The rise and fall… of the Arkle

What bridleway? July 2019
The Arkle in flood below Heggs house, July 2019
Remnants of the walled track down to Heggs ford, July 2019

Why is natural flood management so important in our neck of the woods?

For those of us who lived through the devastating effects of the 2019 floods, the answer seems obvious. But some aren’t aware of just how regularly the Arkle Beck breaks its banks.

Heggs ford impassable (and invisible!), Oct 2022

This is very easy for us to observe on the cluster, where the Ford crossing to Heggs becomes impassable several times a year, and tide lines of debris act as clear indicators of the Arkle’s continual rise and fall. 

Tide lines of debris at Heggs ford, Oct 2022

During these times, the riverside footpath between the Ford and the first hillock often becomes submerged too, washing away top soil and leaving the roots of the Alder on the banks more exposed.

Opposite the island of Scott’s pine, the flood plain sees constant use throughout the wetter months, and the flow pathways of the Arkle change at a surprising rate. Of course the function of the flood plain is to absorb such events. What we’re keen to do here — as along the whole stretch of riverfront — is to better support and stabilise the bank, through a mix of planting and coppicing. 

The flood plain doing its job, July 2019

So what causes the Arkle to rise?

Increased surface run-off.

Fremington Edge is covered by seasonal springs, gills and underground channels, that soon kick into action during periods of heavy rain. Pausing on Arkengarthdale Road, you can often see streams of white water pouring down the fell; gills that are dormant for 7 months of the year suddenly become torrents, and water bubbles out of the hillside at ever-changing locations.

Surface run-off above and along Heggs track, July 2019

Surface run-off is caused in part by poor soil infiltration; in part by large amount of rainfall in a very short period of time. We experience a mix of both at the cluster.

Our planned Natural Flood Management works — including leaky dams, scrapes, sediment traps and riparian planting — all aim to reduce surface run-off. In addition to biodiversity uplift, our new 30ha woodland hopes to do the same.

How?

Various studies show that a vegetative layer with high ground cover ie broad leaf woodland is more efficient in reducing surface run-off on sloping sites. This is because woodlands intercept rainfall in their canopy and release it to the ground more slowly, allowing more throughfall to infiltrate into the soil. Their extensive root system plays a part too — averaging 3m long, compared to 0.5m for grasses — increasing the soil’s water storage capacity, and minimising erosion.

How to monitor and measure this? We’re working on it…

Liz

No more of this please! Surface run-off behind Heggs house, Nov 2022

We have lift off…

Thanks to a welcome break in the rain, the heli-lifting team managed a productive afternoon’s work today, transporting dumpy bags filled with stakes and guards up to the planting site.

The difficult terrain of Fremington Edge, coupled with heavily restricted access, and sheer scale of the planting site, have made the logistics of our scheme extremely challenging, at every step of the way.

Simply assembling all the materials on the opposite side of the valley had already involved several days of work by a four-strong team on the ground, and several more still for the sorting and organising: We are technically planting two neighbouring allotments, and (due to the variance in altitude and soil) these are divided into two different zones, each with a different planting density and species composition. That’s a lot of labelling!

We now eagerly await the arrival of our 25,000 sum trees…

NB Heli-lifting part 2 is pencilled in for Friday (if the weather cooperates). Good views can be enjoyed from the lay-by on Arkengarthdale Road.

Liz

Beavering away…

We spent Wednesday and Thursday last week learning how to construct leaky barriers at three different locations across the cluster; each where channels begin to flow in the wetter months. 

Volunteers constructing a leaky dam below Heggs house

The idea is to let ‘normal flow’ pass through unobstructed, but temporarily hold water back during periods of high rainfall. This water is then released more slowly into the Arkle, thereby reducing the peak flow of the beck. 

The barriers are constructed by laying a large foundation log across the channel, bedding it into each side, and staking it to hold it firm. Subsequent logs are laid in an X-shape on top of this; before smaller branches and brash are woven through — plugging any gaps, and making the barrier more solid. (A simple ‘shake test’ soon showed whether or not our barriers would stand up to increased water pressure!) 

