Archaeological works for Masbrough Weir fish pass

As part of the works to create a fish pass at Masbrough Weir in Rotherham, an archaeological watching brief was carried out. Here, ArcHeritage tells us about some of the things they found out …

Recent works on the River Don were undertaken on Masbrough Weir at Rotherham to install a larinier fish pass. As the weir is an historic structure, the works were monitored by an archaeologist from ArcHeritage, part of the York Archaeological Trust. Working on a structure submerged within the river offers many challenges. The principal contractor, Bailey Construction Ltd, installed a coffer dam to divert the river around the works area, though the extremely wet weather in February meant that it was not possible to completely prevent water incursion.

View southwest across the weir prior to the fish pass works. Photo by ArcHeritage

The date of the weir is uncertain, though it is first documented in 1722 on a plan of the proposed River Don Navigation. The weir fed water to Rotherham Town Mill, a corn mill that stood on the eastern bank of the river. A mill is likely to have been in this location from the medieval period onwards, and it is possible that the original weir was also medieval. The weir may have been rebuilt along with reconstruction of the Town Mill in 1753. The southwest end of the weir abuts Forge Island, which was created by the construction of the Don Navigation canal. The name comes from the iron forge built by Walker and Co., who leased the island from 1754. The forge was powered by water diverted from the Don, and Walkers’ lease included an annual payment towards maintenance of the weir. Water power was still being used to drive a helve hammer at the iron works in 1858, though steam power was also used at that date. It is likely that water power was no longer used by the late 19th century, and the town mill was demolished between 1888 and 1901. The weir may no longer have had a significant function by that date, but was retained and appears to have been modified on at least one occasion in the 20th century.

Ordnance Survey town plan, published 1888, showing the weir with Forge Island to the left and the town mill above right.

Observation during the cutting of a 50cm deep channel for the fish pass through the southwest end of the weir revealed a core of earth and stone rubble, including some sandstone blocks that may have derived from an earlier structure. This was stabilised by a timber frame of three horizontal cross-beams held in place by upright stakes driven through the core into the riverbed. The upper face of the horizontal beams had been cut to give a sloping profile and they were joined by lap beams reinforced with an iron bolt drilled through the joint. The uprights had pointed ends reinforced with iron ‘shoes’, and were connected to the cross-beams with mortise and tenon joints. An upper surface of sandstone blocks was laid over the core and frame, placed tightly together with no evidence for any type of bonding. The blocks varied from 30cm to 1m in length and were mostly around 25cm wide and 30cm thick. No dating evidence was recovered from the weir, and the timber working methods could have been used at any point from the post-medieval period to the 19th century.

Schematic cross-section through Masbrough Weir. Illustration by Arran Johnson

This was the fifth fish pass installation on the Don to be monitored by ArcHeritage, which has allowed a greater understanding of the typical methods used to construct weirs in the Sheffield and Rotherham area. The earth and rubble core, timber frame and stone surfacing recorded at Masbrough Weir are common to three of the other weirs, though the form and choice of surfacing material may have been influenced by what was cheaply available. For example, at Sanderson’s Weir, Brightside, the surfacing included steel-making waste (crozzle) between larger sandstone ribs, this material being freely available to the steel manufacturers constructing the weir. A fourth weir had a supporting structure of stone rather than timber. Direct dating of these weirs was not possible, but all were extant by the 18th century and at least two had been rebuilt in the early 19th century.

Detail of timber joints used within the weir. Illustration by Arran Johnson

The Salmon’s Tale: The Lower Don

Join us for the next part of the Salmon’s Tale! In this blogging series by DCRT trustee Chris Firth, follow Salmo the salmon smolt as he travels from the River Don’s headwaters to the low, meandering reaches of the river. Can you guess which species he meets along the wayfrom the descriptions (answers at the bottom)?

Salmo had reached Rotherham and was about to descend the weir in the centre of the town. He had become used to these walls across the river and normally he found them only a minor problem. He had also noticed that an increasing number of other smolts were building up at these locations and their presence was beginning to attract a  number of large black birds which chased the smolts. As he descended further this was to become an increasing risk.

