Physical fieldwork Flashcards
Enquiry question:
To investigate how discharge changes downstream
Hypothesis:
The discharge will increase going downstream
Studysite:
River Brett
Locations on the river Brett:
Hitcham pump, Bilderston, Semer Bridge, Hadleigh Weir
Description of River Brett:
small river, flows through countryside of Suffolk in E Anglia
Geology of River Brett:
clay, chalk, sand, gravel
Upper course location:
Hitcham pump
Middle course locations:
Bildeston (meander + river cliff)
Semer Bridge
Lower course location:
Hadleigh Weir (weir and channelisation)
How was width measured:
tape measure from one wet edge to another
How was depth measured:
width/6 and then at each interval a metre stick is used to measure the depth
Velocity:
at each interval, use a hydroprop to measure velocity, by timing the period it takes for the the spinning to stop
Limitations width:
hard to judge wet edge as water is constantly moving
Limitations depth:
parallax error and water splashing on the ruler
Limitations velocity:
human error when timing due to reaction time
Improvements width:
aim to keep the tape measure taught and above the water
Improvements depth:
crouch down and take the reading at eye level, and keep the metre stick perpendicular to flow
Example of risk and a strategy to minimise risk
-hypothermia so wear layers
-low hanging branches so proceed with caution
Example of quantitive technique:
annotating a photo of the site
Reason for quantitive technique:
to identify how geographical processes interact with the natural environment
Limitations of qualitative technique:
subjective
Improvement qualititive technique:
have an example for comparison and a reference
What were the three methods of data representation?
-cross sectional profile
-scatter graphs
-GIS located proportional symbols
positive CSA
represents width and depth of the river visually
negative CSA
does not represent all the data
What do scatter graphs represent?
the velocity
positive of scatter grap:
visual so easy to spot trends
negative of scatter graph:
does not represent the width, depth or discharge (only one dependent variable)
Positive of GIS located proportional symbols:
can see where your data comes from irl + easy to manipulate
Negative of GIS located proportional symbols:
complicated and need a key to understand + basic training
increase in width
+ 5.22m
increase in depth
+ 0.105
trend in velocity:
increased from site one to two but then decreased for site three then increased again
trend in discharge + net increase:
increase by 0.046 cumecs
but did decrease from site two to three
conclusion:
the discharge increases because as the river bed become smoother and the river larger due to abrasion there is less friction which leads to an increase in velocity and an increase in discharge
Is it a strong conclusion?
-no as inconsistencies in trends
causes of inconsistencies in trends:
Bildeston has a river cliff and a meander and Hadleigh weir has a weir and channelisation which could impact results
improvements:
-more sites
-use stratified sampling to reduce bias completely, however may cause the locations to cluster
-use temporal sampling to reduce external factors impacts on results
