Page 101 - The World About Us

Fieldwork
1.1.1
3 1.1.1
2.2.3

How can fieldwork be critically assessed?

A class of geography students carried Sketch map p: You should prac se described in the Schumm Model.
out a piece of fieldwork in the Ogwen drawing sketch maps of your two field We would have been able to draw the
valley in Snowdonia. They decided to study areas. Remember to add a north data together on a single graph just like
measure the width and depth of the arrow. This student remembered that the Schumm Model itself. We could have
Afon Ogwen to see if these feature Llyn Ogwen was 1.5km long, allowing her drawn a much stronger conclusion.
matched those described by the to add an approximate scale line to the
Schumm model. The students answered map. Evaluate the use of one sampling
exam-style ques ons on their fieldwork. Evaluate to what extent one method you strategy used in your physical enquiry.
One student’s answers are below. We used systema c sampling to
used to collect your primary fieldwork
State your fieldwork ques on for data was a success. select 16 sites along the 21km of the
inves ga on. Afon Ogwen. This would give us one site
At each sample point, we measured every 1.35 km: an effec ve number of
Does the Afon Ogwen match key the depth of the river at eleven different sites with which to carry out a sta s cal
features of the Schumm Model? places across the channel. We did this by analysis. We selected these sites using
dividing the width by ten and then
Explain the suitability of one key the Ordnance Survey map of the river
ques on or hypothesis that you chose to measured the depth with a metre rule, at valley.
help answer your fieldwork ques on for the two banks and nine points between.
The 16 sites did give us a range of
inves ga on. This was successful as we used the samples in the upper, middle and lower
same method at all 16 sites on the river.
My hypothesis was, ‘The width and course and provided a clear view of the
depth of the Afon Ogwen will increase We held the metre rule thin edge onto trends in the data.
with distance from source.’ the water. This stopped water building up
on the face of the rule and giving an However, one weakness was that
This hypothesis allowed me to see inaccurate reading. By measuring at systema c sampling did not take into
whether some of the most important eleven loca ons, each at 10% of the considera on health and safety concerns
elements of the Schumm Model which width, we avoided bias, picking or accessibility. In some places the
relate to a river's cross-sec onal area interes ng places to measure. We could selected sample site was too deep and
were replicated in a small misfit stream in also draw a cross-sec on from which to dangerous to measure (for example, in
Wales. If the data collected showed a calculate an accurate average depth. the middle of Llyn Ogwen).
decrease in either width or depth my In other places the banks of the river
fieldwork could cast doubt on the validity However, by measuring at 10% our were on private land (for example, in
of a geographical model when the river points were close together in the upper gardens while the river flowed thorough
flows in a glacial trough rather than a course, where the river was narrow, but Bethesda). In these circumstances we
more typical river valley. several metres apart in the lower course,
where the river was wide. This meant we moved our sample site upstream or
Draw a sketch map to show the were more likely to miss very deep or downstream to the nearest, safe access
loca on of your field study area. point and measured there. Strictly
very shallow parts of the lower course by
chance. As a result, our data was more speaking our method was no longer
Bangor Flats accurate for the upper course. systema c but had become an a empt at
N systema c sampling, with amendments
Suggest how you could have improved
Mouth for access and safety.
your method to answer you key ques on
more effec vely? Jus fy one method used to present the
approx. data you collected.
We decided to measure two elements
1.5km
of the Schumm model: width and depth. I used a sca er graph with a ‘line of
This would allow us to calculate the best fit’ to present my data. This method
cross-sec onal area. In hindsight, we is perfect for presen ng data collected in
The Afon Bethesda would have been be er to measure the pairs; in this case distance downstream
(River) velocity of the river at each site as well. with width and depth. Drawing a sca er
Ogwen We could have used a floa ng satsuma or graph was quick, easy and accurate.
flow meter for this. We could have It was easy to iden fy a posi ve trend
measured the gradient at each site using in both width and depth by looking at the
Penrhyn a clinometer. data plots. They were rising across the
Slate Ffynnon graph from le to right. The 'line of best
Quarry Loer This way we could have calculated the
Source discharge, by mul plying width with fit' confirmed the posi ve trend. The fact
depth, and then with velocity. Adding that many of the data plots were close to
discharge and gradient would have the 'line of best fit' confirmed that the
Nant Ffrancon
provided data for all five elements correla on was not just posi ve but a
Fig.265 Student’s sketch map. strong posi ve correla on.
Lynn Ogwen

101

Geography fieldwork.