Below the weir the habitat varied little from that above but after a few miles things began to change. The water began flowing very slowly and became increasingly deep. In this new environment an increasing number of new fish species began to appear. Dominating the population were large shoals of silvery fish with vivid orange fins. These fish varied in size and seemed mainly concentrated close to the bottom. There were also smaller shoals of a brightly coloured fish with a dorsal fin that they raised like a sail when they became agitated. They were olive green in colour with darker bars extending down their bodies but it was their bright red fins which were the most striking.


Eventually he reached the weir at Thrybergh, this was by far the biggest walled structure that he had encountered and presented a more daunting prospect to descend. Around him were several hundred other smolts all milling around and their presence had attracted the attention of at least half a dozen of the large black predatory birds. The birds were amazingly agile swimmers and despite the agility of the smolts many were being captured. In his panic Salmo, followed many of his fellows who overcame their reluctance and dropped over the weir into the pool below.

Here the habitat changed once again and for several miles the river became a series of pools and shallows with a strong steady flow. The fish population resembled that that he had encountered between Rotherham and Sheffield although there were a few additions. The most common of these were large shoals of a mottled brown fish which, in shape resembled the barbel Salmo had met earlier in his journey. They had the same whiskers around their mouths but were all small like Salmo.

He had now reached the confluence with the River Dearne and again the conditions were changing. The flow reduced and the depth increased dramatically. He also noticed that it was becoming increasingly hard to breathe and the water was discoloured. Again, new species were appearing with one in particular very abundant. They were large deep bodied fish, brown or black in colour and were present in large shoals which seemed engaged in sucking up and blowing out the sediment from the river bottom. As Salmo watched them through the murky water, there was a sudden, deafening noise, reverberating and pounding through the river. The fish around him scattered towards the edges as a huge black, floating object came churning up the river stirring up the bottom and creating huge turbulence. For some time after the object passed it was almost impossible to see where he was and he became extremely disorientated. It took almost an hour for conditions to improve and for the shoals of fish to return back to their normal feeding activities.

Despite still feeling sickened and a little scared, Salmo continued his downstream journey. He reached another large weir at Sprotbrough but resting here was most uncomfortable. As he struggled to breathe he began to feel listless, and reluctant to continue but, eventually, passed over the weir into the pool below. Thank goodness! He instantly felt the benefit of the oxygenated water tumbling over the structure. Resting close to a tree which had fallen into the river, a huge torpedo like fish with a mouth filled with evil looking teeth rushed towards him. The fish was green in colour, almost three feet in length and missed grabbing him by no more than a few inches. Terrified he shot off as quickly as he could.

Many of the fish he had seen previously were even more abundant in this section, but there was one different to anything he had ever seen before. Long, thin and snake-like it wriggled along the bottom.  The other fish ignored him as it buried into a dense weed bed alongside the bank.

Salmo was nearing the final obstacle on his downstream journey. He had reached Doncaster, the upstream limit of the rivers tidal influence. The final obstacle he had to contend with was a rock ramp fish pass made up of large rocks laid along a descending channel. This was much easier to deal with than the usual weirs and reminded him of the cascading water of the upper river where he once lived.

He had made it! All he had to do now was follow the rivers tidal flow down into the Humber Estuary. There would be hazards before he reached the sea, but his prospects were much improved. With good fortune, in two years’ time, he would be returning as a magnificent silver salmon which would retrace its steps back to the very same moorland section of river where he was born.


The shoal of silver fish with orange fins were roach, the predominant species in the River Don. These fish can grow up to 2.5kls but rarely exceed half this weight in the Don. They can form huge shoals and for this reason are popular with anglers.

The fish with the bright red fins and striped backs were Perch. This species can be extremely predatory feeding on the fry of other species. They have a large dorsal fin with sharp spines at the tips which they erect when threatened.

The large deep bodied brown/black fish were bream. This species has become increasingly common in the lower reaches of the river and form shoals which can sometimes reach several hundred fish.

The small mottled brown fish which resembled young barbel were gudgeon. These fish rarely grow to more than a few grams in weight but form huge shoals. They have a preference for gravelly sections of river bed where there is a steady flow.

The large torpedo shaped fish was a Pike. These vicious predators dominate the rivers food chain and can grow up to 20kg in weight. They feed predominantly on fish but will not hesitate to take young ducklings if the opportunity arises. They prefer to wait for prey near reed beds where they dart out to intercept their victims.

