Waterways
Indonesia has 21,579 km of navigable waterways (As of 2005), of which about one half are on Kalimantan, and a quarter each on Sumatra and Papua. Waterways are highly needed because the rivers on these islands are not wide enough to hold medium-sized ships. In addition to this, roads and railways are not good options since Kalimantan and Papua are not like Java, which is a highly developed island. With the current length of waterways, Indonesia ranked seven on the countries with longest waterways.
Read more about this topic: Transport In Indonesia