The Changing Valley of the River Wharfe

The River Wharfe flows from Beckermonds to Buckden and beyond.  (If you missed out on the map that went out with my newsletter at the start of this series, send me a message and I’ll email a copy to you.)

At Yockenthwaite

At first its valley slopes down to the river bank, keeping the river in its channel and the channel fairly straight.

Further downstream the sloping valley sides are further apart. The river meanders across a relatively flat area.

If the river channel fills to the top and it overflows, the water will spread out over a large area. This area is called the floodplain.

Have you been to your local river to find your own example of a meander yet?

The Strid

The River Wharfe flows through the beautiful valley of Wharfedale.

On the day that I visited, the river was rather full, due to the recent heavy rain. The river bed was covered all the way across. Many islands were submerged apart from their trees.

So at the section known as The Strid, on the Bolton Abbey estate, you’d perhaps be wondering where all the water has gone.

The River Wharfe goes from being about 9 metres wide to the size of a long stride, in less than 100 metres. So where does all the water go?

If you read my first post in this series , then you may be thinking that the water has disappeared into the ground. That’s kind of right but there is so much water going through that a lot of the ground has actually been washed away.

As the river flows along it carries stones of various sizes. These swirl around in the current and scrape potholes in the river bed, helping to enlarge the natural cracks in the rock.

At The Strid, the narrowing of the channel means that the water is moving very fast. The potholes and cracks have enlarged forming a passage of interconnected caverns.

So where has all the water gone? Well it is still there, in a chasm about 9 metres deep. (That’s about the height of two double-decker buses). It’s as though the river has turned onto its side!

Looks innocent doesn’t it?

But if you fall in you don’t stand a chance. You’d be sucked under (both banks overhang) and thrown against the rocks by the turbulent flow. Many lives have been lost here.

A Wordsworth poem “The Force of Prayer” tells the story of one such tragedy. You can read it here.

If you would like a sheet of notes on the poem, sign up to receive the Blog About Britain newsletter and opt for “Geography worksheets and ideas for further study”.

The Meandering River Wharfe

The River Wharfe has many bends, especially where its valley is wide, and thus lives up to its name, which in Celtic means ‘twisting’.

A river bend is called a meander.


The river is flowing towards the camera on the left and away from the camera on the right. As it comes towards the camera it is heading straight for the bank where I am standing. But the shape of the channel sends it around the bend. This means that the fastest flow, the strongest current, is right below the bank on the outside of the bend. The strong flow easily picks up any loose material and gradually erodes the bank away. So I am actually standing above a bit of a cliff.

Here’s another meander on the River Wharfe.

Now you can see the steep bank on the outside of the bend. The trees at the bottom of the slope look rather unstable, with the water washing away the soil around their roots.

The land on the opposite side from the river cliff is lower and flatter.

Can you find your own example on a river where you live?

Next week I’ll be telling you about a beautiful but sinister spot on the River Wharfe.

Exploring Wharfedale

The River Wharfe begins high on the Pennines in a peaty bog known as Cam Fell.


From here many springs arise, forming streams.


The faint lines show where streams are flowing down the slope. These form Oughtershaw Beck.

 

This flows on, through a deepening valley, to Beckermonds, an isolated hamlet (that’s a place that is too small to be considered a village). Here Oughtershaw Beck joins with Green Field Beck.


The combined river becomes the River Wharfe.
And then it disappears!

Well ok it depends on how much water there is to start with; how much rain there has been. It may not all disappear but some of it certainly does as there is less water flowing along the next stretch.  It had rained a lot when I was there but this is what can happen.

At Beckermonds, the River Wharfe flows over limestone rock. Limestone has lots of cracks in it and some of the water disappears down these. If the weather has been dry, and the river flow is already low, then the whole River Wharfe can disappear underground. It usually re-emerges about 3km downstream near Yockenthwaite.

‘Wharfe’ is a Celtic word meaning twisting or winding and the River Wharfe certainly does plenty of that. Next week we will take a look at some of the Wharfe’s twisting meanders and discover features that you can look out for on any river.

Meanwhile sign up for the Blog About Britain newsletter and choose ‘Geography worksheets and ideas for further study’ to get a map of the places mentioned in today’s blog.