fry of all the other species indicated that the goit was once more offering suitable nursery habitat.

Chub and gudgeon found in the goit

The results speak for themselves. Good news. No wonder the local kingfishers have been far more frequent visitors of late! I’m excited to see what further changes will bring to the goit in 2022.

Prof Jonny Grey (Wild Trout Trust)

Electrofishing with Saltaire Angling Association and the Aire Rivers Trust in September 2021

Spring Special: Identifying non-native invasive species

Spring sees green shoots appearing along our riverbanks but not all of them are welcome. Some of the plants (or flora) you find along our rivers are "non-native invasive species." These were brought to the United Kingdom from around the world and have spread causing harm to the environment. You can help protect native species and river visitors by learning how to identify and report them.

Himalayan Balsam

Top Trumps card for Himalayan balsam

Himalayan balsam is controlled by pulling plants before they go to seed. It is a popular summer activity with our volunteers.

The seeds are spread by flood water. We focus on controlling it high up catchments to prevent its spread or on sites with high ecological value.

As the first true pair of leaves appears you can see the distinctive serrated edges. It has orchid pink flower.

It is widespread throughout the middle Aire catchment but less so in the Upper Aire.

Two leaves sit in a graphic that divides text

Japanese knotweed

Japanese knotweed is controlled by injecting stems with pesticide. We treat Japanese knotweed along Bradford Beck. YorGreenCIC treat it in the Bradford area.

Japanese knotweed has heart shaped leaves and a tall stem that looks like a cross between rhubarb and bamboo. It can reach over head height and regrow from fragments of roots.

Reporting it through the Yorkshire Wildlife Trust INNS Mapper site is the most effective way to ensure it is treated.

Two leaves sit in a graphic that divides text

Giant hogweed

Identifying giant hogweed seedlings is challenging as they can be confused with native hogweed species.

Giant hogweed looks like an enormous cow parsley. It is significantly larger and can reach heights between 1.5m and 5m with a spread of between 1 and 2m. Leaves are jagged and lobed and a flower spike formed in the second year before setting seed.

Their stems are green with purple blotches and stiff, white hairs. The leaves are huge (up to 1.5m wide and 3m long) and is deeply divided into smaller leaflets. Flowers appear in June and July.

Reporting it through the Yorkshire Wildlife Trust INNS Mapper site is the most effective way to ensure it is treated. In Leeds, this is done by the River Stewardship Company.

Two leaves sit in a graphic that divides text

Signal crayfish can be found throughout the catchment. There is currently no viable method of control in the United Kingdom.

Large specimens can sometimes be seen from bridges or found under rocks. It is illegal to trap or fish for them without a license from the EA.

Pockets of native white-clawed crayfish populations still remain within the Aire catchment. The best way to protect them is careful biosecurity to prevent the spread of signal crayfish.

How to report them

Both Japanese Knotweed and giant hogweed can be reported through the Yorkshire Wildlife Trust INNS Mapper site is the most effective way to ensure it is treated. You have to create an account to do this. In a future blog we will take you through the process of reporting.

The Electronic Aire

Brown trout after being tagged below Newlay weir

Lockdown. Restriction. Isolation. Are a few of the many words used to describe 2020. However, these words may also be used to refer to our river systems and the challenges faced by many of the fish populations that reside within them. Whilst many of us were house bound in 2020, construction of four fish passes to help reconnect habitats for river resident and migratory fish species in the River Aire commenced. Here I hope to give you all an insight into how I tagging fish by implanting electronic tags allows us to find out what is going on beneath the water surface, and what difference these fish passes are having on the lives of our fish.

The effect of weirs on wildlife

Barriers such as weirs and dams disrupt fish migration routes, fragment fish populations, and are a major contributing factor to the extinction of fish species globally. In 2020, a scientific paper (Belletti et al., 2020) highlighted how there are over 1 million barriers that fragment European rivers, with an estimated 48,293 barriers in UK waterways, each restricting or halting the movements of native fishes in some form.

The River Aire has 34 major weirs situated along its 114-km length that are barriers to resident and migratory fish. Fish passage solutions (fish passes) have been installed on many of these weirs to help improve movements of fish along the River Aire. The DNAire project is constructing fish passes on another four weirs (Armley, Newlay, Kirkstall & Saltaire), with the major aim of enabling upstream migrating adult Atlantic salmon to reach spawning grounds at Skipton.

