Coastal fieldwork.
Beach profiles
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Aims
· To survey the shape (morphology) of a beach
· To compare beaches or coastlines in different locations
· To examine the effects of management on beach processes and morphology
· To investigate seasonal changes in the beach profile
· To examine relationships between the beach profile and other factors, for example rock type, cliff profile, sediment size or shape
Equipment
· Tape measure
· Ranging poles
· Smart-phone clinometer app.
· Compass or smart-phone compass app.
· Recording sheet
Methodology
1. Select sampling points for beach profiles across the width of the beach
2. At each sample point in turn, place a ranging pole at the start and finish. The first point should ideally be the low tide mark, or as close to this as is safe
3. Note the main changes in slope angle up the beach, and use them to inform the ‘sections' for the profile.
4. For each change in slope, use the clinometer to take a bearing to record the slope angle. It is important to ensure that the bearing is taken from a point on the ranging pole that coincides with the eye level of the person using the clinometer. Many ranging poles have stripes which can be used for this purpose. Alternatively, bearings can be taken from the eye level of a person of a similar height holding the ranging pole
5. Measure the distance along the ground of the section, and record this information alongside the slope angle
6. Repeat processes four and five for each break in slope that you have identified
Considerations and possible limitations
· Varying tidal conditions can affect access and safety. Make sure you check tide times before you embark on your fieldwork
· Low tide is the best time to measure beach profiles, but places a time constraint on the activity.
· It is important to ensure that the ranging poles are held straight and prevented from sinking into sand, both of which may affect angle readings
· Sampling technique is an important consideration. A balance needs to be struck between time available and the need for a number of profiles across the width of the beach to ensure the validity of results
· There may be some user error when taking readings with a clinometer, and the sophistication of models of clinometer can vary enormously. It is usually necessary to have a “holder” and a “reader” working together
Using the data within an investigation
· Data can be used to draw profiles onto graph paper using distance from sea as the horizontal axis and using an angle measurer to complete the profiles. The graphs can then be analysed and comparisons made across the width of the beach
· Profiles can be measured at different locations on the same stretch of coastline and compared
· Different stretches of coastline which may have different natural characteristics, for example sand and shingle, or human characteristic, for example managed and unmanaged can also be compared
· Beach profiles can be used in conjunction with other data collected to examine relationships between different variables