physical fieldwork 3 Flashcards
1
Q
where is the River Ogmore ? 4
A
- in South Wales
- runs from north to south
- source - Ogmore Vale
- mouth - Bristol Channel
2
Q
what was your hypotheses ?
A
- velocity increases downstream due to the increased volume of water from tributaries joining, lateral erosion and less friction
- cross sectional areas increases downstream due to vertical and lateral erosion
- the bedload size decreases and becomes more round due to attrition
3
Q
why did you chose those hypotheses ?
A
we would be able to see the change easily throughout the course of the river
4
Q
what secondary data did you use ?
A
- OS map to see distance downstream
- weather forecast and receding weather
- features affecting discharge
- data collected by other groups in other years
- igeology app on iPads
5
Q
what primary data did you collect ?
A
- bedload size
- width
- velocity
- pebble size
6
Q
how did you collect the width of the river data + and - ?
A
- tape measure
- hold tape measure from bank to bank
+ easy to read - had to make sure tape measure ends were exactly opposite
7
Q
how did you collect the depth of the river data + and - ?
A
- metre stick
- held metre stick in water
+ easy to read - ground was sometimes uneven
8
Q
how did you collect the cross sectional area of the river data ?
A
- cross sectional area = width x depth
- measure width and depth
9
Q
how did you collect the velocity of the river data + and - ?
A
- use impeller
- held impeller upstream
+ easy to obtain - sometimes didn’t work so had to move position of impeller
10
Q
how did you collect the river bedload and size data + and - ?
A
- use callipers
- picked random pebbles with mixed geology and measured them
- used Powers’s visual comparison chart to see how rounded the pebbles were
+ easy to measure and read - slightly bias
11
Q
what risks did we face ? 5
A
- drowning
- poisonous plants
- unsanitary water
- trips and slips
- tics
12
Q
how did we manage those risks ? 5
A
- no deeper than knee height in water
- don’t eat plants
- don’t drink water
- wear suitable footwear
- check skin for tics
13
Q
how many sites did we visit, why and how were they chosen ?
A
- stratified
- 4 sites
- chose areas we expected to see most change
14
Q
what graphs did we use ? 6
A
- field sketches
- cross section
- bar charts
- located proportional flow arrows
- scatter graph
- % bar chart
15
Q
what do you put in your analysis ?
A
- statistics and data
- how did bedload, cross section and velocity change downstream
- did it follow Bradshaw’s model
- why did the river change this way
