3.2. Hard engineering
3.2.1. Seawalls Seawalls, including bulkheads, and revetments are shoreparallel structures armoring the coast to protect the land behind it against episodic storm-induced erosion or long-term chronic erosion by the sea (Fig. 4). China has 10 000 km of these countermeasures distributed along the 18 000 km mainland coastline from north LN to south HN province (Table 3), keeping tens of millions of people and millions of hectares of cultivated land safe. Seawalls and revetments are very effective in stopping local shoreline erosion, but these types of structures hardly change the along-shore transport gradient and, as a result, are often the basic cause of chronic erosion. Hence, erosion of the beach and shore in front of the structure will generally remain. However, down-drift erosion will usually occur at locations where no structures are present. As a result, continuing shore erosion may ultimately lead to an increased wave attack, intensifying the transport capacity and hence erosion.
3.2. Hard engineering 3.2.1. Seawalls Seawalls, including bulkheads, and revetments are shoreparallel structures armoring the coast to protect the land behind it against episodic storm-induced erosion or long-term chronic erosion by the sea (Fig. 4). China has 10 000 km of these countermeasures distributed along the 18 000 km mainland coastline from north LN to south HN province (Table 3), keeping tens of millions of people and millions of hectares of cultivated land safe. Seawalls and revetments are very effective in stopping local shoreline erosion, but these types of structures hardly change the along-shore transport gradient and, as a result, are often the basic cause of chronic erosion. Hence, erosion of the beach and shore in front of the structure will generally remain. However, down-drift erosion will usually occur at locations where no structures are present. As a result, continuing shore erosion may ultimately lead to an increased wave attack, intensifying the transport capacity and hence erosion.
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