WTT Blog Posts

Easements on Eastburn

A number of my blog posts have featured Eastburn Beck. It’s my pet project because it is the first that I cut my teeth on after moving to Yorkshire, because I live overlooking its headwaters and hence it is a very easy and accessible site for me to monitor. It is also exciting because it has ably demonstrated the value of partnership working, and how with critical mass, relatively small habitat improvements are snowballing both up and downstream from the original work plans as word spreads; this is quite typical for projects that the WTT is involved with!

Eastbunr Beck weir mill river restorationEastbunr Beck mill weir river restoration notch

Pre & post some weir notching we undertook on Eastburn Beck at Lyndhurst Wood. The channel width is narrower with more natural pool, riffle, and depositional features

To date, the project has involved me (WTT), the Environment Agency (via the powerhouse that is Pete Turner), Yorkshire Wildlife Trust, Bradford Environmental Action Trust, the Woodland Trust, Aire Rivers Trust, and Green Port Hull, as well as some very cooperative local land / structure owners. It has attracted a reasonable amount of media coverage too: Craven Herald, Keighley News, a colour spread in the Yorkshire Post magazine, and in Fieldsports magazine (the latter two instigated by top WTT chum, Andrew Griffiths). It was even the feature of Pete Turner’s first ever blog!

So, I can’t say that I’ve seen it through to completion – when can we truly say that a river or stream has been completely rehabilitated to a pristine condition with the number and diversity of stressors acting upon them nowadays? It’s a job for life! However, I can say that the Beck is slowly returning to some version of the right track and hopefully you can follow its continuing evolution through these blogs. Check out the green tabs at the bottom of this post which will link you via key words (connectivity, weirs etc).

I’m currently working on a fish easement for the shallow concrete sill of a road bridge next to a former mill. More connectivity issues – see the recent news item for how often these crop up in WTT Conservation Officer workloads. This particular phase of work has been supported by funding from Green Port Hull, via a grant awarded to Aire Rivers Trust & WTT. There are several kilometres of becks and trickles with reasonable to good quality spawning habitat availability above this obstruction, so it is a likely bottleneck on the system limiting trout population potential. It is not classified as main river but one still has to apply for consent to install any structures which might affect flow and perceived flood risk; in this case, North Yorkshire County Council were very cooperative.

Prior to any installation however, the scientist in me was keen to assess just how much of an obstruction this particular weir and culvert combo was. Cue a call to those good folk at Ribble Rivers Trust and in particular Mike Forty (another name you might recognise from a past blog on making connections). Mike carefully set up a pair of telemetry loops at the lower and upper end of the culvert, and then together we spent a day electrofishing to capture trout from upstream. A total of 25 fish were tagged with Passive Integrated Transponders (PIT-tags) and released into the pool immediately downstream of the weir. The premise is that these fish that have been displaced will attempt to return to their ‘preferred’ location upstream; there is a scientific basis for this – see Mike’s report.

The headlines are that 40% (10/25) of the trout were recorded as attempting to jump the weir, and of those there was a passage efficiency of 40%; in other words 40% (4/10) of the trout that attempted to get up and over the weir and into the shallow water in the culvert did eventually make it upstream. I say eventually, it took those 4 fish an average of >10 minutes to negotiate the culvert. Interestingly, it wasn’t the larger fish that made it either, so perhaps the depth of water was insufficient for those larger fish. Despite some difficulties with the study, including a flash flood of epic proportions (2nd highest level ever recorded – typical), Mike and I are in agreement that the structure is a considerable obstruction to fish passage, let along geomorphology!

Now that passage (or lack thereof) has been assessed prior to any interventions, I can proceed with installing some oak baffles and a baulk to focus flows and increase the depth across the sill, whilst providing slack water refugia en route for fish to recover if required. Watch this space for future updates. 

Restoring longitudinal connectivity: a more holistic approach

Anyone who knows anything about fish in the UK will surely know Dr Martyn Lucas, the head of the Aquatic Animal Ecology Research Group within the School of Biological and Biomedical Sciences at Durham University. He’s an absolute legend and all round good bloke with whom I have done some research in the past. From amongst the many projects he is involved with, his group has published two papers this year revolving around fish passage issues. The first was led by Mike Forty (supported by the Catchment Restoration Fund, CRF) who wrote a layman’s version for us in Salmo and whom I have written about before on the WTT blog pages. Below is a quick summary by Martyn, reproduced with his permission, regarding the second output which included brown trout and bullhead as the study species.  

