If you do go down to the water’s edge please keep mini-cachers and geo-hounds safe
If you decided to observe from the road be careful it’s about a 10m drop
Barrowford has two rivers. Pendle Water flows through the town with trout that can often be seen. The other river is Colne Water, which joins Pendle Water behind the site of the now demolished Samuel Holden cotton mill and this river flows down from the moors above the town of Colne, again this river holds good trout.
Pendle Water is a minor river in Lancashire.
Rising on Pendle Hill, Pendle Water cuts a deep valley between Barley Moor and Spence Hill, where it feeds the two Ogden Reservoirs, before making its way eastward through Roughlee, collecting Blacko Water, draining the valley near Wheathead, at Water Meetings - 1 mile west of Blacko, then moving south through Higherford and Barrowford, where it is joined by Colne Water. Pendle Water subsequently runs by the Lomeshaye Industrial Estate west of the Leeds and Liverpool Canal to its confluence with the River Calder in Reedley Hallows northwest of Burnley.
The water was once supplier to Burnley Water Treament Works which is situated on Wood End Lane.
Earth cache lesson
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration or electromagnetism.
In geology sedimentation is often used as the polar opposite of erosion, meaning that sedimentation is the formation of rocks and strata, where erosion is the removal of material.
Settling is the falling of suspended particles through the liquid, whereas sedimentation is the termination of the settling process. This generally happens when the flow of water has been faster but then slows and the particles fall to the bottom of the bed of water.
Generally when you see evidence of sedimentation and settling it is where millions of years ago a river laid down the grit, sand or creatures, they have been compacted into rock and then exposed by faults or erosion.
At this location you can see the process of sedimentation and more particularly setting occurring. There is a faster flow of water upstream where the rocks are rolled and bashed together, chipping small pieces off. These particles are suspended in the water and at this spot they fall to the bottom. You will need to look at the river bed carefully to answers the questions below.
Settling does not occur on all sections of the river, here are some reasons why settling would not occur
- Because the gradient is too steep; if the gradient is too steep, the water will run too fast
- The path of the river is too narrow; this will result in a fast flow of water
- The depth of the river is too wide; this will result in a very shallow flow which is patchy with many small stones showing and little trickles of flow between them.
- The water flow is small, in drought or low water periods there just won’t be enough water to keep particles in suspension.
- The water flow is too high; during flood or spate many particles will be suspended in the water but they won’t get chance to settle due to turbulence.
So as you can see, there are many reasons why settling and therefore sedimentation will not happen, but can you figure out the reason why it does happen, at this location?
Questions
- Describe the appearance of the river bed for the 80m or so down-stream of the footbridge.
- What do you think is causing settling to occur at this location?
- How wide and (optional, how deep) is the river at its widest point below the footbridge
If you feel willing and able please include a photo of your visit, but don’t give away answers to the questions above.
Thank you for visiting the location, I hope you learned something and don’t worry if you struggled, have a go anyway.