Data Collection

Question 1

Velocity hypothesis

Answer 1

As river travels downstream velocity should increase because there is less frictional drag as the different erosion along processes smooth out the river channel

Question 2

Sampling methods for velocity

Answer 2

Stratified sampling by stream order which ensures that the velocity is different at each location
Systematic sampling at 10m intervals 5 times to reduce risk of outliers and human bias. Could also use Spearman’s Rank
Also used systematic to measure distance across river channel so each data set collected at equal distances that averaged out value

Question 3

Velocity collection method

Answer 3

Got into river
Placed hydroprop in river and time taken for impeller the distance of the rod was measured
Half way deep, best because flow is slowest of the surface and the bed

Question 4

Velocity collection advantages

Answer 4

Systematic sampling was representative of entire channel and bias was reduced
Because data converted into m/s data could be easily compared to the other sample sites
Better than golf ball could get caught in eddies

Question 5

Velocity collection limitations

Answer 5

Impeller had a high critical velocity of 0.08m/s so at low velocities river did not have enough energy to turn the impeller. Measurement stopped after a minute
Dirty water could not see impeller
At low channel depths impeller was either touching river bed or appearing above surface of river so could be not accurate
Could have used a digital flow meter to make the readings more accurate

Question 6

Velocity collection conclusions

Answer 6

By collecting data for velocity in Glenderaterra Beck this helped me to prove the validity of Bradshaw’s Model because velocity did increase as the river travelled downstream