Jeroen Tummer’s paper concerns longitudinal connectivity restoration for stream fish communities, particularly in terms of the use of ‘nature-like’ passage solutions and obstacle removal, and the utility of a more holistic approach for evaluating outcomes. One of the key findings of our study is that quantitative fish surveys don't do a very good job in telling us whether connectivity restoration work for stream fishes has worked or not in the short term! There are much better ways of doing this as illustrated in the paper. However, they do provide valuable, contextual evidence about changes in the fish community towards or away from the restoration objectives, including those in the longer term (so long as standardised monitoring at a regular frequency is continued).

The study was part-funded by the Environment Agency's CRF scheme for the Deerness Connectivity Restoration Project run by Wear Rivers Trust in collaboration with several partners, including Durham University.

It is important that CRF has generated deeper "evidence" value, like the Tummers et al paper as well as widespread on-the-ground ecological improvements in support of Water Framework Directive improvements. During CRF programme planning, several key stakeholders argued for the importance of peer-review level evidence development as an integral part of CRF - I'm glad that advice was listened to by DEFRA-EA and I'm glad WRT and Durham Uni. have been part of that output.

Let's keep moving towards river connectivity solutions that support ecosystem processes, including dispersal of organisms, rather than those that concentrate on just a few species and life stages!

The paper abstract is available, here.

Food web responses to habitat rehabilitation

Connectivity is a recurrent theme of my blog posts. Last year I wrote about plans for notching some of the redundant low mill weirs on a tributary of the River Aire, local to me. Those plans will come to fruition in the next few weeks as Pete Turner (Environment Agency) and I have had our bespoke environmental permit consented to progress the works, so I’ll report back to show you how the channel is evolving. I also wrote about making connections and how Mike Forty’s PhD research with Ribble Rivers Trust had thrown up some really interesting results, especially regarding the importance of free movement for precocious parr; the published work is available here.

To communicate the worth of habitat restoration work (in supporting the Ecosystem Service approach & Natural Capital principles) to the wider public and to potential future funders, and thus maintain, increase and maximise the potential impact, there is an urgent need for some simple and accessible assessments that a broad audience can appreciate. I have proposed to use the concept of the food web in this context because: a) the knock-on effects of habitat degradation translate into food web alterations very quickly; and b) the food web is recognised by a broad swathe of society (and from a very early age). Hence, measures of food webs can be used as an engagement & educational tool that will increase the understanding and value of restoration projects, as well as a tangible and effective measure for funding applications.

Ribble Calder elctrofishing science weir barrier fish passage

Bluebell Wood Weir on the Calder, Towneley Hall, Burnely

Yesterday, I spent a day putting this idea into action on the Calder at Towneley Hall, Burnley, with Gareth Jones of the Ribble Rivers Trust and keen volunteer, Tim Eldridge. As part of the Heritage Lottery-funded Ribble Life Project (part of a catchment-based approach to river basin management to help deliver the Water Framework Directive), we will use stable isotope analyses to characterise the food webs of short river sections to see how they respond to a weir removal. These will be compared to food webs on reference sections to determine the change associated with the actual weir removal. The weir will be removed in early 2017, so we were taking basal resource, invertebrate (riverfly), and fish samples yesterday to assess the situation prior to any intervention.

volunteer electrofishing research brown trout parr

Weighing and measuring catch; and releasing a fine brown trout parr

It was encouraging to see some fine trout and eel specimens, as well as a reasonable diversity of invertebrates from a river which has been historically shunted to the side of the flood plain, shortened and steepened, fragmented by weirs, bordered with invasive plants, and formalised into a park in areas. Just imagine how good it could be with the barriers removed! 

Calder Towneley Hall Burnley Ribble

Reference section of the R Calder - not perfect, but better than above!

Coping with climate change

After the winter spates and ‘unprecedented’ flows rearranged much of the substrate of my local river, the Aire in N Yorkshire, there has been virtually no rain since. Consequently, it is already at late summer level, and the lack of energy has allowed thick scums of bacteria and other microbes to develop on the bed. The lethargy of some of the trout seems to reflect that of the river. And the forecast is for a hot summer, allegedly.

