Taiwan is a sub-tropical island with a 1,200 km long coastline surrounded by ocean. We have lived by ocean for a long period of time. The island is full of lofty mountains. In the East, there are fault coastlines with high mountains adjacent to deep ocean; the coastal plains are narrow and not far from the coast is the deep ocean. In the West, the coastline is sandier. The mountain range is further from the ocean so the coastal plains are flatter and the ocean is shallower; in addition, most of the main rivers flew west into the Taiwan Strait in the early years. The huge amount of sand and silt accumulated around the coastal area following the flow, making the beach difficult to extend further.
The origin of water flew from the upstream of the mountain, along the rivers and eventually flew into the ocean with silt. The silt in the ocean was then pushed to form mountains through the plate tectonic activities. This was originally a natural cycle; however, we build dams so as to store water resources and check dams for lowering the amount of silt which hampers other silt that should have been discharged into the ocean. This leads to drawback of the coastline as well as soil loss.
The curtailed coastline firstly affects the costal tourism. For instance, in southern Taiwan, 50 m of the beautiful Cijin Coast has disappeared within two years. As the beach is gone, the landscape area is gone as well. The invisible power as such is eroding our living environment little by little.