The large black floating object that Salmo encountered was a commercial barge carrying fuel oil. Commercial operations on the Don system have reduced dramatically over the last 40 years and now only one vessel still operates. When fully laden the keel of this craft almost touches the bed of the river. Fish populations adapt to passing vessels by seeking shelter close to the banks as they pass, however the craft’s movement causes large amounts of sediment to be disturbed.

During periods of very low flow the slower moving sections of river upstream of Sprotborough can suffer periods of low dissolved oxygen. This is due to a build up of nutrients which promote algal blooms. These minute plants take in oxygen during the night, depleting levels to the point where fish can be affected. Most coarse fish species tolerate these conditions, but salmon and trout require higher oxygen levels and can struggle. This was the situation Salmo experienced passing through this section.

“Today I saw…” – Nature Journaling

Hello, it’s matt here.

There’s a real joy in seeing the first signs of spring. Lesser celandine creates a beautiful display of yellow stars along the river bank after what often feels like a long and grey winter, the first song of returning migrants like the chiff-chaff chewing through its two-note performance. The Marsham family (link – must have thought something similar and for a whopping 211 years recorded “indications of spring” – a collection of information on the first time they saw a range of different plants as they came into flower that year – until they were told they were no longer of use.

But this type of anecdotal evidence gave birth to a study known as ‘phenology’ – where we examine the effect of environmental changes on nature which is extremely important as we experience the effects of climate breakdown (if only the Marsham family had continued!!).

Keeping a nature jounal has an added benefit of helping us remember what we’ve seen that day, taking an opportunity to savour our favourite moments and if we’re ever feeling a bit depleted we can even look back on it in years to come and remember “that time I saw…”.

Our friends at Sheffield and Rotherham Wildlife Trust have made this great video for nature journaling with kids

But if I’m truly honest, despite loving seeing nature and talking about it ALOT, I don’t actually keep one myself so I’m going to challenge myself to keep one for a week and I’ll let you know how it goes.

Here’s a few ideas of what I might include in mine –

  • Date, time and location
  • What was it, how many?
  • How were they behaving?
  • A small sketch of what it looked like.

Here’s a page from Sally’s for inspiration



Beginner’s Guide to Botanising

Weed or Wildflower?
“It’s a weed!” is what my Mum would shout on noticing my curiosity at a plant that had popped up unexpectedly in the garden. But to me the plants that wriggled through the cracks in the pavement or scattered the lawn uninvited were wildflowers.  The daisy and the dandelion are the ones we learn early and remember from childhood, but there are many more to find and learn.

Flower Families
With less floral diversity than many other parts of the world, an amateur botanist in the UK has a good chance at learning the names and habits of nearly all the native and introduced wildflowers. However, an easier way to learn, rather than one by one, is to learn the ‘families’ that plants are grouped into. Each family has a selection of characters which we can learn to recognise, for example the wonderful Carrot Family’s members have flowers that sit at the end of umbrella-spoked stems. Or the pea family, which includes clover, recognisable from their lip-shaped petals and neat little leaves.

The St John’s Wort family is an easy one – always yellow, with 5 pointed petals radiating around an explosion of stamens (where the pollen comes from!). The cabbage family, whose members have fat seed pods that point upwards, are alternatively called the Crucifers: the flowers all possess four distinct petals which appear like a cross. The Dead-nettle family (it’s members unrelated to the common nettle but with similar-shaped, un-stinging leaves) are a little trickier to spot. This is where our noses can help us as this family contains those herbs we are familiar with in the kitchen – marjoram, thymes and mints.

Once you’re aware of all the family groups and their defining characters, when you come across a new wildflower you can begin to narrow down where it might belong in the tree of life, and reach an identification much quicker!

The best way to get to grips with the families is with a good guide or key. Francis Rose’s Wildflower key is a firm favourite among amateur botanists. At first it can be daunting, but with practise you can get to grips with the terminology by using the excellent illustrated glossary at the back (whorl and wing, ray and raceme, panicle and papus are a just a few of the words you’ll have to get used to as you learn to identify the plants around you). Francis Rose’s key is beautifully illustrated, but it can be nice to complement it with a photographic guide. Simon Harrap’s Wildflowers field guide is split into the same family groups but contains useful distribution maps and photos of each species, allowing you to be extra sure you’ve named that wildflower right.

