How do river channel characteristics change downstream ? - A study of the river Conwy
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What is the aim of the investigation ?
The aim of the study was to plot points along the first 3km of the upper course of the River Conwy in North wales and to see if the downstream changes which occured would conform to the bragsaw model.
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What were the hypothesis of the investigation ?
Predictions that showed the ... Discharge, channel width, channel depth, average velocity, load quantity will increase and the load particl size, bed roughness and slope angle will decrease.
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What linear strategy was taken in the development ?
Linear strategy was used when taking the points on the river its self.
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What pragmatic sampling was taken in the development ?
We used pragmatic sampling for areas that were hardly accesible such as the marshlands
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What stratified sampling method did we take ?
We used stratified sampling to look at sites which showed significant changes in the river ?
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From the GIS state 3 risks observed
Any from... Main road, house, animals, falling in river, remoteness, lack of paths, difficult terrain
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From the recce state 3 risks that were apparent
Marslands were significant, main road was busyier than expcted, animals, waterfall, lack of phone reception
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What method was used to measure the slope angle ?
The use of a clinometer taken from 10m prior to the sight and aimed 10m beyond.
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What method was used to measure the width ?
Two ranging poles either side with a tape measure.
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What method was used to measure the depth ?
8 different measurements across the river,
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What method was used to measure the cross sectional area ?
We divided the width of the river by 8 and then added up all the depths and divided them by this figure.
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What method was used to measure the bankfull width ?
Two ranging poles either side of banfull point. Measuring tape across
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What method was used to measure the bankfull depth?
Measuerment from the water line to bankfull tape measure added on to the central river depth.
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What method was used to measure the velocity ?
3 measurements with a flow metre. Hold for 1 minute on each point. Take count and average
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What was the null hypothesis for the Mann whitney U-test ?
There will be no significant difference between wetted perimeters with distrance from site.
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What was the hypothesis for the Mann whitney U-test ?
There will be a significant difference between wetted perimetres with distance from site 1.
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What was the conclusion from the Mann whitney U-test ?
The value was 0 so we concluded that there is a statistically significant difference between the two sets of data. The null hpyothesis has been rejected and hypothesis accepted.
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What was the DOF for the spearmans rank correlation ?
10
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What was the conclusion from the Spearmans rank correlation ?
Due to the values being between 0.6 and -0.6 we concluded there was a strong relationship. They have a 1% significance value which equated to 0.75 on the speamans rank
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How many sites did we use ?
12
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What hypothesis did we reject ?
Load quantity, channel bed roughness and slope angle.
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What were the metholodigal limitiations of the investigation ?
Basic Equitment, small section of river, river prone to flooding, as a set of groups we had limited numbers, amount of time
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What future improvements could be made ?
More time, collect more data, underwater camera, More advanced equitment.
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Other cards in this set
Card 2
Front
What is the aim of the investigation ?
Back
The aim of the study was to plot points along the first 3km of the upper course of the River Conwy in North wales and to see if the downstream changes which occured would conform to the bragsaw model.
Card 3
Front
What were the hypothesis of the investigation ?
Back
Card 4
Front
What linear strategy was taken in the development ?
Back
Card 5
Front
What pragmatic sampling was taken in the development ?
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