Rivers Fieldwork Investigation Paper

429 Words2 Pages
Our geography fieldtrip involved looking at the features of a drainage basin. This was done by going to different areas around our local river. To conduct the fieldwork investigation, we first had to prepare to make sure we knew what we were doing in detail. First, we produced a hypothesis that we were going to test. Hypothesis: As valley gradient increases, velocity of the river also increases. Testing this hypothesis required a method with specific equipment, and we decided to use systematic sampling in order to achieve a fair test. Finally, we created tables for data recording. Method: 1. Use clinometer to measure gradient of river valley. 2. Measure depth, width and length of the river site with meter ruler to find discharge. 3. Measure 5 meters with tape measure and mark start to finish. 4. Place floating object at starting point. 5. Start the stopwatch and stop when the object has reached the finishing point. 6. Calculate velocity in cumecs, which is discharge of the river divided by the seconds it took for the object to complete the 5m. From the valley gradient against velocity graph produced from our result table, it is clear that the gradient of the river valley does not affect the velocity of a river and therefore proves our hypothesis wrong. The R squared value of our results graph essentially equals 0, showing that there is no correlation between the two variables. This may be due to a variety of reasons: - Upstream, there is a narrower valley meaning higher wetted perimeter and more contact with the bed. This causes higher friction so velocity naturally gets reduced. - Load particle size and channel bed roughness is higher upstream, which might lead to increased friction and will slow down the water as it collides into rocks, pebbles and boulders more frequently. - The discharge upstream is also much lower due to the narrow

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