What’s in a name!
Wildflowers were once treasured and named for their healing properties. Nowadays few of us would dare to guess which wildflower might provide medicine for an ailment, but these secret medical uses are often hidden in the plant’s common names. Eyebrights (a dainty meadow flower in the Figwort Family) is still used today for eye problems, Speedwell (in the same family) provided curative tonics to speed healing and Feverfew (from the daisy family) in medieval Britain was planted around doorways to protect homes against disease and plague.

When to start? The best time is now!
The first flowers of Spring stick out like sore thumbs after months of winter and grey. First comes Lesser celandine in March, a bright yellow woodland flower (belonging to the Buttercup Family) which is a sure sign of Spring. You might spot Green Alkanet of the Borage family (forget-me-nots belong here too) with bristly spear-like leaves and bright blue five-petaled flowers. Then by the end of April appears Jack by the Hedge (the Cabbage family) with tiny white cross-shaped flowers and garlic-smelling leaves. Aim to learn the new flowers as they appear and watch them carefully as they change throughout the season.

Make a Herbarium
Why not make your own herbarium collection to refer to as you learn!

herbarium snapshot
CLICK HERE to watch the video



Life after Covid-19

We asked DCRT trustee John Housham to tell us his hopes and expectations for life and the environment after the coronavirus pandemic, read on to find out more…

Without a crystal ball it is hard to picture how things will be after our current situation is over, even whether it will be over.

The soothsayers are of course online with their views of our future way of living, government, economy and even the environment.  Some pessimistic, some optimistic and some in between.  Whatever the future becomes, we will all have created it.

What if we took the opportunity to create something better, more compassionate and humane, what could it look like? Here are my hopes on the future.


People will have new habits and values that protect the environment

Many more people will have experienced and interacted with their local environment alongside rivers, lakes and in parks in recent weeks.  There could be even more opportunity for people to connect with rivers and value the wildlife that they see, benefiting from the physical and mental stimulation. The environment will become more important to more people and all our healthcare.


More space and more diverse habitats will be created for wildlife

I recently heard that a fox appeared on platform 6 at Sheffield railway station… there is room for both people and wildlife in our towns and cities. You may have heard about the building of fish passes on the many weirs of the Don that will bring salmon back through Doncaster and Rotherham to Sheffield.  This could be extended to connect even more lengths of the Don up into Stocksbridge and the Peninnes or even opening up the River Dearne to Barnsley and River Rother to Chesterfield.  The River corridors could be teaming with an abundant and diverse wildlife from fish to birds to mammals for people to enjoy and value into the future.


Spark more community pride with more people working together

Pictures from space tell us of a new world with less air pollution brought about by less carbon emissions associated with fossil fuel travel and power generation.  These trends could continue with more working from home and less travel. Together we can all reduce pollution of water, land and air by producing less waste at home and at work and use more sustainable energy sources.

What would you like the future to look like?



The Salmon’s Tale: The Middle Don

Join us for the next part of the Salmon’s Tale! In this blogging series by DCRT trustee Chris Firth, follow Salmo the salmon smolt as he travels from the River Don’s headwaters to the low, meandering reaches of the river. Learn which fish species inhabit the three different reaches of the Don and pick up some of the history of the Don along the way…

Salmo had reached the outskirts of Sheffield and everything he once knew was changing. The clarity of the water was no longer the crystal clear condition he had enjoyed in the upper river and the taste and scent were very different. As he dropped further down the river he felt unnerving vibrations and noises rumbling through the water. The bank side vegetation had been replaced by high stone walls, with strange objects moving along the tops of them.  The only thing which was consistent were the fish species he encountered. Trout and grayling were in abundance down here darting in and out of the bright green weed which stretched in long ribbons across the surface. He felt safe tucked under this weed but his sanctuary was short lived. Suddenly, without warning, a trout came hurtling past pursued by a large brown creature which expertly grabbed the fish in its mouth and swam up to the surface. It quickly carried its struggling victim to the river’s edge, before disappearing into the bankside vegetation.