This leads me to my monthly scan of the literature for research involving brown trout, which has thrown up two recent papers assessing impacts of climate change via modelling. The first was a study of trout populations from two streams on the Iberian Peninsula, where trout are at the edge of their natural distribution. Ben Tyser reported for WTT on earlier work in this region – see the WTT Library (Articles by topic) page on Climate Change: Iberian trout threatened by climate change.

The purpose of the new study was to determine the realised thermal niche, the actual environmental temperature window at which the population was comfortable if you like, and then predict how climate change may affect their range distribution in those streams. The authors comprehensively assessed current trout abundance via electrofishing at 37 sites, and developed a robust relationship between air temperature and water temperature along the altitudinal gradient of the streams to relate to the trout distribution. Being able to convert from air to water temperature allows the authors to use the air temperature predictions available from the Intergovernmental Panel on Climate Change (IPCC) reports to predict the water temperatures that trout may experience in the future.

It appeared from the extensive dataset that water above 18 °C was not favoured by trout and this temperature limit is actually lower than the accepted physiological thermal range, ie trout should be able to function and grow ‘normally’ up to 20-23 °C. Hence, while physiology may dictate the limits of fish tolerance, these limits can be more constrained by additional restrictions, such as competition or hydromorphology, and hence the realised (actual) thermal niche was smaller than the fundamental (theoretical) niche.

Using the most unfavourable climate change scenario predicted by the IPCC, the trout habitat loss based purely upon water temperature change increased to 38% and 11% for the two streams in an upstream direction at the end of the century, 2100. Important then, as WTT so often advises, to maintain and protect riparian vegetation, especially trees to provide shade and keep the water cool alongside many other benefits.

The second paper uses a combined ecological and evolutionary approach to determine whether trout can adapt in time to keep up with climate change. The authors argue that to implement effective management and conservation measures, it is crucial to quantify the maximum rate of change that cold water, freshwater fish populations can withstand. They developed a model that incorporated aspects of river dynamics, the bioenergetics of trout, and adaptive habitat selection, and built in a novel component that allowed for genetic and life-history adaptations. Two key traits, trout size at emergence and the maturity size threshold, the authors proposed would be highly influential.

trout life cycle

A modeller's view of the trout life-cycle

To illustrate potential applications of the model, the authors analysed trout population shifts and evolutionary dynamics under scenarios of climate change-induced warming (ie similar to the first study reported above), and warming plus flow reduction resulting from climate and land use change. They compared the outcomes of their model to a baseline of no environmental change.

The model predicted severe declines in trout density and biomass under climate warming. The rates of decline were substantially greater under the combined warming and flow reduction scenario. Not good news; there was a distinct probability of population extinction over contemporary time frames. Therefore, the adaptive capability of trout (as modelled) could not prevent extinction under high rates of environmental change. We must hope that under real world scenarios, a few of our remarkable trout will have the variation in their genetic tool-box to cope when it comes to the crunch!

If you are interested in reading more (and in layman’s terms) on how trout adapt to warmer waters, it is worth returning to your latest edition of Salmo (May 2016) for the excellent article by Dr Eoin O’Gorman – Icelandic trout: adapting to life in warm water. As he pointed out, trout do show remarkable tolerance to warmer waters, but it is the lethal limit for development of trout embryos that may be critical and if fish cannot migrate to cooler waters to spawn then the population will suffer. Connectivity is key! Let’s hope the new research project he is involved with, Ring of Fire, sheds further light: follow @Arctic_Biology on Twitter for updates of that work.

Extinction of Experience

April was a quiet month for me as my academic commitments stole the lion’s share. But I can’t believe we are already at the end of May! May is probably my favourite month…. here in North Yorkshire, the ramsons and bluebells are in full swing and the beech buds burst to dapple them in shade and provide such a vibrant, fresh green for a week or so. And then there are mayflies of course but that’s another story.








I get an even stronger urge to be outside as much as possible, to immerse myself in the busy comings and goings of late spring. Luckily for me, the Conservation Officer role of my Wild Trout Trust duties (and occasionally my academic research) allows me to do so.

