4. Describing, analysing and explaining data Data Set Main findings Links to other data Velocity The Bradshaw model predicts that velocity will increase with Can be linked to distance downstream wider channel Velocity increases with downstream and distance downstream as This was seen in the investigation. Average velocity increased finer sediment predicted by the Bradshaw from 3 m/s in the upper stage to 6 m/s in the middle stage and (less bedload model. 7m/s in the lower stage. friction) This shows that there was a greater increase from the upper to TRUE middle course than the middle to lower course. I think this increase is due to the channel getting much wider and deeper the further you go downstream. This makes the channel more efficient at moving water. B Axis Sediment Size The Bradshaw model predicts that B axis sediment size will decrease downstream. Less bedload B axis reduces with distance friction appear to downstream as predicted by B axis was largest in the upper stage with an average size (ten cause velocity to the Bradshaw model. pebbles measured) of 53mm. increase as B axis sediment size is In the middle stage sediment size was on average 28mm which reduced. is significantly smaller than that in the upper stage. TRUE In the lower stage of the river sediment was the smallest which was predicted. The average B axis size was 16mm RANGE - gets smaller showing more sorting of sediment downstream. INTERQUARTILE RANGE - shows similar smaller range between lower and upper quartile. The IQR is often seen as a better measure of spread than the range as it is not affected by outliers. Photograph Survey The photograph survey was used to see if the rivers natural Photographs also features matched those seen on the Longitudinal Profile show channel Do landforms reflect those Model. width increasing predicted in the longitudinal (as measured) and model? In the upper stage the channel was narrow and there is clearly more efficient a V shaped valley created by vertical erosion. This has created channel (velocity TRUE interlocking spurs. increase).
4. Describing, analysing and explaining data Data Set Main findings Links to other data Velocity Velocity increases with distance downstream as predicted by the Bradshaw model. TRUE The Bradshaw model predicts that velocity will increase with distance downstream This was seen in the investigation. Average velocity increased from 3 m/s in the upper stage to 6 m/s in the middle stage and 7m/s in the lower stage. This shows that there was a greater increase from the upper to middle course than the middle to lower course. I think this increase is due to the channel getting much wider and deeper the further you go downstream. This makes the channel more efficient at moving water. Can be linked to wider channel downstream and finer sediment (less bedload friction) B Axis Sediment Size B axis reduces with distance downstream as predicted by the Bradshaw model. TRUE The Bradshaw model predicts that B axis sediment size will decrease downstream. B axis was largest in the upper stage with an average size (ten pebbles measured) of 53mm. In the middle stage sediment size was on average 28mm which is significantly smaller than that in the upper stage. In the lower stage of the river sediment was the smallest which was predicted. The average B axis size was 16mm RANGE - gets smaller showing more sorting of sediment downstream. INTERQUARTILE RANGE - shows similar smaller range between lower and upper quartile. The IQR is often seen as a better measure of spread than the range as it is not affected by outliers. Less bedload friction appear to cause velocity to increase as B axis sediment size is reduced. Photograph Survey Do landforms reflect those predicted in the longitudinal model? TRUE The photograph survey was used to see if the rivers natural features matched those seen on the Longitudinal Profile Model. In the upper stage the channel was narrow and there is clearly a V shaped valley created by vertical erosion. This has created interlocking spurs. Photographs also show channel width increasing (as measured) and more efficient channel (velocity increase).
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