Geographical Skills Investigation River Answer Flash Cards

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The aim of my inv estigation was to ev aluate the relativ e influence of the v ariables identified by the Bradshaw M odel
on the pattern of discharge along a section of upland riv er. I used Spearman's Rank Correlation Coefficient (rs) to
determine the strength of the relationship between discharge and distance downstream. The Spearman correlation
coefficient, rs, can take v alues from +1 to -1. A rs of +1 indicates a perfect association of ranks, a rs of zero indicates no
association between ranks and a rs of -1 indicates a perfect negativ e association of ranks. The closer rs is to zero, the
weaker the association between the ranks. This allowed me to either accept or reject my null hy pothesis.
Data analysis/ how appropriate was it to First I tabulated the data, ranking them giv ing the highest the v alue '1'. Identical v alues were giv en equal ranks. Next I
found the difference (d) between the ranks and squared them (d2). I then did the sum of d2 and used the formula to get
the data? the coefficient. I interpreted the data, +1 being a perfect positiv e and -1 being negativ e. I compared this to a significance
table to determine the strength of the correlation. This rev ealed that there was only a 0.01% probability that a strong
0.93 probability was down to chance. This didn't prov e a causal relationship but does form the basis for further inquiries
to establish the reasons, assessing the contribution of the key v ariables.
The positiv es of using Spearman's Rank Correlation Coefficient are that it shows the significance, can prov e or disprov e
the correlation between discharge and distance, allows for further analy sis and it doesn't assume a normal distribution.
It is a statistical measurement, so is a non-bias measurement of the relationship between two v ariables, to test the
significance of the correlation. For example, the result for wetted perimeter was 0.855 and was significant when
compared to a critical v alues table, and we found that this had a 99% confidence lev el that the relationship didn't occur
by chance, making it v alid.
The negativ es include: that it is a difficult and complex equation, it can be misinterpreted and it needs two sets of
v ariable data.
A risk assessment was conducted both prior to and continuously throughout the process of
primary data collection. A score of the likelihood of the event, was given to each hazard, this
was multiplied by the potential outcome. If it exceeded the acceptable level then it would
either have to be reduced or the trip would have to have been cancelled. Whilst travelling to
and from sites in the minibus, wearing seatbelts was compulsory, providing protection in the
Describe and justify measures taken to case of collision. Food allergies were identified and catered for. Appropriate footwear was
worn (e.g. wellies and walking boots) to prevent hypothermia and to reduce the chance of
reduce risks.
slipping. Waders were also worn as a hypothermia prevention method. When entering the
river, a stable, low bank with easy access was chosen, to reduce the chances of slipping or
falling over. Also there was no independent entering of the river, everyone entered in groups of
3 or more, in order to support each other and prevent accidents from occurring. We stayed
together at all times, having designated partners. We only entered at suitably shallow riffles,
where it reached no higher than knee level, and the water was moving at a relatively low
velocity. This was done in order to ensure that no one was overpowered by the river and thus
prevented the risk of drowning. Sites 6 and 5 were considered too deep when conducting our
continuous risk assessment, so we responded by moving further downstream.
Our chosen location was the river Glaven, North Norfolk. The area
sampled was just outside Holt and Hunworth and finished at
Glanford. The river is chalk bedded, and runs through a mixture
Describe the characteristics and location of deciduous and evergreen trees. The river continues into
of your field work marshes at Blakeney Point. The surrounding farmland is mixed
arable. We sampled 10 sites along its 17km stretch. The gradient
was very flat all along the river as the surrounding area had been
drained. Site 1 was 40m above sea level and site 10 was less than
10m, making it an unusual river.
I was able to identify that the Bradshaw Model is not applicable to all rivers.
For example, I found a negative correlation between discharge and distance
downstream, Spearman's Rank Correlation Coefficient turning up a value of
Explain how your enquiry improved your -0.697. This is the exact opposite of what the model suggests. In turn I had
to accept my null hypothesis. More research would be required as it is
understanding of the topic likely that there are errors in the investigation and other rivers might turn
up differing results, proving the Bradshaw model. The investigation allowed
me to extend my understanding of the limitations of the methods used to
investigate a river, which is hard to truly comprehend and visualise without
hands on experience.
The Bradshaw Model is a theoretical model which describes the
changes (in terms of the characteristics and behaviour) we would
expect to see as a river travels from its source regions in its upper
course with increasing distance downstream towards its mouth. It
Explain the geographical theory behind graphically represents how a number of variables change
your fieldwork enquiry downstream. The aim of my geographical investigation was to
assess the validity of this model. Specifically, testing factors
influencing discharge (cumecs) - wetted perimeter, cross-sectional
area and velocity. The Bradshaw model suggests that as the
discharge increases, so does velocity, wetted perimeter and cross-
sectional area, as a result of the channels increasing smoothness.

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A risk assessment was conducted prior to the trip, which involved
the identification of risks and how to prevent them. When at the
site we carried out an ongoing risk assessment. At site 5 and 6
How did you respond to risks associated there was the consideration that in places the river was too deep
with undertaking your primary data to safely enter and conduct research.…read more

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In order to calculate the discharge (cumecs), of the riv er we had to work out v elocity x cross-sectional area.
We carried out 2 methods of measuring v elocity :
1) We set up 2 poles, 10m apart and timed how long it took for an orange to trav el between them. This gav e us the
v elocity (or float time) of the surface, in m/s.…read more

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To evaluate the relative influence of the variables
identified by the Bradshaw Model (cross-sectional
State the aim of your investigation area, average velocity, efficiency and relative friction
as determined by bedload size and shape i.e.
gradient and channel smoothness) on the pattern of
discharge along a section of upland stream. The
Bradshaw Model graphically represents how a
number of variables change downstream.…read more

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Quantitative data is referred to as data in numbers. It is easily measured, compared
and analysed. It is usually in the form of numbers/ statistics. An example of
quantitative data gathered in my investigation was that of velocity, calculated using a
With reference to your results, Hydroprop. However, there are negatives associated with this form of data. Many
argue that it doesn't give much/ enough detail.…read more


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