A month or so earlier, a paper popped up on my academic radar on ‘Extinction of experience: the loss of human-nature interactions’. It struck an immediate chord, having felt stifled and starved of those very interactions for the 10 years I worked in London. Fewer and fewer people, especially children, have daily contact with nature. This ongoing alienation prompted Robert Pyle to coin the phrase ‘extinction of experience’ some 20 years ago. The authors of the current paper report that some consequences of the loss of interaction with nature include deteriorating public health and well-being, a reduced emotional affinity toward nature, and a decline in pro-environmental attitudes and behaviours, which implies a cycle of apathy toward nature. They recommend that the policy makers of today need to focus more attention and effort on planning how best to reduce the extinction of experience and reconnect people with nature. The benefits seem obvious: achieving a healthier society and overcoming a wide range of environmental issues.

I am a proud father of a three year old daughter (the ‘Greyling’ - a definite PB), and such things play on my mind. I want her to have the opportunity to experience nature as I did. And I get an enormous kick from her curiosity toward nature. ‘Hornathorn’ (hawthorn) trees smell funny apparently. Sung to the tune of Rudolph the red-nosed reindeer (about our bird feeder frequenting pheasant) is ‘Ferdy the gaudy birdie, has a very splendid tail’. And whenever I pick her up from nursery with a rod wedged next to her car seat there is the inevitable question, ‘Yuk, do trout really eat flies like that?’    

Strikes me, although I am biased, that fishing is a great way to counter the extinction of experience. There’s the simple, out-of-the-house (off the sofa / video game) aspect, a curiosity angle of not knowing quite what might emerge from under the water, welfare and respect for other creatures stemming from catch and release, as well as all the other wildlife that we hear and see on the bank or which we can turn to when we blank! We will all have some experience that springs immediately to mind. This year especially, The Angling Trust have been trying to help young people create opportunities via their scheme Get Hooked On Fishing. My daughter has been kayak fishing with me several times on holiday and loves it. She’s chief shark spotter on the prow!

Riverfly monitoring is another great scheme to engage and mentor young people and instil a sense of environmental stewardship, but speaking from personal experience (and I would dearly love to be wrong) I haven’t seen anyone below the age of twenty doing it. I have spent many an hour with the Greyling, poring over a plastic tray, surreptitiously using her keener eyesight to best effect. So, are we missing a trick? There seems to be a distinct need to maintain the momentum gathered from all the fantastic ‘trout/troot in the classroom’ schemes around the British Isles now that I blogged about back in January, and forge links to riverfly groups and youth angling opportunities. Maybe that way, and with the Environment Agency considering a free licence for juniors under the age of sixteen, we will finally see a decline in the number of juniors taking up fishing and perhaps the slowing of another extinction event…..

Mike Blackmore's 'Mad March'

Mike is the WTT Conservation Officer for the South and West. 

At this time of year, there is often a hectic dash to get money spent before the end of the financial year and get trees pollarded/coppiced/hinged before the start of the bird nesting season. March 2016 was no exception and my very understanding wife allowed me to work through three weekend days and a bank holiday to fit it all in.

On the River Biss just outside Trowbridge, some delicate chainsawing and back-wrenching rope-pulling was undertaken to demonstrate different ways of managing fallen trees without removing them from the river. The largest of these was tackled by Land Rover and winch but the rest was done on volunteer power alone.

A short skip across the border from Wiltshire to Somerset and eight days were spent in the river officially known as the Somerset Frome (to distinguish it from the Dorset Frome, Bristol Frome or the Gloucestershire Frome) but known locally as the Frome Frome after the town Frome through which the Frome flows (At this point it is important to note that if the eight times you just heard Frome in your head, it rhymed with 'home', you’re saying it wrong! Now read it again and this time rhyme it with 'broom'. These things matter in the Westcountry!)

This project involved using live willow to protect eroding banks, hinging trees for marginal cover and transforming a straightened, silty backwater into a sinuous and flowing fish nursery.

The sixteen volunteers that gave up their time to help out, and the ever helpful Council Rangers worked extremely hard and should be rightly proud of themselves. The project has kick-started further improvements and provided a platform for further fund raising by the Bristol Avon Rivers Trust.

Both projects were funded by rod license money from the Environment Agency team at Bridgewater and a special mention should go to Technical Fisheries Officer Matt Pang who helped out in between nights spent patrolling for eel poachers and doing shifts in the family chip shop. This after not long becoming a father – who needs sleep?!

Photos: Somerset Frome project phase 1 . The project included a green erosion repairs, junk removal, juvenile fish/marginal plant habitat enhancement and a bit of river restoration.

