Cowside Beck

Question 1

On the Bradshaw’s model, what increases with distance downstream?

Answer 1

discharge, occupied channel width, channel depth, velocity, and load quantity

Question 2

On the Bradshaw’s model, what decreases with distance downstream?

Answer 2

load particle size, channel bed roughness, slope angle

Question 3

Aim of fieldwork

Answer 3

To investigate how applicable the Bradshaw Model is to a stretch of Cowside Beck

Question 4

Hypothesis

Answer 4

Discharge will increase with distance downstream

Question 5

Location

Answer 5

• Cowside Beck, Arncliffe
• Flows north east to confluence with the Skirfare
• Skirfare is tributary to the River Wharfe

Question 6

Why did we select Cowside Beck?

Answer 6

• upland stream
• exhibits majority of changes over short distance
• deep enough to allow measurements without being excessively deep/wide
• could access enough sites for systematic sampling
• scree slopes common so affected bedload size and shape :(

Question 7

Secondary Data

Answer 7

OS map to locate and plot 9 sites

Question 8

ICT skills used (secondary data)

Answer 8

• digital OS map to explore changes in valley cross-profile and channel
• weather forecast online

Question 9

How long was the sample site?

Answer 9

5km

*long enough to expect to see recognisable changes

Question 10

How far apart were the sites?

Answer 10

500m

Question 11

What type of sampling was used?

Answer 11

systematic

Question 12

Why was this sampling technique used?

Answer 12

Gave us good coverage of the beck

Allowed us a statistically significant amount of sites

Question 13

What needed to be considered when the sites were chosen?

Answer 13

Access and safety

Question 14

Why didn’t we use random sampling?

Answer 14

We wanted to cover all sections of the river, and this may not have occurred if random was used
Access needed to be considered

Question 15

Improvement to sampling technique?

Answer 15

Stratified sampling would have allowed two different sites to be compared, and could be paired with random and systematic within the chosen sites

Question 16

How did we measure depth?

Answer 16

• ran tape measure along river from bank to bank (ensuring it was tight and horizontal)
• divided river into 10
• measured depth at each interval using meter ruler
• recorded results

Question 17

How did we measure X-Sectional Area?

Answer 17

Multiplied average depth of channel by width

Question 18

How did we measure river velocity?

Answer 18

• used a biodegradable float (orange)
• measured 10 m stretch of river
• timed how long it took the orange to travel the distance
• done at each bank and in middle
• found average time and converted it into ms-1
• took measurements using a flow meter

Question 19

Health and Safety

Answer 19

• weather - appropriate clothing needed
• cold, fast flowing water - river levels monitored, told not to go too deep
• bank conditions - overhanging banks collapse easily
• getting lost - kept to designated areas, registers taken, worked in groups
• uneven terrain - good footwear

Question 20

Presenting Depth and Width of the river

Answer 20

We drew the cross section onto graph paper

scale 2cm=1m. This made explaining results easier.

Question 21

Measuring river discharge

Answer 21

multiplied average velocity by cross sectional area

Question 22

Site 9 Mean velocity

Answer 22

1.1 ms-1

Question 23

Site 9 X sectional area

Answer 23

1.85 m2

Question 24

Site 9 discharge

Answer 24

2.035 cumecs

Question 25

Analysis of results

Answer 25

Scattegraph
X axis - distance downstream (IV)
Y axis - discharge
POSITIVE CORRELATION

Question 26

Stats Test

Answer 26

Spearmans’ Rank

Question 27

Spearmans’ results

Answer 27

Calc value - 0.983

Accept H1 at 99% significance level

Question 28

Conclusion

Answer 28

Discharge does increase with distance downstream

Question 29

Why is site 9 an anomaly?

Answer 29

velocity and discharge are less than 9, but could be due to slope processes