Geo introduction

Data-collection

Our methods of collecting data was random sampling, this consisted of reaching into the water and gathering random bits of bed load, to measure depth we selected a random part of the river and ran a tape from a ranging pole on both sides of the waters edge and took 10 measuremants across the width of the river, to measure river velocity a ranging pole was placed 2m up stream form another ranging pole. A float is released from the 1st ranging pole and the time it is taken to reach the 2nd pole is measured. This is repeated to make it a fairer test. All the data collected is recorded on capture document.

Processing Raw Data

Health and Safety

• A parental consent is required for all activities taking place outside school.
• An emergency contact number is required encase of an accident ect on the trip.
• We must apply for an activity permit from the forestry service; this means that if there as an accident on their land they take no responsibility.
• 1st aid kits to help treat small injuries.
• Suitable clothing must be warned to reduce the risk of injury e.g. school uniforms not suitable for climbing over gates and paddling around rivers.

Procedure (methodology)

• Gradient – To measure gradient we got two ranging poles placed one a good distance downstream from the other. To get a accurate result and avoid irregular river bed features the very end of the pole should just be on the surface of the water. To measure the angle we used a simple gun clinometer and stood at the bottom ranging pole then point at the same point on the top ranging pole and putt the trigger, let the wheel settle and release the trigger again to lock the wheel. Then record your angle, this should be repeated for accuracy purposes.
• Bed load – Selecting a random piece of bed load from the river bed. It is important that you do not always pick the same size of bed load it should be completely random or the results are inaccurate. To measure the selected piece, pick it up, use either callipers or a ruler to measure the size from one side to the other of the bed load.
• Width – place a ranging pole at either side of the waters edge, get a taper and line it from one pole to the other, ensure the tape is tought and not slack or this will cause the reading to be more than the actual width.
• Depth – it is best to do depth just after width as the ranging poles are already in place, there should also be a tape between the poles to give a straight line and to you know what distance to take the next measurement, use the width and divide it by 10 as you will take 10 depth readings across the river. Use your 1m rule every width divided by 10 and stick it straight in to the water (0cm end to the river bed), now the position at which the water sits on the ruler is your depth.
• Velocity – Place one ranging pole up stream of another at a uniform distance, ensure that there are no obstacles in the way as you will be releasing a float and timing the time it takes to reach the other pole. Have a stop watch ready release the float from the ranging pole up stream and at the same time start the stop watch. When the float reaches the bottom pole stop it. Now take the time and divide it by the distance in metres between the poles, this will give you the velocity in M per second.
• Discharge – Width x Depth x velocity we used a programme ‘Channel analysis’ to work this out, it considered all the factors and gave a very accurate result.