MB frome work


 MB frome







MB frome 3

MB frome 4







MB frome 5


MB frome 5







Before and after shots of how the brushwood berms filled up with silt after just ONE day’s high flows. Exactly what we want to allow plants to establish.

Frome berms  MB frome berms with silt


What do we need, to know if it works?

Typical! Not two weeks after completing my round-up for the Science Spot in Salmo trutta, the annual glossy WTT publication that our members receive, an interesting paper on IMWs (Intensively Monitored Watersheds) lands on my desk. While not exactly on topic, it includes interesting snippets that would have embellished my article. However, as I wrote in the Salmo piece, the means by which knowledge is transferred nowadays means: I can (and have already) tweeted about this paper (but not included any precis or personal view of its content); I can (here, now) blog about it and impart some detail; or I can sit on it for 12 months and tell you all about it in the 2017 issue of Salmo!

IMWhats? In the Pacific Northwest, a vast tract of land with a very loosely defined boundary but it’s roughly 67 times the size of Wales if you’re interested in that sort of thing, there are at least 17 IMWs. They are an attempt to test the effectiveness of a broad range of stream restoration actions for increasing the freshwater production of anadromous salmon and steelhead and to better understand fish–habitat relationships. This is no mean feat, and the paper by Bennet and his colleagues reports on the lessons learned so far.

Billions of dollars have been invested in stream restoration across the US since 1990 alone, on the premise that improvements in freshwater habitat will lead to increased population viability and the potential delisting of threatened or endangered species. To achieve this, one needs to assess population responses to restoration, and these have rarely been documented because many restoration projects have not been monitored at the population scale. Instead:

  • Monitoring has tended to focus upon the reach scale and/or has occurred over too short a time period (less than 5 years). Experiments need to be 10 years or.
  • Restoration projects have typically been of a small size relative to the size of the watershed, and include a variety of restoration ‘actions’ such as culvert removal, reducing diffuse pollution, and installation of large woody material, which confounds an assessment of the effectiveness of each individual restoration type.
  • Identifying good ‘control’ streams to compare responses against is difficult, and it is also difficult to guarantee that control streams will remain suitable for their intended role for the duration of any project.

Add to that, inherently high natural environmental variability; all these contrive to limit power to detect a response in any one fish population. As an aside, these are exactly the underlying factors that affect our assessments of natural flood management, particularly pertinent in light of recent winter spates and ongoing reviews of how we will respond to those in the future. One of the closest analogues to an IMW we have in the UK, in terms of detailed monitoring of a population, not the efficacy of restorations, is provided by the long-term Atlantic salmon research on the River Frome; small scale by comparison, yet still valuable to inform stock management and conservation measures.

So, an IMW is an experiment that uses a management action (restoration) as a treatment and intensive monitoring to detect whether a watershed-scale fish response to that action occurred. The required scale, in both space and time, mean that this is an expensive business and not the sort of undertaking that can be applied to a typical WTT restoration! Also, because the IMW concept uses broad-scale, long-term ecological experimental designs, the expectations of stakeholders need to be managed carefully!

LWD woody material restoration river habitat wild trout trust

However, these sorts of ecosystem-scale experiments are required to provide the empirical data to test assumptions of improved fish populations, as well as provide reliable, robust and compelling evidence of the efficacy of common restoration techniques that are applied the world over (and certainly by WTT). If we drop X trees into Y barren stretches of straightened river channel, will the local angling club catch more fish because of it in Z years time?

While IMWs are still in their infancy, emerging data are positive, and the headline-grabbing figures are certainly encouraging:

  • Juvenile coho salmon survival in an Oregon river increased 50% in summer and 300% in winter after restoration improved rearing habitat.
  • 250% increase in numbers of juvenile fish in areas of a Washington creek with restored habitat compared to those without.
  • By helping beavers to construct dams to reduce erosion and boost the water table on an Oregon river, the production of juvenile steelhead correspondingly increased 175%.
  • Reconnection of side channels expanded habitat availability on a Washington river and fish numbers in those areas increased by 400-800%.

Each individual project undertaken by WTT (and the many other valuable works carried out by rivers and wildlife trusts, the Environment Agency etc) may fall into the ‘small size restoration’ category compared to an average IMW, but look at the number and coverage within the British Isles, and they start to tot-up. And as I have alluded to before here, we shouldn’t dwell on size because while they might not all add up to fish population increases, there are other benefits to be found.

