The Loughton Brook catchment (drainage basin) covers an area of 5.8km². 60% is within Epping Forest. The remaining 40% is in Loughton. A drainage basin is……………………. The Loughton Brook and its tributaries rise in dense vegetation mostly different kinds of trees flowing over impermeable Clay gate beds and London Clay drift material.
Hypothesis 1: The velocity of the river increases with distance from source.
Method:
In this part of the investigation, we measured the velocity of the river by using a cork and saw how long it travelled along a distance of 1 metre. The investigation was done three times on each site because it had to be done on the left, middle and right of the river. Below is a map showing the site where we done this part of the investigation.
Below is the equipment we needed for this investigation:
- Gun clinometer
- 2 ranging poles
- 1 cork
- 1 metre ruler
- 1 measuring tape (30 metres long)
- Recording sheets
- 1 clipboard
- 1 stopwatch
- 1 small container (for pebble collection)
- A pair of Wellington Boots
- A few pieces of paper for sketches
- 1 Augur (needed for extracting soil from the ground)
For this part of the investigation, we used a cork, stopwatch and a metre ruler. Velocity is speed going in a certain direction. Velocity is measured in seconds because we will use a stopwatch to record the time it takes for the cork to go from one end of the metre ruler to the other end.
Results:
Below is the table of results showing the velocity of the river at three specified sites (source, middle & mouth).
Hypothesis 2: The width and the depth of the river channel increases as we go downstream (cross-sectional area).
Method:
In this part of the investigation, we measured the width and the depth of the river channel by using a measuring tape and metre ruler and using the metre ruler I saw how deep the river was. Using the measuring tape, I saw how long the water width was by measuring the width form one bank to the other. The investigation was done three times on each site because it had to be done on the left, middle and right of the river. Below is a map showing the site where we done this part of the investigation.
Water width is the width of the river form bank to bank. Water depth is how deep the river is in three certain areas (left, middle and right). Water width and water depth are measured in metres.
Results:
Below is the table of results showing the water width and water depth of the river at three specified sites (source, middle & mouth).
Hypothesis 3: The river load becomes smaller and more rounded as we go downstream (Pebble Analysis).
Method:
In this part of the investigation, we measured the river load of the river by using a small container to get some pebbles out of the river , using a metre ruler to find the long axis and by using the Powers’ Roundness index we recorded the pebbles Long axis (cm), Roundness index (0-5) and the sphericity (high / low). We collected 11 pebbles from each site. Below is the Powers’ Roundness Index and a map showing the site where we done this part of the investigation.
River load is the load that the river carries from source to mouth. The River load was measured by using the Powers’ Roundness Index and metre ruler.
Results:
Below is the table of results showing the water pebble analysis of the river at three specified sites (source, middle & mouth).
