Measuring River Load: Fieldwork Equipment and Methods

Essential Equipment for River Load Analysis

You will need the following equipment for river load investigations:

• Cord or washing line: To stretch across the river to act as the base-line for your investigations.
• Tent pegs: To secure the base-line.
• Metre rule: For measuring depth and distance.
• Scoop: A dustpan may also be useful.
• Scale of roundness: This will help you to pick out particular shapes in the materials you investigate. Five main shapes are recognized, and you can make a set from pencil erasers. Some patience will be needed! Label each eraser with indelible (waterproof) ink. Your reconnaissance visit will have shown whether you need all five shapes or just 'angular', 'sub-rounded', and 'well-rounded'.
• Quadrat: For choosing river-bed material, if you have decided to use one.
• Equipment for measuring particles: A pebble measure, calipers, or a ruler. Sieving can be done at school or at home.
• Weighing equipment: If you weigh the materials during your fieldwork, a spring-balance and a mesh bag are ideal. Fishing tackle shops always sell spring-balances.

Fieldwork Methodology

Setting Up the Base-Line

1. Stretch your cord or washing line across the river's channel at right angles to the direction in which the river is flowing. Secure it on each bank with a tent-peg, heavy stone, or tie it around a tree trunk. This will be the base-line for your measurements.

Systematic Data Collection

2. Work systematically across the base-line from one side to the other to take your measurements. Remember that the left bank is to your left when facing downstream. Record the name of the site and at which bank you started to take measurements. According to the sample interval that you have chosen, work out with a metre rule the point at which you will take measurements as follows:

Sampling River Bed Material

Use your hand to feel whether there are big pebbles on the river bed. Remember that the pebbles must be loose. Lay down the quadrat if you have decided to use it, making sure that it is not swept away by the moving water. Collect a scoopful of loose material and put it into a container.

Measuring Suspension Load

Measure the depth of the water. At four-tenths (4/10ths) of the depth, as measured from the bed upwards, hold your collecting jar horizontally and facing upstream.

Analyzing Large Particles

For the biggest particle in each sample of river-bed material:

• Weigh it using your weighing equipment.
• Measure the longest and shortest axes.
• Use your roundness guide to describe its shape.
• Describe its color and appearance. You may be able to link this to the geology of the area.
• Replace the particle in the river.