Fieldwork Flashcards
(37 cards)
What was the aim of the physical fieldwork?
To investigate how river depth, speed and load change across the bend of a river
What was the hypothesis?
The river is deeper on the outside, the river is faster on the outside, the river load is smaller on the outside
Describe the location
Borrowdale at ‘Grange’- a tributary of the river Derwent
Why was the location suitable?
It was safe and accessible, it was near to Keswick, appropriate for investigation, meander
What were the risks?
There were slippery rocks, there was fast flowing water, debris in river, uneven river bed
How were the risks reduced?
Facing upstream, bending knees, aware of surrowndings, focus on task, work in teams, suitable shoes and clothes, warned, moving slowly, supervision
How was the width of the river measured?
One prson stands on the river bank, second person walks across the river with the end of the tape measure, tape measure is kept tight and above the river, width is read out and written down by a group member on the river bank
What were the problems with measuring the width of the river?
The tape measure got caught in the channel making the river seems wider than it actually was
How was the depth of the river measured?
While the tape is being held across the river by two group members, a third group member uses a metre ruler to measure the dpth across the river at every 50cm, the depth is read out and recorded by a group member on the river bank
What were the problems with measuring the depth?
Pushing the metre ruler down too hard may make the channel seem deeper than it actually was
How was the speed of the river of the river measured?
One person holds the flow metre in the river channel with the propeller facing upstream, it is held in the water for one minute and the digital reading is read out to the person on the river bank who records it, this is completeted at three locations across the channel- at each edge and in the middle
What were the problems with measuring the speed?
There were people upstream from each group doing the same measurements which could affect the speed of the water, it was difficult to hold the flow metre still, the distance across the river channel was not measured, it was just guessed
How was the bed load measured?
At every 100cm across the river channel a rock from the river bed was picked up and passed tot he person on the river bank, this person then measured the longest length of the rock and qrote the measurement down to the nearest 0.5cm
What were the problems with measuring the bed load?
Most people always went to pick up the biggest rock which might skew the results, only one rock was picked up from each location, should measure all sides, use callipers, take more samples at each point
What did the data for depth show?
The depth data was presented as a cross sectional diagram, the cross section shows that the river was deepest on the outside bend of the river, the inside bend was 15cm deep whereas the outside bend was 73cm deep at its deepest, this is because the river travels fastest on the outside bend so it has more erosive power (it erodes more because it is faster and has more power), this makes the channel deeper, there was a slight anomally because the deepest point was 7 metres across the channel, the river then got shallower (65cm) and then deeper again (68cm), it is not a smooth, perfect example
What did the data for sediment show?
The data for sediment was presented as a scatter graph, the river bed sediment was found to be bigger on the inside bend than on the outside bend of the river, the three largest pieces of sediment were 16.5cm, 11cm and 10cm in length and they were found between the edge of the inside bend and up to 3m into the channel, this is relative to the outside bend where the sediment was between 3cm and 6cm, this is because the river has less energy on the inside bend so cannot transport the larger pieces of sediment, they have been deposited on the slip off slope when the river’s energy has decreased, this happens on the inside bend
What did the data for speed show?
The data for speed was recorded in a table, the results showed that the river was flowing fastest on the outside bend
Depth conclusion
The hypothesis was correct- the river was deeper on the outside bend compared to the inside bend
Sediment conclusion
The hypothesis was correct- the river bed sediment was largest on the inside bend compared to the outside bend
Speed conclusion
The speed of the river was fastest on the outside bend
Depth evaluation
Data was collected by every group but the data was averaged so if some people were slightly inaccurate the results will be affected, the river was constantly moving so it was hard for it to be measured at an exact depth, not all the data was collected at the same time or on the same day so to improve the results, all of the gropus should of collected data at the same time on the same day
Sediment evaluation
There was lots of data collected as each group measured the size of ten rocks, however, to improve the accuracy of the results each group could of measured the length of three rocks at each location which would make a total of thirty rocks being measured by each group, there was also a tendancy for groups to pickup the largest rocks which would make the data unreliable as the sediment may appear larger than it actually was, however, if this was done at each location the pattern of th largest rocks being on the inside bend would still be true, the length of the rock was also the only measurement that was taken rather than the length and width
Speed evalutation
One group should of measured the speed of the river at one time because people being in the river furthur upstream could of affected the results
Human fieldwork location
Keswick, Cumbria, north west of England
