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Coastal Process Summary

How is the type of beach influenced by the energy exposure?

Longshore Drift Cell

Depositional Shores

These are moderately stable shorelines especially in areas of low energy exposure.  Areas of low exposure may have distinct backshores with shorelines that advance as sediment is accumulated. In areas of high exposure they may form spits and larger beaches. Smaller pocket beaches, which tend to be scarce and highly valued shorelines, may form in medium exposure areas.  In areas of low exposure they may form estuaries, mud flats and tidal marshes, which have highly productive aquatic habitats that are very sensitive to contamination.

Transport Shores

These are relatively stable shorelines although they may 'wobble' between periods of erosion or deposition especially in areas of high and medium energy exposure; this effect can also be exacerbated by storms.  With increased energy exposure there may be very large volumes of sediment movement making them very dynamic.  Structures that interfere with sediment movement can trap sediment resulting in the loss of downshore beaches. Transport shores with low energy exposure tend to have highly productive aquatic habitat.

Eroding Shores

Increasing energy exposure results in very unstable shorelines where storms can cause dramatic changes to the shoreline. With increased exposure there is more sediment input into the longshore drift system. Lower exposure shorelines have more sediment input from streams or rivers.

Vegetation can be difficult to establish in high exposure areas, while low exposure areas may have well established backshore vegetation.

Shoreline protection measures are likely to fail in high exposure areas.

Page last updated: 01/10/15
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