River Holford field work (paper 3)

Question 1

what is the fieldwork title for this assessment

Answer 1

investigating downstream change on the river Holford

Question 2

what is your hypothesis for this assessment

Answer 2

• discharge will increase with distance downstream on the river holdford because more tributries join to creater a larger river so more water
• velocity will increase with distance downstream on the river Holford because more water and energy with a bigger channel means less friction so water moves more freely
• cross-section area will increase as we move down stream

Question 3

how long is the river Holford

Answer 3

8km

Question 4

describe the geologies of the river Holford in the upper, middle and lower courses

Answer 4

• upper = sandstone
• midde = mudstone
• lower = limestone

Question 5

explain the advantage of the fieldwork location used for your enquiry

Answer 5

• accessibly - mainroad ~ A39
• we can walk along it - good idea of change in a timely manner ~ small river
• accessable car park
• previous schools hae studied here so it was safe and legal to do so

Question 6

what was your chosen sampling method

Answer 6

statified = geographical knowledge to choose location (after each tributry)

Question 7

why was your samplying method appropiate for your enquriy

Answer 7

it is feesable in the timelimit, we know where the river changes and we can locate change at those sites and easily collect data

Question 8

give two risk assessments and how to avoid them

Answer 8

• slipping/tripping = sensible footwear, follow paths
• drowning = avoid deep fast flowing water, stick to footpaths

Question 9

what samplying method could have you done instead of stratified

Answer 9

systematic # measurements taken every 1km = less bias and manageable

Question 10

what was your qualitative method of assessment

Answer 10

we used a field sketch and annotated around the skets to highlight chacteristics of each site (gradient, pepple size, land use)

Question 11

what were the two quantitive methods of analysis

Answer 11

• cross section area
• velocity of water

Question 12

explain how cross section area was used to assess river Holford

Answer 12

• we used a tape measure to measure the width from wetted edge to wetted edge
• we divided the width by 10
• we used a meter ruler to measure the depth at the same points, ensuring the thin side faced upstream to reduce splash and inaccuracy
• we then used these measurements to calculate the area by multiplying them together

Question 13

explain how velocity measurement was used to assess river Holford

Answer 13

• we used a tape measure and divided the width by 3 so we could take 3 readings per site
• we used a flow metre, ensuring the impellor faced upstream
• we timed how long it took the impellor to reach the base and recorded the value
• we then calculated the avergae at each site

Question 14

how did you ensure reliablility for these measurements taken

Answer 14

• width = pull the tape taught and water to water
• depth = thin end upwards and bottom touching the base of river
• speed = ensure impellor was not touching base and it was facing upstream

Question 15

explain why the pattern of your results for cross profile may not be completely accurate

Answer 15

we only took 5 measurements along the width and it would be more accurate if we took more as we may of missed a particulary deep or shallow section

Question 16

explain the advantage of collated the class data

Answer 16

• anomolies wouldnt stand out as much
• more results recorded on a whole so more reliable

Question 17

explain the overall pattern shown by the discharge measurements you took

Answer 17

• the further the distance downstream the large the volume of discharge gets
• becasue the river gets wider and deeper due to erosion by abrasion
• this allows for a larger channel with more discharge
• and as more tributries join, more water does as well

Question 18

what were you data representations on the river Holford assessment

Answer 18

• cross profiles (width and depth)
• scatter graph (discharge)
• GIS location proportional symbols

Question 19

explain the advantages and disadvantages of using cross profiles as a data representation

Answer 19

• • easy to read and compare
• • allows a view of depth and width
• • geolocated
• • you can miss points which are more shallow or deeper

Question 20

explain the advantages and disadvantages of using a scatter graph to show discharge along the river Holford

Answer 20

• • shows anomolies well
• • allows for estimate of discharge in unassessed areas
• • read off it well
• • not geolocated = cannot tell where the measurements were taken

Question 21

explain the advantages and disadvantages of using GIS location proportional syboms to show the discharge along the river Holford

Answer 21

• • geolocated = shows exactly where data is from
• • easy to read the proportional circles
• • can preform spacial analysis
• • cannot get exact values ~ you’re given a range

Question 22

overall how was your presentation of data… effective or ineffective

Answer 22

effective becuase we could know where our data was from and allowing us to spacially analysis our results to reach our conclusion

Question 23

describe youre results from the assessment

Answer 23

• as we travelled downstream velocity increased, discharge increase and cross sectional area increased. for instance the average wdith increased from 40cm to 2.1m from site 1 to site 5

Question 24

outline your conclusion from your assessment down the river Holford

Answer 24

• as we travelled downstream, velocity, discharge and cross sectional area increased; supporting the Bradshaw model
• it was valid because our methods were reliable and we used technical equipment (flow meter)
• however human error did reduce accuracy as some anomolies were present although we did a line of best fit which supported our hypothesis nevertheless

Question 25

comment on the strenght of your conclusion

Answer 25

it is semi-reliable as it fits in the bradshaw model, although the sampling rate is not high enough to fully be reliable

Question 26

give two improvements included in your evaluation

Answer 26

• it would be better is we used a digital flow metre rather than an impellor to increase accuracy
• it would have been better if we used a laser metre rather than a tape measure to measure the width to increase reliablity
• we could have used a larger sample size by measuring more sites to increase reliability