Equipment
Ranging Rods.
Flowmeter.
Callipers.
Metre Rule.
Tape Measure.
Clinometer.
Method.
We placed 2 ranging rods in the ground at either side of the river and tied the tape measure in between the two rods making sure that it was tight. This was then use to measure the points from which measurements would be taken. These points were at 1-metre intervals. Depth was measured with the metre rule. A sample of the sediment was taken from the river randomly and measured using the callipers. Width, length and height were measured for the sediment sample. Velocity was measured using the flow meter in rotations at each of these points by placing the flow meter halfway in between the riverbed and surface and timing for 30 seconds. A member of our team stood t the side and recorded all these results with a clipboard; this person also timed the 30 seconds used to measure speed with a stopwatch. Finally we collected the 2 ranging rods and 2 people walked from the centre of the river 10 paces in opposite directions (upstream and downstream) and placed the ranging rods in the river bed. Then we measured the gradient of the steam using a Clinometer.
Results.
I have used tables to show my raw data as they are clear and make it easy to transfer my data into other methods of display such as scattergraphs which are used later in this piece.
Site 1.
Gradient = 4
Site 2.
Gradient = 5
Site 3
Gradient = 3
Site 4
Gradient = 4
Site 5
Gradient = 2
Site 6
Gradient = 5
Analysis Hypothesis 1
Average Speeds for Each Site
This table shows that the average width of the river is:
10+5+8+5+6+9 = 7.1666666m which is approx. 7.1m
6
The table also shows the overall average speed to be.
219+241.2+207.4+346.6+172.3+117.4 =273.31666 which is approx. 273
6
This would show the ratio of width to speed to be
71:2730
We can use this ratio to produce the line of best fit on the graph below by making sure that the line of best fit passes through the point (273, 7.1) and is spread evenly above and below the points from the table which will also be included in the graph.
The graph shows that there is a weak correlation between river width (wetted perimeter) and the speed that the river flows at. This shows me that although the points follow a similar pattern, they are not consistent enough to provide a definete answer to my hypothesis. There are no points that are a very large distance from my line of best fit and so it can be said that there are no anomalous results or outliers. This tells me that my study was carried out acuratelly and that with more time to study more sites along other rivers I may have been able to prove my hypothesis beyond reasonable doubt.
Analysis Hypothesis 2
I am now going to show the speed at which the river was flowing at different points across the river and attempt to prove that rivers flow faster in the centre which is my second hypothesis.
I have used Bar charts with pyramids to show my data here as they seem to show a shape that is consistent with the change of speed across the river width and so would make it easy to tell from 1 look at the graph if it follows my hypothesis.
The graph above shows my results from site 1. On the y-axis velocity is shown and on the x-axis the river width. This graph seems to agree with my hypothesis to a small degree and would follow the shape I expected to find if the first and last bars were removed as shown below.
On the second graph I have placed a curved line to show the expected shape as predicted by my hypothesis, and as you can see the graph now follows this shape a lot more closely. Therefore I think that this site follows my theory although it should not be taken as firm evidence.
The graph shown on the next page is of site 2 of my river study and seems to show a flat pattern with all values very similar and so nothing can be proved or disproved from this site. If anything can be concluded from this graph it could be possible to cast doubt on my hypothesis as this site does not seem to follow my idea of river flow.
I have placed another line on this graph showing where my theory would place the tops of the bars on this graph.
The graphs produced for velocity across the width of the river are a mixed bunch and seem to have some results that follow my theory near the centre of the river (such as site 5) and others that seem completely random (such as site 1). I think that the results taken in this test are probably very unreliable because they were only tested once and so provide a lot of anomalous results. Because of this I feel that my theory cannot be proved as only of the 6 sites follow the pattern explained in my hypothesis.
Evaluation
I think that I have stuggled to prove my theories through geographical evidence as I believe that our result taking methods were not accurate enough and so gave us a lot of anomalous results. Also I feel that far to few sites were studied and If more results were taken I believe I would have been able to prove my hypothesis to a high degree. If I were to take part in another trip of this kind I would like to be able to spend longer there and build up a large collection of accurate results and then I feel that I would have been more confident in my hypothesis.
I would like to thank;
Mrs Lloyd, Mr Wilson and Mr Rowland for taking us on this trip and I would like to thank Mr Rowland and Mr Redstall for helping me with this coursework.