One of the finished leaky dams below Heggs house – visible from the riverside footpath

Where suitable trees were located along the side of the channel, we used hinge cuts to lay ‘living logs’ as the foundations. We also harvested willow from elsewhere on the cluster, staked this in at either end and interwove it throughout the layers of logs and brash, adding another regenerative element to our leaky barriers. 

It was very rewarding — and enjoyable! — to see the constructions take shape, and in several places the water began to pool almost immediately. 

Series of three leaky barriers across a channel that carries a significant amount of water during periods of heavy rain

The irony is not lost however that 10 people spent a considerable number of hours across two days on a job that a native semi-aquatic mammal would do naturally…

We wonder what mark they’d give us out of ten?

A huge thank you to Rhiannon O’Connell from the Yorkshire Dales Rivers Trust, for leading the works, and to all the volunteers who helped on the days. 

Look out for our next installment of Natural Flood Management works…coming soon… 

Liz

Help us to slow the flow this winter…

One of several planned leaky barrier sites at Heggs Farm

On Wednesday 9th and Thursday 10th November we will be installing leaky barriers as a part of the Yorkshire Dales Rivers Trust’s ‘Arkengarthdale Natural Flood Management’ project.

Led by Rhiannon O’Connell from the Yorkshire Dales Rivers Trust, we’ll use tools and bits of trees to create leaky barriers in overland flow pathways that will help slow and store flood waters.

This is the first of a variety of Natural Flood Management interventions that will be coming to the cluster, each providing multiple benefits of water management and habitat creation.

If you would like to be involved, we have 5 volunteering spaces available.

The day’s work will require a good level of physical strength. Wellies, waterproofs and a pack lunch are recommended, and the usual tea, coffee etc will be provided.

For further info and to sign-up, please email heggs.castle.cluster@gmail.com.
NB Times, meeting location etc will be provided once your place is confirmed.

We hope to see you there!

Liz

“Mighty oaks from little acorns grow”

At least that’s what we’re hoping will happen as a result of Saturday’s workshop — when a group of 12 volunteers met outside Heggs cow byre to get hands-on with nature restoration. 

Volunteers enjoying the sunspot in front of Heggs Farm cow byre

Led by Carol Douglas from the Yorkshire Dales Millennium Trust, as part of the Growing Trees Together initiative, the aim of the workshop was to make our own germination boxes, that would then safely protect and nurture a variety of local tree seed, collected the previous week from the ancient Ivelet Woods in Gunnerside. 

Volunteers constructing the sides of the germination box from soft wood

Working in pairs, there was plenty of time to knock up a simple box with mesh-covered lid (crucial to keep small mammals out). And some more handy than others, even managed two! 

Volunteers making use of spare furniture to saw pieces for the box’s lid

Delicious home cooked soup, accompanied by breads and cakes from Reeth’s Two Dales Bakery, rounded off the morning nicely. Oh, and did we mention the sun shone throughout?!

The finished article.

We’re now eager to see which seeds germinate successfully (we chose Holly for our own) and hope that this is just the first small step towards creating a thriving tree nursery right here in Swaledale.

Liz

Size does matter

So we soon learned as many hands made light work yesterday removing tree shelters on The Cluster. Done alone, it can be a slightly soul destroying task. Done as part of a group and it immediately becomes tolerable… enjoyable even as you work together to liberate each tree from its outgrown PPE.

This time our volunteers were an enthusiastic group of Raleigh International alumni, some of whom hadn’t seen one another since their scientific expedition to Indonesia, back in ’86.

With their help, we managed to remove, separate, and sort out several hundred tree shelters, ties and stakes for recycling and reuse elsewhere on The Cluster.

Separating and sorting HQ

The visual difference to the landscape was immediate, as was the very satisfying feeling you always get from ‘tidying up’!

Shelters be gone!

Tubex sells tree shelters (tubes) in packs of five – ranging from smaller to larger in diameter so that they slot inside one another – and this is how they’d like them returned for recycling.

Our ‘that’s interesting…’ observation of the day was that most of the reusable tree shelters were the largest size; reusable because they could be removed intact from saplings that had failed. The smaller sizes more often than not, had to be slit to be removed from still-flourishing trees. Is this a common trend? If so, why bother with the largest sizes at all? Is it merely a P&P convenience? (Off to research…)

Many thanks to Jeremy and his Raleigh International group for making a real difference on the ground!

