Describing, analysing and explaining data

• cross section graphs

  the bradshaw model shows that the channel width increases with distance downstream and the channel depth increases with distance downstream so therefore the channel cross sectional area must increase as well
• cross section graphs

  my results matched this model because the mean depth, cross-sectional area and channel cross profile all increase with distance downstream
• cross section graphs

  human intervention may have affected this as there may have been more in the middle course, however it does show the bradshaw model
• cross sectional area results:

  • upper course: 828 cm squared
  • middle course: 2108 cm squared
  • lower course: 10788 cm squared
• velocity vs distance downstream scatter graph

  this graph has a weak positive correlation. site 10 velocity decreases due to human intervention. at site 8 we chose a place that was humanly edited and had a footpath in the middle of the channel, so this was an anomoly - velocity was lower
• velocity vs distance downstream scatter graph

  overall, the data matches the bradshaw model as it got faster overall aside from a few anomolies as the channel becomes deeper and there is less friction between the water and the bed and banks of the river which results in velocity increasing
• velocity vs distance downstream scatter graph

  in the river holford, there is some evidence of slowing the flow in the upper course to prevent flooding by using dead trees in the channel. in the lowercourse, the river was contained in a car park with a narrower, deeper channel made by humans
• dispersion graph for clast size

  the graph actually shows that the clast size gets bigger, which does not match bradshaws theory, this is probably due to human error, as naturally we would have chosen the bigger rocks due to a bias, especially as the river got deeper
• the depth of the river increased with distance downstream overall, as site 1 had an average 6cm depth, whereas site 10 was on average 34.8 cm deep, which matches the bradshaw model
• the width of the river increased with distance downstream overall, as site 3 was 138cm wide whereas site 10 was on average 310cm wide, this matches the bradshaw model
• the velocity of the river increased overall with distance downstream as site 1 was 0.246m/s on average, whereas site 9 was 0.992 m/s on average, however site 10 had a lower velocity of 0.582 m/s which was due to human intervention at the water treatment centre. this partially matches the bradshaw model, but human intervention did affect it
• human intervention sites:

  • trees placed in the upper course to slow the flow of rover to avoid and prevent flooding, it is natural debris
  • the river has been made deeper and less wide by the carpark near Kilve beach
  • the river has been split into two channels to go around the water treatment plant near kilve beach
• velocity results:

  • site 1: 0.246 m/s
  • site 9: 0.992 m/s
  • site 10: 0.582 m/s
• width results:

  • site 3: 138cm
  • site 10: 310cm
• depth results:

  • site 1: 6cm
  • site 10: 34.8cm
• clast size results mean:

  • site 3: 4.91 cm
  • site 7: 6.76 cm
  • site 10: 8.36 cm