'To what extent does the River Lyn conform to the Bradshaw model of River characteristics?'

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Introduction.Aims of investigation + my key questions.

The aim of my investigation is to see ‘To what extent does the River Lyn conform to the Bradshaw model of River characteristics?’ To help me answer this main question I have split it up into key questions. They are:

  1. Does the size and speed of the River increase going downstream? And therefore does the discharge increase as you go downstream?
  2. Does the gradient decrease as you go downstream?
  3. Does the load particle size decrease as you go downstream?

Background information.

         The River Lyn has two channels which meet about two thirds along the River Lyn, and carry on as one until it reaches the Bristol Channel at Lynmouth. They join at Watersmeet, and from Watersmeet to the mouth the length of the River Lyn is 2.5 miles and drops 110 metres. The gradient can be up to 1 in 63 at some parts of the River Lyn. Canoeing takes place November to February (on a restricted scale), and at other times fishing is allowed.

        The East and West Lyn rivers once flowed parallel to the coast eroding 660 ft deeply into the plateau, where it entered the sea at Lee Bay. With the breaching of the valley sides the East and West Lyn rivers cascaded to the shore at Lynmouth, and now there is a fossil filled Riverbed high above the active river.

        On the 15th August 1952 there was a huge flood, there was high rainfall levels and all the water in the Exmoor catchment went into the River. Above Lynmouth the catchment area of a total 39.2 square miles are of gentle sloping and flat toped moors. Large boulders and rocks were carried in the flow towards Lynmouth destroying houses, roads and bridges. Many lost their lives during the flood. Changes have been made nearer the mouth of the River Lyn due to this.

The Bradshaw model of River characteristics.

This is what I will be comparing the River Lyn with to see, ‘to what extent does the River Lyn conform with the Bradshaw model of River characteristics?’

                

                        Fig. 1

                        

Annotated sketch maps of location.


Hypothesis

Fig. 4

Method.


Methodology table

The weather, time of day and year, and the accuracy of our samples could have effected the measurements as well as the extra limitations in the table.

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In addition to the equipment stated in the table, I also used a map, recording sheet, clipboard (covered for waterproofing), pencil, Wellington boots, and waterproof clothes.

What I did-how, why and the sampling techniques I used

Water + channel depth.

        I measured the depth of the River, but when it got too deep I was unable to measure the depth. I will have to get secondary data to help me see how much it conforms to the Bradshaw model of River characteristics.

                                        Fig. 5

Water + channel width.

                                         Fig. 6

Wetted perimeter.

        The way I measured ...

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