Start 'em young

There has been much ‘Twittering’ of late as various organisations across the UK are venturing into classrooms to engage with children via aquatic beasties, and particularly our totemic species - the brown trout.

WTT chums at the Clyde River Foundation (CRF) coordinate #Clydeintheclassroom. It’s a huge venture, working with some 90 classes to engage with >2000 kids this year alone. It’s also very much a hands-on project, using aspects of the trout life history to promote awareness of river ecology, to engage with nature, and to help young people across the River Clyde catchment develop a sense of pride in their local environment. Furthermore, it provides a great basis for outdoor learning and STEM education.

Clyde River Foundation classroom education outreach enegagement science trout

On a recent visit to chat with Willie Yeomans, Catchment Manager at CRF, I learned that through the project, they have engaged with over 20,000 children at almost 400 schools. Check out the info-graphic above; that's some reach! Willie is keen to point out that on the Clyde, the trout are not used as part of a stocking project but purely as an educational tool; they’ve used triploids for a number of years now.

I’ve also been chatting with Gareth Jones, Catchment Science Coordinator for Ribble Life Together at Ribble Rivers Trust. Within the Ribble catchment and currently only in primary schools, they operate #troutintheclassroom with similar aims to those of Clyde RF. At Ribble, they are building upon the trout life-cycle by adding a variety of new activities from angling development / coaching, invertebrate monitoring, mayfly in the classroom, demonstration tables for river form and functioning, to poetry and musical events. Check out some of the enthusiastic school blog posts available on Burnley’s Urban River Enhancement Site.

In my day, things like this were definitely 'extra-curricular'! Excellent ventures I'm sure you'll agree, and they are not the only ones, just two I have personally come across recently. If you are a Twitter user, try the #hashtags mentioned above to see the kids (and trout) in action!

WTT has for a long time offered a similar educational project - Mayfly in the classroom – with free, downloadable resources on the WTT website, here.


Sediment sources and salmonid successes

Village pond weir dam sediment

On my WTT-inspired ramblings recently, I came across a shocking sight, above. Shocking because firstly, I was expecting to see a village pond complete with a raft of local ducks bobbing around, not a barren mudscape stuck behind a defunct dam; and secondly, because I immediately started to wonder where all that accrued sediment was being washed away to….. and where it was being deposited… and might it not be being dumped upon some salmonid redds at a rather inopportune time?

Sear sediment source salmonid embryo alevin

And a couple of days later, I was alerted to this. The image above depicts the graphical abstract of a recently published research paper by Professor David Sear, a key figure on the WTT Scientific Advisory Panel. While fine sediments are known to be a cause of embryo mortality in benthic spawning fish species such as brown trout, most research to date has focussed on the quantity accumulating around eggs, rather than any 'quality' issues associated with particular sediments.

For instance, some sediments will be mostly mineral, while others will contain a proportion of organic matter; it is the latter component which could be particularly detrimental to salmonid (and other species') embryos because of the potential for microbial breakdown of that organic matter, thereby reducing oxygen concentrations available to the eggs.

David and his colleagues exposed the embryos of two salmonids, brown trout and Atlantic salmon, to different sediment loads from different sources. Importantly, source as well as mass of sediment affected spawning habitat quality. While brown trout were less sensitive to sediment impacts compared to salmon, both were markedly affected by sediments derived from sewage treatment works; even the results from damaged road verges was worrying.

The organic content was the key driver determining the impact of a sediment source. Moreover, the effects were still apparent in surviving alevin via reductions in mass, length and yolk sack mass relative to experimental controls, so the overall fitness of the progeny that make it through the egg stage is still compromised. Any detrimental impacts at the vulnerable alevin stage is likely to lead to population consequences later on.

This important research highlights the inadequacy of current metrics and sediment targets which are based on quantity of sediment of a given size, or total daily maximum loads, on the assumption that all fine sediments will have an equal impact upon aquatic ecology. It thus provides resource managers with the evidence to support the development of sediment screening techniques, enabling them to target particular sediment source control strategies in the landscape. Critically, these strategies must encompass the characteristics of the mobilised sediment delivered to waterbodies from specific sources and not just the proportion of different sources of fine sediment.

