Unit 2 answers: 1. Outline the theory, concept or idea that formed the basis of your fieldwork investigation (aim):
The fieldwork investigation took place upon the Glenderaterra Beck River and our aim was to measure and interpret how fluvial channel characteristics changed downstream at our stratified sampling sites in comparison to the Bradshaw Model. This model suggests that as you progress downstream, the discharge increases as erosion widens and deepens the channel. Velocity is also said to increase as tributaries input discharge into the river and friction plays a weaker role so the velocity increases. Load quantity increases additionally as erosion has caused the banks of the river to fall into the channel flow and the higher energy levels enable the river to carry a larger load. It also suggests that pebble roughness and gradient reduces as you progress downstream as lateral erosion comes into play and decreases the steepness of the gradient as well at attrition and abrasion smoothing the edges of rocks and pebbles. We also looked at the Hjulström curve as an additional theory in terms of energy in a river and how this determines whether a river will erode, transport, or deposit sediment. The graph takes sediment particle size and water velocity into account. The upper curve shows the critical erosion velocity in cm/s as a function of particle size in mm, while the lower curve shows the deposition velocity as a function of particle size. Note that the axes are logarithmic. 2. Outline the purpose of the fieldwork:
The purpose of the fieldwork investigation was to assess downstream changes of the Glenderaterra Beck River located in the North West of England. This included looking at depth, width, pebble shape and size and discharge. These changes were then to be compared to the Bradshaw Model. Our purpose could additionally be said to include