Geography St. Patrick’s Comprehensive
Hypothesis
As the river flows downstream:


A) The width of the channel increases
B) The depth of the channel increases


C) The speed of flow decreases


D) The volume of flow increases


E) The size of load decreases


River Studies - Method


When we arrived we split up into separate groups. We chose six locations along the river and at each location tested each stage of the Hypothesis.



A) We first of all measured the width of the river using a measuring tape, one person held one end on one side of the river and another person held the other end on the opposite bank.


Problems We Had With This Test & How We Overcame Them;





· The wind blowing the tape made keeping it rigid difficult, which made getting accurate results even more difficult. We overcame this by holding the tape tightly and getting a measurement when the wind dropped.


B) Next we measure the depth of the river using a metre ruler, we measured at 25 cm intervals across the river


Problems We Had With This Test & How We Overcame Them;





· Rocks, holes and the current meant that the readings would not always be accurate, we overcame this by gently pushing the ruler down until it dug into the riverbed slightly, but not enough to give us inaccurate readings.


· With the ruler being flat on one side we had to turn it side ways on so the thin part was facing the flow of the water, this cut down the resistance greatly and stopped it being shifted by the water.


C) To calculate the speed of flow of the river we measured upstream 5 metres from the chosen location. One person stayed there with a squash ball whilst another stood at the original point. The person released the ball into the water and we timed how long it took for the other person to receive it, we did this 5 times at each location to get an average time.



Problems We Had With This Test & How We Overcame Them;








· The ball would get caught in the reeds or be tossed up onto the river bank, to avoid this affecting our results we redid the test until it had a perfect run and to avoid erroneous results.


· The distance needed to achieve these results needed to be quite large, so we used a substantial difference to make sure our timing was as accurate as possible.


D) At each location we also took systematical sampling. This involved picking 5 random stones from the riverbed bed at each location, recording their width and length and then putting them back.



Problems We Had With This Test & How We Overcame Them;


Not all of the rocks in the water were formed by erosion of the river, there could have been other factors in how they came to there final destination, eg. People throwing stones into the river, we attempted to overcome this problem by taking a selection of 5 stones from each location, although this does not guarantee accurate readings.


Systematic Sampling


1


2


3


4


5


1


100 - 80


120 - 70


130 - 60


80 - 50


180 - 90


2


100 - 80


140 - 140


150 - 90


80 - 50


110 - 150


3


70 - 45


200 - 130


120 - 75


110 - 80


140 - 90


4


130 - 70


155 - 100


140 - 140


140 - 140


110 - 110


5


110 - 170


160 - 110


140 - 130


110 - 90


100 - 90


6


160 - 100


130 - 85


120 - 80


90 - 70


75 - 45


River Width & Depth Graphs
Analysis


My analysis is to test two main parts. Firstly to describe what pattern the results showed, and secondly to be able to account for them. If you look at my results, they didn’t exactly follow the expected hypothesis.


If you look at my results for the width of the channel, you will see that they follow no identifiable pattern. At location 1 the width of the channel was 2.5 metres. It then dropped to 2.2 metres at location 2. At location 3 the width increased by 1.6 metres to 3.8 metres. The next three locations showed no particular pattern. A factor, which could have caused these readings, is the fact that some of the locations were on a meander. There was a lot of material gathered on one side of the bank, caused by the slower moving