Being in a relatively upland location with little improved land surrounding it, and situated in a small village, I am hoping that the pond sediments I found are of low organic content. Plus, recent snow melt has hopefully flushed it rapidly through the system so it has not had time to settle on any favourable spawning gravels. Hopefully!

For access to the research paper, click here, and for further recent information on land use and soil impacts on rivers, click here to be taken to a WTT news item from last year.

Reflecting on all this rain

Lothersdale farm fields

This is the view from my office window. Of late, I have been lucky to see across the valley. When it has been sufficiently clear there has been a stark message staring me in the face. So, what’s wrong in this image? OK, it’s not a great image but then it was taken in blowing rain. The field (centre shot) has a similar slope / exposure as those surrounding it yet it is the only one veined with rivulets of water. It is also the only one under permanent livestock grazing as compared to the fields on either side through which stock is rotated regularly. The result is a reduced crop plant height, root structure (and probably diversity), and more compacted soils leading to serious (visible) overland flow during times of heavy rain. At the bottom of that field is a tributary of the River Aire; little wonder that the Aire is often occupying the full width of its floodplain (below).

Aire flood


Everyone and their dog has had a view on the recent flooding in Cumbria and Lancashire, and not surprisingly these views tend to polarise; those driven by raw emotion as personal possessions and property are lost or destroyed, versus more objective analyses based upon long-term data records. Inevitably there are some commentators calling for the construction of more and better flood defences whilst there are those advocating more upstream thinking and rewilding of the upper catchments to slow the flow by intercepting rainfall and buffering impacts downstream.

Let’s face it, we have to contend with a long historical legacy of denuding the catchment of natural vegetation and in particular trees, as well as the development of village to city scale infrastructure upon floodplains with vast areas of impermeable surface and many pinch-points on watercourses like bridges and culverts. It is difficult to envisage the scale of defences that would be required to withstand the unprecedented rainfall at the beginning of December (1 in 1300 year; CEH site). Certainly, the aesthetic amenity and access values of having a babbling brook flowing through a village, or river gliding through a town centre, i.e. reasons that those very sites were originally settled, would be lost completely. It is also estimated (from models, because obviously there are no empirical data available) that 100% reforestation of the upper catchment would be unlikely to completely prevent such a scale of flooding when the water reached more urbanised / less natural infrastructure in the lowlands.

For a very measured consideration of the role trees may play in soaking up excess rainwater, read this contribution to The Conversation. I say measured, the message is positive from tree planting programmes such as the Pontbren Project, which followers of WTT will have heard us talk about on numerous occasions. However, providing robust and replicated scientific evidence along the lines of 'X trees planted here saves Y households over there from flooding following Z rainfall' is difficult.

There are clear evidence-based benefits to be derived from an integrated approach involving the whole catchment (summarised in the UK National Ecosystem Assessment Technical Report, here). And there are tantalising glimmers of potential uptake of such measures with the Environment Secretary announcing the investigation of upstream options for slowing key rivers amidst the Cumbrian Floods Partnership goals, calls for increasing the existing target of 11 million trees planted by 2020 to be upped to 200 million (via Confor), and established projects for ‘slowing the flow’ such as that in the Vale of Pickering reported in the recent Environment Agency blog ‘Creating a better place’. There is clearly no point in simply ploughing money into flood defences at the lower end of the catchment and expecting them to withstand the brunt of the water conveyed there by a depauperate system upstream, a point raised again and again by George Monbiot, and plain for all to see, unfortunately, in Keswick and Carlisle.

The key is integration and that includes depolarising the ‘camps’ currently at loggerheads, such as the ‘rewilding’ versus farming contingent. There are undoubtedly opportunities for more extensive areas of woodland (re)generation in the uplands, but not to the detriment of farmers, who are in essence the cultural element that is critical to the survival of communities in such rural areas. Hence, upstream options need to be (carefully) put into place to complement any (hopefully) sensitive ‘softer’ engineering within our urban environments such as SUDS – Sustainable Urban Drainage Systems. I say softer engineering in the hope that the dredging debate does not rear its ugly head again. Constraining water to an overly deep channel and conveying it downstream as quickly as possible costs millions, requires costly upkeep, is typically reactive, and rarely works as recent events show; and the environmental costs are always high (see the WTT view on dredging).

There is no panacea, but by thinking holistically to embrace and fortify natural ecosystem resilience to extreme events, perhaps we can move away from the oft repeated rhetoric of flood defence.

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