These fish passes do not just open up migration routes for the iconic salmon, they will hopefully provide passage routes for river-resident coarse and salmonid fish species too.

How efficient are fish passes?

In conjunction with the DNAire project, the University of Hull International Fisheries Institute (HIFI) together with the Environment Agency are investigating the movements of fish in the Aire.

One of the key aims of this investigation is to assess the efficiency of the DNAire fish passes at Newlay and Saltaire weirs. To achieve this aim, HIFI have spent the last three years capturing and tagging fish (brown trout, barbel, roach and chub) between Armley and Hirst Mill. In addition, efforts are being made to capture and tag Atlantic salmon in the lower Aire that will hopefully migrate upstream and pass through the DNAire fish passes. Passive Integrated Transponder (PIT) tags, similar to those put in cats and dogs, enable us to identify individual tagged fish.

These tags do not have a battery – and thus last the life of the fish – and emit a unique ID when activated by an electromagnetic antennas installed inside the fish passes. The antennas are strategically located to detect when fish approach, enter and ascend each fish pass. With this data, we can calculate the fish pass performance as well as provide additional information on environmental conditions when particular species move through the catchment.

Saltaire fish pass during construction. The baffles in the Larinier fish pass (left) can be seen with PIT antennas mounted on wooden beams across them. The plastic eel pass can also be seen (right).

Building knowledge for the future

Investigating fish pass performance and factors influencing passage is key to understanding effectiveness of fish passes constructed during the DNAire project and for developing future fish passes. We are all working towards a more natural and healthy River Aire that both fish and society can benefit from. We will continue to collect data in the coming months and will hopefully share results with you in a future blog.

My Time at the Newlay Fish Pass Site

To quickly introduce myself, my name is Hannah, ART’s new placement student and I study BSc Geography at the University of Leeds. Starting my position with the trust during these unprecedented times was so daunting, however, I have enjoyed every minute of it so far. From meeting volunteers at our Friday workdays to creating videos with Abby, the last student. One of the major projects I get to be a part of is the DNAire, Developing the Natural Aire project. As a result of this, I was given the awesome opportunity to go and work at the Newlay Fish Pass site for two weeks, gaining insight into the daily operations that goes into engineering and construction. 

It was the first day at Newlay. I remember driving early Monday morning to get there and thinking my past 8-year-old self would never have envisioned me in a hard hat and steel toe boots, but 13 years later, here we are. The team working for Suttles, welcomed me with socially distanced arms and introduced me to the site. Before this, I have only ever seen a fish pass once. Now I was about to watch one being constructed. I observed how the machines operate to carry out different jobs, why different materials were used for different stages of the pass and the unpredictability of working alongside a river which can change the programme of the day within minutes. 

During the course of the two weeks, a few days of heavy rainfall led to the site flooding twice, halting work and slowing progression. Whilst the river levels were rising, the engineer on site showed me how to use the digital levelling equipment to help construct a basic flood risk model. Having used optical levelling equipment throughout my degree, using a more precise bit of kit was very exciting. I felt very cool. 

The fish passes along the Aire are Larinier Passes. These have aluminium baffles along the base to churn up the water, increasing friction ultimately slowing the rate of flow, allowing fish to swim up. A resting pool is positioned halfway up the pass, giving the fish time to rest before continuing their journey. This differs to the Eel and Lamprey side, which is made of tiles with cone structures, enabling individuals to manoeuvre between each cone. 

Mid construction photo at Kirkstall fish pass. These show the aluminium baffles used to churn up the water along the fish side of the pass.

All in all, I am very excited for the completion of all these passes and the benefits they will bring to reconnecting the river to the wider world. Thank you to Suttles, the Environment Agency and The Aire Rivers Trust for this awesome opportunity! 

My year with the Aire Rivers Trust

As my placement comes to a close and I return to the University of Leeds at the end of September, I wanted to take the time to reflect on my year with ART and all of the opportunities and experiences I have gained, and how I have grown over the last year in my role as a Community Engagement Assistant and STEM Ambassador.