This event prompted a desperate urge to keep up his descent. He had been coming upon an increasing number of the walls which stretched across the river but in most cases these had sections cut out of the top which enabled him to drop down into the pools below without much delay. He was now reaching the downstream outskirts of the city and having just descended a particularly large obstruction, noticed a large flow of water entering. This inflow almost doubled the flow of the river and had a particularly unusual taste and smell which he found rather distasteful. Nevertheless, within this flow were hundreds of small fish, very similar in size to himself. They were silvery in colour with slightly orange coloured fins, and appeared to be feeding on small particles in the flow. As he passed through this shoal he also noticed, on the fringes, a number of much larger fish drifting backwards and forwards. These were powerful looking and were clearly attempting to pick off weaker members of the small fish. They were bronze in colour with distinctive orange fins and black tails. They had large mouths that they opened and closed almost in anticipation of taking an easy meal. In an attempt to avoid them Salmo swam close to the opposite bank where there was some overhanging vegetation.

At this point the habitat was beginning to change even more, with very deep pools running into shallows. Fish seemed to everywhere but one group particularly caught his attention. They were laid close to the bottom on the gravelly shallows. They were huge, bronze in colour with the same bright orange fins, and their mouths seemed to be under their heads with strange whiskers hanging from their lips. Their size unnerved Salmo but, as he passed they completely ignored him.

Our salmon was now approaching the outskirts of Rotherham where another river joined the Don. From this point on the changes he was to encounter would be even more profound.

Add a heading(1)

The new fish species that Salmo encountered were dace, chub and barbel. These three species were introduced back into the recovering river Don in 1990 being released at several locations including below Sandersons Weir. The fish were purchased by Yorkshire Water from a fish farm run by the National Rivers Authority. These were some of the first coarse fish to be artificially reared in this country and before introduction were placed in tanks where the flow was steadily increased. This developed their strength, giving them the ability to swim against the flowing river. From these introductions the populations of these species have developed and are now fully sustainable.

Dace live in large shoals preferring steadily flowing water. They feed close to the surface and are sometimes seen in large numbers taking small insects as they drift down.  They rarely exceed 300g in weight or 20cm in length.

In their immature stage Chub can be easily mistaken for Dace. The easiest way to tell them apart is to look at the shape of the fins, particularly the anal fin. In dace the end of the fin is concave where as in chub the fins are convex. Chub can grow up to 4kls in weight. They have a very varied diet but can be extremely predatory feeding heavily on the fry of other species.

The iconic Barbel are extremely powerful fish and in the Don specimens of over 7kgs have been taken. They prefer conditions where there is a good flow pushing food downstream along the riverbed, such as below weirs. They can be found throughout the middle and lower reaches of the Don.



It’s National Hedgehog Awareness Week!

Why are we promoting National Hedgehog Awareness Week?

We’ve lost a third of our urban hedgehogs and over half in rural areas so it’s important we can do whatever we can to slow the rate at which we’re loosing them.

Also when you picture the river you may not imagine a hedgehog there but when you start thinking about the river as a catchment of an area where water flows off the land into it, it encompasses everywhere including all the animals that live within it (and I’m sure a few hedgehogs have taken a drink from the river at some point).

Here’s a video from Catchment Officer Matt showing you what you can do to give hedgehogs a helping hand in your garden/allotment.

The adventures of Paxton the rescue hedgehog!

Next, we have an interview Matt did with Christine and Ava – two of our catchment volunteers that join us on days when we’re Moss Valley.

Hi Christine and Ava, I found out recently that you’ve got a rescued hedgehog living in your back garden and since it’s national hedgehog awareness week I wanted to ask you a few questions about it…

Why do hedgehogs need rescuing?
Hedgehog numbers are seriously in decline and there are various reasons why we may be able to help them along. They are often found injured by dog or rat attacks, they can be injured by a strimmer or they can get caught in garden netting and then starve. They can be underweight in the Autumn if they are from a second litter. If they are found wandering in the daytime it means something is wrong.
Where did you adopt your hedgehog from?
We adopted the Hedgehog from a friend who had been asked to look after it. On the 18/10/2019 it was found wandering around  in the middle of the day by a South Yorkshire Police Officer, so the Hedgehog was taken into custody!  My friend lives next door to the police officer and as the Officer knew she loves wildlife, they asked her to look after it. She rang the British Hedgehog Preservation Society (BHPS) who put her in touch with people locally who look after Hedgehogs, but they didn’t  have  room so asked her to look after it.

