# The aims of our study were to measure and analyse the changing characteristics of a river as it travels downstream, and to obtain "primary data".

Extracts from this document...

Introduction

* Title page * Questions * Introduction * Hypothesis 1 * Hypothesis 2 * Hypothesis 3 * Hypothesis 4a & 4b * Conclusion * Evaluation * Bibliography * Appendix * Maps > Contents of a hypothesis:- > Equipment list > Method > Drawing of method > Table of results > Graph Planning 1. What are the aims of the study? i.e. What do you hope to learn/find out? The aims of our study were to measure and analyse the changing characteristics of a river as it travels downstream, and to obtain "primary data". The aims were to find out how channel characteristics such as gradient, angularity and load size change downstream and the flow characteristics, such as velocity and discharge change downstream. We collected primary data by visiting River Ballymully. Measurements were taken and carefully recorded at each study site. 2. Identify 4-5 HYPOTHESES to test (a statement to test) 1) The gradient of the river decreases with distance from the source. 2) The velocity of the river decreases with distance from the river. 3) The discharge of the river increases with distance from the river. 4) The load size decreases with distance from the source. 5) The angularity of the load decreases with distance from the source. 3. What information will you need to collect for these hypotheses? 4. What instruments will you need? * Tape Measure * Meter Stick * Rake * Rubber gloves * Measuring box * Five Stop Watches * Five Table Tennis balls * Range/ Surveying Poles * Clinometers * Clip Board * Pencil/Pen * Results Table 5. How will you collect/ record your data? We will collect my data in a results table; these are shown on pages - . 6. How many sampling points will you need? In order to obtain our results we had to decide on a sampling strategy. This depended on: 1) The amount of time we had to visit the sites we needed to complete our investigation. ...read more.

Middle

d. I will then repeat steps b and c a further, two times. e. I will then average out the three speeds. f. Once I have the results I will use the following equation to work out the speed of the river: Stretch of river = speed in metres per second Average time in table tennis ball I think the velocity of the river will increase with increasing distance downstream. I expect to find this because of the growing tributaries joining the River Ballymully as we move downstream towards the mouth. We can find the velocity by the following equation: Velocity (m/s) = Distance (m) Time (sec) To find the true velocity: TRUE VELOCITY = V X 0.85 = **M/SEC Analysis: Put in no.is a positive correlation from my spearman's rank test. I can now say there is a slightly strong relationship between the distance downstream and the depth of the river. My hypothesis was correct. Although the correlation wasn't as strong as I first anticipated. Interpretation: A result of put in no. is a positive correlation. This time, I don't think man's interference had much impact on the results. I believe this correlation is quite accurate and I am satisfied with my findings. In an ideal river velocity should increase, and I have now proven this. Sub-Conclusion: From the Spearman's Rank Correlation of put in no., and from the theory of an ideal river, I will accept the hypothesis; that velocity increases with increasing distance downstream. From my result I have obtained a quite strong correlation showing my hypothesis, the velocity increasing with increasing distance downstream, to be correct. As you can see from graphs on the following pages my findings were correct and there is a positive correlation between increasing velocity and increasing distance. Hypothesis Three Discharge Equipment List: * Tape Measure * Meter Stick * Clip Board * Pencil/Pen * Table of Results Method: To find the discharge I will need to find the width and depth of the river. ...read more.

Conclusion

Hydraulic Radius- the hydraulic radius of a channel is calculated by dividing cross-sectional area by wetted perimeter. The river is deeper, wider and has higher discharge in its lower course. It has a higher hydraulic radius than in the upper course. Relatively less water is in contact with the wetter perimeter. 2. Channel Roughness- river's do not have a smooth bank and beds. Where there are large rocks in the bed, energy lost to friction is increased. In the upper course, where erosion is dominant over deposition, angular boulders reduce the efficiency of the river. In the lower course, there is less resistance from the smooth silt and clay banks and bed. Gradient The gradient of a slope is its steepness. It is expressed as the ratio between vertical change over horizontal distance. For rivers, the gradient of the bed is most commonly measured. Gradient changes are found throughout a rivers long profile. The long profile of a river is a longitudinal section of the course of a river drawn along the thalweg (the line or maximum depth along the river channel) from source to mouth. It is drawn as a graph of distance from source against altitude. The ideal long profile for a river in a humid environment is a downward concave curve. There is a gradual decrease in slope gradient. The lowest level to which a river flows is called its base level. In practise, this is often sea level. Changes in gradient are related to changes in discharge. Discharge is higher in the lower course. Since gradient decreases as discharge increases, a river can transport the same quantity and size of sediment load in the gentler lower course as it can in the steeper upper course. Observations from rivers in arid environments provide more evidence for a strong negative correlation between discharge and gradient. These rivers have a downward convex long profile. Since there is a rapid rate of evaporation, the river experiences a net loss of discharge downstream. The steep downstream gradients are produced by deposition during rare flood events. ?? ?? ?? ?? 1 ...read more.

This student written piece of work is one of many that can be found in our AS and A Level Hydrology & Fluvial Geomorphology section.

## Found what you're looking for?

- Start learning 29% faster today
- 150,000+ documents available
- Just £6.99 a month