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Environment and development in coastal regions and in small islands |
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Environment and development in coastal regions and in small islands |
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Coastal
management sourcebooks 1
Chapter 1
The disappearing
beach:
what can be done?
This chapter looks at the many different circumstances that may cause a beach to disappear and suggests some possible responses in each situation.
Figure 2 shows a simple diagram naming the various parts of a beach. A beach can be defined as a zone of loose material extending from the low water mark to a point landward where either the topography abruptly changes or permanent vegetation first appears. Although beaches are often made up of sand particles, they may also consist of clay, silt, gravel, cobbles or boulders, or any combination of these.
Figure 2. Cross-section of a typical beach
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| SEDIMENT SIZES | ||
| Clay | Less than 0.004 mm | Less than 0.00015 inches |
| Silt | 0.004–0.08 mm | 0.00015–0.003 inches |
| Sand | 0.08–4.6 mm | 0.003–0.18 inches |
| Gravel | 4.6–77 mm | 0.18–3 inches |
| Cobbles | 77–256 mm | 3–10 inches |
| Boulders | Greater than 256 mm | Greater than 10 inches |
