PHYSICAL

Question 1

TITLE OF FIELDWORK ENQUIRY

Answer 1

How river depth and sediment size changes across à river bend

Question 2

Risk and reducing risks

Answer 2

!Deep or fast flowing water
- check the depth/speed of water before entering (make sure it’s shallow enough to stand in)
- find a shallow and slow-moving part of the river to conduct fieldwork in

!slippery surfaces
- wear appropriate footwear like waders
-take care when stepping on slippery rocks in river

Question 3

Theory

Answer 3

Question 4

Data collection method for river depth

Answer 4

while the tape measure is being held across the river by two group members, a third group member uses a meter rule to measure the depth across the river channel at every 80cm across the width of the channel. The depth is read out and recorded by the group member on the river bank.

Problems: pushing the meter rule down too hard may make the channel seem deeper than it actually was.

Human error-misread of measurement.

Question 5

Data collection method for bedload

Answer 5

At every 80cm across the river channel a rock from the river bed was picked up and passed to the person on the river bank. This person then measured the longest length of this rock, using a calliper, and wrote the measurement down to the nearest 0.5cm.

Problems:
Most people always went to pick up the biggest rock which might skew the results,

only one rock was picked up from each location.

Question 6

Sampling

Answer 6

Used 80cm intervals to measure both the depth and size of the load of the river channel. This provided us with a systematic sample

Question 7

How did we measure the depth

Answer 7

Used a metre rule from the water surface to the river bed (in cm)

Question 8

How did we measure the size of the load

Answer 8

Took a random sample(within our systematic sample of80cm) of bedload and measured each of their long axis using a calliper

Question 9

Sample results for river depth

Answer 9

Anomaly : deepest wasn’t outer bank , it was site 8 measuring 42cm

Question 10

Sample results for bedload

Answer 10

Anomaly: sediment roundness: the most round sediment was found in the middle of the river with rating 5/6 on scale

Sediment size biggest sediment wasdnt found on the inner bank (site1) it was found at size 7/10 and measured 750mm

Question 11

Justify data presentation method for depth of river

Answer 11

• we created a cross section of the river using a line graph to compare the width and depth
• this allowed us to identify patterns and if the river depth was deeper on the outside bank like the hypothesis predicted
• this was also helpful in identifying any anomalies in the data

Question 12

Justifying data presentation for sediment size

Answer 12

• we produced a scatter graph using averages of the longest axis of three pieces of sediment at each interval (this improves accuracy)
• the scatter graph clearly showed whether there is a correlation between sediment size and distance across the cross section
• By adding a line of best fit this becomes a lot more visual and easier to interpret
• the anomalies are very clear to see

Question 13

Justification of data presentation for roundness

Answer 13

• we designed pictograms to represent each of the Power’s index of roundness and added them to the river cross section graph to present the roundness of the bedload at each site
• although easy to interpret , this was not a strong presentation technique for drawing conclusions as it is not as clear and quick to read
• our drawings are subjective and difficult to keep consistent
• some of the pictograms have very little distinctions between each level of roundness , we decided that this wasn’t a very effective way to present the data ( so we added numbers )

Question 14

Conclusion: trend of the depth of the river

Answer 14

The depth increases from the inside bank to the outside bank

Explain: river is deepest in outside bend and shallowest on the inside bend - fastest flow of water = outside

Question 15

Conclusion: trend of sediment size

Answer 15

There is a negative correlation between depth of the river and the mean sediment size - as river gets deeper , sediment size decreases

• explain (outer bend): because more erosion and had less friction + fastest flow

Question 16

Conclusion: trend of sediment roundness

Answer 16

Sediment roundness increases from the inner bank to the outer bank

Explain: sediment is smoothest on outer end because there is more erosion happening here as it is the deepest , has less friction and has the fastest flow of water

Question 17

Sources of error sample

Answer 17

Sample:
-random sampling within systematic sampling could mean there is room for error as rocks may not be picked up specifically from that depth each time
-sample done once , so unreliable
- small sample of river want representative of whole river

Question 18

Sources of error : equipment

Answer 18

Power roundness scale is subjective - conferred as a group to improve reliability

Human error could’ve contributed as we measured the depth using a metre rule and our own eyes. We made sure atleast 2 students read the depth to improve accuracy

Question 19

Why is location suitable

Answer 19

It was within walking distance from where we were staying

Question 20

Conclusions

Answer 20