Stroud Valley Community School Walk

Lesson Report

By Lois Francis

Photo:Looking at the way the River Frome flows at Capel's Mill.

Looking at the way the River Frome flows at Capel's Mill.

Photo:Noticing the slower flow on the outside of the curve resulting in a build up of material.

Noticing the slower flow on the outside of the curve resulting in a build up of material.

Photo:Playing 'Pooh Sticks' to show the difference in speed.

Playing 'Pooh Sticks' to show the difference in speed.

Photo:The River Frome winding around Lodgemoor Mill.

The River Frome winding around Lodgemoor Mill.

How are canals different to rivers?

Cotswold Canals Knowledge was very fortunate to work with Stroud Valley Community school during March 2012. The school had reached that part of their geography curriculum that dealt with the physical aspects of rivers. CCK suggested the theme for the work could be comparing and contrasting rivers with canals, using the Stroudwater as an example. 

The walk 

So, after some preparatory work the whole of Key stage 2 were guided by Cotswold Canals Knowledge on a walk which started at  the River Frome at Capel's Mill and actually followed the river to Wallbridge, then along the towpath to Lodgemoor Mill and back along the towpath to end at Capel's Mill.

Mills


It is immediately obvious, along this walk, that the River Frome had, for centuries, been used for water power by the millowners. Along it's course, the river encounters so many mills that have their origins in Medieval times, Capel's Mill being one and the now demolished Wallbridge Mill, being another.

It is very clear that the canal builders from 1730, would have had so much opposition to the proposed canal from mill owners fearing that the canal would take all the water from their mills.

However, as time went on and wood for heating water for the dye baths started to disappear, the mill owners needed another fuel and coal could be brought far more cheaply on water than it could across land, especially as the building of the canal helped to promote mining in the Forest of Dean.

The River Frome


The River Frome rises near Brimpsfield and follows a very distinctive course to Sapperton where it turns to the west. 

It has many tributaries flowing into it especially in the immediate Stroud area. These tributaries also had mills along them. The Slad stream flows into the canal at Wallbridge as does the Painswick stream at Lodgemoor. Indeed, even at Dudbridge the Randwick stream flows into the canal. Before the  building of the canal the tributaries would have flowed into the river, which would flood very quickly after heavy rain.


Rivers and their work.


In the upper course of a river, slopes are steep and the river channels are narrow, so the river loaded with eroded material will erode its own channel vertically. This causes steep valley sides, rapids, gorges and waterfalls.
The middle course of a river has more volume and gradients are more gentle, so the river erodes  laterally and deposits material where it flows at it's slowest. This causes meanders to occur. The outside curve of a meander erodes the bank because the river flows very quickly here. The river flows slower around the inside of the curve and so starts to deposit material to form little beaches.
When a river reaches it's last stage, it loses energy and so deposits the load it was carrying, having abraded the load until it becomes sand or mud. Clearly, the River Severn from Gloucester is at that stage.


Capel's Mill

It was here that the children realised how a river naturally meanders. Playing 'Pooh' sticks was an informal way of noticing different flow rates and also noticing that the river bed is not uniformly flat, but has shallower parts known as 'riffles', which are eventually moved outwards to form meanders. The deeper parts of the river bed are spawning grounds for fish.

As the Stroudwater is restored, there are areas that are deeper than others in the bed of the canal and these encourage fish to spawn.

This page was added by Lois Francis on 23/08/2012.

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