Cliff surveys

Aims

• To examine physical characteristics and features along a stretch of coastline

• To identify different rock types and investigate the links between geology and physical features

• To compare coastlines with different geologies

• To study evidence of coastal erosion, including sub-aerial weathering, mass movement, basal erosion by the sea, human activity

• To investigate and analyse strategies for protecting against coastal erosion

Equipment

• Plain paper, pencil and rubber for sketch

• Camera

• Geological guides

• Secondary evidence, for example photographs, maps, newspaper cuttings

• Tape measure

• Clinometer

Methodology

Cliff height

• Standing a safe distance from the cliff, measure distance (A) using a tape measure. A distance of around 10 meters may be appropriate, but this depends on the size of the beach

• Use a clinometer towards the top of the cliff to measure angle (B)

• The height of the cliff is calculated as follows:

• Distance (A) x tan of angle (B) + height of observer

Cliff sketch
A detailed sketch of the physical and human features of the cliffs at predetermined sampling points. Once cliff height has been established, the sketch can be drawn reasonably accurately to scale. Observations and annotations should be made of:

• Obvious features, for example high tide level, caves, wave-cut notch, wave-cut platform, gullying

• Basic geology (can be added later)

• Structure, for example bedding planes and joints, folding and faulting

• Conservation considerations, for example nesting birds, other animals

• Type of vegetation and any evidence of effect on erosion

• Evidence of erosion or mass movement, for example slumping, rock falls

• Human activity, for example built structures, management/protection measures, recreational activities

Photographic evidence can also be used to support and reinforce sketches.

Considerations and possible limitations

• Be aware of the safety implications of working close to cliffs, it can be dangerous

• It is important to consider the sampling strategy, where to carry out cliff surveys and how many to do - before the investigation is started

• There may be some user error when taking readings with a clinometer, and the sophistication of models of clinometer can vary enormously

Using the data within an investigation

• Cliff profiles can be used in conjunction with other data collected to examine relationships between different variables, for example beach profiles or sediment analysis

• An investigation could examine the links between the beach morphology, sediment and cliff features

• An investigation could examine the links between the geology of the cliffs and beach material or movement

• It is possible to compare different stretches of coastline with different geologies to see how they vary in terms of geology, sediment and beach morphology

• Secondary data, for example historical maps, photographs or articles from local newspapers or websites can be used to examine recession rates. Predictions could be made for future rates of cliff recession, alongside suggestions for future management

• A study of the range of different techniques used to manage the cliffs could highlight costs and benefits as well as potential impacts on physical processes and human activity. Each technique could be assessed in terms of its effectiveness at reducing rates of recession