# GCSE GEOG-BLOG

## Day 3

Today the class went to the source of the River Ogmore near the town of Nant-y-moel in the Welsh valleys. The source, found on top of a hill, leads into a waterfall before flowing down the hillside and into the town, although due to a lack of rain very little water was flowing,

We took measurements at 3 upper course sites of the river, investigating aspects such as channel width, velocity, and bedload. After the final measurements were taken the class had a water fight before returning to the centre to begin the write-up of the results.

The first student to fall in was Amandeep, although Junaid H. was caught washing his face in the river by doing what looked like a press-up in the middle of the channel (key term).

## Data Collection

To collect our data we went to various points along the River Ogmore, so far we have visited 3 sites all in the upper middle course and above. In these sites we have measured:

• Width of river channel - we used a tape measure to measure from the right bank of the river to the left and then we used our results to help us with our depth results. Also it helped towards our cross section measurements and it helped with our velocity measurements accuracy.
• Depth of river channel - we measured using a stratified sampling method according to our width measurement by dividing it by 6 and measuring every (n/6) metres. Our depth measurements helped towards our cross section measurement.
• Velocity of river - we used a hydro prop impeller to measure the rate at which the water flowed, this helped towards our converted flow measurement.

We also tested things like bed-load size which we did somewhat systematically however a bit randomly with slight method to it. We also used our measurements to collect more data, such as cross sectional area, the river discharge and the hydraulic radius.

## Mathematical Calculations and Statistics

After we collected our data we plotted it into graphs, I used a variety of different graphs such as bar charts, scatter graphs and cross section profiles. We had to use the results we had collected to work out other measurements. For example, The method we used to calculate the converted flow of a river is:

(3.8255/velocity) + 0.227 = converted flow.

## CROSS SECTION OF A RIVER

To plot a cross section of a river you have to use an exaggerated scale, we use the exaggerated scale because it is easier to plot it, the cross section of a river is based on the width and depth of the river. The x axis represents the width and the y axis the depth. Using the same technique I used to work out the depth, I plotted the cross section profile so that every fifth of the graph the direction of the plotted line would change based on the depth change at that point.

### Bridgend, United Kingdom

#### Bridgend, Wales

Breakfast

Data collection - River Ogmore - 3 final sections.

Data presentation.