Rivers Fieldwork

Question 1

quantitative data

Answer 1

numerical data that gives an amount or quantity or a range of figures

Question 2

qualitative data

Answer 2

measuring the quality of something rather than its quantity. can be in words and descriptions

Question 3

quantitative data methods

Answer 3

• river width
• river depth
• river velocity
• river discharge
• pebble size and roundness

Question 4

qualitative data methods

Answer 4

• field sketch
• photographs

Question 5

types of sampling

Answer 5

• systematic
• random
• stratified
• pragmatic

Question 6

systematic sampling

Answer 6

collecting data in an ordered or regular way, eg at intervals

Question 7

random sampling

Answer 7

unbiased as particular people/places/objects are not specifically selected

Question 8

stratified sampling

Answer 8

dividing sampling into groups eg 3 sites from upper, middle, lower course of a river; or 5 people from each age range

Question 9

river width (quant) method

Answer 9

We measured the width of the river from bank to bank at each of the three sites we visited. The aim was for the sites to be representative of each course of the river. We made sure to measure straight across the river channel by pulling the measuring tape tight. The measuring tape did not fall below the water mark.

This measurement was only taken once at each site.

Question 10

river depth (quant) method

Answer 10

Using the result we got for the river width, we divided the width of the river by 10. At every tenth interval, we measured the depth of the river using a rigid meter stick. This was placed in the river and we measured the water mark on the stick

Sampling method = systematic

Question 11

river velocity (quant) method

Answer 11

A hydroprop was placed underneath the surface of the water. As soon as the hydroprop was submerged, the stopwatch timer was started. The impeller was placed against the flow of the river to ensure the speed was measured accurately.

We measured the speed three times – on the far bank, middle and near bank of the river

Sampling method = systematic

Question 12

field sketch (qualit) method

Answer 12

We observed the river landscape and created field sketches at the upper, middle and lower course of the River Chess.

Question 13

sediment size and roundness (quant) method

Answer 13

We selected 12 pieces of sediment at random. Discarded the largest and smallest sediment to remove anomalies. Using a pair of a callipers, we measured each pebble along the longest axis with a ruler and noted down the length in cm. We calculated the mean pebble size

We then compared each sediment to Powers Index of Roundness to give the pebbles a score according to their shape

Question 14

river width advantages

Answer 14

Professional equipment increased the accuracy of our results as we did not estimate the width, ensuring results were taken to the nearest cm.

Question 15

river width disadvantages

Answer 15

No guarantee that the results were reliable as we only measured the width once. This may reduce our ability to confidently answer our enquiry question, exploring how the River Chess varied with distance downstream.

Question 16

river depth advantages

Answer 16

Increased reliability of results, as we took multiple measurements at each site and therefore could calculate the mean depth.

Use of professional equipment increased the accuracy of our findings

Question 17

river depth disadvantages

Answer 17

Large boulders could have interfered with our readings making the depth less accurate. Furthermore, groups had difficulty reading the water mark due to the weather conditions on the day.

Question 18

river velocity advantages

Answer 18

Use of professional equipment made it easy to collect data to aid the answering of our enquiry question

By measuring the internal velocity three times at each site, the reliability of our investigation was increased

Question 19

river velocity disadvantages

Answer 19

Impeller frequently became stuck or jammed, impacting the time measurement

Question 20

field sketch advantages

Answer 20

Complimented our methods by allowing us to identify features in the landscape not identified by our quantitative data.

Question 21

field sketch disadvantages

Answer 21

Open to interpretation – we may have picked up on certain aspects of the environment that other groups did not. We did not have enough specific understanding of the plant types/build use to support our investigation beyond the variables collected.

Question 22

sediment size and roundness advantages

Answer 22

Increased reliability of results, as we measured 10 pieces of sediment at each site and therefore could calculate the mean sediment size

More reliable to categorise sediment using Powers Index of roundness as allows for fair comparison across the sites

Question 23

sediment size and roundness disadvantages

Answer 23

Selection of pebbles may have been biased as we may have selected sediment, we could easily pick up reducing the accuracy of results.

Categorisation of sediment may be objective, and interpretation could vary at different sites.

Question 24

river width improvements

Answer 24

Use of pragmatic sampling – chose clear boundaries of river channel

Question 25

river depth improvements

Answer 25

Increase sample size – number of intervals to measure depth

Question 26

river velocity improvements

Answer 26

Repeat the measurement so that it is accurate Use systematic sampling – measure intervals across channel to increase sample size

Question 27

field sketch improvements

Answer 27

Annotated photographs instead

Question 28

sediment size and roundness improvements

Answer 28

Work in pairs to agree classification and keep the same people deciding pebble roundness at each site.

Question 29

river width accuracy and reliability

Answer 29

Not reliable – only measured width once and it was hard to tell the edge of the channel Partially accurate – vegetation in the way whilst measuring width

Question 30

river depth accuracy and reliability

Answer 30

Reliable as measured depth at every 10th interval – systematic sampling (large data set) Accurate as measured systematically and we used professional equipment (metre stick)

Question 31

river velocity accuracy and reliability

Answer 31

Somewhat reliable as measured internal velocity three times at each site, however impeller would become stuck increasing time recordings Use of hydroprop increased the accuracy of results and repeated measurements reduced risk of anomalies, measurements were taken from different points of the river.

Question 32

field sketches accuracy and reliability

Answer 32

Cannot draw conclusions from qualitative data alone. Did provide us with information to support understanding May not be accurate/reliable if drawing skills not good

Question 33

sediment size and roundness accuracy and reliability

Answer 33

Partially reliable as sample size was large enough to be representative of the whole Somewhat inaccurate as subject to human error.

Question 34

River Chess conclusions and summary

Answer 34

The purpose of the investigation was to find out if the chosen valley and channel characteristics vary along the River Chess. In conclusion, the river valley and channel characteristics do vary along the River Chess. More specifically, the River Chess does vary with distance downstream: the width and depth of the river increases and the mean velocity and discharge increase. Moreover, for each of these variables, it increased in size as moved from Site 1, in the upper course of the river, to Site 3, close to the river’s confluence with the River Colne. For example, we found that the width increased from 3.24m at Site 1 to 7.68m at Site 3. Data generally supports the Bradshaw Model with only a few anomalies identified. For example, site 2 had anomalous results for discharge and internal velocity. This may be due to several reasons. It may be due to the way the investigation was undertaken by a third party who may have used different methods and therefore not accurate or comparable. Furthermore, it may be due to human influences such as flood defences or urbanisation that have led to the unexpected results.

Question 35

Bradshaw Model

Answer 35

illustrates what should happen in theory, and what usually happens, as a river travels downstream from source to mouth