Liz

Woolly jumpers

You may remember that last winter we planted a lot of willow to try and stop some of The Cluster ending up in the North Sea? See here…https://heggscastlecluster.org/2022/03/11/how-was-your-day/

After the floods three years ago, a large land slip started which with every proceeding flood caused more to be washed into the Arkle and more land to slip and be lost. So we decided to plant the area to try and stabilise it somewhat. ‘Soft engineering’ I believe it is called. Hundreds of willow went in with some being planted in the river itself. 

Despite another very dry spring and summer (so far) they have nearly all grown (95%+). This is good. But as usual there is a ‘this is bad’ side. Although we have almost managed to keep sheep off The Cluster, the odd one or two still find their way in and this summer they have beaten a track to our new willows and have managed to nibble any foliage they can get at. Willow (Salix spp.) are well known for their medicinal effects and so I can only assume that we have been party to sheep in pain! (Look up the medicinal properties if you think I’ve finally lost it).

Some of the willow in the river now hopefully safe from nibbling

As we’ve been removing quite a bit of fencing recently I decided to erect a temporary barrier to see if we could give the willow a better chance of making to next winter, when we intend to plant more willow in the river itself as the sheep don’t appear to enjoy wading for their medicine. Time will tell.

Because sheep numbers are now very low, we have noticed a lot, nay an ‘explosion’ of alder regeneration. There is a lot in and around the willow we planted (sheep don’t seem to nibble it currently) and a lot on The Cluster generally. Alder, like willow, needs damp ground and the places where it is springing up are exactly the places that are most vulnerable to erosion from the river. It’s almost as if nature knows how to look after itself.

Alder natural regeneration (hoorah!)

Funny that!

Martin WW

A little rain must fall…

But why does it have to be 5 1/2 inches in just over three hours?

Three years ago today we had a bit of a shower which caused huge amounts of damage to both The Cluster and the surrounding area. TV crews flooded in (sorry) to the area to document and incorrectly report what was going on.

A search online will reveal hundreds of photos and reports that show the devastation of the event and how a community came together (albeit briefly) to repair the damage to lives and property. But below are some more personal ones. Firstly from on our Cluster and then a few from the locality. I was pleased to be able to find a use for my daughter’s old beach toys which she had long since grown out of, and which within minutes of being put outside the Bridge Inn at Grinton, were being enjoyed by a new generation of children!

Clockwise: Heggs track, Heggs ford, Heggs track, Castle barn.

All the above pictures were taken the following day. The pictures below show just how high the water had got at some properties. Amazingly and thankfully there were no casualties.

The Bridge Inn beach with a couple of properties from Fremington showing how high the water got.

Martin WW

A moist update.

It rained! Seriously. It did. Honest!

It was therefore a bit muddy as we removed another few hundred meters of wire and posts from the Castle end of The Cluster. This fencing was erected some years ago to keep stock out of the alder woodland but floods and erosion had severely damaged it to the point that some it was now buried under flood debris.

It is surprising how much difference removing a fence makes to the feel of a place. We saw that last weekend too with our group of volunteers.

The wire netting we remove will be reused elsewhere to protect natural regeneration/planting spots from errant sheep and the posts will either be reused if good enough or cut and used for fuel.

The old fence line

There is still a few hundred meters to remove, including a rather awkward stretch which is partly underwater. That should be fun!

We’re also making progress with our planting scheme up the hillside with access now enabled through some of the landslips that occurred three years ago tomorrow. I will post some pictures of what exactly happened three years ago tomorrow if I get chance.

All in all a positive few days on The Cluster, including a few new records posted on iNaturalist.

The spoils…

Martin WW

PS. I was just getting some pix sorted for tomorrows post on the flooding three years ago and found some (post said flood) of the fence we removed. So I thought I’d treat you to them…

Before and after…ish

Buses

You wait ages for a blog to come along…

Just a reminder that we try and enter records of things seen on The Cluster (or indeed anywhere else) on https://www.inaturalist.org/home Its a simple to use app which has a feature where it attempts to identify what you’ve photographed. Anything that is recorded on The Cluster will automatically appear in our ‘Project’ window in iNaturalist so we can see what you’ve seen.

Martin WW