In November it  only weighed 750g and needs to be at least 800g to be released, so she decided to over winter it. in December It went into hibernation and came out  in early spring at 800g. She kept it until it had made it back up to 900g, then asked us to give it a “soft release” as we live in the country and have safe water supplies at our ponds. The hedgehog came with it’s house and run and feeding stations. After a couple of days we opened the doors to the cage to allow it to explore our garden and the fields beyond. We have tried to keep track of it with a camera trap but we are not sure if it has been out of it’s run or if it’s still curled up in the house. We’ll keep on putting food down for it at the feeding stations and hopefully it will explore further and further afield and be less dependent on our food.

How do you look after the hedgehog?

Baby Paxton
Baby Paxton!

The British Hedgehog Preservation Societygave loads of advice. The first thing was to to weigh it. It was found to be under weight in October, at only 200g. So she was advised to keep it and feed it up. They gave her a Hedgehog house and a run and gave advise on feeding stations. She fed it on dried “Hedgehog Food” which you can buy at pet shops and wet cat food from pouches and plenty of water. She supplied it with hay which it used for lining it’s nest.
Have you given it a name? Is it a boy or a girl?
The local people from the BHPS, gave it the name of “Paxton” and thought it is a male.
What’s your favourite hedgehog fact you know?
That baby Hedgehogs are called “Hoglets”.

For more information on hedgehogs and what you can do to help this declining species go to –


A Salmon’s tale: The Upper Don

Join us for the next part of the Salmon’s Tale! In this blogging series by DCRT trustee Chris Firth, follow Salmo the salmon smolt as he travels from the River Don’s headwaters to the low, meandering reaches of the river. Learn which fish species inhabit the three different reaches of the Don and pick up some of Chris’s expert identification tips along the way…

For several weeks Salmo the salmon smolt had been experiencing new, and rather strange feelings. He noticed his shape was changing and his scales were becoming a brighter and brighter silver, but most of all he had this compelling urge to leave the area of river in which he had existed for the last two years. The urge was growing stronger and eventually could not be resisted. He began to descend down the river.

The water helped him to drop down, further and futher, swimming backwards most the way. As he decended he noticed that the environment was slowly beginning to change. The river was widening and deeper pools began to appear in which he noticed much larger brown trout. Some of the fish were very aggressive and chased him away. In one of the pools he noticed strange fish which he had never encountered before. They were silvery in appearance but as they turned a flash of green or purple was obvious, particularly on their dorsal fins which were long and seemed to wave in the current. There were more than 30 fish in the shoal and they were intent on taking small flies from the surface. Can you guess this species? Scroll to the bottom for identification!

After two days he noticed that the flow had slowed down and as he looked around noticed several small silver fish which were identical to himself. They were all facing what appeared to be a wall across the river over which just a trickle of water was spilling. For several hours he and the other smolts remained confused and reluctant to try to go over the wall but eventually they found a small notch in the structure where the water was slightly deeper. Over he went dropping several feet into a pool below.

Over the next several days he was to encounter more than a dozen of these structures and his reluctance to descend them diminished. The river was getting much wider now and the pools much deeper. On one occasion whilst he and his fellow smolts rested before descending, he saw through the water surface a large grey bird which lunged forward grabbing the smolt alongside him. The captured fish shook in an attempt to free itself but to no avail. It disappeared down the throat of the bird. Salmo dived towards the sanctuary of the deepest part of the pool as quickly as he could.


Over the next few days the descent involved several changes in the conditions. Several smaller streams merged with the main river and each brought with it changes in the taste and smell of the water. The pools got much deeper and the channel wider. The silvery fish with the large dorsal fins appeared in greater abundance as did the number of brown trout. Weeds rooted to the bottom became more common providing  cover from the increasing number of large trout and large grey birds that sought to consume him. He had reached the outskirts of Sheffield and despite what he had endured could not imagine the experiences that still awaited him downstream.

The species that salmo met on the first phase of his downstream journey were Grayling, sometimes called ‘ The Lady of the Stream’. This very attractive fish lives for up to 6 years and can weigh up to 1.5 kls. Grayling were the first fish species to be introduced to the Don as water quality improved on the upper river. The fish came from the River Hull at Driffield and were introduced to the river at Hazelhead in in 1983.

grayling id