Detailed site account
Site one: _ This is near a secondary school and has drainage pipes flowing into it. This is most probably from the school fields and car parks. The land the river is based on is London Clay. It contained pebbles and had a lot of litter probably dropped by dog walkers and students going home.
Site two: _ Roughly 200 meters from site one, we walked on to this after studying site one. This area was also London clay. There was a lot of vegetation and frogs were living in the long grass. At this site there was a lot less pollution than in site one.
Site Three: _ A grassy area with mud and clay-like land. We walked along after a housing estate through some grassy area. This was the clearest of the three sites and had the least pollution. I liked finishing off here, as it was a nice place instead of the dirty first and second area.
Data Collection
I have also drawn a selection of diagrams to help me explain each process listed below and how I will carry the task out.
Wetted Perimeter
I measured the wetted perimeter using a measuring tape and laid it across the bottom of the riverbed. The problem with that was the measuring tape was being carried by the current of the river. Instead, I could have used a measured size of metal chain; this would then mean that the current of the river could not carry it.
Gradient
To measure the gradient, I used a clinometer. When doing so it was not really a fair test as the ranging poles could be stuck into the ground further than the other. I used a clinometer because it shows whether the gradient is positive or negative.
Depth
Meter rulers were used to measure the depth of the river. I measured the depth of the right bank, left bank and middle of the river. When I placed the meter rulers into each bit, it could have penetrated the bank floor therefore not giving a fair measurement. I used meter rulers, as it was the simplest way of measuring the depth.
Width
When measuring the width of the stream I used a tape measure and measured from the left to right bank. A problem doing so is that the tape measure may have gone slack half way across the stream. The reasons for using a measuring tape is that the measuring could be done quickly and that way we do not have cart around lots of heavy equipment, as the measuring tape is light and compact.
Height of left and right bank
Using ranging poles and meter sticks I measured the height of the left and right bank of the river. I cannot think of way that this could be made easier or better. These were used as we could measure the ranging poles and then place them in the ground then measure the distance between the poles and the riverbank.
River velocity
To measure the velocity of the stream I used a cork and one meter of string we then timed it with a stopwatch. The problem being that the cork sometimes got caught among the reeds. I used cork, string and a stopwatch because then I could time to see how long it takes the cork to travel one meter, therefore giving me the information to calculate the velocity of the river.
The reason for me using such methods is that, in my opinion they are the methods that will give me optimal results within my available equipment. Such as the measuring of width with a tape measure is a good idea as I will be able to take the measurement from the bank more easily than if I was using meter rules and joining them together, which would have caused errors in the reading of results.
Equipment used for collecting data
*Tape measure - Used for measuring wetted perimeter and the width of all three sites along the river.
*Ruler (1 meter) - This was used when measuring the velocity, height of the banks and river depth.
*Ruler (30 centimeter) - Used for measuring the axis and roundness of the pebbles.
*Ranging pole - For height of bank and used when measuring the gradient of the three sites.
*Stopwatch - Used for timing how long it takes a cork to travel along one meter of the three sites.
*Clinometer - The equipment used for measuring the gradient of the river at the three different sites along the river.
Data Presentation
This contains evidence of a range of data e.g.
-Bar graphs
-Pie charts
-Maps
-Field sketches
-Annotated digital photos
-Tally charts
-Locational graphs such as a bar graph on a map of either site one, two or three.
Pebble roundness graph write up
The graph for the pebble roundness shows the difference in roundness of pebbles at the three sites. It is to show the differences if any, to try and help to prove the hypothesis that pebble roundness increases, as they get further downstream. The graph proves the theory that it increases.
Gradient graph of sites 1, 2 and 3 write up
This graph is to try and prove that the gradient decreases as you move downstream along a river. It shows the difference of gradient of all three sites. The graph proves that this happens.
Water depth graph write up
Used for proving whether or not the depth of a river increases with distance downstream. The graph used is a line graph as I thought this would show the results best. The graph actually disproved this theory.
Water width graph write up
The water width graph is for showing whether or not the width of the river increases with distance downstream. That is one of the five hypotheses. This was proven although the second site was narrower than the first but the third was the widest.
Velocity graph write up
Used for showing whether or not the velocity increases with distance downstream. This was proven by the graph and results.
Conclusion
The main hypothesis was that the characteristics of a river change with distance downstream. This was proved by collecting data on different kinds of characteristic at three different points of the river. Each was further downstream than the last.
Depth increases with distance down stream. Proved by measuring the depth of left hand side, middle and right hand side at all three different sites. The data showed that this was true. The graph also shows this.
Width increases with distance downstream. Measuring the width of the river at all three sites proved this. The graph shows this.
Gradient decreases with distance downstream. Proved by measuring the gradient of all three sites. The graph shows that this is true and gradient does decrease with distance downstream.
Velocity increases with distance downstream. Disproved by collecting data on the speed (velocity) of the river. The graph shows that this hypothesis is untrue.
If I were to conduct the experiment again, I would change the positioning of the sites so as to make it fairer. The first site would be the river source. The second would be at the middle of the river and the third would be at the end of the river. That way it makes the hypothesis easier to test and makes the collection of data fairer.
My results show, and help to prove that my hypotheses were all correct and my graphs show that this is true. My graphs depict an honest trend/pattern in my results for each hypothesis and, that my prediction of these things happening was correct.
My cross sections also show that, my hypotheses are correct and this evidence you can gain from examining them. If you look closely, you will see that all the processes mentioned in my hypothesis do in fact, increase or in some cases decrease with distance downstream.
