Paper 3 - River Ogmore - PHYSICAL

Question 1

Why did we choose the River Ogmore?

Answer 1

only 27km long

large change in river over short distance

catchment area is 15km2

dendritic

mix of land uses

Question 2

what was the investigation aim?

Answer 2

How does the River Ogmore change with distance downstream?

Question 3

what data can we collect to answer the question?

Answer 3

• width
• depth
• flow rate
• bed load size/shape
• photos

Question 4

what are the sampling strategies we used and justifications?

Answer 4

stratified - by area - we wanted sites in UC, MC and LC

systematic - cross profile measurements - equidistant

random - bedload - collecting pebbles

Question 5

what was in the risk assessment for River Ogmore?

Answer 5

drowning - don’t go in deeper than welly height
ticks - lymes disease - stay covered
poisonous / dangerous vegetation - don’t touch or eat plants

Question 6

what was the distance downstream at site 1?

Answer 6

0.30km

Question 7

what was the distance downstream at site 2?

Answer 7

1.75km

Question 8

what was the distance downstream at site 3?

Answer 8

3.00km

Question 9

what was the distance downstream at site 4?

Answer 9

9.00km

Question 10

what was the width at site 1?

Answer 10

0.77m

Question 11

what was the width at site 2?

Answer 11

2.10m

Question 12

what was the width at site 3?

Answer 12

3.93m

Question 13

what was the width at site 4?

Answer 13

9.80m

Question 14

what was the mean depth at site 1?

Answer 14

0.03m

Question 15

what was the mean depth at site 2?

Answer 15

0.16m

Question 16

what was the mean depth at site 3?

Answer 16

0.14m

Question 17

what was the mean depth at site 4?

Answer 17

0.14m

Question 18

what was the average velocity at site 1?

Answer 18

0.12m/s

Question 19

what was the average velocity at site 2?

Answer 19

0.20m/s

Question 20

what was the average velocity at site 3?

Answer 20

0.49m/s

Question 21

what was the average velocity at site 4?

Answer 21

0.45m/s

Question 22

what was the cross sectional area at site 1?

Answer 22

0.025m2

Question 23

what was the cross sectional area at site 2?

Answer 23

0.342m2

Question 24

what was the cross sectional area at site 3?

Answer 24

0.557m2

Question 25

what was the cross sectional area at site 4?

Answer 25

1.352m2

Question 26

what was the discharge rate at site 1?

Answer 26

0.003 cumsecs

Question 27

what was the discharge rate at site 2?

Answer 27

0.07 cumsecs

Question 28

what was the discharge rate at site 3?

Answer 28

0.275 cumsecs

Question 29

what was the discharge rate at site 4?

Answer 29

0.611 cumsecs

Question 30

what was the mean bedload at site 1?

Answer 30

700.6mm

Question 31

what was the mean bedload at site 2?

Answer 31

140.8mm

Question 32

what was the mean bedload at site 3?

Answer 32

113.1mm

Question 33

what was the mean bedload at site 4?

Answer 33

158.7mm

Question 34

what was the mode bedload roundness at site 1?

Answer 34

semi angular

Question 35

what was the mode bedload roundness at site 2?

Answer 35

semi rounded

Question 36

what was the mode bedload roundness at site 3?

Answer 36

semi rounded

Question 37

what was the mode bedload roundness at site 4?

Answer 37

rounded

Question 38

what was the hypothesis?

Answer 38

bedload size and shape decreases downstream and become more rounded width and depth increase downstream causing cross section area to increase

Question 39

how did we measure the width

Answer 39

holding. tape measure taut from bank to bank stratified

Question 40

how did we measure the depth

Answer 40

metre ruler at regular intervals across the width systematic

Question 41

how did we measure the velocity

Answer 41

impeller and stop watch

Question 42

how did we measure pebble size and roundness

Answer 42

capillars powers scale random - biased

Question 43

name some secondary data collection

Answer 43

previous groups data OS map

Question 44

how did we present the data?

Answer 44

cross sectional diagrams velocity scatter graphs divided bar chart - load shape and size

Question 45

conclude the cross sectional area hypotheses

Answer 45

The cross sectional area increased downstream from 0.025m2 to 1.352m2 from site 1 to site 4. This is due to vertical and lateral erosion along the river's course

Question 46

conclude the velocity hypothesis

Answer 46

The velocity increased downstream from 0.12m/s at site 1 to 0.45m/s at site 4. This is mainly due to tributstires joining do there is more water therefore more energy. `there is also less friction as the water has eroded the river bed.

Question 47

conclude the bedload size and shape hypothesis

Answer 47

The bedload size and shape decreased downstream from an average of 700.6mm at site 1 to 158.7mm at site 4. This is due to when tributaries join the river there is more energy which causes more attrition - therefore the bedload size becomes smaller and more rounded.

Question 48

evaluate the investigation

Answer 48

I thought that this investigation went well and lots of our results are quite accurate. To improve the investigation I feel that we should have done more repeats for better accuracy. The equipment that we used was good but in some cased the equipment jammed - especially the impellor which could have impacted some of our results. If the river is too shallow to use the impellor, measure how fast it takes a dog biscuit to travel over a set distance.