GENERAL GEOLOGY

Detailed explanation-1: -Groyne measurements Use a tape measure to find the height of beach material on either side of a groyne. Measure in at least three heights along the beach profile for each groyne. You can compare a series of groynes along a length of beach. Beach material is higher on one side of the groyne.

Detailed explanation-2: -Use calipers or a ruler to measure the size of each pebble – you can measure the length of the longest side – The a-axis, or all three axes, a, b and c. For very small sediment you will not be able to measure the size of individual pebbles – in this case you will need to use a grain chart size card.

Detailed explanation-3: -Groynes trap sediments from longshore drift so that the coast behind the sand layer is protected from erosion. Their effectiveness depends on their extension into the river or sea.

Detailed explanation-4: -Decide on an appropriate distance to measure longshore drift over, for example 10 metres. Lay out tape measure close to water and mark start and finish points. Place your float into water in the breakwater zone at the start point. Observe and time the object’s movement across the pre-set distance.