My favourite task

Looking back to my year I have enjoyed and been so proud of what I have achieved I could not just choose one so instead I have chosen 3

  1. One of the biggest achievements I have had was designing and delivering our new schools’ program, River Defenders. I enjoyed doing this as I got to see my vision for the sessions come to life and it was so rewarding to see how excited the children were to both learn and visit the river.
  2. During lockdown I was proud of being able to produce a video to replace our normal talks which highlighted the history of Kirkstall and our DNAire project. The feedback I got from this was incredible and it had over 1.5k views on Kirkstall 1152’s Facebook page!
  3. Lastly I will always remember and have fond memories of our volunteering Fridays, I am proud that I managed to keep spirits high during all weather conditions we faced in the winter months and how much I have contributed to conservation probably planting around 4000 trees, collecting numerous flood debris and litter. Also getting the experience to install leaky dams in the upper Aire.

Challenges I Faced

I think this year we have all had to face challenges adapting to Covid and adapting our normal routines and job roles. Luckily at ART we continued to work, and my placement was not cut short. Although a challenge having to adapt our normal delivery, I enjoyed thinking of new ways for us to connect with others through social media and other platforms. Rather than seeing challenges as a negative thing I see them as being a way to grow my skills and through my placement I have set myself many of these challenges to create displays, videos, leaflets and data collection techniques having to face challenges to teach myself how to use new software or finding suitable ideas along the way.

Things I've Learnt

Through my placement I have learnt the importance and impact of community engagement. It has been a pleasure to work with our volunteers every week and see how much they enjoy and value helping the local area we are in and how much volunteering means to them. It also has been an honour to be able to design and deliver school sessions and hear from parents that their children had spoken about what they had learnt in the classroom mentioning salmon and teaching other members of their family how weirs and fish passes work.

I have also grown and come to see my own skills which I have developed over the last year. I have learnt my strengths such as being creative, being able to engage others, working to deadlines and being passionate and confident about what I am doing. I have also learnt what it is like to work for a small charity in the voluntary sector and I have really enjoyed having this break from university to have a taste of a job in the real world and learn more about what I would like to do in the future with my career.

One thing I would change

Although I am extremely happy with all the opportunities I got this year if I could change one thing about my time at ART it would have been being able to get out and teach more (which was halted due to Covid). I really wanted to be able to keep teaching independently, which I was able to do for 4 classroom sessions but I wanted to be able to get more practice at doing this for my own sense of achievement and capability that I could do it alone. I would also have loved to have spent longer with the Environment Agency to widen my experience in other sectors in case any were to be future career paths.

After a winter filled with volunteering days, I also wish we could have got out in the summer too and enjoyed the sunny days we have had this summer!

Overall, I have loved my time at ART, and thank everyone greatly for the experience and memories.

A placement with our contractors

At the beginning of the month I was lucky enough to have the opportunity to work with Suttles on construction sites along the River Aire as part of our DNAire project in partnership with Environment Agency. These construction sites are allowing fish migration to take place along the Aire, with fish passes being built to allow migratory fish, like salmon, to get back up the river to their spawning grounds of Skipton.

Fish passes are needed on the Aire due to the multiple weirs existing from the industrial revolution. These weirs act as barriers to fish due to a combination of the weirs being too steep and the river being too shallow to allow coarse fish to get the momentum to leap over the weirs. Installing the fish passes is a huge engineering project and I am grateful I got to be part of the experience. We hope that salmon being able to migrate and spawn once more will add to the improving condition of the Aire.

Working on the construction sites has allowed me to see the engineering, hard construction and planning that goes into creating the fish pass structures and how hard it is to be working in and near water. During the building process the river must be dammed and re-directed to allow for a dry workspace before the old weir face can be destroyed and building of the structure for the new fish pass can be started. It is crazy to think that the weir at Kirkstall has been around since the 12th century and that no one will have stood on it and seen the beautiful stone work as I had the opportunity to since then. It also surprised me how large the fish pass structures actually are and the precise engineering needed to make sure the baffles in the fish pass would serve their purpose to churn up the water so that the fish can use the currents to swim against the water up and over the weirs.

The image above shows construction work at Kirkstall Abbey and just how large the fish passes are. Here you can see the steelwork at the top of the fish pass which needs to be put in to make sure the structure will hold against the large pressure of the flowing river. After the steelwork the fish pass is concreted as you can see in the lower part of the fish pass and the baffles installed. To the left of the fish pass there is also going to be an eel pass installed to also help smaller fish and eels get over the weirs.

Im going to be returning to Uni in Leeds soon but Ill be back. I can’t wait to hopefully see salmon in the Aire very soon!

Top