Coastlines can be divided into artificial coastlines and natural coastlines. The total length of coastline equals the length of natural coastline plus the length of artificial constructions. Artificial constructions include embankments, ports, armor blocks, barrier flats, and drainage channels. The natural coastlines-to-artificial constructions ratio must maintain a proper balance to create a sustainable environment where society, economy, and ecology can co-exist and thrive.
Observing the changes in the proportion of natural coastlines and artificial constructions in Taiwan from 1988 to 2018 helps us examine Taiwan’s social, economic, and ecological changes. There were three periods of notable changes in the ratio of artificial constructions, namely from 1988 to 1996, 1997 to 2003, and 2004 to 2018. The first period started in 1988 when Martial Law in Taiwan was lifted, during which the number of artificial constructions increased steadily until 1996. During this period, the total length of natural coastlines showed a trend of decrease. In terms of the ratio of natural coastlines, the highest was 67.67% in 1988 and the lowest was 62.96% in 1996. The second period was between 1997 and 2003. During this period, artificial constructions reduced and therefore its length dropped sharply from 850.2 kilometers in 1996 to 375.54 kilometers in 1997 but grew steadily ever since until 2003. The ratio of natural coastlines during this period was relatively high, peaking at 76.02% in 1997 and dropping to the lowest at 71.17% in 2003. The third period showed a sharp rise in the ratio of artificial constructions in 2004, which then increased in steady increments until 2018. In terms of the ratio of natural coastlines, the lowest point was 50.85% in 2007 and the highest was 55.32% in 2018.
Natural coasts provide habitats for marine animals. The higher the proportion of natural habitats, the higher the stability of the ecosystem. Coastal changes in recent years can serve as a reference for observing the balance between economy, society, and ecology.